Natural attenuation, biostimulation and bioaugmentation on biodegradation of polycyclic aromatic hydrocarbons (PAHs) in mangrove sediments   总被引：6，自引：0，他引：6  

Yu KS  Wong AH  Yau KW  Wong YS  Tam NF 《Marine pollution bulletin》2005,51(8-12):1071-1077

The biodegradability of a mixture of PAHs, namely fluorene (Fl), phenanthrene (Phe) and pyrene (Pyr), in mangrove sediment slurry was investigated. At the end of week 4, natural attenuation based on the presence of autochthonous microorganisms degraded more than 99% Fl and Phe but only around 30% of Pyr were degraded. Biostimulation with addition of mineral salt medium degraded over 97% of all three PAHs, showing that nutrient amendment could enhance Pyr degradation. Bioaugmentation with inoculation of a PAH-degrading bacterial consortium enriched from mangrove sediments did not show any promotion effect and the degradation percentages of three PAHs were similar to that by natural attenuation. Some inhibitory effect was observed in bioaugmentation treatment in week 1 with only 50% Fl and 70% Phe degraded. These results indicate that autochthonous microbes may interact and even compete with the enriched consortium during PAH biodegradation. Natural attenuation appeared to be the most appropriate way to remedy Fl- and Phe-contaminated mangrove sediments while biostimulation was more capable to degrade Pyr-contaminated sediments. The study also shows that although a large portion of the added PAHs (more than 95%) was adsorbed onto the sediments at the beginning of the experiment, most PAHs were degraded in 4 weeks, suggesting that the degraders could utilize the adsorbed PAHs efficiently.  相似文献   

Seismic ground motion relationship in southern China based on stochastic finite-fault model   总被引：1，自引：0，他引：1  

郑斯华  黄玉龙 《地震工程与工程振动(英文版)》2004,3(1):11-21

The characteristics of seismic ground motions in southern China are difficult to determine statistically due to a lack of strong ground motion data. In this study, a stochastic finite-fault ground motion model was adopted to simulate the seismic ground motions at bedrock for southern China, based on parameters derived from small and medium earthquakes that have occurred in the region. From these, the response spectra was estimated. A set of ground motion attenuation relations hipswas then developed based on simulated peak ground motions and response spectral parameters through regression, which would be applicable for use in engineering practice. Through comparisons, it was demonstrated that the proposed ground motion relationships are generally consistent with those obtained from other reported ground motion attenuation models for southern China.  相似文献   

Evaluation of methods of spatial interpolation for monthly rainfall data over the state of Rio de Janeiro,Brazil     

Gustavo?Bastos?Lyra  Tamíres?Partelli?Correia  José?Francisco?de?Oliveira-Júnior  Marcelo?ZeriEmail authorView author&#;s OrcID profile 《Theoretical and Applied Climatology》2018,134(3-4):955-965

Five deterministic methods of spatial interpolation of monthly rainfall were compared over the state of Rio de Janeiro, southeast Brazil. The methods were the inverse distance weight (IDW), nearest neighbor (NRN), triangulation with linear interpolation (TLI), natural neighbor (NN), and spline tension (SPT). A set of 110 weather stations was used to test the methods. The selection of stations had two criteria: time series longer than 20 years and period of data from 1960 to 2009. The methods were evaluated using cross-validation, linear regression between values observed and interpolated, root mean square error (RMSE), coefficient of determination (r ²), coefficient of variation (CV, %), and the Willmott index of agreement (d). The results from different methods are influenced by the meteorological systems and their seasonality, as well as by the interaction with the topography. The methods presented higher precision (r ²) and accuracy (d, RMSE) during the summer and transition to autumn, in comparison with the winter or spring months. The SPT had the highest precision and accuracy in relation to other methods, in addition to having a good representation of the spatial patterns expected for rainfall over the complex terrain of the state and its high spatial variability.  相似文献   

Generation of a stochastic precipitation model for the tropical climate     

Ng  Jing Lin  Abd Aziz  Samsuzana  Huang  Yuk Feng  Wayayok  Aimrun  Rowshon  MK 《Theoretical and Applied Climatology》2018,133(1-2):489-509

Theoretical and Applied Climatology - A tropical country like Malaysia is characterized by intense localized precipitation with temperatures remaining relatively constant throughout the year. A...  相似文献   

Model for multiblock columns subjected to base excitation          下载免费PDF全文

Tamás Ther  László P. Kollár 《地震工程与结构动力学》2018,47(2):418-437

A new model is presented for multiblock columns subjected to earthquakes, which contains an impact and an opening model. Both in the impact and in the opening model, all the possible opening configurations are investigated because it was found that in many practical cases, unexpected patterns may occur. The model is purely mechanical: assuming rigid blocks and classical (inelastic) impact. The effect of energy dissipation during impact was investigated. Using our model in accordance with the literature, it was found that monolithic blocks are more vulnerable to overturning than multiblock systems.  相似文献   

On the breakdown of zircon upon “dry” thermal annealing     

Tamás Váczi  Lutz Nasdala  Richard Wirth  Mathias Mehofer  Eugen Libowitzky  Tobias Häger 《Mineralogy and Petrology》2009,97(1-2):129-138

Zircon samples without and with secondary chemical alteration from diverse sources were subjected to heat treatment at 1400 °C for 96 h. Resulting new phases and textures suggest that decomposition of zircon into component oxides occurred in all experiments to various degrees. The crucible material was found to have a strong influence on the extent of breakdown, especially in the case of altered starting materials. In this study the progressive stages of the breakdown of zircon grains are described. The factors that may govern the decomposition are discussed, including radiation damage, secondary alteration and external reaction conditions (sample container, atmosphere). Alumina crucibles should generally be avoided in dry annealing of zircon, to minimise uncontrolled breakdown into oxides.  相似文献   

Fitting the integrated spectral energy distributions of galaxies     

Jakob Walcher  Brent Groves  Tamás Budavári  Daniel Dale 《Astrophysics and Space Science》2011,331(1):1-51

Fitting the spectral energy distributions (SEDs) of galaxies is an almost universally used technique that has matured significantly in the last decade. Model predictions and fitting procedures have improved significantly over this time, attempting to keep up with the vastly increased volume and quality of available data. We review here the field of SED fitting, describing the modelling of ultraviolet to infrared galaxy SEDs, the creation of multiwavelength data sets, and the methods used to fit model SEDs to observed galaxy data sets. We touch upon the achievements and challenges in the major ingredients of SED fitting, with a special emphasis on describing the interplay between the quality of the available data, the quality of the available models, and the best fitting technique to use in order to obtain a realistic measurement as well as realistic uncertainties. We conclude that SED fitting can be used effectively to derive a range of physical properties of galaxies, such as redshift, stellar masses, star formation rates, dust masses, and metallicities, with care taken not to over-interpret the available data. Yet there still exist many issues such as estimating the age of the oldest stars in a galaxy, finer details of dust properties and dust-star geometry, and the influences of poorly understood, luminous stellar types and phases. The challenge for the coming years will be to improve both the models and the observational data sets to resolve these uncertainties. The present review will be made available on an interactive, moderated web page (), where the community can access and change the text. The intention is to expand the text and keep it up to date over the coming years.  相似文献   

Effect of Wind and Rainfall on Water Exchange in a Stratified Estuary     

Jin-Hee Yuk  Shin-ichi Aoki 《Estuaries and Coasts》2009,32(1):88-99

This study was conducted to estimate the horizontal and vertical exchange of water in response to meteorological effects in Inohana Lake, Japan. To examine the horizontal water flow between Hamana and Inohana Lakes while monitoring horizontal and vertical exchanges of water within the lake, we determined the current velocity, salinity, and water density in the field. We performed regression analysis of the relationship between meteorological factors such as wind and rain and the horizontal water flow between the two lakes. This information was then used to construct a simple box model to estimate the average water exchange and evaluate the meteorological effect based on the average salinity and river discharge. These results revealed that the surface water-volume flux in the channel was heavily influenced by the north–south wind intensity. These findings indicate that a box model is capable of providing a good estimate of the summer-averaged water flow and the exchange rate that is influenced by wind and rain.  相似文献   

An Overview of Thunderstorm-Related Research on the Atmospheric Electric Field, Schumann Resonances, Sprites, and the Ionosphere at Sopron, Hungary     

Gabriella Sátori  Michael Rycroft  Pál Bencze  Ferenc Märcz  József Bór  Veronika Barta  Tamás Nagy  Károly Kovács 《Surveys in Geophysics》2013,34(3):255-292

This paper gives a resume of the papers written in English which (a) describe some of the recording instruments in use at the Nagycenk Observatory (NCK) since the International Geophysical Year (IGY 1957–1958) and up to the present time, (b) summarise the most important and different types of observations associated with thunderstorms which have been made there, and (c) discuss their various geophysical interpretations. The paper describes the main results which have been obtained in four areas of thunderstorm associated atmospheric and geospace science within the context of Earth system science. These relate to the following parameters of atmospheric electricity: the vertical electric potential gradient just above the Earth’s surface and the air–Earth current as well as the point discharge current, Schumann resonance (SR) signals of the Earth-ionosphere cavity at 8, 14 and 20 Hz, transient luminous events (TLEs), and some aspects of the behaviour of the ionosphere. Deductions from these data sets are concerned with the global lightning activity and the conductivity of the air, with diurnal, seasonal, annual and long-term variations of the SR amplitudes and resonant frequencies in terms of migrating thunderstorm centres, with transient SR excitations and with sprites and other TLEs, and with ionospheric disturbances. The paper closes with some thoughts on future research directions based on the observations at NCK and Sopron and the results achieved since the IGY.  相似文献   

Comparison of models calculating the sky view factor used for urban climate investigations     

Martin H?mmerle  Tam��s G��l  J��nos Unger  Andreas Matzarakis 《Theoretical and Applied Climatology》2011,105(3-4):521-527

The sky view factor (SVF) describes the surface geometry and is a commonly used and important measure in urban climate investigations whose aim is the exploration of effects of a complex urban surface on climatological processes in built-up areas. A selection of methods and models for calculating the SVF was compared. For this purpose, fish eye images were taken at several locations in the city of Szeged, southern Hungary. The fish eye images equidistantly follow linear transects to cover a range of SVF values and to analyze the reaction of the methods to a continuously changing environment. The fish eye pictures were evaluated by three methods: the method according to Steyn (Atmos-Ocean 18(3):245?C258, 1980) implemented in a GIS-Script, the ??Edit free sky view factor?? tool of the RayMan model and BMSkyView. The SVF values at the coordinates of the fish eye pictures were calculated with three numerical models (SkyHelios, ArcView SVF extension, and SOLWEIG) with a 3D building data base as input. After comparing the results of the first run, a deviation occurs. The deviation disappears after implementing an option to include a weighting factor in some of the models.  相似文献