Pyrolysis is a well-known process for biomass upgrading, and a great deal of works are available about it. However, they focus on conventional lignocellulosic samples, and the information about any other less common samples, while still valuable, is very difficult to find. For instance, Brazilian ginseng (Pfaffia glomerata) is a feedstock without hemicellulose and a profitable source of target compounds (like beta-ecdysone) via an extraction process, also generating an exhausted solid. However, there is not much information about this biomass in the literature. For this reason, this work deals for the first time with the effect of. different pretreatments on the thermal degradation behavior of Brazilian ginseng. To do so, thermogravimetric analysis (TGA) of the raw material and post-treated samples was done in a synthetic air atmosphere (20% oxygen). The thermograms were fitted via an autocatalytic model (deviation of 4.22%), and the calculated. kinetics were used to analyze how the pretreatment modifies the volatilization and char formation for each individual compound (cellulose and lignin) in all the samples. Additionally, structural changes were observed performing XRD and DSC, explaining why different kinetic parameters were required for each sample. Regarding XRD, a variable crystalline index that ranged from 51% to 75% was obtained. Concerning DSC, the pretreatment produced an endothermic peak between 150 and 200 degrees C.

Raman spectroscopy has been used for a comparative study of the sulphates mineral sequence precipitation in Rio Tinto (Huelva, Spain) under natural and laboratory conditions. In natural conditions spectra were performed in-situ with portable instruments. In laboratory, spectra were performed using a simulator of the riverbank conditions and also small droplets of liquid on different substrates. The capability of the micro-Raman spectroscopy to detect in a fast and reliable way the mineral phases at the mineral grain scale allow a precise identification of these phases as function of time. The use of small droplets increases this capability reducing the experimental time and allowing reproducing the process under greater supersaturation conditions. Finally, a series of computer modeling algorithms have been developed to compare the experimental process with the theory based on the equilibrium properties of the solutions and precipitation kinetics.

In this work, the fractionation of grape seeds as a model biomass was studied using a combination of two processes: solvothermal extraction and hydrothermal fractionation-hydrolysis process in a semicontinuous reactor. First, grape seeds were subjected to an extraction process with ethanol/water (70130 wt.%) at 90 degrees C during 60 min obtaining ca. 13.0 wt.% of oil and extractable components with 4.46 wt.% of polyphenols (66% of the maximum). Afterwards, the solvent was water and the biomass was treated in steps at different temperatures (150 degrees C to 340 degrees C). During the hydrolysis the pH decreased from 5.5 down to 3.0 due to acetyl group liberation. The total quantity of recovered sugars varied around 20.0 to 23.1 wt.%. The best experimental condition for obtaining the maximum amount of pentoses + hexoses + oligosaccharides was 180 degrees C (45 min) + 250 to 265 degrees C (45 min) + 330 to 340 degrees C (45 min). (C) 2014 Elsevier B.V. All rights reserved.

In the present work, the hydrothermal hydrolysis of grape seeds focused on the production of bio-oil was studied. The grape seeds composition in terms of lignin, sugars, ash, extractives and bio-oil was determined. The composition of grape seeds was: 17.0 wt% of extractives; 36.8 wt% of sugars (hemicellulose and cellulose); 43.8 wt% of lignin and 2.4 wt% of ash. The grape seeds were hydrothermally treated using three different temperatures: 250 degrees C, 300 degrees C and 340 degrees C employing a semi-continuous reactor. The solid residue varied from 25.6-35.8 wt% depending on the hydrolysis temperature. The maximum yields of light (15.7 wt%) and heavy bio-oil (16.2 wt%) were achieved at 340 degrees C. The Arrhenius parameters for the kinetics of grape seeds hydrolysis in our system were k(o) = 0.995 g min(-1) and E-a = 13.8 kJ mol(-1). The increment of the flow rate favoured the mass transfer in the system and so, the hydrolysis rate. However, the maximum hydrolysis rate was found at a water surface velocity of 2.3 cm min(-1).

Given the volume of spectral data required for providing accurate compositional information and thereby insight in mineralogy and petrology from laser-induced breakdown spectroscopy (LIBS) measurements, fast data processing tools are a must. This is particularly true during the tactical operations of rover-based planetary exploration missions such as the Mars Science Laboratory rover, Curiosity, which will carry a remote LIBS spectrometer in its science payload. We have developed: an automated fast pre-processing sequence of algorithms for converting a series of LIBS spectra (typically 125) recorded from a single target into a reliable SNR-enhanced spectrum; a dedicated routine to quantify its spectral features; and a set of calibration curves using standard hydrous and multi-cation sulfates. These calibration curves allow deriving the elemental compositions and the degrees of hydration of various hydrous sulfates, one of the two major types of secondary minerals found on Mars. Our quantitative tools are built upon calibration-curve modeling, through the correlation of the elemental concentrations and the peak areas of the atomic emission lines observed in the LIBS spectra of standard samples. At present, we can derive the elemental concentrations of K, Na, Ca, Mg, Fe, Al, S, O, and H in sulfates, as well as the hydration degrees of Ca- and Mg-sulfates, from LIBS spectra obtained in both Earth atmosphere and Mars atmospheric conditions in a Planetary Environment and Analysis Chamber (PEACh). In addition, structural information can be potentially obtained for various Fe-sulfates.

The diffusion of molecular species within a sulfuric acid-water system has been monitored by Raman spectroscopy, a thermodynamic-chemical model of the mass transport properties of the species has been established, and its parameters optimized. It has been shown that the non-ideality of this multicomponent system plays a crucial role in its mass transport properties, which have been explained in terms of a diffusion model for the molecular species. The individual effective diffusion coefficients are not constant (characteristic of ideal systems) but are a function of the concentration of the species in solution. The model has been conceived in such a way that it can be adapted to any multicomponent mixture when the equilibriums among the ions are known. Raman spectroscopy provides the means to derive the speciation and concentration of species in multicomponent systems, and we have shown that the model-based measurement of the diffusion properties using Raman is a robust and accurate technique that allows for measuring the individual diffusion coefficients of the species in the mentioned system.

Data from the ESA ExoMars Rover Mission will provide invaluable input for further studies in astro/exobiology. The search for mineral products as indicators of present and/or past biogenetic activities in Mars' surface and subsurface samples is the main objective of the compact Raman-laser-induced breakdown spectroscopy (LIBS) instrument. The inherent features of Raman spectroscopy and LIBS make the combined instrument a unique and very powerful tool in the search for biomarkers and hence it is regarded as the highest priority instrument for mineral analysis within the mission. We have developed a software package for the on-board processing of the instrument's data outputs, including spectral conditioning and search-match characterization of mineral phases and biomarkers. In this paper we show the mathematical and physical basis of the software package.

The saturated heat capacities of some linear alkylbenzenes (ethylbenzene, propylbenzene, butylbenzene, hexylbenzene, 1-phenylheptane, and 1-phenylhexadecane) and branched alkylbenzenes (in-xylene, cumene, (1-methylpropyl)benzene, (1,1-dimethylethyl)benzene, and (2-methylpropyl)benzene) in the temperature range from (332.15 to 401.15) K have been measured. A Calvet calorimeter C80D from Setaram (France) with batch cells modified from the standard vessels of Setaram, along with the "step by step method", has been used to perform the measurements. The estimated uncertainty of the saturated heat capacities was better than 0.5 % for the substances with higher purity and of the order of 1 % for the others. In the literature there exists C-sat(T) data for some of the liquids studied. Agreement with our measurements is within the range of the experimental uncertainties.

The saturated heat capacities of oxygenated gasoline additives methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), diisopropyl ether (DIPE), and tert-amyl methyl ether (TAME) in the temperature range of 277.15 K to some degrees below their normal boiling temperatures have been measured. A Micro DSC II from Setaram (France) with batch cells designed in our laboratory and the "scanning method" were used to perform the measurements. The estimated uncertainty of the saturated heat capacities was better than 0.3%. In the literature, there exist C-sat(T) data for some of the liquids studied. Agreement with our measurements is within the range of the experimental uncertainties. At each temperature, the saturated heat capacity of liquid MTBE is smaller than those of ETBE, DIPE, and TAME, and the corresponding C,at values of these three liquids are similar. This behavior can be related with the surface fraction of the ether group in each molecule.

The saturated heat capacities of benzene and of some linear (toluene, ethylbenzene, propylbenzene, butylbenzene, hexylbenzene, 1-phenylheptane, and 1-phenylhexadecane) and branched ( m -xylene, cumene, sec-butylbenzene, tert-butylbenzene, and isobutylbenzene) alkyl-benzenes have been measured. A Micro DSC II from Setaram (France) with batch cells designed in our laboratory, and the “scanning or continuous method,” have been used to perform the measurements. The estimated uncertainty of the saturated heat capacities was better than 0.3%. In the literature there exists c sat ( T ) data for some of the liquids studied. Agreement with our measurements is better than 0.5%. For linear alkyl-benzenes and for each temperature, the variation in the saturated heat capacity with the alkyl length is nearly linear. The selected branched alkyl-benzenes are isomers of the linear alkyl-benzenes studied; accordingly, the influence of molecular structure on the saturated heat capacities has been analyzed.