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Rodica Chiriac Jean Carré Yves Perrodin Hervé Vaillant Santiago Gasso Philippe Miele 《Atmospheric environment (Oxford, England : 1994)》2009,43(11):1926-1931
The dispersion of VOCs emitted by a municipal solid waste landfill was studied for a period of over one year. Sixteen VOCs were monitored: linear alkanes from C7 to C11, BTEX, trimethylbenzene, trichlorethylene, tetrachlorethylene, α and β-pinenes, limonene. The analytical procedure was first comprised of static long-term sampling of about 2 months using radial diffusion Radiello tubes containing activated carbon, followed by extraction by solvent (i.e. CS2) and GC/MS analysis. The results were initially analysed on the basis of the total concentration of the quantified VOCs, then by examining the concentrations of certain selected compounds. The influence of different parameters such as operating conditions, meteorological conditions and site morphology was highlighted on the basis of total VOC concentrations. In order to study the VOC's dispersion more closely, 5 compounds were chosen: toluene, benzene, limonene, and the sum trichlorethylene + tetrachlorethylene, as a “marker”, to verify the origin of the VOCs emitted. The results showed that the main source of VOCs is the open cell and lead to different hypotheses on interferences from neighbouring sources and to the proposal of solutions to limit the emission of VOCs and their dispersion. To our knowledge, this type of study has not been accomplished until this day. 相似文献
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Corona P Agrimi M Baffetta F Barbati A Chiriacò MV Fattorini L Pompei E Valentini R Mattioli W 《Environmental monitoring and assessment》2012,184(3):1409-1422
Urban areas are continuously expanding today, extending their influence on an increasingly large proportion of woods and trees
located in or nearby urban and urbanizing areas, the so-called urban forests. Although these forests have the potential for
significantly improving the quality the urban environment and the well-being of the urban population, data to quantify the
extent and characteristics of urban forests are still lacking or fragmentary on a large scale. In this regard, an expansion
of the domain of multipurpose forest inventories like National Forest Inventories (NFIs) towards urban forests would be required.
To this end, it would be convenient to exploit the same sampling scheme applied in NFIs to assess the basic features of urban
forests. This paper considers approximately unbiased estimators of abundance and coverage of urban forests, together with
estimators of the corresponding variances, which can be achieved from the first phase of most large-scale forest inventories.
A simulation study is carried out in order to check the performance of the considered estimators under various situations
involving the spatial distribution of the urban forests over the study area. An application is worked out on the data from
the Italian NFI. 相似文献
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Chiriac R De Araujos Morais J Carre J Bayard R Chovelon JM Gourdon R 《Waste management (New York, N.Y.)》2011,31(11):2294-2301
The emission of volatile organic compounds (VOCs) from municipal solid waste stored in a pilot-scale cell containing 6.4 tonnes of waste (storage facility which is left open during the first period (40 days) and then closed with recirculation of leachates during a second period (100 days)) was followed by dynamic sampling on activated carbon and analysed by GC–MS after solvent extraction. This was done in order to know the VOC emissions before the installation of a methanogenesis process for the entire waste mass. The results, expressed in reference to toluene, were exploited during the whole study on all the analyzable VOCs: alcohols, ketones and esters, alkanes, benzenic and cyclic compounds, chlorinated compounds, terpene, and organic sulphides.The results of this study on the pilot-scale cell are then compared with those concerning three biogases from a municipal waste landfill: biogas (1) coming from waste cells being filled or recently closed, biogas (2) from all the waste storage cells on site, and biogas (3) which is a residual gas from old storage cells without aspiration of the gas. The analysis of the results obtained revealed: (i) a high emission of VOCs, principally alcohols, ketones and esters during the acidogenesis; (ii) a decrease in the alkane content and an increase in the terpene content were observed in the VOCs emitted during the production of methane; (iii) the production of heavier alkanes and an increase in the average number of carbon atoms per molecule of alkane with the progression of the stabilisation/maturation process were also observed.Previous studies have concentrated almost on the analysis of biogases from landfills. Our research aimed at gaining a more complete understanding of the decomposition/degradation of municipal solid waste by measuring the VOCs emitted from the very start of the landfill process i.e. during the acidogenesis and acetogenesis phases. 相似文献
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There is a wide range of applications where calcium phosphate and hydroxyapatite (HA) are used as biomaterials, e.g. as synthetic
bone grafts, coating on metal prostheses (like hip endoprostheses or dental implants) and drug carriers. In the study, the
design and synthesis of composites based on poly(vinyl alcohol-co-lactic acid)/hydroxyapatite (PVA-co-LA/HA) with potential
for biomedical applications, they are presented. The hydroxyapatite particles were surface-grafted with l(+)-lactic acid in the presence of manganese acetate as catalyst, resulting in modified hydroxyapatite (HAm) with improved capacity of bonding, respectively for the preparation of the composite based on PVA-co-LA/HAm. FT-IR spectra further confirmed the existence of PLA polymer on the surface of HA particles. In synthesis of PVA-co-LA copolymer
the different molar ratios PVA/LA (2/1, 1/1, 1/2), toluene/water: 1/2 (as azeotrope solvent mixture) and manganese acetate
as catalyst, were used. The composite materials were synthesized in situ with 10 wt% HA, and respectively HAm (reported to PVA and lactic acid components). The composite materials were characterized by FTIR spectroscopy, thermal analyses
(DSC, DTG), 1H-NMR spectroscopy, particle size distribution and zeta potential. 相似文献
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Rodica Lipsa Nita Tudorachi Cornelia Vasile Aurica Chiriac Anca Grigoras 《Journal of Polymers and the Environment》2013,21(2):461-471
Modified natural polymers have been gaining increasing scientific interest for many years. In this study carboxymethyl starch (CMS) was grafted with L(+)-lactic acid (LA) in different molar ratios CMS/LA (1/36, 1/22 and 1/12), resulting carboxymethyl starch-g-poly(lactic acid) (CMS-g-PLA) copolymers. The grafting reaction was carried out by solution polycondensation procedure in toluene and stannous 2-ethyl hexanoate Sn(Oct)2 as catalyst was utilized. Poly(lactic acid) (PLA) was synthesized in the same conditions with the copolymers for comparative analyses of the physico-chemical and thermal properties. The copolymers and PLA were structurally and morphologically characterized by FT-IR, 1H-NMR spectroscopy, WAXD and SEM analyses, taking CMS as reference. The molecular weight of the copolymers, CMS and PLA were determined, using a dynamic light scattering technique. The thermal behavior of the products was studied by DSC and TG-DTG analyses. The CMS-g-PLA graft copolymers exhibited lower Tg and thermal stability than pure CMS. 相似文献
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