High-temperature and high-pressure behavior of carbonates in the ternary diagram CaCO3-MgCO3-FeCO3

We report the thermal expansion and the compressibility of carbonates in the ternary compositional diagram CaCO3-MgCO3-FeCO3, determined by in situ X-ray powder and single-crystal diffraction. High-temperature experiments were performed by high-resolution X-ray synchrotron powder diffraction from ambient to decarbonation temperatures (25-850 \ub0C). Single-crystal synchrotron X ray diffraction experiments were performed in a variable pressure range (0-100 GPa), depending on the stability field of the rhombohedral structure at ambient temperature, which is a function of the carbonate composition. The thermal expansion increases from calcite, CaCO3, \u3b10 = 4.10(7) 710-5 K-1, to magnesite, MgCO3, \u3b10 = 7.04(2) 710-5 K-1. In the magnesite-siderite (FeCO3) join, the thermal expansion decreases as iron content increases, with an experimental value of \u3b10 = 6.44(4) 710-5 K-1 for siderite. The compressibility in the ternary join is higher (i.e., lower bulk modulus) in calcite and Mg-calcite [K0 = 77(3) GPa for Ca0.91Mg0.06Fe0.03(CO3)] than in magnesite, K0 = 113(1) GPa, and siderite, K0 = 125(1) GPa. The analysis of thermal expansion and compressibility variation in calcite-magnesite and calcite-iron-magnesite joins clearly shows that the structural changes associated to the order-disorder transitions [i.e., R3c calcite-type structure vs. R3 CaMg(CO3)2 dolomite-type structure] do not affect significantly the thermal expansion and compressibility of carbonate. On the contrary, the chemical compositions of carbonates play a major role on their thermo-elastic properties. Finally, we use our P-V-T equation of state data to calculate the unit-cell volume of a natural ternary carbonate, and we compare the calculated volumes to experimental observations, measured in situ at elevated pressure and temperatures, using a multi-anvil device. The experimental and calculated data are in good agreement demonstrating that the equation of state here reported can describe the volume behavior with the accuracy needed, for example, for a direct chemical estimation of carbonates based on experimental unit-cell volume data of carbonates at high pressures and temperatures

Postharvest quality of papaya fruit wrapped with polyvinyl chloride film added with silver.

ABSTRACT: The main goal of this research was to evaluate the postharvest quality during storage of papaya wrapped with polyvinyl chloride containing silver. Fourier Transform Infrared Spectroscopy, scanning electron microscopy and atomic absorption spectroscopy were employed for the film characterization. For the postharvest experiments, unwrapped fruits were compared to individually wrapped ones in both conventional polyvinyl chloride film and polyvinyl chloride film containing silver and stored under two conditions (10 days at 15°C, and 2 days at 22°C to simulate market conditions). The physicochemical analyzes, including soluble solids, titratable acidity, ratio, pH, ascorbic acid, weight loss, firmness and color were performed every two days of storage, while microbiological analyzes were performed on the 1st and 10th day of storage. Sensory analysis was carried on the last day of storage. Physicochemical analyses showed that fruits wrapped with polyvinyl chloride films presented a lower weight loss compared to than unwrapped fruits. These results were in accordance with sensory analysis. More importantly, papaya wrapped with polyvinyl chloride film containing silver kept papaya peel green for longer time causing a delay in ripening, indicating its potential to extend postharvest shelf-life of papaya and reduce postharvest losses.V International Symposium on Postharvest Pathology: From Consumer to Laboratory-Sustainable Approaches to Managing Postharvest Pathogens

Party-group relations in new southern European democracies in the crisis era

UID/CPO/04627/2013 PTDC/IVC-CPO/1864/2014publishersversionpublishe

“Either Everyone Was Guilty or Everyone Was Innocent”: The Italian Power Elite, Neopatrimonialism, and the Importance of Social Relations

Rarely does the Byzantine world of football administration get exposed as clearly as during the 2006 calciopoli scandal. This scandal laid bare the interpersonal relationships of football administrators at the top three Italian men’s football clubs: Juventus, Inter, and AC Milan. This article draws on the media leaks that revealed the inner workings of those working within football to argue that the football clubs are pyramids of power for club presidents that allows them to operate within the Italian power elite. This is done through interpersonal clientelistic networks that operate within a neopatrimonial system. Theoretically, this article draws on four main concepts: C. Wright Mills’s concept of the Power Elite, Lomnitz’s model of “Pyramids of Power,” Eisenstadt’s notion of neopatrimonialism, and Mauss’s utilization of the gift. Power is exercised through quid pro quo relationships, with certain key individuals operating as brokers to the flow of favors throughout the network