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The combined effect of low viscous biofuel and EGR on NO-smoke tradeoff in a biodiesel engine—an experimental study 全文
2020
Rajasekar, Venkatesan | Geo, Varuvel Edwin | Martin, Leenus Jesu | Nagalingam, Beddhannan
The present study aims to study the effect of low viscous biofuel, namely pine oil (PO) and orange oil (O) blending with Jatropha methyl ester (JOME) along with exhaust gas recirculation (EGR) on NO-smoke tradeoff in a single-compression ignition (CI) engine. Two blends of pine oil and orange oil (30% by volume) with JOME were prepared and tested at 10%, 15%, and 20% EGR rates for various load conditions and compared with base fuels. JOME operation increased NO emission by 4% and reduced smoke opacity by 10% in comparison to diesel at maximum load condition. Poor physical properties of JOME, namely high viscosity and inferior volatility leads to reduced brake thermal efficiency with higher HC and CO emissions. Blends of JOME with low viscous biofuel reduces smoke emission with a further increase in NO emission in comparison to JOME as a result of combustion enhancement. Addition of EGR with JOME70 + PO30 and JOME70 + O30 aids in the reduction of NO emission with a slight increase in smoke opacity. Considering the NO-smoke tradeoff, JOME70 + O30 + EGR (10%) is optimum, NO emission is reduced by 14% and 11% in comparison to JOME and diesel and smoke opacity is reduced by 5% and 15% in comparison to JOME and diesel at maximum load, respectively.
显示更多 [+] 显示较少 [-]Does ozone exposure affect herbivore-induced plant volatile emissions differently in wild and cultivated plants? 全文
2020
Brosset, Agnès | Saunier, Amélie | Kivimäenpää, Minna | Blande, James D.
Concentrations of tropospheric ozone have more than doubled in the Northern Hemisphere since pre-industrial times. Plant responses to single abiotic or biotic stresses, such as ozone exposure and herbivore-feeding, have received substantial attention, especially for cultivated plants. Modern cultivated plants have been subjected to selective breeding that has altered plant chemical defences. To understand how ozone might affect plant responses to herbivore-feeding in wild and cultivated plants, we studied the volatile emissions of brassicaceous plants after exposure to ambient (~ 15 ppb) or elevated ozone (80 ppb), with and without Plutella xylostella larvae-feeding. Results indicated that most of the wild and cultivated plants increased volatile emissions in response to herbivore-feeding. Ozone alone had a weaker and less consistent effect on volatile emissions, but appeared to have a greater effect on wild plants than cultivated plants. This study highlights that closely related species of the Brassicaceae have variable responses to ozone and herbivore-feeding stresses and indicates that the effect of ozone may be stronger in wild than cultivated plants. Further studies should investigate the mechanisms by which elevated ozone modulates plant volatile emissions in conjunction with biotic stressors.
显示更多 [+] 显示较少 [-]Public perspectives on reducing the environmental impact of onshore wind farms: a discrete choice experiment in South Korea 全文
2020
Lee, Hye-jeong | Yoo, Seung-Hoon | Huh, Sung-Yoon
Onshore wind farms have the advantage of a lower cost than offshore wind farms, but their negative environmental impact has been pointed out as a problem. If this environmental impact can be lessened, public acceptance of onshore wind farms will be significantly increased. This study investigates public attitudes to the lessening of the environmental impact of onshore wind farms, focusing on three specific attributes: visual impact, ecosystem destruction and noise pollution. The area of empirical analysis is South Korea, and the choice experiment data are analysed using a mixed logit model to reflect the heterogeneity of the respondents’ preferences. The analysis results show that there is considerable heterogeneity in respondents’ preferences and that they regard the visual impact and the ecosystem destruction as more important than the noise pollution. Respondents are willing to pay KRW 197, KRW 138 and KRW 69 for a 1% improvement in visual impact, a 1% reduction in ecosystem destruction and a 1-dB reduction in noise, respectively. The results of the scenario analysis show that simultaneous improvements in the three attributes should be made in order to ensure a certain level of public acceptance. Related policy implications are provided based on the analysis results.
显示更多 [+] 显示较少 [-]Garbage in garbage out: the contribution of our industrial advancement to wastewater degeneration 全文
2020
Unuofin, John O.
Natural water sources are habitually marred by insidious anthropogenic practices and municipal wastewater discharges that contain either of xenobiotic pollutants and their sometimes more toxic degradation products, or both. Although wastewater is considered as both a resource and a problem, as explained in this review, it is however daunting that, while the global village is still struggling to decipher the mode of proper handling, subsequent discharge and regulation of already established aromatic contaminants in wastewater, there emanates some more aggressive, stealth and sinister groups of compounds. It is quite ironic that majority of these compounds are the ‘go through’ consumables in our present society and have been suspected to pose several health risks to the aquatic ecosystem, eliciting unfavourable clinical manifestations in aquatic animals and humans, which has heightened the uncertainties conferred on freshwater use and consumption of some aquatic foods. This review therefore serves to give a brief account on the metamorphosis of approach in detection of aromatic pollutants and ultimately their implications along the trophic chains in the community.
显示更多 [+] 显示较少 [-]Biosorption of tungstate onto garlic peel loaded with Fe(III), Ce(III), and Ti(IV) 全文
2020
Wang, Yaoyao | Huang, Kai
In present study, garlic peel (GP) was modified by loading with Fe(III), Ti(IV), and Ce(III) through a cation exchange process, i.e., nGP-COOH + Mⁿ⁺ = (nGP-COO)-Mⁿ⁺ + nH⁺ (M = Fe, Ce, Ti), which could adsorb tungstate effectively under the weakly acidic conditions. The optimal initial pH for maximum adsorption of W(VI) was determined at 1~3 for Ti-GP, 1~4 for Fe-GP, and 3 for Ce-GP, respectively; and at pH 2.5, the corresponding maximum adsorption capacity for Fe-GP, Ti-GP, and Ce-GP was evaluated as 91.5 mg/g, 83 mg/g, and 84 mg/g tungsten respectively. Coexisting anions like chloride, sulfate, and carbonate showed little effect on tungsten adsorption, while fluoride and phosphate inhibited the adsorption drastically. The column adsorption showed that the breakthrough point for Ce-GP, Ti-GP, and Fe-GP was 180 min, 200 min, and 270 min respectively. And 0.1 mol/L NaOH effectively eluted the adsorbed tungsten, and concentration of the eluted solution had almost 6, 19.9, and 22 factors of the initial tungstate concentration correspondingly.
显示更多 [+] 显示较少 [-]Investigation of exhaust emissions of an isolated diesel engine blended with ethylhexyl nitrate using experimental and ANN approach 全文
2020
Sevinc, Huseyin | Hazar, Hanbey
Thermal barrier coating (TBC) implementations and oxygenated additives are remarkable issues that may decrease the exhaust emissions of engines. This study examines the effect of chromium oxide (Cr₂O₃) coating and the addition of ethylhexyl nitrate (EHN) on exhaust emissions of a diesel engine. In addition, an artificial neural network (ANN) model was designed which estimates exhaust emissions based on engine speed in order to reduce time, labor, and costs lost in experimental studies, and the performance of the ANN was evaluated. Piston crown and valves of engine were processed with Cr₂O₃. The E3, E6, and E9 blends were produced by blending 3%, 6%, and 9% (vol.) ratios of 2-ethylhexyl nitrate with diesel fuel. Engine speed was used as input parameter and carbon monoxide (CO), nitrogen oxide (NOX), hydrocarbon (HC), and smoke density were used as output parameters. To evaluate the performance of ANN, error rates, and regression (R) values were considered. Experimental results revealed that CO, HC, and smoke density decreased in the CE whereas NOX values increased compared with the UE. The addition of EHN reduced NOX emission and smoke density, whereas it increased CO and HC emissions. The result showed that ANN model can predict the exhaust emissions at a high accuracy rate. The lowest regression results were achieved as 0.98395, 0.99047, 0.99268, and 0.98383 for the CO, NOX, smoke density, and HC, respectively. Moreover, the average R values of NOX, HC, CO, and smoke density were obtained as 0.99767, 0.99131, 0.99396, and 0.99741. The maximum error rates of the estimated outcomes were obtained as 5.25% on average. Graphical abstract
显示更多 [+] 显示较少 [-]Role of public-private partnerships investment in energy and technological innovations in driving climate change: evidence from Brazil 全文
2020
Ahmad, Mahmood | Raza, Muhammad Yousaf
This study aims to examine the impact of public-private partnerships (PPP) investment in energy, technological innovations (TI), economic growth (EG), exports, and foreign direct investment (FDI) on CO₂ emissions in Brazil over the period from 1984 to 2018. In doing so, we employ the Ng-Perron unit root test to examine the stationarity and autoregressive lag distributed (ARDL) model for cointegration between CO₂ emissions and its determinants. The outcomes are as follows: first, in the long run, the PPP investment in energy deteriorates the environmental quality by increasing CO₂ emissions, while TI has a significant negative effect on CO₂ emissions. It is also found that the exports and FDI degrade the environmental quality and the relationship between EG and CO₂ emissions is inverted U-Shaped, presence of the EKC hypothesis. Second, in the short run, PPP investment in the energy sector is negatively influencing, while TI has a positive association with carbon emissions. The empirical findings provide new insights for policymakers to regulate PPP investment in the energy sector for the improvement of environmental quality in Brazil. Graphical abstract
显示更多 [+] 显示较少 [-]The performance of micro-meso-pore HY zeolite for supporting Mo toward oxidation of dibenzothiophene 全文
2020
Dadashi, Mohaddese | Mazloom, Golshan | Akbari, Azam | Banisharif, Farhad
A uniformly distribution of 3 wt.% Mo (with tetrahedral coordination) on a commercial HY zeolite having both micro- and meso-pores, provided a new active catalyst which resulted 100% removal of DBT in this work. Respectively, H₂O₂ and acetonitrile were used as the oxidant and extraction solvent for oxidative desulfurization (ODS) at a mild condition. The structure of three-dimensional meso-pores, despite major micro-pores, was proved to be intriguing for the use of acidic HY zeolite as a support material in this process. The catalyst samples were characterized by different analyses of XRPD, XRF, FTIR, SEM, EDX, TEM, N₂ adsorption desorption, BET, BJH, UV-vis, and NH₃-TPD. High amounts of Mo were not in favor of the catalytic performance because of increasing non-framework polymolybdate formation, which led to decreasing meso-pore volume. Acid sites strength also decreased by increasing Mo content. The Mo active sites at a low loading of 3 wt.% reached the best performance for the complete removal of DBT (t = 90 min, T = 60 °C, catalyst/fuel = 8 g/L, O/S = 2, VSₒₗᵥₑₙₜ/VOᵢₗ = 1/2, DBT = 1000 ppm), mainly due to the presence of isolated Mo species in the framework of HY. The efficiency still reached to 90% after recycling the catalyst three times. The reusability of catalyst revealed the adsorption of the aqueous phase by this hydrophilic catalyst during the process being as a major deactivation factor. This was significantly diminished via a subsequent washing by acetonitrile.
显示更多 [+] 显示较少 [-]Optimizing reaction conditions and experimental studies of selective catalytic reduction of NO by CO over supported SBA-15 catalyst 全文
2020
Souza, Monique S. | Araújo, Rinaldo S. | Oliveira, Alcineia C.
Selective catalytic reduction of NO with CO (CO-SCR) was investigated based on optimizing the operating conditions by response surface methodology (RSM) and by appropriately choosing the supported SBA-15 catalysts. The effects of the CO-SCR reaction parameters such as NO:CO molar ratios and oxygen concentrations on the catalytic performance were determined by RSM to evaluate the NO conversion using a first-order polynomial model. The CuO/SBA-15 and Fe₂O₃/SBA-15 catalysts were synthesized by a hydrothermal method and characterized by X-ray diffraction (XRD), atomic absorption spectroscopy (AAS), N₂ adsorption-desorption (BET), scanning electron microscopy coupled to energy dispersive X-Ray spectroscopy (SEM-EDS), and Fourier transform infrared spectroscopy (FTIR) to investigate the physicochemical properties of the solids. The RSM showed a very good agreement between predicted values and experimental results with the Pareto analysis confirming the accuracy and reliability of the model. The optimized results indicated the maximum NO conversion at 500 °C with using the NO to CO molar ratio of 1:2 (500:1000 ppm) in the absence of oxygen. Under these conditions, CuO/SBA-15 catalyst achieved 99.7% of NO conversion, whereas Fe₂O₃/SBA-15 had 98.1% of the catalytic parameter. Catalytic tests in CO-SCR reaction were performed on both catalysts at optimum operating conditions with CuO/SBA-15 exhibiting better performance compared to that of Fe₂O₃/SBA-15. The results revealed that CuO/SBA-15 was a promising catalyst for CO-SCR of NO due to the well-dispersed CuO phase on SBA-15 surface that allows the solid being more tolerant to the presence of oxygen.
显示更多 [+] 显示较少 [-]Toxicological potential of penconazole on early embryogenesis of white mice Mus musculus in either pre- or post-implantation exposure 全文
2020
El-Shershaby, Abd El-Fattah M. | Lashein, Fakhr El-Din M. | Seleem, Amin A. | Ahmed, Abeer A.
The present investigation was conducted to evaluate the effect of penconazole (PEN) fungicide on early embryogenesis of white mice. In the first experiment, 48 pregnant females were divided into different groups; the first group is control (G1). The second group (G2) was treated daily with PEN (30-, 20-, 10-, 5-mg/kg BW). The third group (G3) was treated with PEN (5-mg/kg BW; day after the other day). The fourth group (G4) was treated with PEN (2.5-mg/kg BW daily) during pre-implantation stage (from the 1st to the 4th day of gestation). The fifth group (G5) was treated with PEN (2.5-mg/kg BW daily) during post-implantation (from the 5th to the 8th day of gestation). The pregnant females were sacrificed at the 14th day of gestation. In the second experiment, 63 pregnant females were classified into control, PEN-treated during pre-implantation period (2.5-mg/kg BW), and PEN-administered during post-implantation period (2.5-mg/kg BW). Each group was sacrificed at stages E6.5, E7.5, E8.5, E9.5, E11.5, E14.5, and E18.5. The high doses of PEN in the first experiment showed failed pregnancy, foetoresorption, and embryo disorganization. High doses of PEN induce alterations in the uterus tissue at the level of histology and immunohistochemistry for the expression of TGFβ2, TNFR2, Caspase 10, and HSP70. The low doses of PEN in the second experiment showed upregulated expression of TGFβ2, TNFR2, Caspase 10, and HSP70 at stages E6.5 and E7.5. In conclusion, PEN was found to alter the suitable uterine environment for proper implantation and development at the levels of histological and immunohistochemical that could create a risk during the full course of embryogenesis.
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