(PFW-PT) ceramics were synthesized via a modified two-stage solid-state reaction. This method utilized Fe 2 WO 6 , prepared at a first-stage, which was subsequently reacted with a stoichiometric amount of PbO and TiO 2 at the second stage. This procedure efficiently suppressed the formation of lead tungstates and leads to getting dense ceramics. Electric and dielectric properties of (1-x)Pb(Fe 2/3 W 1/3)O 3-xPbTiO 3 solid solutions were investigated as a function of the frequency and temperature. All samples present density higher than 96% of the theoretical one, low percentage of pyrochlore phase (<2%) and relatively high electrical resistivity (<10 10 Ω.m). RF dielectric measurements over the temperature showed the presence of a peak, which is related to the ferro-paraelectric phase transition and conductive contributions (in the range 200-700 K), associated to a electronic hoping mechanism. The dielectric properties of the PFW shows a typical relaxor behaviour for x = 0 and 0.10 with frequency-dependent peak temperature (Tm), while the samples with higher PT-content undergo a 'normal' para-ferroelectric transition at the Curie temperature T C .The FE phase transition of PFW is shifted to higher temperatures by PbTiO 3 (PT) additions and high resistivity are obtained for PT containing samples. Different types of magnetic activity dependent on composition and temperature were found.

Gd5(Ge1-xSi x), x < 4 based alloys are potential candidates for magnetic refrigeration in the range ~20 - ~290 K. However, one of the greatest obstacles for the use of that technology in large scale is the utilization of high pure Gd metal (99.99 wt. (%)) to produce the GdGeSi alloys, since the impurity elements decrease the intensity of the magnetocaloric effect (EMC)¹. In this work, we prove that annealing of the Gd5Ge2Si2 can promote remarkable values for the EMC in comparison to those obtained for the alloy with high pure Gd. Also, the as cast alloy and the annealed alloy are not monophasic, but have at least two crystalline phases in their microstructure. Results for X-ray analysis, optical and electronic microscopy and magnetization measurements are reported

There is a consensus that Urban Heat Island phenomenon -UHI occurs in every large city. This effect is characterized by higher air temperatures in cities than in the neighboring countryside at night. However, to date, there has been no systematic study on the Fortaleza case, the Brazil's 5th largest city. By the comparison between screen-level air temperature measured by two automatic weather stations, one located in the city and the other in the neighboring region, this work shows the occurrence of the UHI in Fortaleza, even during the rainy season. In an attempt to find some effect of the UHI on precipitation (and vice-versa), historical series of air temperature and precipitation were analyzed from 1966 to 2020. Besides the considerable increase in air temperature over the years, a slight downward trend was observed in UHI and even more in precipitation between the hours of 15:00 and 21:00 (local time). However, one believes that these trends may be related to climate change at large scale rather than an urban scale.

On the search for better cores for cryogenic magnetic refrigeration, magnetic and structural properties, such as synchrotron x ray diffraction and magnetization of Tb1-xPrxNi2 were studied. The results show the linear behavior of the lattice parameter and the Curie temperature.