Search results for " mixture"
showing 10 items of 1018 documents
Effects of forest restoration treatments on the abundance of bark beetles in Norway spruce forests of southern Finland
2009
Abstract Restoration of protected areas in boreal forests frequently includes creating substantial volumes of dead wood. While this benefits a wide range of dead wood dependent invertebrate species, some of these are regarded as forest pests. Therefore, the risk of elevated levels of tree mortality in surrounding commercial forests must be considered. In a large-scale field experiment in southern Finland, we studied the effects of restoration treatments on the abundance of bark beetles within and in the vicinity of restored areas, in particular focusing on Ips typographus and Pityogenes chalcographus . The treatments applied to managed Norway spruce forests were controlled burning and parti…
Asphalt mixtures modified with basalt fibres for surface courses
2018
Abstract This paper shows the results of an experimental study concerning the effect of introduction of basalt fibres in asphalt mixtures for surface course, mainly with regard to those to be used in urban areas, for dedicated bus lanes. Surface layers, where tire-pavement interactions occur, have to provide different properties such as high friction (very important for users’ safety), stability, resistance to meteorological agents, and contribution to the overall pavement performances. Considering that basalt fibres provide considerable physical and mechanical properties and above all high abrasion resistance, scope of the study is to evaluate the effects of these fibres on mixtures proper…
Changes in soil chemical properties as affected by pyrogenic organic matter amendment with different intensity and frequency
2017
Pyrogenic organic matter (PyOM) has long been used as a soil amendment to improve soil physicochemical properties. However, few studies simultaneously investigated both intensities and frequencies of PyOM addition on soil chemical properties of soil base cations, soil pH buffering capacity (pHBC), and plant available micronutrients. In the main food production area of lower Liaohe River Plain in Northeast China, a field manipulation of PyOM addition was initiated in 2013 to examine how the intensities (0, 1%, 3%, and 5% of 0–20 cm soil mass) and frequencies (3% of soil mass applied once versus yearly for 3 years) of PyOM amendment affected soil chemical properties. Higher intensity of PyOM …
Influence of parent material and soil use on arsenic forms in soils A case study in the Amblés Valley (Castilla-León, Spain)
2014
Abstract The total, water soluble and extractable concentrations with EDTA of As from topsoils from the Ambles Valley (Avila, Spain) were determined. The geochemical baseline concentrations of total As were established, and the relationships between the concentration of the different As forms and soil properties were investigated. Total As content in soils was related with parent material, whereas anthropogenic activities affected its mobility. Iron, aluminium, clay content, soil organic matter and soil pH were the main controlling factors for As soil concentrations. The geochemical baseline concentrations obtained (mg kg − 1 ) were 7.3–35 in soils on granite parent material and 2.2–6.8 in …
Effect of sulfur dioxide on mucociliary activity and ciliary beat frequency in guinea pig trachea
1994
The effects of 30 min exposure to sulfur dioxide on mucociliary activity (MCA) and ciliary beat frequency (CBF) were studied in 31 guinea pig tracheas. MCA was measured by recording the light reflected from ciliated mucous membranes using an infrared bar code reader. CBF of single ciliated cells obtained by brushing was measured with phase-contrast microscopy. Each tracheal sample was exposed to SO2 at concentrations ranging from 2.5 to 12.5 ppm, or to air for control purposes. MCA and CBF were measured before and immediately after gas exposure. A reduction in mean MCA of 63% (P = 0.0007) and statistically insignificant changes in CBF (P > 0.05) were recorded at concentrations of 2.5 PPM SO…
A Derivation of the Vlasov-Stokes System for Aerosol Flows from the Kinetic Theory of Binary Gas Mixtures
2016
In this short paper, we formally derive the thin spray equation for a steady Stokes gas, i.e. the equation consists in a coupling between a kinetic (Vlasov type) equation for the dispersed phase and a (steady) Stokes equation for the gas. Our starting point is a system of Boltzmann equations for a binary gas mixture. The derivation follows the procedure already outlined in [Bernard-Desvillettes-Golse-Ricci, arXiv:1608.00422 [math.AP]] where the evolution of the gas is governed by the Navier-Stokes equation.
Application of a low transition temperature mixture for the dispersive liquid–liquid microextraction of illicit drugs from urine samples
2021
© 2021 by the authors.
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.