[en] To obtain an homogeneous temperature in a cylindrical model during a heating process using Joule effect, it is shown that is necessary to introduce secondary electrodes. Neglecting the electrical and thermal resistances at the interface between these secondary electrodes and the sample, it is possible to find an analytical expression of the homogeneous fraction of the whole system. Then it is possible to solve the problem of the length of the secondary electrodes. To take the thermal and the electrical contact resistance into account, a numerical model is used and percent temperature deviations are calculated. Simulation show that secondary electrodes made of the same material as the sample are preferable to other secondary electrodes ant it is shown that is better to choose a high current intensity

[en] The present paper deepens the analysis on the dynamics and thermal-fluid-dynamics of a sprinkler nozzle-emitted water droplet traveling in air before reaching the ground. The following analysis variables were considered, as main causes of the phenomenon assessed: initial droplet diameter, initial droplet velocity, initial droplet temperature, variable droplet temperature, air temperature, diffusion coefficient of water in air, air relative humidity, inlet droplet throw inclination, thermal radiation, and wind velocity. These variables proved their effect on the droplet travel distance, the droplet time of flight, and the final droplet temperature. The study was carried out thanks to an analytical-numerical model, recently proposed by the same authors of this paper, equipped with a few assumptions that did not alter the realistic description provided. The results proved the effect of each analysis variable and clarify the picture of a complicate yet extremely important phenomenon.

[en] In this paper, a detailed investigation on MHD flow over a porous stretching sheet was conducted by taking power-law heat flux and heat source into account. Series solutions are achieved for the reduced nondimensional ordinary differential equations by admitting an analytical technique known as a homotopy analysis method (HAM). A precise way of convergence of series solutions is also furnished. The attained results of the present study are in excellent connection with the previous results. Nature of magnetic parameter, permeability parameter, radiation parameter, Prandtl number, Eckert number, heat generation parameter and suction/injection parameters on velocity, temperature, skin friction coefficient and Nusselt number are presented in tables and graphs.

[en] Accurate and sensitive nanoscale thermal probing for thermophysical property characterization is appealing but still a challenge to date. Previous studies have revealed that graphene quantum dots (GQDs) are good temperature markers for their small dimension and superior fluorescence excitation. In this work, we show that the thermal response of fluorescence spectrum of GQDs is strongly pH-dependent. Significant decrease (about 56% to 30%) for temperatureinduced intensity reduction within a small range of 75°C under different excitation wavelengths of 370 nm, 390 nm, and 410 nm is observed as pH value increases from pH = 1 to pH = 13. The temperature coefficients of peak wavelength change from positive to negative with the increase of pH value, meaning that the blue shift happens as the condition is changed from acidity to alkalinity. Temperature dependence of peak width is also studied with the largest coefficient of 0.2255nm/°C, which is remarkable. These suggest that when using GQDs in nanoscale thermal probing, the pH value is an important factor that should be considered besides the excitation wavelength. Regarding the superior biocompatibility and low cytotoxicity, GQDs could play an important role in thermal probing or mapping in a complex biology system such as a cell, and help to develop novel treatments and diagnoses.

[en] Centaurea jacea has been suggested as a potential bioindicator for ozone, but little is known about its intraspecific variation in sensitivity, especially at molecular level. The effects of ozone (200 ppb, 5 h) on sensitive and resistant lines of Centaurea have been investigated at the end of fumigation. Sensitive plants showed characteristic symptoms of injury in the form of diffuse discoloration stipples on leaves. A PCR-based approach was used to identify and isolate a partial-length cDNA coding for PAL and CHS genes. The northern analysis of PAL showed accumulation of transcript in both lines correlated with a typical increase of PAL activity (+41 and +91% in resistant and sensitive material, respectively, compared to controls). On the contrary, the transcripts of CHS, in resistant and sensitive plants, did not change after treatment. Total phenols were not affected by ozone, while anthocyanins were quickly utilised by resistant clone as antioxidant compounds. - Characterization and isolation of PAL and CHS genes in Centaurea jacea exposed to O₃

[en] Ozone (O₃) exposure at Italian background sites exceeds UN/ECE concentration-based critical levels (CLe_c), if expressed in terms of AOT40. Yet the occurrence of adverse effects of O₃ on forests and crops is controversial. Possible reasons include (i) ability of response indicators to provide an unbiased estimate of O₃ effects, (ii) setting of current CLe_c in terms of cut-off value and accumulation level, (iii) response functions adopted to infer a critical level, (iv) environmental limitation to O₃ uptake and (v) inherent characteristics of Mediterranean vegetation. In particular, the two latter points suggest that critical levels based on accumulated stomatal flux (CLe_f) can be a better predictor of O₃ risk than CLe_c. While this concept is largely acknowledged, a number of factors may limit its applicability for routine monitoring. This paper reviews levels, uptake and vegetation response to O₃ in Italy over recent years to discuss value, uncertainty and feasibility of different approaches to risk assessment. - While the flux-based approach is scientifically sounder, a more practical concentration-based approach is still necessary for routine monitoring