Role of BP-ANN in simulating greenhouse gas emissions from global aquatic ecosystems via carbon component-environmental factor coupling.

Inland waters (IW), estuarine areas (EA), and offshore areas (OA) function as aquatic systems in which the transport of carbon components results in the release of greenhouse gases (GHGs). Interconnected subsystems exhibit a greater greenhouse effect than individual systems. Despite this, there is a lack of research on how carbon loading and its components impact GHG emissions in various aquatic systems. In this study, we analyzed 430 aquatic sites to explore trade-off mechanisms among dissolved organic carbon (DOC), particulate organic carbon, dissolved inorganic carbon (DIC), and GHGs. The results revealed that IW emerged as the most significant GHG source, possessing a comprehensive global warming potential (GWP) of 0.78 ± 0.08 (10-2 Pg CO2-ep ha-1 year-1) for combined carbon dioxide, methane, and nitrous oxide. This surpassed the cumulative potentials of EA and OA (0.35 ± 0.05 (10-2 Pg CO2-ep ha-1 year-1)). Additionally, structural equation modeling indicated that GHG emissions resulted from a combination of carbon component loading and environmental factors. DOC exhibited a positive correlation with GWPs when influenced by biodegradable DOC. Total alkalinity and pH influenced DIC, leading to elevated pCO2 in aquatic systems, thereby enhancing GWPs. Predictive modeling using backpropagation artificial neural networks (BP-ANN) for GWPs, incorporating carbon components and environmental factors, demonstrated a good fit (R2 = 0.6078, RMSEaverage = 0.069, p > 0.05) between observed and predicted values. Enhancing the estimation of aquatic region feedback to GHG changes was achieved by incorporating corresponding water quality parameters. In summary, this study underscores the pivotal role of carbon components and environmental factors in aquatic regions for GHG emissions. The application of BP-ANN to estimate greenhouse effects from aquatic regions is highlighted, providing theoretical and experimental support for future advancements in monitoring and developing policies concerning the influence of water quality on GHG emissions.

Bird community structure is driven by urbanization level, blue-green infrastructure configuration and precision farming in Taizhou, China.

Land use/land cover (LULC) changes and high urbanization rates are the main drivers of avian habitat loss in developing countries. However, few studies have examined the effects of urbanization intensity on avian diversity distribution and its importance in guiding eco-friendly urban planning. We surveyed bird distribution (n = 67 species) in different seasons using local ecological knowledge (LEK) and transect line methods in Jiangyan District from July 2018 to May 2019. One-way analysis of variance (ANOVA) was used to assess the effects of urbanization levels on birds relative density and richness during spring-summer (breeding season) and autumn-winter seasons (non-breeding season). Generalized linear models (GLM) were identified for the landscape composition and configuration that drive relative density and richness in native bird communities. Using redundancy analysis (RDA), we identified the landscape composition and configuration factors affecting bird foraging and roosting at urbanization levels. The results showed high dependency of waders and granivores on paddy fields and dry arable land respectively during the breeding season. During non-breeding season, wetland abundance, land cover, connectivity and total area of BGI were important habitat factors in attracting birds. Moreover, the landscape composition and configuration factors of BGI: wetlands as well as farmland habitats, are the main environmental cues that influence bird foraging. Therefore, to increase habitat suitability over landscape matrix, we propose creation of multiple waterbodies and green corridors of variable types and sizes on natural patches to improve the connectivity of ecological network. We also recommend land management interventions in farmland ecosystems, which could contribute to natural habitat restoration and improve bird biodiversity in urban areas.

Development and Validation of an Interactive Efficient Dose Rates Distribution Calculation Program Arshield for Visualization of Radiation Field in Nuclear Power Plants.

Point kernel integration (PKI) method is widely used in the visualization of radiation field in engineering applications because of the features of quickly dealing with large-scale complicated geometry space problems. But the traditional PKI programs have a lot of restrictions, such as complicated modeling, complicated source setting, 3D fine mesh results statistics and large-scale computing efficiency. To break the traditional restrictions for visualization of radiation field, ARShield was developed successfully. The results show that ARShield can deal with complicated plant radiation shielding problems for visualization of radiation field. Compared with SuperMC and QAD, it can be seen that the program is reliable and efficient. Also, ARShield can meet the demands of calculation speediness and interactive operations of modeling and displaying 3D geometries on a graphical user interface, avoiding error modeling in calculation and visualization.

Adsorption of copper(II) on multiwalled carbon nanotubes in the absence and presence of humic or fulvic acids.

The adsorption of Cu(II) on multiwalled carbon nanotubes (MWCNTs) as a function of pH and ionic strength in the absence and presence of humic acid (HA) or fulvic acid (FA) was studied using batch technique. The results indicated that the adsorption is strongly dependent on pH but independent of ionic strength. A positive effect of HA/FA on Cu(II) adsorption was found at pH <7.5, whereas a negative effect was observed at pH >7.5. The adsorption isotherms can be described better by the Freundlich model than by the Langmuir model in the absence and presence of HA/FA. Adsorption isotherms of Cu(II) at higher initial HA/FA concentrations are higher than those of Cu(II) at lower FA/HA concentrations. The thermodynamic data calculated from temperature-dependent adsorption isotherms suggested that the adsorption was spontaneous and enhanced at higher temperature. Results of this work suggest that MWCNTs may be a promising candidate for the removal of heavy metal ions from aqueous solutions.

Sorption of copper(II) onto super-adsorbent of bentonite-polyacrylamide composites.

In this work, bentonite embedded in the polyacrylamide (PAAm) gels was used as a novel adsorbent for the removal of Cu(II) from aqueous solution. The sorption and desorption of Cu(II) on bentonite-polyacrylamide (BENT-PAAm) was investigated as the function of pH, ionic strength, adsorbent content, Cu(II) concentrations and temperature. The results indicated that the sorption of Cu(II) on BENT-PAAm was strongly dependent on pH, ionic strength and temperature. The sorption increased from about 9% to 97% at pH ranging from 2.4 to 7. The sorption of Cu(II) on BENT-PAAm increased with increasing temperature and decreasing ionic strength. The sorption of Cu(II) on BENT and on BENT-PAAm was an endothermic and irreversible process. The results of desorption indicated that the adsorbed Cu(II) ions on solid particles were difficult to be desorbed from solid to liquid phase. From the comparison with BENT, BENT-PAAm showed higher sorption capacity with C(smax) increasing from 29 to 33 mg/g at pH 6.2 and from 11 to 20mg/g at pH 5.0 for the sorption of Cu(II) from BENT to BENT-PAAm composites. The average standard enthalpy change (Delta H degrees) and the entropy change (DeltaS degrees ) of Cu(II) sorption on BENT-PAAm are higher than those of Cu(II) sorption on BENT. The BENT-PAAm composites can be used as a super-adsorbent for the removal of Cu(II) from aqueous solution.

Sorption of Ni(II) on GMZ bentonite: effects of pH, ionic strength, foreign ions, humic acid and temperature.

Bentonite has been widely studied in nuclear waste management because of its special physicochemical properties. In this work, the sorption of Ni(II) from aqueous solution onto GMZ bentonite as a function of contact time, pH, ionic strength, foreign ions, humic acid (HA) and temperature was investigated under ambient conditions. The results indicated that the pseudo-second-order rate equation simulated the kinetic sorption process well. The sorption of Ni(II) on GMZ bentonite was strongly dependent on pH and on ionic strength. At low pH, the sorption of Ni(II) was dominated by outer-sphere surface complexation and ion exchange with Na(+)/H(+) on GMZ bentonite surfaces, whereas inner-sphere surface complexation was the main sorption mechanism at high pH. A positive effect of HA on Ni(II) sorption was found at pH<8, whereas a negative effect was observed at pH>8. The Langmuir, Freundlich, and D-R models were used to simulate the sorption isotherms of Ni(II) at three different temperatures: 303.15, 318.15 and 333.15K. The thermodynamic parameters (DeltaH(0), DeltaS(0) and DeltaG(0)) of Ni(II) sorption on GMZ bentonite at the three different temperatures were calculated from the temperature-dependent sorption isotherms. The results indicated that the sorption process of Ni(II) on GMZ bentonite was endothermic and spontaneous. Experimental results indicate that GMZ bentonite is a suitable sorbent for pre-concentration and solidification of Ni(II) from large volume solutions.

Repeated positioning in accurate radiotherapy based on virtual net technique and contrary reconstruction scheme.

This paper presents a new repeated positioning system for external radiotherapy. A new scheme is proposed to rebuild patient's body surface 3-D image based on simple stereo vision model and virtual net technique, which improves the reconstruction precision of the template. For the calculation of the positioning error, the contrary reconstruction scheme is adopted and the positioning speed is greatly improved. The 3-D reconstructed video image of the right position in the first positioning is used as the reference template for the next positioning, and the positioning error is evaluated by projecting the template image into the patient's real-time video images and calculating the correlation ratio in the areas limited by the triangle of the reference image.

'A finite size pencil beam for IMRT dose optimization'--a simpler analytical function for the finite size pencil beam kernel.

A simple and finite-termed analytical function for the finite size pencil beam kernel was constructed. The dose cross-profile of a semi-infinite field with field edge at x = 0 can be well fitted by the Boltzmann function. The pencil beam cross-profile of width 2x(0) can be obtained as the difference between two semi-infinite fields shifted by 2x(0). If the profile is centred about x = 0, it can derive from P(x + x(0)) - P(x - x(0)). The penumbra influence can be taken by the penumbra tuning factor f. The parameters A(1), A(2), A(3), A(4), f can be obtained by fitting depth-dose curves and cross-profiles for a set of square fields. The two-dimensional dose distribution F(x, y, x(0), y(0), A(1), A(2), A(3), A(4), f(1), f(2)) of a pencil beam of width (2x(0), 2y(0)) is defined by multiplication of two independent one-dimensional profiles.

Diffusion of Eu(III) in compacted bentonite-effect of pH, solution concentration and humic acid.

The effect of pH, Eu(III) solution concentration and humic acid on the diffusion of Eu(III) in compacted bentonite (rho(b) = 1000 +/- 30 kg/m(3)) was studied with "in-diffusion" method at an ionic strength of 0.1M NaClO(4). The results (K(d) values from the first slice and theoretical calculation, apparent and effective diffusion coefficients) derived from the new capillary method are in good agreement with the literature data under similar conditions, and fit the Fick's second law very well. The results suggest that the diffusion of Eu(III) is dependent on pH values and independent on solution concentration in our experimental conditions. Humic acid forms precipitation/complexation with Eu(III) at the surface of compacted bentonite and thus deduces the diffusion/transport of Eu(III) in compacted bentonite. The K(d) values in compacted bentonite are in most cases lower than those in powdered bentonite obtained from batch experiments. The difference between the K(d) values from powdered and compacted bentonite is a strong function of the bulk density of the bentonite. The results suggest that the content of interlaminary space plays a very important role to the diffusion, sorption and migration of Eu(III) in compacted bentonite.