Search results for "mixture"
showing 10 items of 1178 documents
Evidence for shifts in the structure and abundance of the microbial community in a long-term PCB-contaminated soil under bioremediation.
2011
International audience; Although the impact of bioremediation of PCB-contaminated sites on the indigenous microbial community is a key question for soil restoration, it remains poorly understood. Therefore, a small-scale bioremediation assay made of (a) a biostimulation treatment with carvone, soya lecithin and xylose and (b) two bioaugmentation treatments, one with a TSZ7 mixed culture and another with a Rhodococcus sp. Z6 pure strain was set up. Changes in the structure of the global soil microbial community and in the abundances of different taxonomic phyla were monitored using ribosomal intergenic spacer analysis (RISA) and real-time PCR. After an 18-month treatment, the structure of th…
Thermal transformation of micro-crystalline cellulose in phosphoric acid
2011
Use of crude oil derivatives such as diesel and gasoline is becoming unsuitable due to their detriment to environment and to the increasing worldwide energy demand which is driving crude oil reservoirs towards exhaustion. Replacement of diesel and gasoline with biofuels (i.e. biodiesel and bioethanol, respectively) is very desirable. In fact, biofuels are not only environmentally sustainable, but also potentially inexhaustible due to the large amounts of waste biomasses from which they can be retrieved. In the present study, a model compound (micro-crystalline cellulose) was dissolved in phosphoric acid and converted at 80 °C to glucose, thereby providing the possible substrate for fermenta…
HONO Emissions from Soil Bacteria as a Major Source of Atmospheric Reactive Nitrogen
2013
From Soil to Sky Trace gases emitted either through the activity of microbial communities or from abiotic reactions in the soil influence atmospheric chemistry. In laboratory column experiments using several soil types, Oswald et al. (p. 1233 ) showed that soils from arid regions and farmlands can produce substantial quantities of nitric oxide (NO) and nitrous acid (HONO). Ammonia-oxidizing bacteria are the primary source of HONO at comparable levels to NO, thus serving as an important source of reactive nitrogen to the atmosphere.
Mammary pheromone-induced odour learning influences sucking behaviour and milk intake in the newborn rabbit
2016
Newborn rabbits, Oryctolagus cuniculus, locate their mother's nipples through typical orocephalic movements elicited by odour stimuli, in particular by the mammary pheromone (MP). The MP also promotes neonatal odour learning: after single pairing with the MP, an initially neutral odorant becomes able to elicit sucking-related head-searching/oral-grasping movements. However, the behavioural significance of the MP-induced odour learning remains poorly understood. We carried out three experiments to explore its influence on milk intake and compare its consequences with those resulting from nursing-induced conditioning. First, pups conditioned to an odorant by pairing with the MP on postnatal d…
Advancing cyanobacteria biomass estimation from hyperspectral observations: Demonstrations with HICO and PRISMA imagery
2021
Retrieval of the phycocyanin concentration (PC), a characteristic pigment of, and proxy for, cyanobacteria biomass, from hyperspectral satellite remote sensing measurements is challenging due to uncertainties in the remote sensing reflectance (?R) resulting from atmospheric correction and instrument radiometric noise. Although several individual algorithms have been proven to capture local variations in cyanobacteria biomass in specific regions, their performance has not been assessed on hyperspectral images from satellite sensors. Our work leverages a machine-learning model, Mixture Density Networks (MDNs), trained on a large (N = 939) dataset of collocated in situ chlorophyll-a concentrat…
Influence of carbon and nutrient additions on a decomposer food chain and the growth of pine seedlings in microcosms
2001
Abstract Because of N deposition plant production is becoming increasingly limited by other nutrients in boreal forests. At the same time more C is suggested to become available for below-ground food webs because of enhanced CO2 fixation. We studied the effects of carbon and nutrient addition on a fungus–nematode food chain and on the growth of mycorrhizal or nonmycorrhizal pine seedlings (Pinus sylvestris L.) in microcosms with N-rich mineral soil and a humus layer. The role of the food chain and mycorrhizal fungi for pine growth was tested in a smaller set-up. The total pine biomass was not N-limited at the scale of two experimental growing seasons. In accordance with established knowledg…
Interannual Variability of Biomass (SMOS Vegetation Optical Depth) Over the Contiguous United States
2021
Interannual variability in biomass represented by SMOS vegetation optical depth (VOD) and precipitation was assessed over the Contiguous United States. The greatest interannual variability in both VOD and precipitation occurred in shrubs and herbaceous (grasslands), with forests the least variable. At a continental scale, VOD was strongly correlated with annual precipitation. Results showed a significant correlation coefficient (∼ 0.93) between interannual variability of precipitation and biomass, indicating that the interannual variability of precipitation could be a good predictor of the interannual variability of biomass.
Evaluation of Ligno Boost™ softwood kraft lignin epoxidation as an approach for its application in cured epoxy resins
2018
Abstract In this study, modification of LignoBoost™ softwood kraft lignin with epichlorhydrin in water-organic solvents media was realized. Lignin-based epoxy resins were obtained by two ways: acetone extraction of glycidylated lignin or glycidylation of the acetone soluble lignin fraction. The effect of glycidylation regimes on the yields of acetone soluble fractions, their functional composition and physical-chemical characteristics was investigated using wet chemistry methods, FTIR spectroscopy, size exclusion chromatography (SEC) and differential scanning calorimetry (DSC). The positive effect of the biphasic phase transfer catalytic system – KOH/quaternary ammonium salt – on glycidylat…
Evaluation of the laboratory prediction of surface properties of bituminous mixtures. Construction and Building Materials. Volume 23. Issue 2. Elsevi…
2009
An experimental and analytical investigation was carried out both in laboratory and in situ on wearing courses. The approach presented in this paper aims to predict the in situ density and surface properties of bituminous layers, during the phase of mix design in laboratory. Therefore, the main attempt of this study is to identify, amongst the commonly available laboratory equipments, the most adequate for producing specimens that, used for carrying out simple and reliable laboratory test, allow the prediction of the surface characteristics of the mixture as laid on site. This is done by comparing the data collected from an experimental site with those calculated from laboratory specimens c…
A comparative life-cycle assessment of asphalt mixtures for railway sub-ballast containing alternative materials
2018
Abstract Bituminous sub-ballast in railway track-bed can mitigate the variation of the moisture content in the subgrade and reduce vertical stiffness variations of the track leading to a more durable infrastructure. Nevertheless, durability is only one of the aspects that affects the sustainability of an infrastructure. Other relevant aspects are related to the environmental and economic issues. This research work joins the worldwide effort towards a paradigm shift in civil engineering devoted to assess the sustainability of infrastructures at the design stage. With this in mind, in this study different alternative bituminous sub-ballast mixtures containing recycled materials, namely crumb …