排序方式： 共有22条查询结果，搜索用时 281 毫秒
11.
Diisopropanolamine Biodegradation Potential at Sour Gas Plants 总被引：1，自引：0，他引：1
Lisa M. Gieg E. Anne Greene Debora L. Coy Phillip M. Fedorak 《Ground Water Monitoring & Remediation》1998,18(3):158-173
The potential for aerobic and anaerobic biodegradation of a sour gas treatment chemical, diisopropanolamine (DIPA), was studied using contaminated aquifer materials from three sour gas treatment sites in western Canada. DIPA was found to be readily consumed under aerobic conditions at 8°C and 28°C in shake flask cultures incubated with aquifer material from each of the sites, and this removal was characterized by first-order kinetics. In addition, DIPA biodegradation was found to occur under nitrate-, Min(IV)., and Fe(III)-reducing conditions at 28°C, and in some cases at 8°C, in laboratory microcosms, DIPA loss corresponded to consumption of nitrate, and production of Mn(II) and Fe(II) in viable microcosms compared to corresponding sterile controls. A threshold DIPA concentration near 40 mg/L was observed in the anaerobic microcosms. This report provides the first evidence that DIPA is biodegraded under anaerobic conditions, and our data suggest that biodegradation may contribute to DIPA attenuation under aerobic and anaerobic conditions in aquifers contaminated with this sour gas treatment chemical. 相似文献
12.
We analyse a hydrodynamical simulation model for the recurrent heating of the central intra-cluster medium (ICM) by active galactic nuclei (AGN). Besides the self-gravity of the dark matter and gas components, our approach includes the radiative cooling and photoheating of the gas, as well as a subresolution multiphase model for star formation and supernova feedback. Additionally, we incorporate a periodic heating mechanism in the form of hot, buoyant bubbles, injected into the intragalactic medium (IGM) during the active phases of the accreting central AGN. We use simulations of isolated cluster haloes of different masses to study the bubble dynamics and heat transport into the IGM. We also apply our model to self-consistent cosmological simulations of the formation of galaxy clusters with a range of masses. Our numerical schemes explore a variety of different assumptions for the spatial configuration of AGN-driven bubbles, for their duty cycles and for the energy injection mechanism, in order to obtain better constraints on the underlying physical picture. We argue that AGN heating can substantially affect the properties of both the stellar and gaseous components of clusters of galaxies. Most importantly, it alters the properties of the central dominant (cD) galaxy by reducing the mass deposition rate of freshly cooled gas out of the ICM, thereby offering an energetically plausible solution to the cooling-flow problem. At the same time, this leads to reduced or eliminated star formation in the central cD galaxy, giving it red stellar colours as observed. 相似文献
13.
Christian Ferrarin Andrea Cucco Georg Umgiesser Debora Bellafiore Carl L. Amos 《Continental Shelf Research》2010
To describe the exchange of water and sediment through the Venice Lagoon inlets a 3-D hydrodynamic and sediment transport model has been developed and applied to a domain comprising Venice Lagoon and a part of the Adriatic Sea. The model has been validated for both current velocities and suspended particle concentration against direct observations and from observations empirically derived fluxes from upward-looking acoustic Doppler current profiler probes installed inside each inlet. The model provides estimates of the suspended sediment transport in the lower 3 m of the water column that is not detected by acoustic Doppler current profiler sensors. The bedload model prediction has been validated against measured sand transport rates collected by sand traps deployed in the Lido and Chioggia inlets. Results indicate that, in the Lido inlet, 87% of the total load is in suspension, while the rest moves as bedload. 相似文献
14.
Debora Bellafiore Edoardo Bucchignani Silvio Gualdi Sandro Carniel Vladimir Djurdjević Georg Umgiesser 《Ocean Dynamics》2012,62(4):555-568
Modeling studies of future changes in coastal hydrodynamics, in terms of storm surges and wave climate, need appropriate wind
and atmospheric forcings, a necessary requirement for the realistic reproduction of the statistics and the resolution of small
scale features. This work compares meteorological results from different climate models in the Mediterranean area, with a
focus on the Adriatic Sea, in order to assess their capability to reproduce coastal meteorological features and their possibility
to be used as forcings for hydrodynamic simulations. Five meteorological datasets are considered. They are obtained from two
regional climate models, implemented with different spatial resolutions and setups and are downscaled from two different global
climate models. Wind and atmospheric pressure fields are compared with measurements at four stations along the Italian Adriatic
coast. The analysis is carried out both on simulations of the control period 1960–1990 and on the A1B Intergovernmental Panel
for Climate Change scenario projections (2070–2100), highlighting the ability of each model in reproducing the statistical
coastal meteorological behavior and possible changes. The importance of simulated global- and regional-scale meteorological
processes, in terms of correct spatial resolution of the phenomena, is also discussed. Within the Adriatic Sea, the meteorological
climate is influenced by the local orography that controls the strengthening of north-eastern katabatic winds like Bora. Results
show indeed that the increase in spatial resolution provides a more realistic wind forcing for the hydrodynamic simulations.
Moreover, the chosen setup and the global climate models that drive the regional downscalings appear to play an important
role in reproducing correct atmospheric pressure fields. The comparison between scenario and control simulations shows a small
increase in the mean atmospheric pressure values, while a decrease in mean wind speed and in extreme wind events is observed,
particularly for the datasets with higher spatial resolution. Finally, results suggest that an ensemble of downscaled climate
models is likely to provide the most suitable climatic forcings (wind and atmospheric pressure fields) for coastal hydrodynamic
modeling. 相似文献
15.
The aromatic fraction from crude oil has a substantial solubility in water and as a result makes up the major hydrocarbon components of processed ballast water.1,2 The purpose of this study was to investigate the metabolism of several of the major components of this processed water by Chinook salmon, Oncorynchus tschawytscha, liver microsomes. The metabolic products of toluene and ethylbenzene in this microsomal system, as determined by gas chromatography-mass spectrometry, were benzyl alcohol and 1-phenylethanol, respectively. The conditions for the microsomal incubations were 20°C, pH 7·5, and an ionic strength of 0·126. A linear rate of benzyl alcohol and 1-phenylethanol formation is observed during the first 30 to 60 min followed by a decrease in the rate between 60 and 90 min. 相似文献
16.
Christian Ferrarin Georg Umgiesser Marco Bajo Debora Bellafiore Francesca De Pascalis Michol Ghezzo Giorgio Mattassi Isabella Scroccaro 《Estuarine, Coastal and Shelf Science》2010
The hydraulic regime-based zonation scheme of the Lagoons of Marano and Grado (Italy) has been derived by means of numerical models. A finite element modelling system has been used to describe the water circulation taking in account different forces such as tide, wind and rivers. The model has been validated by comparing the simulation results against measured water levels, salinity and water temperature data collected in several stations inside the lagoons. The analysis of water circulation, salinity and spatial distribution of passive tracers released at the inlets, led to a physically-based division of the lagoons system into six subbasins. The derived classification scheme is of crucial value for understanding the renewal capacity and pollutants distribution patterns in the lagoon. 相似文献
17.
18.
Debora B. Thompson 《Ground water》1987,25(2):212-212
Abstract. Single-well tests based on the rate of water-level recovery after raising or lowering the water level in a well have long been used as a quirk and simple method of obtaining order-of-magnitude estimates of hydraulic conductivity. The BASICS program presented allows for the rapid interpretation of these tests for most field situations. 相似文献
19.
The seismic inversion problem is a highly non‐linear problem that can be reduced to the minimization of the least‐squares criterion between the observed and the modelled data. It has been solved using different classical optimization strategies that require a monotone descent of the objective function. We propose solving the full‐waveform inversion problem using the non‐monotone spectral projected gradient method: a low‐cost and low‐storage optimization technique that maintains the velocity values in a feasible convex region by frequently projecting them on this convex set. The new methodology uses the gradient direction with a particular spectral step length that allows the objective function to increase at some iterations, guarantees convergence to a stationary point starting from any initial iterate, and greatly speeds up the convergence of gradient methods. We combine the new optimization scheme as a solver of the full‐waveform inversion with a multiscale approach and apply it to a modified version of the Marmousi data set. The results of this application show that the proposed method performs better than the classical gradient method by reducing the number of function evaluations and the residual values. 相似文献
20.