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291.
Estimating the Cumulative Ecological Effect of Local Scale Landscape Changes in South Florida 总被引:1,自引:0,他引:1
Hogan DM Labiosa W Pearlstine L Hallac D Strong D Hearn P Bernknopf R 《Environmental management》2012,49(2):502-515
Ecosystem restoration in south Florida is a state and national priority centered on the Everglades wetlands. However, urban
development pressures affect the restoration potential and remaining habitat functions of the natural undeveloped areas. Land
use (LU) planning often focuses at the local level, but a better understanding of the cumulative effects of small projects
at the landscape level is needed to support ecosystem restoration and preservation. The South Florida Ecosystem Portfolio
Model (SFL EPM) is a regional LU planning tool developed to help stakeholders visualize LU scenario evaluation and improve
communication about regional effects of LU decisions. One component of the SFL EPM is ecological value (EV), which is evaluated
through modeled ecological criteria related to ecosystem services using metrics for (1) biodiversity potential, (2) threatened
and endangered species, (3) rare and unique habitats, (4) landscape pattern and fragmentation, (5) water quality buffer potential,
and (6) ecological restoration potential. In this article, we demonstrate the calculation of EV using two case studies: (1)
assessing altered EV in the Biscayne Gateway area by comparing 2004 LU to potential LU in 2025 and 2050, and (2) the cumulative
impact of adding limestone mines south of Miami. Our analyses spatially convey changing regional EV resulting from conversion
of local natural and agricultural areas to urban, industrial, or extractive use. Different simulated local LU scenarios may
result in different alterations in calculated regional EV. These case studies demonstrate methods that may facilitate evaluation
of potential future LU patterns and incorporate EV into decision making. 相似文献
292.
Ikechukwu D. Anyaogu Paul M. Ejikeme John A. Ibemesi 《Journal of Polymers and the Environment》2010,18(2):104-115
Soybean oil (SBO) was dimerized and the crude dimer acid product reacted with 1,2-phenylene diamine at 210 ± 5 °C under inert
atmosphere to obtain fatty polyamide (FPA). The FPA was used to modify a commercial alkyd resin by reacting a mixture of the
alkyd resin with 5 wt% of FPA at 120 °C for 80 min under inert atmosphere. The FTIR spectrum of the FPA modified resin showed
evidence of higher degree of H-bonding than was found for the unmodified alkyd. White gloss coatings of 15, 20, 25, and 30%
solids were formulated from the modified and unmodified resins and examined for performance with respect to: leveling, sag
resistance, drying time, pigment settling, skinning tendency and film hardness. Results showed that the unmodified alkyd coatings
exhibited good leveling but poor sag resistance at all solid contents. In contrast, FPA modified alkyd coatings combined good
leveling with high sag resistance indicating their thixotropic nature. A strong tendency to pigment settling was observed
for unmodified alkyd coatings but was not observed in the FPA modified alkyd coatings. The modified alkyd coatings showed
skinning while the unmodified alkyd coatings did not skin. A 30% solids coating formulation of the FPA modified resin showed
shorter surface dry time but longer hard dry time than the unmodified alkyd resin coating. 相似文献
293.
Preparation and Characterization of Hydrogel Based on Poly(vinyl alcohol) Cross-Linked by Different Cross-Linkers Used to Dry Organic Solvents 总被引:1,自引:0,他引:1
Poly(vinyl alcohol) (PVA) hydrogels were chemically cross-linked with/without different cross-linkers such as glutaraldehyde
and epichlorohydrin, in the presence of a catalyst, or activator (potassium hydroxide) to produce three types of hydrogels.
The structures of PVA and the prepared gel types were determined by FTIR spectroscopy, the mechanical and thermal properties,
of these hydrogels were examined. The effects of different pH values and temperatures on the swelling properties of the prepared
gels were examined. From the obtained results, it was found that, the low concentration of the cross-linker produced hydrogel
with moderate properties, but in absence of the cross-linker, the obtained hydrogel exhibited good properties and can be used
as friendly environmentally moisture absorbents from the organic solvents. The insolubility and swelling properties of gels
were tested in these solvents. The results indicated that these hydrogels can be used as moisture absorbents and solvent dryers. 相似文献
294.
Hossain M. Anawar 《补救:环境净化治理成本、技术与工艺杂志》2010,20(4):61-67
A considerable number of contaminated mining sites in Europe and other parts of the world pose environmental hazards. Given the multifaceted benefits of phytoremediation, screening of plant communities grown in contaminated areas is being conducted to identify hyperaccumulating plant species. A few arsenic (As) hyperaccumulating plants are found in tropical countries; however, generally, they are not grown in contaminated mining sites of cold and temperate countries (Europe and other parts of the world). The transgenic plants identified to date are not believed to be suitable for commercial use of phytoremediation. A few tolerant plant species in mining sites that are found to have elevated As levels primarily concentrate As in their roots. The remediation potential of many of these tolerant plants is limited because of their slow growth and low biomass. Therefore, phytostabilization of contaminated mining sites using tolerant plant species with high biomass and a more extensive root system is the only solution to date in Europe and some other parts of the world. © 2010 Wiley Periodicals, Inc. 相似文献
295.
Se Jin Choi Ssang Sun Jun Jae Eun Oh Paulo J. M. Monteiro 《Journal of Material Cycles and Waste Management》2010,12(4):275-282
This article investigates the effects of stone powder sludge on the microstructure and strength development of alkali-activated fly ash and blast furnace slag mixes. Stone powder sludge produced from a crushed aggregate factory was used to replace fly ash and granulated blast furnace slag at replacement ratios of 0%, 10%, 20%, and 30% by mass. The unit weight and compressive strength of the samples were measured, and scanning electron microscopy/energy dispersive spectroscopy and X-ray diffraction (XRD) analyses were performed. The test results indicated that the compressive strength of alkali-activated blast furnace slag mixes using stone powder sludge was higher than that of the alkali-activated blast furnace slag control mix, but the compressive strength of alkali-activated fly ash mixes decreased with increasing replacement ratio of stone powder sludge. Microscopy results indicated that for alkaliactivated blast furnace slag samples, broken surfaces were more evident than for the alkali-activated fly ash samples. For all XRD diagrams, broad and diffuse peaks were observed around 2θ = 35° (d = 2.96–3.03 Å), implying amorphous or short-ordering structure phases. 相似文献
296.
297.
Accumulation and biological cycling of heavy metal in four salt marsh species, from Tagus estuary (Portugal) 总被引:2,自引:0,他引:2
Pools of Zn, Cu, Cd and Co in leaf, stem and root tissues of Sarcocornia fruticosa, Sarcocornia perennis, Halimione portulacoides and Spartina maritima were analyzed on a bimonthly basis, in a Tagus estuary salt marsh. All the major concentrations were found in the root tissues, being the concentrations in the aboveground organs neglectable for sediment budget proposes, as seen by the low root-aboveground translocation. Metal annual accumulation, root turnovers and cycling coefficients were also assessed. S. maritima showed the higher root turnovers and cycling coefficients for most of the analyzed metals, making this a phytostabilizer specie. By contrast the low root turnover, cycling coefficient and low root necromass generation makes S. perennis the most suitable specie for phytoremediation processes. Although the high amounts of metal return to the sediments, due to root senescence, salt marshes can still be considered sinks of heavy metals, cycling heavy metals mostly between sediment and root. 相似文献
298.
T.M. McIntire O.S. Ryder P.L. Gassman Z. Zhu S. Ghosal B.J. Finlayson-Pitts 《Atmospheric environment (Oxford, England : 1994)》2010,44(7):939-944
It is commonly assumed that atmospheric oxidation of hydrocarbon particles or hydrocarbon coatings on particles leads to polar products and increased water uptake, altering atmospheric visibility and increasing the likelihood they will act as cloud condensation nuclei (CCN). We show here through laboratory experiments that increased water uptake depends on the 3-dimensional structure of the particles. Laboratory studies of particles formed during ozonolysis of surface-bound alkenes, present as terminally unsaturated self-assembled monolayers (C8= SAM) on a silica substrate, were carried out at room temperature and 1 atm pressure. SAMs were exposed to ~1013 O3 molecules cm?3 for 40 min and resultant particles were analyzed using single particle Fourier transform infrared micro-spectroscopy (micro-FTIR) and secondary ion mass spectroscopy (SIMS). Spectroscopy results show that –COOH and other polar groups are formed but are buried inside a hydrophobic shell, consistent with earlier observations (McIntire et al., 2005, Moussa et al., 2009) that water uptake does not increase after reaction of the terminal alkene with O3. These insights into the 3-D structure of particles formed on oxidation have important implications for the ability of secondary organic aerosols to act as CCN. In addition, the nature of the surface of the particles is expected to determine their uptake into biological systems such as the surface of the lungs. 相似文献
299.
A set of criteria allowing demarcation between algocenoses is proposed. These criteria characterize the species composition,
group of dominants, and taxonomic and ecological structure of algocenoses. 相似文献
300.
The effect of invertebrate predation pressure by the cladoceran Leptodora kindti on the population structure of Daphnia galeata and D. hyalina has been estimated by analyzing the occurrence frequency of the normal and spined morphotypes in Lake Baikal. It is shown
that the growth of L. kindti population density leads to an increase in the proportion of the spined morphotype, while that of that of the normal morphotype
decreases. 相似文献