Characterisation of the physico-mechanical parameters of MSW

Following the basics of soil mechanics, the physico-mechanical behaviour of municipal solid waste (MSW) can be defined through constitutive relationships which are expressed with respect to three physical parameters: the dry density, the porosity and the gravimetric liquid content. In order to take into account the complexity of MSW (grain size distribution and heterogeneity larger than for conventional soils), a special oedometer was designed to carry out laboratory experiments. This apparatus allowed a coupled measurement of physical parameters for MSW settlement under stress. The studied material was a typical sample of fresh MSW from a French landfill. The relevant physical parameters were measured using a gas pycnometer. Moreover, the compressibility of MSW was studied with respect to the initial gravimetric liquid content. Proposed methods to assess the set of three physical parameters allow a relevant understanding of the physico-mechanical behaviour of MSW under compression, specifically, the evolution of the limit liquid content. The present method can be extended to any type of MSW.     

Towards the Prediction of Heat and Mass Transfer in an Air-Conditioned Environment for a Life Support System in Space

Long-term flights or the establishment of permanent bases in space provide serious challenges for life support systems. Plants are essential companion life forms for such space missions, where human habitats must mimic the cycles of life on earth to generate and recycle food, oxygen and water. Nowadays, the chemical–mechanical recycling systems used in the international space station are much more compact, less labour intensive and more reliable than plant-based systems, but these systems would be too expensive for the long-term human exploration. In order to improve living conditions for humans and plants, we need an accurate characterisation of the mass transfer phenomena related to condensation of humid air. We are interested in developing an experimental protocol, which would help us to establish a theoretical model describing the heterogeneous transfers along a wall or a plant in an air-conditioned environment. Initially, we started in dry conditions by measuring the velocity profiles within the boundary layer that develop on a horizontal or a vertical flat plate in a wind tunnel. The velocity ranged from 0.5 to 2.5 m s^?1. Existing coupled heat and mass transfer measurement results relevant to our applications are discussed.     

Fate of a stilbene-type fluorescent whitening agent (DSBP) in the presence of Fe(III) aquacomplexes: from the redox process to the photodegradation

The behaviour of 4,4′-bis(2-sulfostyryl)biphenyl (DSBP), a fluorescent whitening agent, was investigated in the presence of Fe(III) aquacomplexes at room temperature. In the dark, a two-step reaction was observed when adding Fe(III) to a solution of DSBP: an initial fast redox reaction between DSBP and the monomeric species Fe(OH)²⁺ and a slower reaction leading to the coagulation of oxidised DSBP and iron. This phenomenon is due to the formation of a complex or an ion-pair between Fe(II) and/or Fe(III) with oxidised DSBP and it probably occurs by charge neutralisation in our experimental conditions. The precipitation of DSBP depends on the initial concentration in Fe(OH)²⁺ and is achieved for a ratio [Fe(OH) ²⁺]/[DSBP] of 5 approximately. Under irradiation at 365 nm, a complicated behaviour was observed: a complexation of iron by oxidised DSBP favoured by irradiation and a degradation of DSBP induced by an intramolecular electron transfer in the complex or by a photoredox of Fe(OH)²⁺ species generating OH radicals in the supernatant. The complete degradation of DSBP is reached four times faster in the presence of Fe(III) with respect to the direct photolysis of DSBP alone. Moreover, the total mineralization of DSBP obtained in less than 120 h upon irradiation at 365 nm is only observed in the presence of the ferric ions, enlightening the efficiency of the method involving Fe(III) and UV irradiation.     

Experimental study on the thermal oxidation of 2-chlorophenol in air over the temperature range 450-900 degrees C

The thermal oxidation of 2-chlorophenol (2-CP) in air was investigated using a perfectly stirred reactor at 1 atm over the temperature range 450–900 °C. The relative concentration of 2-CP was 1000 ppmV (equivalence ratio Φ = 0.03). About fifty organic products were identified as trace species. The concentration profiles of 2-CP, carbon oxides as well as those of seventeen major organic intermediates and six non-to-lower chlorinated dioxins and furans were presented as a function of temperature for a residence time of 2 s. The most abundant intermediate products were carbon monoxide, 2 H-pyran-2-one, chlorobenzene, 4-cyclopenten-1,3-dione, phenol, benzofuran, 2-chlorohydroquinone and 2-indanone. These concentration profiles have revealed that temperatures of at least 900 °C were needed to completely oxidize 2-CP, CO and all other organic byproducts to carbon dioxide. Reaction pathways accounting for the formation of most observed products are proposed.     

Towards a multidisciplinary and integrated strategy in the assessment of adverse health effects related to air pollution: the case study of Cracow (Poland) and asthma

Complex interaction between anthropogenic activities, air quality and human health in urban areas, such as in Cracow sustains the need for the development of an interdisciplinary and integrated risk-assessment methodology. In such purpose, we propose a pilot study performed on asthmatics and based on a combined use of a biomarker, such as metallothionein 2A (MT-2A) in the characterization of human exposure to one or a mixture of pollutants and of Geographical Information Systems (G.I.S.) which integrates climatic and urban anthropogenic parameters in the assessment of spatio-temporal dispersion of air pollutants. Considering global incidence of air pollution on asthma and on peripheral blood lymphocytes MT-2A expression should provide a complementary information on biological risks linked to urban anthropogenic activities. Such study would help for the establishment of a sustainable development in urban areas that can maintain the integrity of air quality and preserve human health.     

Social experience influences the development of a central auditory area

Vocal communication develops under social influences that can enhance attention, an important factor in memory formation and perceptual tuning. In songbirds, social conditions can delay sensitive periods of development, overcome learning inhibitions and enable exceptional learning or induce selective learning. However, we do not know how social conditions influence auditory processing in the brain. In the present study, we raised young naive starlings under different social conditions but with the same auditory experience of adult songs, and we compared the effects of these different conditions on the development of the auditory cortex analogue. Several features appeared to be influenced by the social experience, among which the proportion of auditory neuronal sites and the neuronal selectivity. Both physical and social isolation from adult models altered the development of the auditory area in parallel to alterations in vocal development. To our knowledge, this is the first evidence that social deprivation has as much influence on neuronal responsiveness as sensory deprivation.     

Taking Action Against Ocean Acidification: A Review of Management and Policy Options

Ocean acidification has emerged over the last two decades as one of the largest threats to marine organisms and ecosystems. However, most research efforts on ocean acidification have so far neglected management and related policy issues to focus instead on understanding its ecological and biogeochemical implications. This shortfall is addressed here with a systematic, international and critical review of management and policy options. In particular, we investigate the assumption that fighting acidification is mainly, but not only, about reducing CO₂ emissions, and explore the leeway that this emerging problem may open in old environmental issues. We review nine types of management responses, initially grouped under four categories: preventing ocean acidification; strengthening ecosystem resilience; adapting human activities; and repairing damages. Connecting and comparing options leads to classifying them, in a qualitative way, according to their potential and feasibility. While reducing CO₂ emissions is confirmed as the key action that must be taken against acidification, some of the other options appear to have the potential to buy time, e.g. by relieving the pressure of other stressors, and help marine life face unavoidable acidification. Although the existing legal basis to take action shows few gaps, policy challenges are significant: tackling them will mean succeeding in various areas of environmental management where we failed to a large extent so far.     

Precipitation of liquid swine manure phosphates using magnesium smelting by-products

Swine manure contains considerable amounts of total (P) and soluble phosphorus (PO(4)-P) which may increase the soil P content when applied in excess to crop requirements and, consequently, risk water eutrophication. The feasibility of using magnesium (Mg) from the by-product of electrolysis and foundries (BPEF) for the removal of P from liquid swine manure was studied by adding up to 3 g of Mg as BPEF per liter of nursery (NU) and grower-finisher (GF) swine manure in 25-L plastic buckets. Changes in P and other elements were monitored for up to 360 h. Small amounts of Mg as BPEF (0.5 and 1.0 g Mg L(-1) manure) reduced the total P concentration of the liquid fraction by 70 to 95% of both manure types with respect to the control treatment of mixed raw manure. A settling period of 8 h or more was necessary to significantly reduce the liquid fraction's total P concentration for both manure types. Reduction of PO(4)-P varied from 96 to 100% in the liquid fractions for both manure types, which along with natural settling, explains most of the total P reduction in that fraction. The addition of BPEF did not influence the N content of manure. The low P liquid fraction can be safely applied to saturated P soils whereas the high P solid fraction offers the opportunity of transporting manure to agricultural soils deficient in P. Since N is conserved, both liquid and solid fractions could be valuable fertilizer manure by-products.