Power Quality Evaluation of a Photovoltaic System on an Electric Grid

This paper focuses on tests of photovoltaic systems in order to address two case studies with silicon monocrystalline and silicon polycrystalline panels, respectively. The first case is an identification of the three parameters of the single-diode equivalent circuit for modelling photovoltaic systems with conclusion about the inevitably age degradation. A comparison between experimental observed and computed I-V and V-P characteristics curves is carried out at standard test conditions. The second case is an experimental observation on a photovoltaic system connected to an electric grid in what regards the quality of the energy injected into the grid. A measuring of the harmonic content in the voltage and in the current waveforms at the terminals of the photovoltaic system is carried out in order to conclude about the conformity with the Standard EN 50160 and the IEEE 519-1992, respectively.

Analytical instrumental approaches and strategies to support the sensory assessment of virgin olive oils

At the beginning, this Ph.D. project led to an overview of the most common and emerging types of fraud and possible countermeasures in the olive oil sector. Furthermore, possible weaknesses in the current conformity check system for olive oil were highlighted. Among those, despite the organoleptic assessment is a fundamental tool for establishing the virgin olive oils (VOOs) quality grade, the scientific community has evidenced some drawbacks in it. In particular, the application of instrumental screening methods to support the panel test could reduce the work of sensory panels and the cost of this analysis (e.g. for industries, distributors, public and private control laboratories), permitting the increase in the number and the efficiency of the controls. On this basis, a research line called “Quantitative Panel Test” is one of the main expected outcomes of the OLEUM project that is also partially discussed in this doctoral dissertation. In this framework, analytical activities were carried out, within this PhD project, aimed to develop and validate analytical protocols for the study of the profiles in volatile compounds (VOCs) of the VOOs headspace. Specifically, two chromatographic approaches, one targeted and one semi-targeted, to determine VOCs were investigated in this doctoral thesis. The obtained results, will allow the possible establishment of concentration limits and ranges of selected volatile markers, as related to fruitiness and defects, with the aim to support the panel test in the commercial categorization of VOOs. In parallel, a rapid instrumental screening method based on the analysis of VOCs has been investigated to assist the panel test through a fast pre-classification of VOOs samples based on a known level of probability, thus increasing the efficiency of quality control.