Search results for "GC"
showing 10 items of 606 documents
Melting of sediments in the deep mantle produces saline fluid inclusions in diamonds.
2019
We demonstrate the formation of highly saline mantle fluids by the reaction of subducted sediment with peridotite.
Recent developments in the acoustical properties of perforated and porous materials containing dead-end pores
2017
It was shown recently in Nevers, France, Sherbrooke, Canada and Salford, UK, that porous materials with semi-opened pores or materials with open pores bearing lateral cavities or resonators at the microscopic scale of the pores can result in peculiar sound absorption properties. Various examples of these materials can be found in engineering and in everyday life including bio-based materials. The cavities and resonators can be assimilated to dead-end pores, which are opened at one end and closed at the other. The dead-end pores are known to geophysicists. We studied them more recently in the field of engineering acoustics where the saturating fluid is air. The closed ends prevent the fluid …
Revisiting Vs30 as a proxy parameter for site effects: a case study using KIKNET data
2011
The local geology can strongly affect the seismic ground motion at the surface. One standard index used to classify local site effects is the average shear wave velocity in the first 30 meters, namely Vs30. The higher the Vs30 the stiffer the material is and therefore less amplification is expected. However, this index does not map the complexity of the velocity at depth. Indeed, some sites may have close Vs30 values, but quite different velocity distribution at depth. In this study, we propose the ratio between the average shear wave velocity up to depths having at least 800 m/s and Vs30. This ratio gives information about the velocity distribution at depth. Lower ratios mean stronger simi…
Pyrolysis-gas chromatography : mass spectrometry analysis of di- and triterpenoids
2017
The objective of this work was to study a specific class of extractives existing in lignocellulosic biomass and more precisely in wood materials, and their thermochemical behavior during pyrolysis. The focus was centered on the class of terpenes and terpenoids; specifically two model compounds, abietic acid and betulinol, were chosen to represent the subclasses of di- and triterpenoids, respectively. The model compounds were investigated via pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and the main objective was to study their product profiles and characteristic fragmentations, as well as the influence of specific variables (pyrolysis temperature and time) on pyrolysis products…
Characterization of key aroma compounds in Burgundy truffle
2021
International audience
Essential oils as multi-target compounds for novel food safety strategies
This research work has been developed in the context of the potencial applications of essential oils as multi-target compounds for novel food safety strategies, such as active packaging technologies. Essential oils are aromatic oils derived from plants and usually extracted by hydrodistillation when intended to be used in food. There is an increasing interest in the antimicrobial properties of essential oils due to the possibility of using them to replace ‘synthetic’ preservatives in food or, in general, to reduce viable numbers of pathogens along the food chain.
Chemical composition, antioxidant and anticholinesterase activity of the essential oil of algerian cachrys sicula L
2021
In this work, in order to explore a new Algerian medicinal plant used in traditional medicine, the essential oil of the leaves of Cachrys sicula L. (Apiaceae) collected from Algeria, obtained by hydrodistillation, was analyzed by GC/MS. Thirty-two compounds were identified accounting for 98.6% of the total oil, which is characterized by a high content of monoterpene hydrocarbons (74.8%). The main constituents of the essential oil were β-pinene (17.9%), sabinene (17.8%), myrcene (12%), and α-pinene (11.4%). In vitro antioxidant activity of the essential oil was assayed by three methods, namely ABTS•+, metal chelating, and DPPH• assays. The antioxidant activity of the oil was higher in the AB…
Impact of oxydoreduction potential on biosynthesis of volatile compounds in acid skim milk gel: identification and quantification
2008
International audience; Oxydoreduction potential (Eh) is an environmental parameter which defines balances between oxidant species (acceptors of electrons) and reduced species (donors of electrons) of a medium. It may modify the growth capacity of microorganisms, the metabolic fluxes, participate to the quality of fermented products (2, 6, 7) and affect the production and/or stability of volatile compounds (3,5). (...)