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Modeling and comparison of count data containing zero values: a case study of Setipinna taty in the south inshore of Zhejiang, China Texte intégral
2021
Liu, Xiaoxue | Gao, Chunxia | Zhao, Jing | Tian, Siquan | Ye, Shen | Ma, Jin
To effectively use the fishery count data containing zero values, Setipinna taty in the coastal waters of south inshore of Zhejiang in China from 2017 to 2019 was used in this study. Environmental factors, such as water temperature, water depth, and salinity, were selected to establish models and compare based on the generalized additive model (GAM) of the Tweedie distribution (Tweedie-GAM) and two-stage GAM, Ad hoc method, and generalized additive mixed model (GAMM). The results showed that each station accounted for a higher proportion of zero values and the two-stage GAM model had a higher deviation interpretation rate, and GAM I and GAM II had 19.6% and 60.4% deviation interpretation rates. The cross-validation results showed that the performance evaluation of the two-stage GAM model was the best and showed the highest R² value, the lowest average absolute error, and the relatively small root mean square error. This study found that the abundance of S. taty in the south inshore of Zhejiang was highest at around 21°C and 18°C in spring and autumn, and the abundance reached the highest at a water depth of about 20 m. In spatial distribution, the high value of the abundance of S. taty was mostly distributed in the coastal waters in the south of 28°N. In future research, models should be fitted and compared for different sampling zero-value ratios, and more environmental factors should be included to accurately find an optimal model and provide references for the conservation of fishery resources.
Afficher plus [+] Moins [-]Camphor wood, a potentially harmful museum storage material: an analytical study using instrumental methods Texte intégral
2021
Shen, Jingyi
Camphor wood is welcomed by museums due to its insect-repelling effect but the smell indicates a potential risk to the collections. In order to judge the suitability of camphor wood as a museum storage material, typical camphor wood (Cinnamomum camphora) samples aged for different years were evaluated by conducting the Oddy test. Gas chromatography–mass spectrometry (GC-MS), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), and time of flight–secondary ion mass spectrometry (ToF-SIMS) were applied to identifying the volatile organic compounds (VOCs) emitted by the materials and the corrosion products, respectively. The results showed that the camphor wood samples led to visible corrosion on copper and lead coupons. GC-MS indicated that the major VOCs emitted were terpenes and their derivatives, while XRD, EDS, and ToF-SIMS provided various clues to the corrosion mechanisms. Pb₁₀(CO₃)₆(OH)₆O and CuO were regarded as the major corrosion products of lead and copper coupons, respectively. The study provides the museum curators and the conservators with abundant information to reassess the application of camphor wood to museums as well as a different way to understand the mechanism of metallic corrosion caused by camphor wood.
Afficher plus [+] Moins [-]Production and characterization of Komagataeibacter xylinus SGP8 nanocellulose and its calcite based composite for removal of Cd ions Texte intégral
2021
Bhattacharya, Amrik | Sadaf, Ayesha | Dubey, Swati | Singh, Rajesh P. | Khare, Sunil Kumar
In the present study, fermentative production of bacterial nanocellulose (BNC) by using Komagataeibacter xylinus strain SGP8 and characterization of nanocellulose is presented. The bacterium was able to produce 1.82 g L⁻¹ of cellulose in the form of pellicle in standard Hestrin-Schramn (HS) medium. The morpho-structural characterization of the BNC using scanning electron microscopy (SEM) and X-ray diffraction (XRD) studies, respectively revealed nanofibrillar structure and high crystallinity index (~86%). The thermogravimetric analysis (TGA) showed the stability of BNC up to 280 °C, further rise in temperature to 350 °C results in depolymerization of the sample. In order to show the applicability of produced BNC, it was modified first using calcite (CaCO₃) and thereafter characterized using SEM, XRD, FTIR, and TGA studies. The BNC-CaCO₃ composites as a sorbent resulted in >99% removal of initial 10 mg L⁻¹ of Cd (II) at pH 5, 7 and 9 after 12 h of treatment. Moreover, the composite was also found to be competent in removing high concentrations of Cd (25 and 50 mg L⁻¹) from the solution (69–70%). Overall, the above results suggest that cellulose produced by K. xylinus strain SGP8 showed excellent material properties, and modified BNC (BNC-CaCO₃ composite) could effectively be used for remediation of toxic levels of Cd from the contaminated system.
Afficher plus [+] Moins [-]Effects of process factors on the performance of electrochemical disinfection for wastewater in a continuous-flow cell reactor Texte intégral
2021
Lin, Che-Jen | Zhang, Ruolin | Waisner, Scott A. | Nawaz, Tabish | Center, Lori | Gent, David B. | Johnson, Jared L. | Holland, Sabin
Although electrochemical disinfection has been shown to be an effective approach to inactivate bacteria in saline water, the effects of process parameters and reactor design for its application in low-salinity water have not been well understood. In this study, factorial experiments were performed to investigate the direct and confounded effects of applied current (5–20 mA), contact time (2.5–20 min), anode surface area (185–370 cm²), and chloride concentration (50–400 mg L⁻¹) on the disinfection efficiency in fresh water and the secondary effluent of municipal wastewater. An electrochemical disinfection reactor cell with an internal volume of 75 cm³ was designed and fabricated. Residence time distribution analysis showed that the internal mixing of the reactor is similar to that of a dispersed plug-flow reactor. All studied process parameters showed significant effect on the kill efficiency, with the applied current and contact time having the most dominant effect. Although the effect of chloride concentration, which is responsible for electrochemical production of free chlorine in water, is statistically significant, it is not as prominent as those reported for high salinity water. A synergistic effect between chloride concentration and anode surface area was identified, leading to high kill efficiency (99.9%, 3 log kill) at low current density (0.0135 mA cm⁻²). Response surface modeling results suggested that a scaled-up disinfection reactor can be designed using large anode surface area with long contact time for high chloride water (400 mg L⁻¹) or high current density with short contact time for low chloride water (50 mg L⁻¹). The power requirement of a portable system treating 37.85 m³ day⁻¹ (10,000 gpd) of municipal wastewater was estimated to be 1.9 to 8.3 kW to achieve a 3 log kill, depending on the reactor design.
Afficher plus [+] Moins [-]Decomposition of oil refinery sludge using E+-Ozonation process for carbon source releasing and TPH removal Texte intégral
2021
Yang, Kaiyan | Sun, Zhiyi | Wang, Luochun | Lou, Ziyang
To utilize carbon source and decompose the petroleum hydrocarbon substances simultaneously, adding the electrolysis to ozonation (E⁺-Ozonation) was employed to deal with hazardous activated petroleum waste sludge (P-sludge). It was found that E⁺-Ozonation could accelerate the ozone utilization and hydroxyl radical (·OH) generation rate. Soluble chemical oxygen demand (SCOD) increased around 16.3 times than the control one (from 471 to 7700 mg/L). The potential carbon source, such as the short-chain carbon of acetate and propionate, increased from 50 to 1088 mg/L and from 27 to 614 mg/L respectively, and approximately accounted for a quarter of total SCOD. Total petroleum hydrocarbon (TPH) decomposition was observed with a much higher removal rate of 84.3% simultaneously, and the substances with the function group of C=C and C–C bonds decomposed greatly. The long- and medium-chain substances in TPH were converted into the short-chain substances (90% of C₂₈–C₄₀ of hydrocarbons was removed, while C₁₀–C₁₈ increased by 13.8%). E⁺-Ozonation process could be one of the promising methods for P-sludge decomposition through carbon source releasing and TPH removal.
Afficher plus [+] Moins [-]Sludge disintegration using UV assisted Sono-Fenton process Texte intégral
2021
Olabi, Asaad | Yildiz, Sayiter
In this study, the effects of combination of ultrasonic process with UV light and both classical Fenton (CFP) and modified Fenton (MFP) processes on disintegration of waste sludge were investigated. Fe²⁺ and Fe⁰ dosage, hydrogen peroxide dosage, reaction time, pH, and different UV lamps were optimized to achieve a high degree of disintegration (DD). In addition, kinetic study and toxicity analysis were performed under optimum conditions for all processes. For CFP, the best DD 22.85% was found with optimum pH 3, reaction time 60 min, 7 g/kg TS Fe²⁺, 35 g/kg TS H₂O₂ doses, and UV-C light, while this value increased to 37.83% with ultrasound (US) application. For MFP; the best DD was achieved as 25.84% with optimum pH 3, reaction time 60 min, 5 g/kg TS Fe⁰, 25 g/kg TS H₂O₂ doses, and UV-C light; however, it rose to 42.32% in the presence of US. The use of US in all processes increased the germination percentage that expresses the sludge toxicity, up to 100%. In the kinetic study, it was found that all processes are in compliance with zeroth-order kinetics. It was concluded with this study that US has an important synergistic effect on Fenton applications and contributes to sludge disintegration.
Afficher plus [+] Moins [-]Effects of effluent discharges from a cement factory on the ecology of macroinvertebrates in an Afrotropical river Texte intégral
2021
Arimoro, Francis O. | Meme, Francis K. | Keke, Unique N.
Cement factory waste water impacts on the ecology of macroinvertebrate assemblages of the Oinyi River, North Central area of Nigeria, were evaluated bi-monthly for 1 year as part of a study to understand the effects of pollution processes in the lotic system that may initiate the development of policy and improved regulation. Three sampling stations, each 100 m long, were selected along 11-km stretch of the river. Station 1, located upstream of the discharge point from the cement factory plant; station 2, immediately downstream of the effluent discharge point; and station 3, 4 km downstream, were sampled. The waste water from the cement effluent factory impacted negatively on the water chemistry by elevating the levels of some heavy metals (Mn, Zn, Cu, and Ni), and other physicochemical parameters such as turbidity, chemical oxygen demand (COD), conductivity, and total suspended solid. A total of 81 macroinvertebrate taxa combined were recorded from the river. The community structure, diversity, and abundance depicted distinct variation between the effluent-impacted site, and the upstream station as the most sensitive macroinvertebrate taxa such as Neoperla and Cheumatopsyche species was completely missing from the effluent-impacted site. The preponderance of some dipteran taxa (Tanypus sp., Eristalis tenax, Simulum sp., Empis sp., and Atherix sp.) and drastic reduction in the Ephemeroptera-Plecoptera-Trichoptera (EPT) organisms in the impacted station is an indication that the chemical components of the cement effluent waste water were lethal to some aquatic forms. Extrapolations from canonical correspondence analysis (CCA) results revealed that turbidity, conductivity, BOD, orthophosphate-phosphorus, and heavy metals were strongly associated with the impacted station. Generally, the community structure of station 1 was more diverse with more sensitive taxa, different from those of stations 2 and 3, which were prone to intense human activities. The need for careful consideration of the water quality and indicator organisms is important for restoration of this river.
Afficher plus [+] Moins [-]Accumulation and clearance of tissue residues and health status of Nile tilapia Oreochromis niloticus (L.) juveniles as influenced by the extended oral oxytetracycline-dosing Texte intégral
2021
Abraham, Thangapalam Jawahar | Roy, Anwesha | Julinta, Roy Beryl | Singha, Jasmine | Patil, Prasanna Kumar | Krishna, Edapparambil Krishnappan Nanitha | Rajisha, Ravindran | Kumar, Kesavan Ashok
Antibiotics are considered an important primary therapy for bacterial diseases in aquaculture. This study evaluated the influence of oral administration of oxytetracycline (OTC) on feed intake, growth, mortality, residue accumulation and clearance, and histopathological changes in the vital organs of six groups of Nile tilapia Oreochromis niloticus when fed at 0–10 times the therapeutic dose (1×: 80 mg/kg biomass/day) for 10 and 20 consecutive days. The feed intake was reduced only slightly, viz., 2% in 10-day and 4.25% in 20-day dosing trials at 1× dose compared to control. While in other groups, an OTC-dose-dependent reduction in feed intake up to 31.25% was noted. The fish of the 0.5× and 1× groups recorded significantly high biomass, while the other OTC-dosed groups recorded significantly lower biomass than the control. The fold change in biomass between the control and 1× groups was insignificant. Dose-dependent mortalities were recorded in OTC-dosed fish in 10-day (1.67–6.67%) and 20-day (3.33–8.33%) trials. The OTC concentration in fish muscle established a dose- and time-response relationship. The OTC residue levels in muscle even on day 20 OTC-dosing were lower than the maximum residue limit (MRL) permitted by Codex Alimentarius (200 ng/g). On day 23 post OTC-dosing, the residue levels were traces to <10 μg/g in all groups, except the 10× group. The OTC-dosing caused mild to moderate pathological changes in the gills, liver and kidney of O. niloticus and the fish were able to mount adaptive biological responses to overcome the stress with time.
Afficher plus [+] Moins [-]WO3 nanoplates decorated with polyaniline and CdS nanoparticles as a new photocatalyst for degradation of imidacloprid pesticide from water Texte intégral
2021
Merci, Sanaz | Saljooqi, Asma | Shamspur, Tayebeh | Mostafavi, Ali
This study focused on the photocatalytic degradation of imidacloprid (IM) in water as the model pesticides. The effective division of photogenerated charge carriers is important in the photocatalytic reactions. So, a new PANI/WO₃-CdS photocatalyst was synthesized by a simple method. The prepared PANI/WO₃-CdS nanocomposite was characterized using Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy compatible with energy dispersive spectroscopy (FESEM-EDS), and X-ray diffraction (XRD). Degradation of IM pesticide under visible light irradiation was carried out to investigate the photocatalytic efficiency of the prepared nanocomposite. The effect of operational parameters on the degradation performance of pesticides was studied by response surface methodology (RSM). The optimum conditions for photocatalytic degradation of IM (94.7%) were found to be 10 ppm of IM, 150 mg of PANI/WO₃-CdS, and pH = 3.0. The apparent rate constant of IM photodegradation over PANI/WO₃-CdS was 0.016 min⁻¹. According to results, PANI/WO₃-CdS can serve as an efficient, and recyclable photocatalyst for imidacloprid degradation in an aqueous media.
Afficher plus [+] Moins [-]An ANN experiment on the Indian economy: can the change in pollution generate an increase or decrease in GDP acceleration? Texte intégral
2021
Mele, Marco | Nieddu, Luciano | Abbafati, Cristiana | Quarto, Angelo
In recent years, the concept of sustainable development has enriched numerous scientific researches. Therefore, the combination of economic growth and the environment has been the subject of numerous econometric and statistical models. They demonstrated that there is a two-way relationship between economic growth and pollution. So, we use data from the World Bank database (1971–2014) to assess the possibility that a change (positive or negative) in pollution in India generates a gross domestic product acceleration. Through a Machine Learning approach via artificial neural network analysis, empirical findings show that a deep neural network can predict the outcome under study. The novelty of this paper is to have determined the results through a model based on a comparison with a highly developed country (Japan). The results obtained show that in a country like India, 76% of the time, a change in pollution evolves into a change in the acceleration of the economic growth.
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