Highlights The chitosan obtained shows physicochemical properties similar to commercials. The low molecular chitosan for harvesting microalgae shows better results than aluminum sulfate. The use chitosan for harvesting microalgae reduces the process costs.

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In this study, the effect of the metal/acid balance of Pt/mordenite catalysts on the activity, product distribution, and main reaction pathways during the hydroconversion of 2-methylnaphthalene (2-MN) was analyzed. The hydroconversion study was performed on Pt/mordenite catalysts having different metal/acid ratios in a batch reactor at 4.13 MPa (cold charge) and 523–573 K. The catalysts were characterized by XRD, 27Al NMR spectroscopy, FTIR spectroscopy of adsorbed pyridine, and TEM. The results indicate that, by using a bifunctional catalyst consisting of a well-crystallized mordenite whose acid function consists mainly of Brönsted acidity and with a strong hydrogenating function such as dispersed platinum, it is possible to promote the hydroconversion of 2-MN through a complex reaction scheme consisting of isomerization, hydrogenation, ring contraction, ring opening, and cracking. These reactions produce high-value hydrocarbons such as alkyl cycloparaffins, paraffins, and isoparaffins, which decrease the aromatic character of the feed and open a potential route to improve the quality of the polyaromatic-rich fractions.

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A b s t r a c t. For a herbaceous species, the inverse of the fresh leaf surface density, the Hughes constant, is nearly conserved. We apply the Hughes constant to develop an absolute method of leafarea measurement that requires no regression fits, prior calibrations or oven-drying. The Hughes constant was determined in situ using a known geometry and weights of a sub-set obtained from the fresh leaves whose areas are desired. Subsequently, the leaf-areas (at any desired stratification level), were derived by utilizing the Hughes constant and the masses of the fresh leaves. The proof of concept was established for leaf-discs of the plants Mandevilla splendens and Spathiphyllum wallisii. The conservativeness of the Hughes constant over individual leaf-zones and different leaftypes from the leaves of each species was quantitatively validated. Using the globally averaged Hughes constant for each species, the leaf-area of these and additional co-species plants, were obtained. The leaf-area-measurement-by-mass was cross-checked with standard digital image analysis. There were no statistically significant differences between the leaf-area-measurement-by-mass and the digital image analysis measured leaf-areas and the linear correlation between the two methods was very good. Leaf-areameasurement-by-mass was found to be rapid and simple with accuracies comparable to the digital image analysis method. The greatly reduced cost of leaf-area-measurement-by-mass could be beneficial for small agri-businesses in developing countries.K e y w o r d s: leaf area, leaf mass, planimetry

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