排序方式: 共有45条查询结果,搜索用时 31 毫秒
21.
Mitchell D. Harley Umberto Andriolo Clara Armaroli Paolo Ciavola 《Journal of Coastal Conservation》2014,18(5):551-565
On beaches where natural shoreline variability is significant, beach nourishment is a useful engineering method to augment the dry beach and protect infrastructure and/or unstable cliffs. In this study, a low-cost video monitoring system is used to monitor the shoreline response to a nourishment operation on a dynamic gravel embayed beach in Central Italy. Video-derived shorelines were collected over a 15-month period to measure the evolution of the beach with regards to three specific parameters: the dry beach width, the dry beach area and the beach orientation. Moderate increases in the dry beach width of 3.6 m and 6.7 m across the embayment were observed in response to two different gravel nourishments of approximately 40,000 m3 and 46,000 m3 respectively. The orientation of the beach meanwhile was found to rotate rapidly in the clockwise direction and more gradually in the counter-clockwise direction. Analyses of individual storm events suggest these rapid clockwise rotations are caused by ESE storms, which result in beach retreat particularly at the southern end. The combination of an overall narrow beach width and a clockwise beach orientation is observed to cause a cliff erosion event at a vulnerable point along the embayment. 相似文献
22.
Ezio Ranieri Umberto Fratino Andrea Petrella Vincenzo Torretta Elena Cristina Rada 《Environmental science and pollution research international》2016,23(16):15983-15989
The comparative effectiveness for hexavalent chromium removal from irrigation water, using two selected plant species (Phragmites australis and Ailanthus altissima) planted in soil contaminated with hexavalent chromium, has been studied in the present work. Total chromium removal from water was ranging from 55 % (Phragmites) to 61 % (Ailanthus). After 360 days, the contaminated soil dropped from 70 (initial) to 36 and 41 mg Cr/kg (dry soil), for Phragmites and Ailanthus, respectively. Phragmites accumulated the highest amount of chromium in the roots (1910 mg Cr/kg(dry tissue)), compared with 358 mg Cr/kg(dry tissue) for Ailanthus roots. Most of chromium was found in trivalent form in all plant tissues. Ailanthus had the lowest affinity for CrVI reduction in the root tissues. Phragmites indicated the highest chromium translocation potential, from roots to stems. Both plant species showed good potentialities to be used in phytoremediation installations for chromium removal. 相似文献
23.
Wieslaw Jedrychowski Frederica P. Perera Umberto Maugeri Dorota Mrozek-Budzyn Elzbieta Mroz Elzbieta Flak Susan Edwards John D. Spengler Ryszard Jacek Agata Sowa Agnieszka Musiał 《Environment international》2009,35(6):877-884
The main goal of the paper was to assess the pattern of risk factors having an impact on the onset of early wheezing phenotypes in the birth cohort of 468 two-year olds and to investigate the severity of respiratory illness in the two-year olds in relation to both wheezing phenotypes, environmental tobacco smoke (ETS) and personal PM2.5 exposure over pregnancy period (fine particulate matter). The secondary goal of the paper was to assess possible association of early persistent wheezing with the length of the baby at birth. Pregnant women were recruited from ambulatory prenatal clinics in the first and second trimester of pregnancy. Only women 18–35 years of age, who claimed to be non-smokers, with singleton pregnancies, without illicit drug use and HIV infection, free from chronic diseases were eligible for the study. In the statistical analysis of respiratory health of children multinomial logistic regression and zero-inflated Poisson regression models were used. Approximately one third of the children in the study sample experienced wheezing in the first 2 years of life and in about two third of cases (67%) the symptom developed already in the first year of life. The early wheezing was easily reversible and in about 70% of infants with wheezing the symptom receded in the second year of life. The adjusted relative risk ratio (RRR) of persistent wheezing increased with maternal atopy (RRR = 3.05; 95%CI: 1.30–7.15), older siblings (RRR = 3.05; 95%CI: 1.67–5.58) and prenatal ETS exposure (RRR = 1.13; 95%CI: 1.04–1.23), but was inversely associated with the length of baby at birth (RRR = 0.88; 95%CI: 0.76–1.01). The adjusted incidence risk ratios (IRR) of coughing, difficult breathing, runny/stuffy nose and pharyngitis/tonsillitis in wheezers were much higher than that observed among non-wheezers and significantly depended on prenatal PM2.5 exposure, older siblings and maternal atopy. The study shows a clear inverse association between maternal age or maternal education and respiratory illnesses and calls for more research efforts aiming at the explanation of factors hidden behind proxy measures of quality of maternal care of babies. The data support the hypothesis that burden of respiratory symptoms in early childhood and possibly in later life may be programmed already in prenatal period when the respiratory system is completing its growth and maturation. 相似文献
24.
25.
U. Nicolini J. Santolaya O. E. Ojo N. M. Fisk C. Hubinont M. Tonge C. H. Rodeck 《黑龙江环境通报》1988,8(9):665-671
Seventy-one fetal blood samplings (FBS) were attempted from the intrahepatic portion of the umbilical vein (IHV) at 18–34 weeks; 54 were attempted primarily and 17 secondarily after a failed attempt at the placental cord insertion. Fetal blood was obtained in 89 per cent of the cases. Intravascular transfusion (IVT) was attempted on 31 occasions and successful in 24 (77 per cent). In all cases of failed sampling or transfusion via the IHV, prenatal diagnosis and/or therapy was accomplished using alternative procedures. On only one occasion was the procedure postponed. There were no losses or neonatal morbidity attributable to the procedure. FBS from the IHV may be considered as an alternative approach to sampling the placental cord insertion. It is recommended in cases where the approach to the placental cord insertion is difficult or hazardous. 相似文献
26.
A critical comparison between combustion- and gasification-based waste-to-energy systems needs a deep knowledge of the mass flows of materials and elements inside and throughout the units. The study collected and processed data from several moving grate conventional incinerators and high-temperature shaft gasifiers with direct melting, which are in operation worldwide. A material and substance flow analysis was then developed to systematically assess the flows and stocks of materials and elements within each waste-to-energy unit, by connecting the sources, pathways, and intermediate and final sinks of each species. The patterns of key elements, such as carbon, chloride and heavy metals, in the different solid and gaseous output streams of the two compared processes have been then defined. The combination of partitioning coefficients with the mass balances on atomic species and results of mineralogical characterization from recent literatures was used to estimate a composition of bottom ashes and slags from the two types of waste-to-energy technologies. The results also allow to quantify some of the performance parameters of the units and, in particular, the potential reduction of the amount of solid residues to be sent to final disposal. 相似文献
27.
Arena U 《Waste management (New York, N.Y.)》2012,32(4):625-639
The paper proposes a critical assessment of municipal solid waste gasification today, starting from basic aspects of the process (process types and steps, operating and performance parameters) and arriving to a comparative analysis of the reactors (fixed bed, fluidized bed, entrained bed, vertical shaft, moving grate furnace, rotary kiln, plasma reactor) as well as of the possible plant configurations (heat gasifier and power gasifier) and the environmental performances of the main commercially available gasifiers for municipal solid wastes. The analysis indicates that gasification is a technically viable option for the solid waste conversion, including residual waste from separate collection of municipal solid waste. It is able to meet existing emission limits and can have a remarkable effect on reduction of landfill disposal option. 相似文献
28.
Umberto Colombo 《Environment international》1984,10(5-6)
This paper reviews the current energy supply and consumption. Worldwide, there was an increase in the annual energy consumption of 5% between 1955 and 1973 and of 2.7% between 1973 and 1979, but there was a decrease of 0.2% from 1979 to 1983. The role of oil grew from 31% to 47% of world energy consumption between 1955 and 1973 but dropped to 40.3% in 1983. Despite an overall decline in energy consumption in the last few years, the consumption of electricity continues to grow. Nuclear energy has not completely recovered from the crisis of the second half of the 1970's. This is in part because of social acceptance factors and hostility to large plants. World energy problems will continue over the next 20 years. A comprehensive approach is needed which stresses renewable energy and nuclear fission. 相似文献
29.
Umberto Iemma Fabio Pisi Vitagliano Francesco Centracchio 《International Journal of Sustainable Engineering》2017,10(3):147-157
The present work deals with a multi-objective optimisation approach to incorporate up-to-date financial models in the multidisciplinary conceptual design of a commercial aircraft. Design optimisations based on financial objective functions are compared to standard performance-based optimal solutions. The main novelty is in the extension of the financial models to the long-term investments of a wider group of stakeholders. The rationale underlying this research stems from two considerations: (i) the environmentally sustainable development of the air transportation system in the next 20 years is subordinate to breakthrough technologies, since the consolidated ones have reached their saturation point; (ii) the economic impacts of highly innovative concepts on the stakeholders chain is still uncertain. The problem is addressed at the conceptual design level and the analysis is performed within a comprehensive multidisciplinary framework, adopting all the technical constraints required in aeronautical design. The Pareto fronts obtained using performance and financial merit factors, reveal that the proposed financial model yields highly efficient, technically sound concepts. The design space point corresponding to the negative cash flows minimum turned out to be very close to the one corresponding to minimum acoustic emissions, confirming that the financial model drives the optimiser towards environment-friendly designs. 相似文献
30.
Climate Warming and the Recent Treeline Shift in the European Alps: The Role of Geomorphological Factors in High-Altitude Sites 总被引:1,自引:0,他引:1
Global warming and the stronger regional temperature trends recently recorded over the European Alps have triggered several
biological and physical dynamics in high-altitude environments. We defined the present treeline altitude in three valleys
of a region in the western Italian Alps and reconstructed the past treeline position for the last three centuries in a nearly
undisturbed site by means of a dendrochronological approach. We found that the treeline altitude in this region is mainly
controlled by human impacts and geomorphological factors. The reconstruction of the altitudinal dynamics at the study site
reveals that the treeline shifted upwards of 115 m over the period 1901–2000, reaching the altitude of 2505 m in 2000 and
2515 m in 2008. The recent treeline shift and the acceleration of tree colonization rates in the alpine belt can be mainly
ascribed to the climatic input. However, we point out the increasing role of geomorphological factors in controlling the future
treeline position and colonization patterns in high mountains. 相似文献