bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamic root uptake model for neutral lipophilic organics
Authors: Trapp Stefan 
Published: February 2010

AbstractIn current European risk assessment, an equilibrium approach is used to estimate chemical uptake from soil into root vegetables. Here a dynamic model for uptake of neutral lipophilic compounds from soil into roots is presented. Using experimental results, it is compared with the equilibrium approach. Very lipophilic compounds (e.g., DDT) diffuse very slowly into plant tissue, so they are likely to remain in the peel of root vegetables. In addition, a dynamic (steady-state) flux model for uptake with transpiration water into thick roots is presented. The model considers input from soil and output to stem with the transpiration stream plus first-order metabolism and dilution by exponential growth. For chemicals with low or intermediate lipophilicity (log KOW &lt; 2), there was no relevant difference between dynamic model and equilibrium approach. For lipophilic compounds, the dynamic model gave concentrations far below the thermodynamic equilibrium. The approach was tested against experimental uptake data of benzo[a]pyrene, polychlorinated biphenyls (PCBs), and chlorobenzenes from soil into carrots. Measured concentrations in carrot peels were up to 100 times higher than in the core. The equilibrium approach can predict concentrations in the peels, but for carrot cores and for the whole carrot, the flux model is superior and should be preferred for a more realistic risk assessment.
Running unstructured grid‐based CFD solvers on modern graphics hardware
Authors: Corrigan Andrew , Camelli Fernando F. , Löhner Rainald , Wallin John 
Published: February 2010

AbstractTechniques used to implement an unstructured grid solver on modern graphics hardware are described. The three‐dimensional Euler equations for inviscid, compressible flow are considered. Effective memory bandwidth is improved by reducing total global memory access and overlapping redundant computation, as well as using an appropriate numbering scheme and data layout. The applicability of per‐block shared memory is also considered. The performance of the solver is demonstrated on two benchmark cases: a NACA0012 wing and a missile. For a variety of mesh sizes, an average speed‐up factor of roughly 9.5 × is observed over the equivalent parallelized OpenMP code running on a quad‐core CPU, and roughly 33 × over the equivalent code running in serial. Copyright © 2010 John Wiley & Sons, Ltd.
Tests for the Use of La2Mo2O9‐based Oxides as Multipurpose SOFC Core Materials
Authors: Jacquens J. , Farrusseng D. , Georges S. , Viricelle J.‐P. , Gaudillère C. , Corbel G. , Lacorre P. 
Published: February 2010

AbstractThe mixed ionic–electronic conductivity under dilute hydrogen, the stability and the catalytic activity under propane:air type mixtures of a series of LAMOX oxide‐ion conductors have been studied. The effect of exposure to dilute hydrogen on the conductivity of the β‐La2(Mo2 – yWy)O9 series at 600 °C depends on tungsten content: almost negligible for the highest (y = 1.4), it is important for La2Mo2O9 (y = 0). In propane:air, all tested LAMOX electrolytes are stable at 600–700 °C, but get reduced when water vapour is present. La2Mo2O9 is the best oxidation catalyst of the series, with an activity comparable to that of nickel.The catalytic activity of other tested LAMOX compounds is much lower, (La1.9Y0.1)Mo2O9 showing a deactivation phenomenon. These results suggest that depending on composition, La2(Mo2 – yWy)O9 compounds could be either electrolytes in single‐chamber SOFC and dual‐chamber micro‐SOFC (y = 1.4) or anode materials in dual‐chamber SOFC (low y) or oxidation catalysts in SOFCs operating with propane (y = 0).
Suitability of LiDAR point density and derived landform curvature maps for channel network extraction
Authors: Pirotti Francesco , Tarolli Paolo 
Published: February 2010

AbstractThis study uses landform curvature as an approach for channel network extraction. We considered a study area located in the eastern Italian Alps where a high‐quality set of LiDAR data was available and where channel heads and related channel network were mapped in the field. In the analysis, we derived 1‐m DTMs from different ground LiDAR point densities, and we used different smoothing factors for the landscape curvature calculation in order to test the suitability of the LiDAR point density and the derived curvature maps for the recognition of channel network. This methodology is based on threshold values of the curvature calculated as multiples (1–3 times) of the standard deviation of the curvature. Our analyses suggested that (i) the window size for curvature calculations has to be a function of the size of the features to be detected, (ii) a coarse ground LiDAR point density could be as useful as a finer one for the recognition of main channel network features and (iii) rougher curvature maps are not optimal as they do not explore a sufficient range at which features occur, while smoother curvature maps overcome this problem and are more appropriate for the extraction of surveyed channels. Copyright © 2010 John Wiley & Sons, Ltd.
Sap flow of Artemisia ordosica and the influence of environmental factors in a revegetated desert area: Tengger Desert, China
Authors: Lei Huang , Zhi‐Shan Zhang , Xin‐Rong Li 
Published: February 2010

AbstractArtemisia ordosica is considered as an excellent sand‐fixing plant in revegetated desert areas, which plays a pertinent role in stabilizing the mobile dunes and sustaining the desert ecosystems. Stem sap flows of about 10‐year‐old Artemisia ordosica plants were monitored continuously with heat balance method for the entire growing season in order to understand the water requirement and the effects of environmental factors on its transpiration and growth. Environment factors such as solar radiation, air temperatures, relative humidity, wind speed and precipitation were measured by the eddy covariance. Diurnal and seasonal variations of sap flow rate with different stem diameters and their correlation with meteorological factors and reference evapotranspiration were analysed. At the daily time scale, there was a significantly linear relationship between sap flow rate and reference evapotranspiration with a correlation coefficient of R2 = 0·6368. But at the hourly time scale, the relationship of measured sap flow rate and calculated reference evapotranspiration (ET0) was affected by the precipitation. A small precipitation would increase the sap flow and the ET0; however, when the precipitation is large, the sap flow and ET0 decrease. Leaf area index had a coincident variation with soil water content; both were determined by the precipitation, and meteorological factors were the most significant factors that affected the sap flow of Artemisia ordosica in the following order: solar radiation > vapour pressure deficit > relative humidity > air temperature > wind speed. The close correlation between daily sap flow rate and meteorological factors in the whole growing season would provide us an accurate estimation of the transpiration of Artemisia ordosica and rational water‐carrying capacity of sand dunes in the revegetated desert areas. Copyright © 2010 John Wiley & Sons, Ltd.
Geoelectrical structure and hydrogeological investigations of the southern Rif Cordillera (Morocco)
Authors: Zouhri Lahcen 
Published: February 2010

AbstractAn electrical prospecting survey is conducted in the Rharb basin, a semi‐arid region in the southern part of the Rifean Cordillera (Morocco) to delineate characteristics of the aquifer and the groundwater affected by the marine intrusion related to Atlantic Ocean. Analysis and interpretations of electrical soundings, bi‐logarithmic diagrams and the geoelectrical sections highlight a monolayer aquifer in the southern part, a multilayer system in the northern part of the Rharb basin and lenticular semi‐permeable formations. Several electrical layers have been deduced from the analysis of bi‐logarithmic diagrams: resistant superficial level (R0), conducting superficial level (C0), resistant level (R), intermediary resistant level (R′), conducting level (Cp) and intermediary layer of resistivity (AT). Spatial distribution of the resistivity deduced from the interpretation of apparent resistivity maps (AB = 400 and 1000 m) and the decreasing of resistivity values (35–10 Ωm), in particular in the coastal zone show that this heterogeneity is related to several anomalies identified in the coastal area, which result from hydraulic and geological processes: (i) heterogeneous hydraulic conductivity in particular in the southern part of the Rharb; (ii) lateral facies and synsedimentary faulting and (iii) the relationship between the electrical conductivity and chloride concentration of groundwater shows that salinity is the most important factor controlling resistivity. The distribution of fresh/salt‐water zones and their variations in space along geoelectrical sections are established through converting subsurface depth‐resistivity models. Copyright © 2010 John Wiley & Sons, Ltd.
Assessing the impact of mixing assumptions on the estimation of streamwater mean residence time
Authors: Fenicia Fabrizio , Wrede Sebastian , Kavetski Dmitri , Pfister Laurent , Hoffmann Lucien , Savenije Hubert H. G. , McDonnell Jeffrey J. 
Published: February 2010

AbstractCatchment streamwater mean residence time (Tmr) is an important descriptor of hydrological systems, reflecting their storage and flow pathway properties. Tmr is typically inferred from the composition of stable water isotopes (oxygen‐18 and deuterium) in observed rainfall and discharge. Currently, lumped parameter models based on convolution and sinewave functions are usually used for tracer simulation. These traditional models are based on simplistic assumptions that are often known to be unrealistic, in particular, steady flow conditions, linearity, complete mixing and others. However, the effect of these assumptions on Tmr estimation is seldom evaluated. In this article, we build a conceptual model that overcomes several assumptions made in traditional mixing models. Using data from the experimental Maimai catchment (New Zealand), we compare a complete‐mixing (CM) model, where rainfall water is assumed to mix completely and instantaneously with the total catchment storage, with a partial‐mixing (PM) model, where the tracer input is divided between an ‘active’ and a ‘dead’ storage compartment. We show that the inferred distribution of Tmr is strongly dependent on the treatment of mixing processes and flow pathways. The CM model returns estimates of Tmr that are well identifiable and are in general agreement with previous studies of the Maimai catchment. On the other hand, the PM model—motivated by a priori catchment insights—provides Tmr estimates that appear exceedingly large and highly uncertain. This suggests that water isotope composition measurements in rainfall and discharge alone may be insufficient for inferring Tmr. Given our model hypothesis, we also analysed the effect of different controls on Tmr. It was found that Tmr is controlled primarily by the storage properties of the catchment, rather than by the speed of streamflow response. This provides guidance on the type of information necessary to improve Tmr estimation. Copyright © 2010 John Wiley & Sons, Ltd.
Comparative probabilistic assessment of the hydrological performance of reconstructed and natural watersheds
Authors: Keshta Nader , Elshorbagy Amin , Barbour Lee 
Published: February 2010

AbstractThe oil sands industry has committed to returning the mine sites to a productive condition. The reconstructed soil covers must have sufficient available water holding capacity (AWHC) to supply enough moisture over the growing season, to promote vegetation. In order to assess the sustainability of various soil cover alternatives, a generic, system dynamic watershed model entitled GSDW was used along with the available historical meteorological records to estimate the maximum soil moisture deficit and annual evapotranspiration fluxes. A probabilistic framework was adopted; consequently, frequency curves of the maximum annual moisture deficit values are constructed and used to assess the probability that various reconstructed and natural watersheds can provide the associated moisture demands. In general, the study showed a tendency for the reconstructed watershed to provide less moisture for evapotranspiration than natural systems. Watersheds of various soil types, layering, thicknesses and topography were studied. The gained knowledge was used to predict the possible performance of a hypothetical reclamation cover. The results indicated that the hypothetical cover performed in a similar manner to the thickest existing soil cover which confirmed a high probability of that cover to survive under the same existing climatic conditions. Moreover, this probabilistic framework was found to be useful for integrating information gained from natural watersheds (e.g. the canopy of mature natural systems and transfer the results to the reconstructed system). The results show that the canopy influenced the moisture deficit regime positively which signifies a greater possibility that reconstructed covers will adapt to vegetation type. In brief, the adopted approach enables better understanding of the response of reconstructed systems via multiple simulations of ‘what‐if’ scenarios using different soil/vegetation alternatives. Copyright © 2010 John Wiley & Sons, Ltd.
Suspended sediment and dissolved load budgets of two Amazonian rivers from the Guiana Shield: Maroni River at Langa Tabiki and Oyapock River at Saut Maripa (French Guiana)
Authors: Sondag Francis , Guyot Jean Loup , Moquet Jean Sébastien , Laraque Alain , Adele Georges , Cochonneau Gérard , Doudou Jean Claude , Lagane Christelle , Vauchel Philippe 
Published: February 2010

AbstractThis study presents the data collected within the framework of an Observatory of Research in Environment on the Amazonian Basin—the ORE HYBAM. It relates to the dissolved and solid loads of the two main rivers of French Guiana, the Maroni and Oyapock rivers, running on the Guiana Shield and draining respectively 64 230 and 24 630 km2. The low coefficient of variation of the average annual flows of the two rivers indicates an inter‐annual hydrological stability probably related to the immediate vicinity of the Atlantic Ocean. The sedimentary load is mainly composed of quartz and kaolinite. The total suspended solid (TSS) concentrations are among the world's lowest values; they range from 1 to 130 mg l−1 during the hydrological cycle, with averages of 22 and 12 mg l−1, for the Maroni and Oyapock rivers, respectively. The seasonal variability of these values is significantly higher than that of hydrologic flows, but without simple relationship with the discharge. Water chemical composition of the two rivers indicates a very weak mineralization, very similar to that found in the Amazonian rivers running on the Brazilian and Guianese shields, and in the Congo River and its tributaries in the Central African Shield. Seasonal variations are observed in both basins; they correspond to higher concentrations during low water stage (from October to February) and to more diluted water during the flood, from April to July. A signature enriched in Cl− is present at the Saut Maripa station on the Oyapock River indicating a more marked influence of the trade winds in this basin. The computation of atmospheric contributions to ions budget indicated a weak contribution for Ca2+ and Mg2+, which originates mainly from water‐rock interactions in both stations, while more than half of Na+ is derived from atmospheric inputs. Copyright © 2010 John Wiley & Sons, Ltd.
Sediment and solute transport on soil slope under simultaneous influence of rainfall impact and scouring flow
Authors: Guo Tailong , Wang Quanjiu , Li Dingqiang , Wu Laosheng 
Published: February 2010

AbstractSoil erosion and nutrient losses with surface runoff in the loess plateau in China cause severe soil quality degradation and water pollution. It is driven by both rainfall impact and runoff flow that usually take place simultaneously during a rainfall event. However, the interactive effect of these two processes on soil erosion has received limited attention. The objectives of this study were to better understand the mechanism of soil erosion, solute transport in runoff, and hydraulic characteristics of flow under the simultaneous influence of rainfall and shallow clear‐water flow scouring. Laboratory flume experiments with three rainfall intensities (0, 60, and 120 mm h−1) and four scouring inflow rates (10, 20, 30, and 40 l min−1) were conducted to evaluate their interactive effect on runoff. Results indicate that both rainfall intensity and scouring inflow rate play important roles on runoff formation, soil erosion, and solute transport in the surface runoff. A rainfall splash and water scouring interactive effect on the transport of sediment and solute in runoff were observed at the rainfall intensity of 60 mm h−1 and scouring inflow rates of 20 l min−1. Cumulative sediment mass loss (Ms) was found to be a linear function of cumulative runoff volume (Wr) for each treatment. Solute transport was also affected by both rainfall intensity and scouring inflow rate, and the decrease in bromide concentration in the runoff with time fitted to a power function well. Reynolds number (Re) was a key hydraulic parameter to determine erodability on loess slopes. The Darcy–Weisbach friction coefficients (f) decreased with the Reynolds numbers (Re), and the average soil and water loss rate (Ml) increased with the Reynolds numbers (Re) on loess slope for both scenarios with or without rainfall impact. Copyright © 2010 John Wiley & Sons, Ltd.
Transient solution for radial two‐zone flow in unconfined aquifers under constant‐head tests
Authors: Chang Y. C. , Yeh H. D. , Chen G. Y. 
Published: February 2010

AbstractThe constant‐head test (CHT) is commonly employed to determine the aquifer parameters. This test is also applied to many environmental problems such as recovering light nonaqueous phase liquids (LNAPL) and controlling off‐site migration of contaminated groundwater in low‐transmissivity aquifers. A well skin near the wellbore may be produced due to the well construction or development and its formation properties are significantly different from the original ones. A more appropriate description for the skin effect on the aquifer system should treat the well skin as a different formation instead of using a skin factor. Thus, the aquifer system becomes a two‐zone formation including the skin and formation zones. This study presents a mathematical model developed for analyzing a two‐zone unconfined aquifer system and the associated solution for CHTs at partially penetrating wells under transient state. The solution of the model may be used either to identify the in situ aquifer parameters or to investigate the effects of the wellbore storage and well skin on the head changes in unconfined aquifers under constant‐head pumping. Copyright © 2010 John Wiley & Sons, Ltd.
Accelerated aging, natural aging, and small punch testing of gamma‐air sterilized polycarbonate urethane acetabular components
Authors: Kurtz S. M. , Siskey R. , Reitman M. 
Published: February 2010

AbstractThe objectives of this study were three‐fold: (1) to determine the applicability of the small punch test to characterize Bionate® 80A polycarbonate urethane (PCU) acetabular implants; (2) to evaluate the susceptibility of PCU acetabular implants to exhibit degradation of mechanical behavior following gamma irradiation in air and accelerated aging; and (3) to compare the oxidation of gamma‐air sterilized PCU following accelerated aging and 5 years of natural shelf aging. In addition to attenuated total reflectance‐Fourier transform infrared spectroscopy, we also adapted a miniature specimen mechanical test, the small punch test, for the deformable PCU cups. Accelerated aging was performed using ASTM F2003, a standard test that represents a severe oxidative challenge. The results of this study suggest that the small punch test is sufficiently sensitive and reproducible to discriminate slight differences in the large‐deformation mechanical behavior of Bionate 80A following accelerated aging. The gamma‐air sterilized PCU had a reduction of 9% in ultimate load after aging. Five years of shelf aging had little effect on the mechanical properties of the PCU. Overall, our findings suggest that the Bionate 80A material has greater oxidative stability than ultra‐high molecular weight polyethylene following gamma irradiation in air and exposure to a severe oxidative challenge. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010
Effect of calcination on microstructure and antibacterial activity of silver‐containing silica coatings
Authors: Durucan Caner , Akkopru Betul 
Published: February 2010

AbstractSilver nanoparticle containing silica coatings on soda‐lime glass were prepared by the sol–gel process. The effect of thermal densification treatment at different temperatures in the range of 100–700°C on microstructure and antibacterial properties of the coatings were examined. The structural characterization of the coatings was performed by using scanning electron microscope, X‐ray diffraction, UV–visible and X‐ray photoelectron spectroscopy (XPS), and atomic force microscope (AFM). The antibacterial activity of the coatings was determined against Staphylococcus aureus by disk diffusion method. The mechanisms for formation and distribution of silver nanoparticles in the silica matrix with respect to the calcination temperature are discussed, and the correlation between the microstructural properties and antibacterial activity is described. The investigations revealed that silver nanoparticles were mainly in the metallic state during thermal treatments. AFM and XPS examinations proved that silver accumulated on the surface diffuse into glass substrate at higher calcination temperatures. A high level of antibacterial activity was observed for the coatings calcined at 300°C or lower temperatures allowing accommodation of silver on the surface of the coating. Silver diffusion into bulk via ion‐exchange with sodium and calcium ions from glass substrate during calcination at higher temperatures (500 or 700°C) resulted in apparent degradation in the antibacterial activity. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010