排序方式: 共有19条查询结果,搜索用时 671 毫秒
1.
Georgios Fontaras Georgios Karavalakis Panayotis Pistikopoulos Evangelos Bakeas Zissis Samaras 《Environmental pollution (Barking, Essex : 1987)》2010,158(5):1451-10343
Five biodiesels from different feedstocks (rapeseed, soy, sunflower, palm, and used fried oils) blended with diesel at 10% vol. ratio (B10), were tested on a Euro 3 common-rail passenger car. Limited effects (−2% to +4%) were observed on CO2 emissions. CO and HC emissions increased between 10% and 25% on average, except at high speed - high power where emissions were too low to draw conclusions. NOx emissions increased by up to 20% for two out of the five blends, decreased by up to 15% for two other blends, and remained unchanged for one blend. Particulate matter (PM) was reduced for all blends by up to 25% and the reductions were positively correlated with the extent of biodiesel saturation. PM reductions are associated with consistent reductions in non-volatile particle number. A variable behaviour in particle number is observed when volatile particles are also accounted. 相似文献
2.
Elias Vouitsis Leonidas Ntziachristos Panayiotis Pistikopoulos Zissis Samaras Loukia Chrysikou Constantini Samara Chrysi Papadimitriou Petros Samaras George Sakellaropoulos 《Environmental pollution (Barking, Essex : 1987)》2009,157(8-9):2320-2327
Particulate matter (PM) emitted from three light-duty vehicles was studied in terms of its physicochemical and ecotoxicological character using Microtox® bioassay tests. A diesel vehicle equipped with an oxidation catalyst emitted PM which consisted of carbon species at over 97%. PM from a diesel vehicle with a particle filter (DPF) consisted of almost equal amounts of carbon species and ions, while a gasoline vehicle emitted PM consisting of ~90% carbon and ~10% ions. Both the DPF and the gasoline vehicles produced a distinct nucleation mode at 120 km/h. The PM emitted from the DPF and the gasoline vehicles was less ecotoxic than that of conventional diesel, but not in direct proportion to the emission levels of the different vehicles. These results indicate that PM emission reductions are not equally translated into ecotoxicity reductions, implying some deficiencies on the actual environmental impact of emission control technologies and regulations. 相似文献
3.
PCDD/F inhibition by prior addition of urea to the solid fuel in laboratory experiments and results statistical evaluation 总被引:2,自引:0,他引:2
The objectives of this work were to study the effect of urea addition to the fuel before the combustion on the suppression of PCDD/F emissions, to examine the influence of urea to PCDD/F isomer patterns by employing statistical analysis techniques and to determine the most effective method of urea addition. Urea in the form of powder and as an aqueous solution was mixed with RDF and the fuel mixtures were incinerated in a lab-scale reactor at 1000 degrees C. PCDD/F emitted during combustion experiments were collected in a quartz wool filter downstream the reactor unit. Analysis and quantification of PCDD/F showed that urea significantly affected PCDD/F emissions. Combustion of RDF containing 10% w/w urea resulted in PCDD/F emissions lower than 8 I-TEQ ng/g RDF, while the corresponding average value from single RDF combustion was 17 I-TEQ ng/g RDF. The PCDD/F prevention capacity of urea was independent from the method of urea addition to the fuel, as similar results were obtained after the addition of urea in the solid and in the aqueous phases. Results assessment by statistical methods showed that isomer patterns remained almost stable and were not affected by the method of urea addition. 相似文献
4.
Olga S. Arvaniti Marilena E. Dasenaki Alexandros G. Asimakopoulos Niki C. Maragou Vasilios G. Samaras Korina Antoniou Georgia Gatidou Daniel Mamais Constantinos Noutsopoulos Zacharias Frontistis Nikolaos S. Thomaidis Athanasios S. Stasinakis 《Frontiers of Environmental Science & Engineering》2022,16(11):148
5.
Coagulation-flocculation pretreatment of sanitary landfill leachates 总被引:15,自引:0,他引:15
Sanitary landfill leachates are considered as heavily polluted industrial wastewaters, presenting significant time and spatial variations of their physical-chemical parameters. Special care is required for their efficient treatment and disposal. The main aim of this work was to examine the application of coagulation-flocculation for the treatment of raw and partially stabilized leachates. Jar-test experiments were employed in order to determine the optimum conditions for the removal of organic matter and color, i.e. coagulant-flocculant combination, effective dosage and pH control. Ferric chloride, aluminium sulphate and lime were tested as conventional coagulants, whereas four commercial polyelectrolytes were co-examined: one anionic, two cationic and a non-ionic polymer. High chemical oxygen demand (COD) removal capacities (about 80%) were obtained during the addition of ferric chloride to the partially stabilized leachates, whereas low COD reductions (i.e. lower than 35%) were measured during the addition of coagulants in the raw samples. The addition of polyelectrolytes and pH adjustment in the alkaline region were found to affect slightly the removal of pollutants. The physico-chemical process may be used as a useful pretreatment step, especially for fresh leachates, prior to biological treatment, or as a post-treatment (polishing) step for partially stabilized leachates. 相似文献
6.
Kyle Meisterling Constantine Samaras Vanessa Schweizer 《Journal of Cleaner Production》2009,17(2):222-230
A streamlined hybrid life cycle assessment is conducted to compare the global warming potential (GWP) and primary energy use of conventional and organic wheat production and delivery in the US. Impact differences from agricultural inputs, grain farming, and transport processes are estimated. The GWP of a 1 kg loaf of organic wheat bread is about 30 g CO2-eq less than the conventional loaf. When organic wheat is shipped 420 km farther to market, organic and conventional wheat systems have similar impacts. These results can change dramatically depending on soil carbon accumulation and nitrous oxide emissions from the two systems. Key parameters and their variability are discussed to provide producers, wholesale and retail consumers, and policymakers metrics to align their decisions with low-carbon objectives. 相似文献
7.
Kungolos A. Hadjispyrou S. Petala M. Tsiridis V. Samaras P. Sakellaropoulos G. P. 《Water, Air, & Soil Pollution: Focus》2004,4(4-5):101-110
In the present study toxicity tests were performed in order to determine the toxic properties of four organotin compounds and three heavy metals and to examine the interactive effects of binary metal mixtures on two different test species: the freshwater crustacean Daphnia magna and the marine bacterium Vibrio fischeri. D. magna proved to be more sensitive to metals than V. fischeri. Tributyltin chloride and copper were found to be the most toxic substances on both test organisms. The interactive effects between trimethyltin chloride/copper and trimethyltin/chromium on both test species were investigated and synergistic, additive and antagonistic actions were observed. 相似文献
8.
Z Samaras T Zachariadis R Joumard D Hassel F J Weber R Rijkeboer 《Journal of the Air & Waste Management Association (1995)》2001,51(6):913-938
This paper provides an overview and the main results of a study aiming to evaluate current and alternative inspection and maintenance (I/M) programs to control emissions from in-use cars in Europe. For this purpose, a large number of passenger cars from five countries (France, Germany, Greece, the Netherlands, and the United Kingdom) were tested according to a common test protocol that included a variety of driving cycles and short tests, both legislative and specifically developed for this exercise. Evaluation of all test results was conducted with the objective of defining effective I/M test procedures and examining the potential of periodic I/M programs to reduce pollutant emissions and improve fuel economy of in-use cars. The results indicate that the current idle test used for catalyst-equipped cars in Europe is probably ineffective, while short transient loaded testing was found to offer higher potential in environmental terms. Regarding conventional gasoline cars, it is concluded that the idle test is sufficient, provided that the CO cut point is reduced and an HC test is added at high idle. Finally, the effectiveness of the free acceleration smoke test for diesels is questioned, while a transient cycle with continuous opacity measurement was found to be very promising. A companion paper further uses these results to analyze the likely cost-effectiveness on a per-country basis and discusses the possible effect of maintenance on emissions. 相似文献
9.
Ntziachristos L Samaras Z 《Journal of the Air & Waste Management Association (1995)》2010,60(10):1223-1236
This paper presents the measurement of airborne particle properties with use of a dedicated sampling protocol and a measurement setup directly installed in the exhaust line of vehicles and engines. The sampling system dilutes a small part of the exhaust directly at the tailpipe without the need of exhaust gas transfer lines that may lead to sampling artifacts. Dilution takes place in two steps with a primary dilution ratio universally set at a value of 12.5:1 for all vehicles and engines tested, and subsequent dilution steps reducing particle concentration within the measuring range of the instruments used. Dilution air temperature and residence time were set at 32 degrees C and 2.5 sec respectively, to allow repeatable measurement of nucleation-mode particles. The paper summarizes the specifications of the system, evaluates its performance in comparison to real-world dilution (chasing experiments), and presents the repeatability and reproducibility of measurements performed in different laboratories. In general, after taking precautions for the setup and condition of instruments, both measurement quality indices reached levels similar to the measurement of particulate matter (PM) mass. Application of the system, using the same protocol, to measure many light-duty vehicles and engines is finally demonstrated, providing useful conclusions for the emission performance of different sized engines. The study concludes that the use of partial-flow sampling systems may offer advantages for the measurement of particle emissions from low-emission engines compared with constant volume sampling facilities, including lower cost of purchase and operation, versatility, lack of artifacts, and possibilities for standardization in different environments. 相似文献
10.
Occurrence of endocrine disrupters and selected pharmaceuticals in Aisonas River (Greece) and environmental risk assessment using hazard indexes 总被引:1,自引:0,他引:1
Stasinakis AS Mermigka S Samaras VG Farmaki E Thomaidis NS 《Environmental science and pollution research international》2012,19(5):1574-1583