Search results for "Gradation"
showing 10 items of 1275 documents
Agriculture and grazing environments
2019
Abstract The increase in world population increases the pressure on soil resources and triggers land degradation. Agricultural and grazing environments are one of the most vulnerable ecosystems to this process. Degradation affects importantly soil fertility. Millions of hectares are affected and soil productivity is endangered. This decreases soil ability to provide ecosystem services in quantity and quality. Managers and decision-makers should be open to adopt environmentally-friendly practices and contribute to land degradation neutrality. This chapter focuses on the problems induced by some of the most common soil degradation processes caused by in agriculture and grazing activities. Rev…
Assessment of soil suitability for improvement of soil factors and agricultural management
2019
The dramatic growth of the world&rsquo
Dependence of accelerated degradation of atrazine on soil pH in French and Canadian soils
2000
Abstract A series of agricultural soils varying in their atrazine treatment history were sampled from 12 sites in France and two sites in Canada. The soils varied widely with respect to soil chemical, physical and microbiological (total microbial biomass, kinetics of C and N mineralization) properties. Soils treated with as few as two successive atrazine field applications mineralized [U- ring - 14 C]atrazine significantly more rapidly in 35 d laboratory incubations than did soils which had never received atrazine. Longer treatment history tended to favour more rapid mineralization in the so-called “adapted” soils. Up to 80% of the initially applied 14 C-atrazine was mineralized at the end …
The effects of solar radiation in archaeological sites
2013
Ruined walls, paving and decorative elements of archaeological sites are mainly composed of materials with chemical, physical and biological degradation problems that are primarily due to environmental factors. The conservation of archaeological finds requires a protection against these factors. Solar radiation may constitute one of those causes of deterioration. In recent decades the use of glass to cover archaeological sites has been more and more widespread (Fig. 1). The purpose of those glass covers is to reconcile the need of the display capabilities with the preservation of the remains. In general, a protective cover structure determines new conditions that must be carefully controlle…
Rediscovery of the enigmatic solifuges (Arachnida: Solifugae) at Lampedusa Island (Italy)
2018
Solifuges were recorded in Italy for the first time in 1956, on the island of Lampedusa (Strait of Sicily), and classified as Biton ehrenbergi Karsch, 1880 and Biton velox Simon, 1885. More than 60 years later, we carried out the first targeted investigation of these little-known animals. A survey conducted during both spring and autumn 2017 confirmed the presence of solifuges on Lampedusa Island. We identified all specimens as B. velox and not B. ehrenbergi. We concluded that B. ehrenbergi is absent from the island, on the basis of both newly collected data and a re-evaluation of the past records. Morphology and taxonomic position of the examined specimens are discussed in light of the unr…
A statistical design of experiments for optimizing the MALDI-TOF-MS sample preparation of polymers. An application in the assessment of the thermo-me…
2011
[EN] The sample preparation procedure for MALDI-TOF MS of polymers is addressed in this study by the application of a statistical Design of Experiments (DoE). Industrial poly (ethylene terephthalate) (PET) was chosen as model polymer. Different experimental settings (levels) for matrixes, analyte/matrix proportions and concentrations of cationization agent were considered. The quality parameters used for the analysis were signal-to-noise ratio and resolution. A closer inspection of the statistical results provided the study not only with the best combination of factors for the MALDI sample preparation, but also with a better understanding of the influence of the different factors, individua…
Influence of substrate and temperature on the biodegradation of polyester-based materials: Polylactide and poly(3-hydroxybutyrate-co-3-hydroxyhexanoa…
2020
[EN] The extended use of polymers from renewable resources such as aliphatic polyesters or polyhydroxyalkanoates boosted the necessity to understand their behaviour in an end-of-life scenario. Although they can be degraded in reasonable shorter times than traditional polymers, understanding the degradation mechanisms under dissimilar conditions will contribute to further developments in this field. This work aimed to study the effect of temperature and substrate in the degradation of polylactide (PLA) and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) in a simulated laboratory scale to ascertain their contribution, separately or in combination. For this purpose, nine parallel degradat…
Assessing the MALDI-TOF MS sample preparation procedure to analyze the influence of thermo-oxidative ageing and thermo-mechanical degradation on poly…
2011
[EN] Multiple processing by means of successive injection cycles was used to simulate the thermo-mechanical degradation effects on the oligomeric distribution of PLA under mechanical recycling. Likewise, an accelerated thermal ageing over PLA glass transition was performed in order to simulate its service life. MALDI-TOF MS was used for the analysis and the sample preparation procedure was assessed by means of a statistical Design of Experiments (DoE). The quality effects in use for the analysis were signal-to-noise ratio and Resolution. Different matrixes, analyte/matrix proportions and the use of NaTFA as cationization agent were considered. A deep inspection of the statistical results pr…
Carbon Nanomaterial Doped Ionic Liquid Gels for the Removal of Pharmaceutically Active Compounds from Water.
2019
Due to large drug consumption, pharmaceutically active compounds (PhACs) can be found as water contaminants. The removal of PhACs is a significant issue, as they can easily overtake traditional purification methods. Because of their surface properties, carbon nanomaterials are among the most efficient materials able to adsorb PhACs. However, their limitation is their recovery after use and their possible leakage into the aquatic system. Consequently, new hybrid supramolecular ionic liquid gels (HILGs) have been designed for the adsorption of some antibiotic drugs (ciprofloxacin and nalidixic acid) from water. The chemical&ndash
Evaluation of carbamazepine uptake and metabolization by Typha spp., a plant with potential use in phytotreatment
2011
Abstract Phytoremediation technologies such as constructed wetlands have shown higher efficiencies in removal of pharmaceuticals from wastewaters than conventional wastewater treatment processes, and plants seem to have an important role in the removal of some of those compounds. In this context, a study was conducted to assess tolerance, uptake, and metabolism of the epilepsy drug, carbamazepine, by the macrophyte Typha spp. This evaluation was conducted in hydroponic solutions with 0.5–2.0 mg/L of this pharmaceutical for a maximum period of 21 days. The removal of carbamazepine from nutrient solutions by the plants reached values of 82% of the initial contents. Furthermore, a metabolite (…