Primary fragmentation of limestone under oxy-firing conditions in a bubbling fluidized bed

Primary fragmentation of two limestones was studied in a lab-scale bubbling fluidized bed under simulated oxy-firing conditions and, for comparison, under traditional air-firing conditions. The influence of bed temperature, particle size and simultaneous occurrence of sulphation reaction was tested. Additional experiments in a heated strip apparatus were performed to determine if primary fragmentation occurred under high heating rate conditions, but in the absence of particle collisions.Results of the experiments show that only limited fragmentation occurred to both limestones tested under all operating conditions. Under oxy-firing conditions primary fragmentation was significantly reduced with respect to air-fired operation, most likely because of the absence of limestone calcination under high CO₂ atmospheres. Thermal shock upon limestone injection in the hot bed appears not to be able to induce significant particle fragmentation by its own.Particle size, bed temperature and simultaneous occurrence of sulphation reaction were found not to influence significantly the limestone primary fragmentation extent under both oxy-firing and air-firing conditions. On the contrary, the limestone type was found to be a more important variable with respect to the fragmentation tendency.     

Effect of properties of MWPECVD polycrystalline diamond films on photoemissive response

Diamond is an extremely interesting material for photoemission applications, due to the negative electron affinity of its surface, which can be obtained after suitable treatments. In the present work two sets of polycrystalline diamond films, characterized by different thicknesses and deposition conditions, are analyzed. In particular, in the examined films the relationship among the grain size, the amount of non-diamond carbon (sp²) located at the grain boundaries and their efficiency as photocathodes has been found and carefully investigated. The photoemission yield in the UV range is evaluated for all the samples, before and after hydrogenation, and after air exposure. The crucial parameter for the photocathode performances has been found not to be the film thickness, but the properties of polycrystalline diamond films, tunable with the plasma modulation and the methane percentage in the gas mixture.     

On the need of projections in input‐error model reference adaptive control

The main objective of this note is to contribute, if modestly, toward the understanding of the input‐error model reference adaptive control scheme revealing an instability mechanism that arises if the projection of the plant high‐frequency gain coefficient estimate is omitted. In addition, a self‐contained proof of global convergence of the scheme with the projections for a simple first‐order plant is given.     

Diversity of bacterial population of table olives assessed by PCR-DGGE analysis

Nocellara Etnea and Geracese table olives are produced according to traditional process, in which lactic acid bacteria (LAB) and yeasts are the dominant microorganisms. With the aim to evaluate the effect of selected starter cultures on dynamics of bacterial population during fermentation and on growth/survival of Listeria spp. artificially inoculated into the olive brine, a polyphasic approach based on the combination of culturing and PCR-DGGE analysis was applied. Plating results showed a different concentration of the major bacterial groups considered among cultivars and the beneficial effect of LAB starters, which clearly inhibited Enterobacteriaceae. Moreover, results indicated that the brine conditions applied did not support the growth/survival of Listeria monocytogenes strain, artificially inoculated, highlighting the importance of selecting right fermentation parameters for assuring microbiological safety of the final products. Comparison of DGGE profile of Nocellara Etnea and Geracese table olives, displayed a great difference among cultivars, revealing a wide biodiversity within Lactobacillus population during Geracese olives fermentation. Based on cloning and sequencing of the most dominant amplicons, the presence, among others, of Lactobacillus paracollinoides and Lactobacillus coryniformis in Geracese table olives was revealed in table olives for the first time.     

Inhibition of Autophagy Negates Radiofrequency-Induced Adaptive Response in SH-SY5Y Neuroblastoma Cells

In the last years, radiofrequency (RF) has demonstrated that it can reduce DNA damage induced by a subsequent treatment with chemical or physical agents in different cell types, resembling the adaptive response, a phenomenon well documented in radiobiology. Such an effect has also been reported by other authors both in vitro and in vivo, and plausible hypotheses have been formulated, spanning from the perturbation of the cell redox status, to DNA repair mechanisms, and stress response machinery, as possible cellular mechanisms activated by RF pre-exposure. These mechanisms may underpin the observed phenomenon, and require deeper investigations. The present study aimed to determine whether autophagy contributes to RF-induced adaptive response. To this purpose, SH-SY5Y human neuroblastoma cells were exposed for 20 h to 1950 MHz, UMTS signal, and then treated with menadione. The results obtained indicated a reduction in menadione-induced DNA damage, assessed by applying the comet assay. Such a reduction was negated when autophagy was inhibited by bafilomycin A1 and E64d. Moreover, CRISPR SH-SY5Y cell lines defective for ATG7 or ATG5 genes did not show an adaptive response. These findings suggest the involvement of autophagy in the RF-induced adaptive response in human neuroblastoma cells; although, further investigation is required to extend such observation at the molecular level.     

Adaptive state observation of linear time-varying systems with delayed measurements and unknown parameters

In this article, we address the problem of adaptive state observation of linear time-varying systems with delayed measurements and unknown parameters. Our new developments extend the results reported in our recently works. The case with known parameters has been studied by many researchers. However in this article we show that the generalized parameter estimation-based observer design provides a very simple solution for the unknown parameter case. Moreover, when this observer design technique is combined with the dynamic regressor extension and mixing estimation procedure the estimated state and parameters converge in fixed-time imposing extremely weak excitation assumptions.