Thermal effects on chaotic directed transport

We study a chaotic ratchet system under the influence of a thermal environment. By direct integration of the Lindblad equation we are able to analyze its behavior for a wide range of couplings with the environment, and for different finite temperatures. We observe that the enhancement of the classical and quantum currents due to temperature depend strongly on the specific properties of the system. This makes difficult to extract universal behaviors. We have also found that there is an analogy between the effects of the classical thermal noise and those of the finite $\hbar$ size. These results open many possibilities for their testing and implementation in kicked BECs and cold atoms experiments.Comment: 5 pages, 4 figure

Optically switched magnetism in photovoltaic perovskite CH3_3NH3_3(Mn:Pb)I3_3

The demand for ever-increasing density of information storage and speed of manipulation boosts an intense search for new magnetic materials and novel ways of controlling the magnetic bit. Here, we report the synthesis of a ferromagnetic photovoltaic CH$_3$NH$_3$(Mn:Pb)I$_3$ material in which the photo-excited electrons rapidly melt the local magnetic order through the Ruderman-Kittel-Kasuya-Yosida interactions without heating up the spin system. Our finding offers an alternative, very simple and efficient way of optical spin control, and opens an avenue for applications in low power, light controlling magnetic devices

Minimization of the primary energy consumption of residential users connected by means of an energy grid

open4noIn this paper, a physics-based model is developed to simulate the interaction between residential users and energy systems. The simulation model is coupled with a dynamic programming algorithm which identifies the optimal operation strategy that allows the minimization of the primary energy consumption of three residential users, arranged with different energy system configurations. The reference scenario, which considers that the users employ a domestic boiler for meeting thermal energy demand, while electric energy is taken from the national electric grid, is compared to the CHP scenario, this latter being differentiated by considering shared thermal and electric energy storages and also shared PM. The most suitable energy system configuration is identified by jointly evaluating primary energy consumption, prime mover working hours and thermal and electric energy share of the prime mover itself.openCattozzo M., Manservigi L., Spina P. R., Venturini M.,Cattozzo, M.; Manservigi, L.; Spina, P. R.; Venturini, M

Revisiting the 16 Cygni planet host at unprecedented precision and exploring automated tools for precise abundances

The binary system 16 Cygni is key in studies of the planet-star chemical composition connection, as only one of the stars is known to host a planet. This allows us to better assess the possible influence of planet interactions on the chemical composition of stars that are born from the same cloud and thus, should have a similar abundance pattern. In our previous work, we found clear abundance differences for elements with Z$\leq30$ between both components of this system, and a trend of these abundances as a function of the condensation temperature (T$_{c}$), which suggests a spectral chemical signature related to planet formation. In this work we show that our previous findings are still consistent even if we include more species, like the volatile N and neutron capture elements (Z $>$ 30). We report a slope with T$_{c}$ of $1.56 \pm 0.24 \times 10^{-5}$ dex K$^{-1}$, that is good agreement with both our previous work and recent results by Nissen and collaborators. We also performed some tests using ARES and iSpec to automatic measure the equivalent width and found T$_c$ slopes in reasonable agreement with our results as well. In addition, we determine abundances for Li and Be by spectral synthesis, finding that 16 Cyg A is richer not only in Li but also in Be, when compared to its companion. This may be evidence of planet engulfment, indicating that the T$_{c}$ trend found in this binary system may be a chemical signature of planet accretion in the A component, rather than a imprint of the giant planet rocky core formation on 16 Cyg B.Comment: 11 pages, 5 figures, accepted for publication in A&

Hepatic PPARs: their role in liver physiology, fibrosis and treatment

Complex molecular and cellular mechanisms are involved in the pathway of liver fibrosis. Activation and transformation of hepatic stellate cells (HSCs) are considered the two main reasons for the cause and development of liver fibrosis. The peroxisome proliferator-activated receptors (PPARs) belonging to the family of ligand-activated transcription factors play a key role in liver homeostasis, regulating adipogenesis and inhibiting fibrogenesis in HSCs. Normal transcriptional function of PPARs contributes to maintain HSCs in quiescent phase. A reduced expression of PPARs in HSCs greatly induces a progression of liver fibrosis and an increased production of collagen. Here, we discuss role and function of PPARs and we take into consideration molecular factors able to reduce PPARs activity in HSCs. Finally, although further validations are needed, we illustrate novel strategies available from in vitro and animal studies on how some PPARs-agonists have been proved effective as antifibrotic substances in liver disease

ARX LINEAR MODEL SET-UP FOR FAULT DIAGNOSIS OF GAS TURBINE SENSORS

ABSTRACT The diagnosis of gas turbine sensor faults requires models of the system to calculate estimates of the measured output system variables. The model set-up phase is of great importance since the reliability of the diagnostic tool depends on the model accuracy. In the paper two different methodologies of I/O linear model set-up are analyzed and compared to find the more simple and general one. The first methodology consists in obtaining the I/0 linear models by directly linearizing the physical laws (system modeling). The second one uses statistical methods (system identification) to calculate model parameters from time series data measured on the machine. The models used are of the ARX (Auto Regressive with eXtemal input) type. The number of models and the measured variables correlated by each of them have been determined in order to obtain unambiguous fault signatures for each sensor. The system identification method proves to be more suitable to the system modeling because of its greater simplicity in the fault diagnosis application. NOMENCLATUR