Humic Acids Copper Binding Following Their Photochemical Alteration by Simulated Solar Light     

Roza Vidali  Emmanouela Remoundaki  Marios Tsezos 《Aquatic Geochemistry》2010,16(1):207-218

Humic substances exposed to solar light play the role of photosensitizers in aquatic photochemical processes, generating free radicals during UV and visible light irradiation. During irradiation, high molecular weight structures are destroyed and low molecular weight constituents are formed. Alterations of the humic acids metal binding capacity due to their photochemical alterations occur. The present work reports controlled laboratory experimental results on the binding of copper by a certified purified peat humic acid (PPHA) before and after irradiation in a laboratory scale photoreactor. A reference curve of copper binding by photochemically unaltered humic acid was experimentally determined as a function of solution pH by potentiometric titrations. The experimental data series correspond to a pH range from 3 to 8.5, necessary for the simultaneous consideration of complexation and metal species solubility contribution in the obtained results. From the experimental results, it was apparent that copper is strongly bound by humic acid even at the acidic range of pH where the percentage of copper bound reached 60 and 95% at pH values of 3.5 and 5.5, respectively. During 12 and 20 days of irradiation experiments, humic acid photoalteration was experimentally monitored by a size exclusion chromatography system (HPLC-SEC). From the potentiometric titrations of the irradiated humic acid solutions by a copper selective electrode, it was apparent that the copper binding capacity of photoaltered humic acid solutions was significantly reduced for pH values up to 6.  相似文献   

Tidal mass loss from collisionless systems     

Marios Kampakoglou  Andrew J. Benson † 《Monthly notices of the Royal Astronomical Society》2007,374(3):775-786

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Disc galaxy evolution along the Hubble sequence     

Marios Kampakoglou  Joseph Silk 《Monthly notices of the Royal Astronomical Society》2007,380(2):646-656

Galaxy discs are characterized by star formation histories that vary systematically along the Hubble sequence. We study global star formation, incorporating supernova feedback, gas accretion and enriched outflows in discs modelled by a multiphase interstellar medium in a fixed gravitational potential. The star formation histories, gas distributions and chemical evolution can be explained in a simple sequence of models which are primarily regulated by the cold gas accretion history.  相似文献   

"The water budget myth revisited: why hydrogeologists model," by John D. Bredehoeft, July-August 2002 issue, v. 40, no. 4: 340-345     

Sophocleous M 《Ground water》2004,42(4):618-618

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Book Review: Hydrology for Engineers, Geologists and Environmental Professionals By Sergio E. Serrano, Hydroscience Inc., Lexington, Kentucky, 1997, 452 p., $75.00, ISBN 0-9655643-9-8     

Marios Sophocleous 《Mathematical Geology》1998,30(7):935-936

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Seismic response of slender rigid structures with foundation uplifting   总被引：2，自引：0，他引：2  

Marios Apostolou  George Gazetas  Evangelia Garini 《Soil Dynamics and Earthquake Engineering》2007,27(7):642-654

The rocking of rigid structures uplifting from their support under strong earthquake shaking is investigated. The structure is resting on the surface of either a rigid base or a linearly elastic continuum. A large-displacement approach is adopted to extract the governing equations of motion allowing for a rigorous calculation of the nonlinear response even under near-overturning conditions. Directivity-affected near-fault ground motions, idealized as Ricker wavelets or trigonometric pulses, are used as excitation. The conditions under which uplifting leads to large angles of rotation and eventually to overturning are investigated. A profoundly nonlinear rocking behavior is revealed for both rigid and elastic soil conditions. This geometrically nonlinear response is further amplified by unfavorable sequences of long-duration pulses in the excitation. Moreover, through the overturning response of a toppled tombstone, it is concluded that the practice of estimating ground accelerations from overturning observations is rather misleading and meaningless.  相似文献   

    

J. F. Devlin  Marios Sophocleous 《Hydrogeology Journal》2006,14(7):1386

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Assessment of porous aquifer hydrogeological parameters using automated groundwater level measurements in Greece          下载免费PDF全文

Kirlas Marios C 《地下水科学与工程》2021,9(4):269-278

In this paper, the hydrogeological parameters of a confined aquifer, such as transmissivity (T), storativity (S) and radius of influence (R), have been assessed using real groundwater level measurements recorded by a monitoring network, consisting of automated municipal water supply boreholes at Nea Moudania aquifer, Chalkidiki, Greece. Particularly, the paper focused on the correlation between the drawdown and the constant flow rate during pumping time. So the Cooper-Jacob and the recovery test method were applied in order to delineate if turbulent head losses occur, as well as the impact of incorrect measurements of the radial distance (r) in the accuracy of estimating S values. The results show that a) the occurrence of a linear correlation between s and Q indicates a negligible turbulent head loss in the pumping wells and thus a reasonable flow rate usage, b) the validity of storativity values could be compromised if the r value is not accurately measured, and c) recovery test method can be used as an indicator of residual drawdown (s’) caused by previous pumping cycles, when the straight line intersecting the logarithmic t/t’ axis has a value greater than 1.  相似文献   

Towards sustainable groundwater use: setting long-term goals, backcasting, and managing adaptively   总被引：7，自引：0，他引：7  

Gleeson T  Alley WM  Allen DM  Sophocleous MA  Zhou Y  Taniguchi M  VanderSteen J 《Ground water》2012,50(1):19-26

The sustainability of crucial earth resources, such as groundwater, is a critical issue. We consider groundwater sustainability a value-driven process of intra- and intergenerational equity that balances the environment, society, and economy. Synthesizing hydrogeological science and current sustainability concepts, we emphasize three sustainability approaches: setting multigenerational sustainability goals, backcasting, and managing adaptively. As most aquifer problems are long-term problems, we propose that multigenerational goals (50 to 100 years) for water quantity and quality that acknowledge the connections between groundwater, surface water, and ecosystems be set for many aquifers. The goals should be set by a watershed- or aquifer-based community in an inclusive and participatory manner. Policies for shorter time horizons should be developed by backcasting, and measures implemented through adaptive management to achieve the long-term goals. Two case histories illustrate the importance and complexity of a multigenerational perspective and adaptive management. These approaches could transform aquifer depletion and contamination to more sustainable groundwater use, providing groundwater for current and future generations while protecting ecological integrity and resilience.  相似文献   

On understanding and predicting groundwater response time   总被引：1，自引：0，他引：1  

Sophocleous M 《Ground water》2012,50(4):528-540

An aquifer system, when perturbed, has a tendency to evolve to a new equilibrium, a process that can take from just a few seconds to possibly millions of years. The time scale on which a system adjusts to a new equilibrium is often referred to as "response time" or "lag time." Because groundwater response time affects the physical and economic viability of various management options in a basin, natural resource managers are increasingly interested in incorporating it into policy. However, the processes of how groundwater responds to land-use change are not well understood, making it difficult to predict the timing of groundwater response to such change. The difficulty in estimating groundwater response time is further compounded because the data needed to quantify this process are not usually readily available. This article synthesizes disparate pieces of information on aquifer response times into a relatively brief but hopefully comprehensive review that the community of water professionals can use to better assess the impact of aquifer response time in future groundwater management investigations. A brief exposition on dimensional/scaling analysis is presented first, followed by an overview of aquifer response time for simplified aquifer systems. The aquifer response time is considered first from a water-quantity viewpoint and later expanded to incorporate groundwater age and water-quality aspects. Monitoring programs today, as well as water policies and regulations, should address this issue of aquifer response time so that more realistic management expectations can be reached.  相似文献