A Simple Interpretation of Hubbert’s Model of Resource Exploitation

The well known “Hubbert curve” assumes that the production curve of a crude oil in a free market economy is “bell shaped” and symmetric. The model was first applied in the 1950s as a way of forecasting the production of crude oil in the US lower 48 states. Today, variants of the model are often used for describing the worldwide production of crude oil, which is supposed to reach a global production peak (“peak oil”) and to decline afterwards. The model has also been shown to be generally valid for mineral resources other than crude oil and also for slowly renewable biological resources such as whales. Despite its widespread use, Hubbert’s modelis sometimes criticized for being arbitrary and its underlying assumptions are rarely examined. In the present work, we use a simple model to generate the bell shaped curve curve using the smallest possible number of assumptions, taking also into account the “Energy Return to Energy Invested” (EROI or EROEI) parameter. We show that this model can reproduce several historical cases, even for resources other than crude oil, and provide a useful tool for understanding the general mechanisms of resource exploitation and the future of energy production in the world’s economy

Computational Speciation Models: A Tool for the Interpretation of Spectroelectrochemistry for Catalytic Layers under Operative Conditions

none7In this study,the first coupled FEXRAV and chemical speciation modelling study of the Pd deactivation is presented. Due to the high brilliance of synchrotron light, FEXRAV can investigat edeeply buried surfaces. More specifically, we directly analyzed the evolution of the Pd/C catalytic layer during a voltammetric cycle, through a specifically designed electrochemical cell. Still, we observed a complex interfacial chemistry of Pd, which impairs a straightforward interpretation of FEXRAV data. Exploiting thermodynamic chemical speciation modelling we were able to overcome this issue. The study leads to three main results: 1) the confirmation of the relationship between the change of the Pd/Pd(II) ratio and the change of the Fluorescence intensity 2) the investigation of the deactivation mechanism 3)the identification of the relevant species leading to the electrodissolution of Pd under operative conditions. This study opens new perspectives for the application of the chemical speciation modelling to the study of the deactivation mechanism of Pd in Pd/C catalytic layers under operative conditions in different electrolytes.mixedMontegrossi, G.; GIACCHERINI, ANDREA; BERRETTI, ENRICO; DI BENEDETTO, FRANCESCO; INNOCENTI, MASSIMO; D'Acapito, F.; LAVACCHI, ALESSANDROMontegrossi, G.; Giaccherini, Andrea; Berretti, Enrico; DI BENEDETTO, Francesco; Innocenti, Massimo; D'Acapito, F.; Lavacchi, Alessandr