No abstract

We present densities of pure 2-butanol and tert-butanol from 283.15 to 363.15 K and 303.15 to 363.15 K at pressures up to 66 MPa. We have measured the densities using a vibrating tube densimeter, and the calibration of the apparatus uses the forced path calibration method (FPMC). This calibration method depends upon the mechanical properties of the cell and allows us to have a standard uncertainty in the density less than 0.0004 g/cm3. The new experimental densities of agree within 0.1% with densities in the literature.

In this work, we present densities at high pressures of three branched hydrocarbons: 3-methylpentane, 2,4-dimethylpentane, and 2,3,4trimethylpentane from 283.15 to 363.15 K and at pressures up to 65 MPa. We have used a vibrating tube densimeter along with the forced path calibration method. This method considers mechanical properties of the cell and allows us to reach standard uncertainties less than 0.0004 g•cm 3 . For 3methylpentane, the new density data agree within 0.2% with densities from the literature. For the case of 2,4-dimethylpentane and 2,3,4-trimethylpentane, densities at high pressures have not been reported in the literature. Isobaric expansibility and isothermal compressibility are calculated using an equation of state correlated to the experimental density data.

<abstract> <p>The advent of large volumes of <italic>Sargassum sp</italic>. on the Mexican Caribbean coast has become an emerging issue for the Mexican population. The most frequent action is harvesting, but a correct treatment or energy recovery strategy is still missing. This work aimed to evaluate the energy potential of <italic>Sargassum fluitans</italic>, through elemental calculations and direct measurements, considering the effect of its washing. The calorific value determined by the direct method was 9.24 ± 0.28 MJ/kg and 12.64 ± 0.18 MJ/kg for dirty and washed <italic>Sargassum</italic>, respectively. The washing effect increased the calorific values in <italic>Sargassum fluitans</italic> by 36.80%. The washing effect increased the calorific values determined by indirect methods, increasing 10.10% and 41.04%, each method, respectively. The content of toxic metals was lower in both materials than that established for non-woody biomass from energy use, concerning the ISO 17225:2014 standard. The unit energy cost of <italic>Sargassum fluitans</italic> is ＄0.007 and ＄0.011 per MJ for dirty and washed conditions, respectively. Finally, the results of this work indicate that the <italic>Sargassum</italic> wash provides better characteristics to be considered an alternative fuel option in combustion systems such as thermo-electric plants (based on carbon), sugar mills, and cement kilns with co-processing of solid waste. Attending from a bioenergetic approach, <italic>Sargassum's</italic> emerging seasonal problem affects the Mexican Caribbean coast.</p> </abstract>

Dairy products are now part of many people's diets. In 2017 global production was 700 million tons of milk, which are marketed in the form of liquid milk (54%), yogurt and fermented milk (16%), cheese (7%) and other products. The regions of the world with the highest production are Asia (30%), the European Union (28%) and North and Central America (18%). Revenues from this industry, in 2017, were 45 billion U.S. dollars, with France, Ireland and Germany controlling much of the market (34%).