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Performance of ANFIS versus MLP-NN dissolved oxygen prediction models in water quality monitoring 全文
2014
Najah, A. | El-Shafie, A. | Karim, O. A. | El-Shafie, Amr H.
We discuss the accuracy and performance of the adaptive neuro-fuzzy inference system (ANFIS) in training and prediction of dissolved oxygen (DO) concentrations. The model was used to analyze historical data generated through continuous monitoring of water quality parameters at several stations on the Johor River to predict DO concentrations. Four water quality parameters were selected for ANFIS modeling, including temperature, pH, nitrate (NO₃) concentration, and ammoniacal nitrogen concentration (NH₃-NL). Sensitivity analysis was performed to evaluate the effects of the input parameters. The inputs with the greatest effect were those related to oxygen content (NO₃) or oxygen demand (NH₃-NL). Temperature was the parameter with the least effect, whereas pH provided the lowest contribution to the proposed model. To evaluate the performance of the model, three statistical indices were used: the coefficient of determination (R ²), the mean absolute prediction error, and the correlation coefficient. The performance of the ANFIS model was compared with an artificial neural network model. The ANFIS model was capable of providing greater accuracy, particularly in the case of extreme events.
显示更多 [+] 显示较少 [-]Seeds’ physicochemical traits and mucilage protection against aluminum effect during germination and root elongation as important factors in a biofuel seed crop (Ricinus communis) 全文
2014
Alves Silva, Giovanni Eustáquio | Toledo Ramos, Flávia | de Faria, Ana Paula | Costa França, Marcel Giovanni
We determined the length, volume, dry biomass, and density in seeds of five castor bean cultivars and verified notable physicochemical trait differences. Seeds were then subjected to different toxic aluminum (Al) concentrations to evaluate germination, relative root elongation, and the role of root apices’ rhizosphere mucilage layer. Seeds’ physicochemical traits were associated with Al toxicity responses, and the absence of Al in cotyledons near to the embryo was revealed by Al-hematoxylin staining, indicating that Al did not induce significant germination reduction rates between cultivars. However, in the more sensitive cultivar, Al was found around the embryo, contributing to subsequent growth inhibition. After this, to investigate the role of mucilage in Al tolerance, an assay was conducted using NH₄Cl to remove root mucilage before or after exposure to different Al concentrations. Sequentially, the roots were stained with hematoxylin and a quantitative analysis of staining intensity was obtained. These results revealed the significant contribution of the mucilage layer to Al toxicity responses in castor bean seedlings. Root growth elongation under Al toxicity confirmed the role of the mucilage layer, which jointly indicated the differential Al tolerance between cultivars and an efficient Al-exclusion mechanism in the tolerant cultivar.
显示更多 [+] 显示较少 [-]Isovaleraldehyde elimination by UV/TiO₂ photocatalysis: comparative study of the process at different reactors configurations and scales 全文
2014
Assadi, Aymen Amine | Bouzaza, Abdelkrim | Wolbert, Dominique | Petit, Philippe
A proposal for scaling-up the photocatalytic reactors is described and applied to the coated catalytic walls with a thin layer of titanium dioxide under the near ultraviolet (UV) irradiation. In this context, the photocatalytic degradation of isovaleraldehyde in gas phase is studied. In fact, the removal capacity is compared at different continuous reactors: a photocatalytic cylindrical reactor, planar reactor, and pilot unit. Results show that laboratory results can be useful for reactor design and scale-up. The flowrate increases lead to the removal capacity increases also. For example, with pilot unit, when flowrate extends four times, the degradation rate varies from 0.14 to 0.38 g h⁻¹ mcₐₜ ⁻². The influence of UV intensity is also studied. When this parameter increases, zboth degradation rate and overall mineralization are enhanced. Moreover, the effects of inlet concentration, flowrate, geometries, and size of reactors on the removal capacity are also studied.
显示更多 [+] 显示较少 [-]Characterization of SDS-degrading Delftia acidovorans and in situ monitoring of its temporal succession in SDS-contaminated surface waters 全文
2014
Yilmaz, Fadime | Icgen, Bulent
Incomplete removal of sodium dodecyl sulfate (SDS) in wastewater treatment plants may result in SDS residues escaping and finding their way into receiving water bodies like rivers, lakes, and sea. Introduction of effective microorganisms into the aerobic treatment facilities can reduce unpleasant by-products and SDS residues. Selecting effective microorganisms for SDS treatment is a big challenge. Current study reports the isolation, identification, and in situ monitoring of an effective SDS-degrading isolate from detergent-polluted river waters. Screening was carried out by the conventional enrichment culture technique and the isolate was tentatively identified by using fatty acid methyl ester and 16S ribosomal RNA (rRNA) sequence analyses. Fatty acids produced by the isolate investigated were assumed as typical for the genus Comamonas. 16S rRNA sequence analysis also confirmed that the isolate had 95 % homology with Delftia acidovorans known as Comamonas or Pseudomonas acidovorans previously. D. acidovorans exhibited optimum growth at SDS concentration of 1 g l⁻¹but tolerated up to 10 g l⁻¹SDS. 87 % of 1.0 g l⁻¹pure SDS was degraded after 11 days of incubation. The temporal succession of D. acidovorans in detergent-polluted river water was also monitored in situ by using Comamonas-specific fluorescein-labeled Cte probe. Being able to degrade SDS and populate in SDS-polluted surface waters, D. acidovorans isolates seem to be very helpful in elimination of SDS.
显示更多 [+] 显示较少 [-]Effects of environmentally relevant concentrations of metallic compounds on the flatfish Scophthalmus maximus: biomarkers of neurotoxicity, oxidative stress and metabolism 全文
2014
Nunes, Bruno | Brandão, Fátima | Sérgio, Tânia | Rodrigues, Sara | Gonçalves, Fernando | Correia, Alberto Teodorico
Effects of environmentally relevant concentrations of metallic compounds on the flatfish Scophthalmus maximus: biomarkers of neurotoxicity, oxidative stress and metabolism 全文
2014
Nunes, Bruno | Brandão, Fátima | Sérgio, Tânia | Rodrigues, Sara | Gonçalves, Fernando | Correia, Alberto Teodorico
Flatfish species, such as the turbot (Scophthalmus maximus), are common targets for toxic effects, since they are exposed through the food chain (ingestion of contaminated preys) and are in direct contact with the waterborne contaminant and sediments. Furthermore, these fish species live in close proximity to interstitial water that frequently dissolves high amounts of contaminants, including metals. Despite this significant set of characteristics, the present knowledge concerning flatfish contamination and toxicity by metals is still scarce. To attain the objective of assessing the effects of metals on a flatfish species, S. maximus specimens were chronically exposed to lead, copper and zinc, at ecologically relevant concentrations, and biochemical (oxidative stress: catalase and glutathione S-transferases activities, and lipid peroxidation; neurotoxicity: cholinesterase activity) parameters were assessed on selected tissues (gills and liver). Copper had no significant effects on all tested parameters; lead was causative of significant increases in liver GSTs activities and also in lipoperoxidation of gill tissue; exposure to zinc caused a significant increase in catalase activity of gill tissue. None of the tested metals elicited noteworthy effects in terms of neurotoxicity. The obtained results showed that only the metal lead is of some environmental importance, since it was able to cause deleterious modifications of oxidative nature at relevant concentrations.
显示更多 [+] 显示较少 [-]Effects of environmentally relevant concentrations of metallic compounds on the flatfish Scophthalmus maximus: biomarkers of neurotoxicity, oxidative stress and metabolism 全文
1000 | 2014
Nunes, Bruno | Brandão, Fátima | Sérgio, Tânia | Rodrigues, Sara | Gonçalves, Fernando | Correia, Alberto Teodorico
Flatfish species, such as the turbot (Scophthalmus maximus), are common targets for toxic effects, since they are exposed through the food chain (ingestion of contaminated preys) and are in direct contact with the waterborne contaminant and sediments. Furthermore, these fish species live in close proximity to interstitial water that frequently dissolves high amounts of contaminants, including metals. Despite this significant set of characteristics, the present knowledge concerning flatfish contamination and toxicity by metals is still scarce. To attain the objective of assessing the effects of metals on a flatfish species, S. maximus specimens were chronically exposed to lead, copper and zinc, at ecologically relevant concentrations, and biochemical (oxidative stress: catalase and glutathione S-transferases activities, and lipid peroxidation; neurotoxicity: cholinesterase activity) parameters were assessed on selected tissues (gills and liver). Copper had no significant effects on all tested parameters; lead was causative of significant increases in liver GSTs activities and also in lipoperoxidation of gill tissue; exposure to zinc caused a significant increase in catalase activity of gill tissue. None of the tested metals elicited noteworthy effects in terms of neurotoxicity. The obtained results showed that only the metal lead is of some environmental importance, since it was able to cause deleterious modifications of oxidative nature at relevant concentrations.
显示更多 [+] 显示较少 [-]Impacts from control operations on a recreationally hunted feral swine population at a large military installation in Florida 全文
2014
Engeman, Richard | Hershberger, Troy | Orzell, Steve | Felix, Rodney | Killian, Gary | Woolard, John | Cornman, Jon | Romano, David | Huddleston, Chet | Zimmerman, Pat | Barre, Chris | Tillman, Eric | Avery, Michael
Feral swine were targeted for control at Avon Park Air Force Range in south-central Florida to avert damage to sensitive wetland habitats on the 40,000-ha base. We conducted a 5-year study to assess impacts from control to this population that had been recreationally hunted for many years. Control was initiated in early 2009. The feral swine population was monitored from 2008 to 2012 using a passive tracking index (PTI) during the dry and wet seasons and using recreational hunter take rates from the dry season. All three indices showed substantial feral swine declines after implementing control, with indices leveling for the final two study years. Military missions and recreational hunting seasons impacted temporal and spatial consistency of control application, thereby limiting further impacts of control efforts on the feral swine population. The PTI was also able to monitor coyotes, another invasive species on the base, and detect Florida black bear and Florida panther, species of particular concern.
显示更多 [+] 显示较少 [-]Sorption characteristics of cyromazine and its metabolite melamine in typical agricultural soils of China 全文
2014
Wang, Hai-yan | Wang, Hui | Tang, Ling-Li | Dong, Yuan-Hua | Zhao, Ling | Toor, Gurpal
A myriad of physical, chemical, and biological processes controls the fate of organic contaminants in soils. The knowledge of bioavailability of a contaminant in soil can be useful to conduct environmental risk assessment. We conducted batch equilibrium experiments to investigate the sorption of cyromazine (CA) and its metabolite melamine (MA) onto five typical soils of China belonging to suborders Ali-Perudic Ferrosols, Udic Argosols, Gleyic-Stagnic Anthrosols, Ustic Cambosols, and Udic Isohumosols. Results showed that sorption of CA and MA onto soils was linear, as indicated by the Freundlich and Langmuir models. Different sorption behaviors of CA and MA were observed on the five agricultural soils, with lgKfvalues (Freundlich model) of 1.6505–2.6557 and 1.632–2.549, respectively. Moreover, the Kfvalues for CA and MA were positively correlated with soil organic matter (r = 0.989, r = 0.976) and significantly negatively correlated with pH (r = −0.938, r = −0.964). The free energy of sorption of CA and MA ranged from −20.8 to −23.0 kJ mol⁻¹and −20.8 to −22.8 kJ mol⁻¹, respectively, suggesting that the sorption of CA and MA onto the soils is primarily a physical process.
显示更多 [+] 显示较少 [-]The problem of sampling on built heritage: a preliminary study of a new non-invasive method 全文
2014
Prieto-Taboada, N. | Isca, C. | Martínez-Arkarazo, I. | Casoli, A. | Olazabal, M. A. | Arana, G. | Madariaga, J. M.
The relevance of a risk assessment of the built heritage was clearly justified due to the fact that it acts as a pollutant repository and hazardous pollutants have the capacity to penetrate into materials. However, the limitation of the sampling processes due to the high value of the built heritage makes a correct evaluation difficult. For that reason, in the present work, the potential of agar gels as non-invasive samplers of built heritage deterioration products, like crusts and patinas, was evaluated. Different gels of agar and Carbopol® (as control gel) were applied on these built surfaces considering several factors: the treatment time, the effectiveness of the addition of EDTA (ethylenediaminetetraacetic acid, C₁₀H₁₆N₂O₈) and its concentration and the use of a buffer at pH 7.5. All these factors were evaluated in order to determine the capacity of these gels as sampling systems under non-controlled atmospheric conditions. The results obtained in the assays were evaluated by visual examination, by evolution of pH and by the most important techniques used in the risk assessment analysis of the built heritage (Raman spectroscopy, scanning electron microscope (SEM)/energy dispersive X-ray (EDX) and inductively coupled plasma mass spectrometry (ICP-MS)). In this evaluation, the agar gels showed an intrinsic capacity as sampler with respect to the gel Carbopol® and thus, the best option between the studied gels consisted on agar gels with 2 % of EDTA and the longest application time. On the whole, the agar gels showed an interesting potential as non-invasive samplers of built heritage deterioration materials which should be studied more in depth.
显示更多 [+] 显示较少 [-]Treatment of a wastewater from a pesticide manufacture by combined coagulation and Fenton oxidation 全文
2014
Pliego, G. | Zazo, J. A. | Pariente, M. I. | Rodríguez, I. | Petre, A. L. | Leton, P. | Garcia, J.
The treatment of a non-biodegradable agrochemical wastewater has been studied by coupling of preliminary coagulation—flocculation step and further Fenton oxidation. High percentages of chemical oxygen demand (COD) removal (up to 58 %) were achieved in a first step using polyferric chloride as coagulant. This reduced significantly the amount of H₂O₂ required in the further Fenton oxidation. Using the stoichiometric amount relative to COD around 80 % of the remaining organic load was mineralized. The combined treatment allowed achieving the regional discharge limits of ecotoxicity at a cost substantially lower than the solution used so far where these wastewaters are managed as hazardous wastes.
显示更多 [+] 显示较少 [-]Composition of weathering crusts on sandstones from natural outcrops and architectonic elements in an urban environment 全文
2014
Marszałek, Mariola | Alexandrowicz, Zofia | Rzepa, Grzegorz
This work presents mineralogical and chemical characteristics of weathering crusts developed on sandstones exposed to various air pollution conditions. The samples have been collected from sandstone tors in the Carpathian Foothill and from buildings in Kraków. It has been stated that these crusts differ in both fabric and composition. The sandstone black crust from tors is rich in organic matter and composed of amorphous silica. Sulphate incrustations accompanied by dust particles have been only sometimes observed. Beneath the black crust, a zone coloured by iron (oxyhydr)oxides occurs. The enrichment of the surface crust in silica and iron compounds protects the rock interior from atmospheric impact. The sandstones from architectonic details are also covered by a thin carbon-rich black crust, but they are visibly loosened. Numerous salts, mainly gypsum and halite, crystallise here, thus enhancing deterioration of the rock. Moreover, spherical particles originated from industrial emissions are much more common. Gypsum in natural outcrops, forms isolated and well-developed crystals, whilst these found on the architectonic details are finer and densely cover the surface. Such diversity reflects various concentrations of acid air pollutants in solutions.
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