Experimental determination of barite dissolution and precipitation rates as a function of temperature and aqueous fluid composition

Barite dissolution and precipitation rates were investigated in closed system reactors, in which total aqueous NaCl concentrations ranged from 0 to 1.5 molal, pH from 2 to 9, and temperature from 25 to 90 °C. Measured barite dissolution and precipitation rates exhibited a reaction order of 0.2 and 1, respectively, with respect to the barite saturation state. Although these different reaction orders suggest distinctly different mechanisms for dissolution and precipitation, the rates for both processes approach equilibrium with a similar slope on a rate versus saturation state plot, consistent with the concept of micro-reversibility. Barite dissolution rate constants increase as a linear function of the square root of ionic strength but vary only slightly with pH. The dissolution rate dependence on temperature is consistent with an activation energy of 25 ± 2 kJ mol−1. Barite dissolution and precipitation rates are not significantly affected by the presence of aqueous calcium, magnesium or strontium. The rates measured in the study were generated in fluids similar to those found in sedimentary basins, ocean floor sediments and oil field reservoirs so the data may provide close estimates for the reactivity of barite during a variety of natural and industrial processes

Co-branding public place brands: towards an alternative approach to place branding

Contrary to the traditional understanding of place branding inspired by product, service and corporation branding, the present paper adopts place branding interdisciplinary literature in order to develop a conceptual framework that focuses on the constituting features of place brands as a form of public brands. The paper suggests the way place brands are constituted is via a co-branded complex and dynamic process in a constant state of change shaped by the interaction of several public brands in particular time-space frames. The co-branded process allows researchers and practitioners to better understand the conditions under which place brands and place brand efforts are emerging. Despite that, the type of co-branded process described in the paper also points out that the process does not necessarily create a linear positive add-on value for all parts involved. Rather, the co-branded process here is fragmented and based on spatial, political and real meaning contexts. The framework is illustrated empirically from material retrieved from a study of a regional branding process. The article concludes with a note on the political dimension of applying a co-branding lens on the public sphere