Analysis of emission characteristics of gas turbine engines with some alternative fuels

The paper concerns the comparative analysis of combustion characteristics of different alternative fuels such as Fischer-Tropsch Synthetic Paraffinic Kerosene (FT-SPK), cryogenic methane, bioethanol, biomethanol, biobutanol, dimethyl ether, biodiesel and conventional aviation kerosene Jet-A as well as analysis of emissions of NO_x, CO, CO₂, H₂O, HNO_y (y = 2,3) and organics for gas turbine engine operating on these fuels. The analysis has shown that the usage of all considered alternative fuels results in the increase of H₂O emission, compared to kerosene-fueled combustor, and, as consequence, in the growth of water vapor supersaturation that can increase the rate of the H₂O vapor condensation and enhance the formation of contrails and cirrus clouds in the atmosphere. The usage of all considered alternative fuels except FT-SPK, cryogenic methane and dimethyl can increase the CO₂ emission compared to using of kerosene. Emission of N-containing species can be reduced upon the usage of considered alternative fuels, except dimethyl ether, for which one can expect the increase in the emissions of HNO₂ and HNO₃ approximately by 10%. The emission of CO decreases for all fuels except biodiesel. The major decrease can be achieved upon the replacement of kerosene to bioethanol.     

埕东油田采油污水回用配聚处理工程实践

采用生物氧化去除还原性物质和生物竞争抑制硫酸还原菌的集成技术处理油田采油污水用于配制聚合物溶液。运行结果表明:采用处理后的采出水配制聚合物溶液,黏度达20 mPa.s以上,且长时间保持稳定,能够满足现场生产需求。     

Harmonised Investigation of the Occurrence of Human Enteric Viruses in the Leafy Green Vegetable Supply Chain in Three European Countries

Numerous outbreaks have been attributed to the consumption of raw or minimally processed leafy green vegetables contaminated with enteric viral pathogens. The aim of the present study was an integrated virological monitoring of the salad vegetables supply chain in Europe, from production, processing and point-of-sale. Samples were collected and analysed in Greece, Serbia and Poland, from ??general?? and ??ad hoc?? sampling points, which were perceived as critical points for virus contamination. General sampling points were identified through the analysis of background information questionnaires based on HACCP audit principles, and they were sampled during each sampling occasion where as-ad hoc sampling points were identified during food safety fact-finding visits and samples were only collected during the fact-finding visits. Human (hAdV) and porcine (pAdV) adenovirus, hepatitis A (HAV) and E (HEV) virus, norovirus GI and GII (NoV) and bovine polyomavirus (bPyV) were detected by means of real-time (RT-) PCR-based protocols. General samples were positive for hAdV, pAdV, HAV, HEV, NoV GI, NoV GII and bPyV at 20.09?% (134/667), 5.53?% (13/235), 1.32?% (4/304), 3.42?% (5/146), 2?% (6/299), 2.95?% (8/271) and 0.82?% (2/245), respectively. Ad hoc samples were positive for hAdV, pAdV, bPyV and NoV GI at 9?% (3/33), 9?% (2/22), 4.54?% (1/22) and 7.14?% (1/14), respectively. These results demonstrate the existence of viral contamination routes from human and animal sources to the salad vegetable supply chain and more specifically indicate the potential for public health risks due to the virus contamination of leafy green vegetables at primary production.     

Rapid sperm evolution in the bluethroat (Luscinia svecica) subspecies complex

Spermatozoa are among the most variable animal cell types, and much research is currently directed towards explaining inter- and intraspecific variation in sperm form and function. Recent comparative studies in passerine birds have found associations between the level of sperm competition and both sperm length and sperm velocity. In species with sperm competition, postcopulatory sexual selection may shape the morphology of sperm as adaptations to the female environment. The speed of evolutionary change in sperm morphology at the species level is largely unknown. In this study, we analysed variation in sperm morphology among morphologically distinct and geographically isolated bluethroat subspecies in Europe. Consistent with previous studies, our analyses of mtDNA and nuclear introns suggest recent divergence and lack of lineage sorting among the subspecies. We found significant divergence in total sperm length and in the length of some sperm components (i.e. head and midpiece). There was a significantly positive relationship between pairwise divergences in sperm morphology and mitochondrial DNA, suggesting a role for genetic drift in sperm divergence. The magnitude of sperm length divergence was considerably higher than that in other geographically structured passerines, and even higher than that observed between several pairs of sister species. We hypothesize that the rapid sperm evolution in bluethroats is driven by sperm competition, and that strong postcopulatory sexual selection on sperm traits can lead to rapid speciation through reproductive incompatibilities.     

Larval ecology of the great barracuda, <Emphasis Type="Italic">Sphyraena barracuda</Emphasis>, and other sphyraenids in the Straits of Florida

The great barracuda (Sphyraena barracuda) is a widespread, ecologically and socioeconomically important coastal fish, yet very little is known about its larvae. We examined spawning and larval ecology of Western Atlantic sphyraenids using monthly ichthyoplankton samples collected over 2 years along a transect spanning the east–west axis of the Straits of Florida (SOF). Samples were dominated by the great barracuda (92.8%) and sennets (Sphyraena borealis and Sphyraena picudilla; 6.6%). While larval sennets and S. barracuda displayed similar vertical distributions (majority in upper 25 m), horizontal and temporal patterns of abundance suggested a spatial and temporal species replacement between larval S. barracuda and sennets that tracks adult ecology. The diet of both taxa consisted largely of copepods, with inclusion of fish larvae at 8 mm SL, and in S. barracuda alone, a switch in the wet season to exclusive piscivory by 12 mm SL (18 days post-hatch). A lack of piscivory in S. barracuda larvae captured in the dry season corresponded to slower larval growth than in the wet season. Larval growth was also related to size-at-hatch and larval age such that larvae that were larger at hatch or larger (older) at capture grew faster at earlier ages, suggesting faster larval growth, and indirectly larger hatch size, conveys a survival advantage. Unlike larval growth, instantaneous mortality rate did not differ with season, and no lunar cyclic patterns in spawning output were identified. Our results provide insight into the pelagic phase of sphyraenids and highlight the importance of both diet and hatch size to the growth and survival of fish larvae in low latitude oceanic environments.     

A Chemical Mass Balance for Volatile Organics in Chicago

Increasing attention to the presence of atmospheric volatile organic compounds has focused interest on the sources and fate of organics in ambient air. The purpose of this study was to develop a chemical mass balance receptor model (CMB) to determine the contributions of major organic pollution source types to ambient pollution levels. Twenty mid-day ambient air samples were analyzed for the presence of volatile hydrocarbons by gas chromatographlc procedures. Based on these measurements, contributions from vehicles, gasoline vapor emissions, and petroleum refineries to ambient organic concentrations were estimated. For the receptor site studied, vehicles were the dominant source type and accounted for 60.8 percent of the organics evaluated. Contributions from refineries, gasoline vapor, and all other sources were 10.1, 11.1, and 17.9 percent, respectively. Validation of the predictions showed that the model is sensitive to the effect of overall upwind emissions. The CMB model was shown to produce reasonable predictive results for vehicles, gasoline vapor, and refinery contributions to ambient non-methane organic concentrations.     

Assessment of occupational and environmental safety associated with medical waste disposal in developing countries: A qualitative approach

A carefully designed survey of medical waste management was undertaken in Dhaka, the capital city of Bangladesh. A range of sampling strategies and data gathering techniques were used. The data gathering techniques included observation, formal structured interview and informal dialogue. Sampling strategies included formal representative sampling for fixed populations and adaptive sampling for roaming populations was developed. Data were collected from healthcare establishments (HCEs) and other waste disposal operatives.Operatives dealing with waste were frequently found to be untrained, and without even a basic understanding of the hazards involved. Personal protective equipment was inadequate in most cases which led to frequent accidental injuries. No HCE was found to have adequate storage facilities for hazardous waste. Thus scavengers were able to gain access to items such as syringes and expired medicines, which they repackaged and resold. The lack of correctly controlled internal storage may be linked to the observation that employees at many HCEs offered contaminated items for sale to scavengers and recycling operatives. In many cases there was no attempt at segregation, but in some cases there was segregation at the point of use, but subsequent remixing with general waste, indicating a lack of management and education rather than a lack of will. In either case, hazardous waste was dumped in city corporation bins, and disposed of on general landfill sites. As well as exposing the waste to scavengers, this could potentially contaminate ground water, especially as the dumps were located in areas subject to frequent flooding.