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Enhanced effects of ash and slag on SO3 formation in the post-flame region
2019
Xiao, Haiping | Cheng, Qiyong | Li, Jian | Ge, Jinlin
The effects of slag, fly ash (formed in boiler above 1500 °C), and experimental ash (formed in muffle furnace at 815 °C) on the formation of sulfur trioxide (SO₃) were studied in a fixed bed rector. The results showed that the slag had the best catalytic effect on SO₃ formation, the effect of fly ash was second, and the effect of experimental ash was the worst. The reason may be that the forms of iron in different samples were different. Iron in the experimental ash all existed in the form of Fe₂O₃. Iron in the fly ash mainly existed in the form of composite iron oxides, such as Fe₀.₃Mg₀.₇SiO₃, Ca₃Fe₂(SiO₄)₃, and MgFe₂O₄. Iron in the slag also mainly existed in the form of composite iron oxides, such as CaFe₂O₄, MgFe₂O₄, and CaMgO₀.₈₈Fe₀.₁₂SiO₄. The different forms of iron had different effects on SO₃ formation. Composite iron oxides could produce more oxygen vacancies owing to lattice defects. This likely promoted the migration and regeneration of lattice oxygen and thus better promoted the formation of SO₃ than Fe₂O₃. Moreover, MgFe₂O₄ and Ca₃Fe₂(SiO₄)₃ could better promote SO₃ formation than CaMgO₀.₈₈Fe₀.₁₂SiO₄ and Fe₀.₃Mg₀.₇SiO₃. In addition, increasing the SO₂ concentration and O₂ concentration increased the SO₃ concentration but increasing the SO₂ concentration decreased the SO₃ formation ratio.
Afficher plus [+] Moins [-]Occurrence, virulence, and antimicrobial resistance of Vibrio parahaemolyticus isolated from bivalve shellfish farms along the southern coast of Korea
2019
Ryu, A Ra | Mok, Jong Soo | Lee, Da Eun | Kwon, Ji Young | Park, Kunbawui
Vibrio parahaemolyticus is the most common pathogen causing seafood-borne illnesses in Korea. The present study evaluated the occurrence, virulence, and antimicrobial resistance of V. parahaemolyticus in seawater and bivalves obtained in 2016 from the southern coast of Korea, an important region for commercial aquaculture industries, especially the Korean raw seafood culture. V. parahaemolyticus was detected in 87 of 160 (54.4%) bivalve samples and in 32 of 130 (24.5%) seawater samples. Especially high levels were detected during summer to early autumn. All the seawater and bivalves contained less than 2 and 5% of the tdh and trh genes of the isolates, respectively, and seawater isolates possessed two fewer genes than the bivalve isolates. Of 23 antimicrobials tested, three agents (ofloxacin, norfloxacin, and trimethoprim/sulfamethoxazole) effectively treated V. parahaemolyticus illness due to the sensitivity of the isolates. The isolates were highly resistant to ampicillin, however, excluding it as a treatment option. More than half of the isolates exhibited resistance to at least three antimicrobials. These findings indicate the importance of an integrated monitoring and surveillance program noting the occurrence, virulence, and antimicrobial resistance patterns of V. parahaemolyticus in various aquatic sources for preventing human health risks from seafood consumption.
Afficher plus [+] Moins [-]Candy consumption may add to the body burden of lead and cadmium of children in Nigeria
2019
Orisakwe, Orish Ebere | Igweze, Zelinjo Nkeiruka | Udowelle, Nnaemeka Arinze
The affordability of candies and chocolates makes their consumption common especially in children. Heavy metal contamination of these candies is well known. This study has estimated health risks associated with heavy metals (HM; Pb, Cd, Cr, Ni, and Zn) in commonly consumed candies in Nigeria. Fifty candies/sweets and chocolates/chewing gums bought from different stores in Port Harcourt and Uyo in Niger Delta, Nigeria, were processed and digested in perchloric acid. The filtrate was analyzed for these heavy metals using atomic absorption spectroscopy (AAS). Pb/Zn and Cd/Zn ratios were calculated. Daily intake, the target hazard quotient (THQ), the hazard index (HI), and the cancer risk were estimated for children. About 80% of the samples exceeded the 0.1 mg/kg permissible lead level in candies. Milk sweet had the highest Pb:Zn and Cd:Zn ratios of 0.99 and 0.40 respectively. For chocolates, the Emperor had the highest Pb:Zn (0.50) ratios and Trident had the highest Cd:Zn (0.57) ratios. The calculated percentage provisional tolerable weekly intake (%PTWI) of cadmium from consumption of chocolates and candies was higher than the Joint Expert Committee for Food Additives (JECFA) standard, and the cancer risk of lead, cadmium, and chromium ranged between 10⁻⁷ and 10⁻³. Consumption of some candies by children in Nigeria may pose significant health risks.
Afficher plus [+] Moins [-]Marine macro-algae attenuates nephrotoxicity and hepatotoxicity induced by cisplatin and acetaminophen in rats
2019
Sohail, Nida | Hira, Khan | Tariq, Amna | Sultana, Viqar | Ehteshamul-Haque, Syed
Cisplatin is considered one of the best anticancer medications often used for the treatment of various cancers even with its adverse effects. Acetaminophen (paracetamol) is a widely used analgesic-antipyretic drug that causes hepatotoxicity at higher than the effective doses. The present study assesses the nephroprotective and hepatoprotective effects of two seaweeds against cisplatin and acetaminophen toxicity in rats. Damage to the liver and kidney was induced by administering a single intraperitoneal dose of acetaminophen (600 mg/kg) or cisplatin (7 mg/kg) to groups of rats. The damage to the liver and kidney was assessed by the elevated liver (ALT, AST, ALP, LDH, electrolytes) and kidney (urea, creatinine) biomarkers. The ethanol extract of brown seaweed reversed the elevated levels of kidney and liver biomarkers along with triglycerides, cholesterol, and glucose. Among the two seaweeds, Sargassum ilicifolium showed better nephroprotective and hepatoprotective effects than the standard drug N-Acetyl-cysteine, Halymenia porphyroides showed only limited protection. Findings of this study provide evidence of nephroprotective and hepatoprotective effects of S. ilicifolium. Seaweed could be a beneficial dietary supplement to attenuate nephrotoxicity and hepatotoxicity.
Afficher plus [+] Moins [-]The efficiency of carbon trading market in China: evidence from variance ratio tests
2019
Zhou, Jianguo | Huo, Xuejing | Jin, Baoling | Yu, Xuechao
On December 19, 2017, China’s National Development and Reform Commission (NDRC) announced the official launch of the much-anticipated national emissions trading system (ETS), which is a critical period for the transition from the eight carbon emission trading pilot projects to the national market at this stage. Comprehensively evaluating the efficiency of China’s eight carbon trading pilots is vital for strengthening the construction of its national ETS. This paper investigates the weak-form efficiency of eight carbon trading markets in China. We use a series of variance ratio tests to identify the efficiency from the market set up to the May 4, 2018, of all markets. The results indicate that the majority of the carbon trading markets are inefficient and only Beijing, Hubei, and Fujian markets are efficient. The China’s carbon trading market is gradually maturing and implemented. In addition, we analyze the factors have impact on the market efficiency. It shows that the liquidity, volume, allocation allowance, and transparency in information are significant factors; meanwhile, the regional policy and cross cooperation also are important factors. Finally, this paper puts forward several policy recommendations on how to strengthen the effectiveness of China carbon trading markets based on the empirical results.
Afficher plus [+] Moins [-]Investigation on the use of plastic pyrolysis oil as alternate fuel in a direct injection diesel engine with titanium oxide nanoadditive
2019
Bharathy, Sachuthananthan | Gnanasikamani, Balaji | Radhakrishnan Lawrence, Krupakaran
The challenges in handling of waste plastics, shortage and price rise of petro fuels may be dealt by producing fuel from waste plastics. A trial has been attempted here to assess the change in properties of PPO (plastic pyrolysis oil) by blending with TiO₂ nanoparticles and also to assess the power output and emission behaviour of a mono cylinder CI engine operating on PPO added with the above mentioned additive. Initially, the PPO was produced from the discarded waste plastics through the pyrolysis process by thermal cracking. Later, the nanoparticles were dispersed on mass fraction into the PPO using a binding agent with a homogenizer and ultrasonicator. Measurements were done to bring out the change in physiochemical properties of TiO₂-added PPO. Tests were conducted on a diesel engine using diesel, PPO, PPO + 25 ppm TᵢO₂, PPO + 50 ppm TᵢO₂, PPO + 75 ppm TᵢO₂ and PPO + 100 ppm TᵢO₂ fuel samples. The output reveals that the brake thermal efficiency (BTE) of PPO with 50 ppm TᵢO₂ sample combination increased by 2.1% when compared to neat PPO at maximum load situation. The CO, HC and smoke pollutants dropped considerably due to the blending of 50 ppm TᵢO₂ to PPO when compared to the other fuel combinations.
Afficher plus [+] Moins [-]Effect of earthworms and plants on the efficiency of vertical flow systems treating university wastewater
2019
Lavrnić, Stevo | Cristino, Sandra | Zapater-Pereyra, Maribel | Vymazal, Jan | Cupido, Domenico | Lucchese, Giovanni | Mancini, Benedetta | Mancini, Maurizio L.
One of the possible ways to improve the operation efficiency of constructed wetlands and to prevent their clogging is the application of earthworms. They have already been successfully applied for vermicomposting and for sludge dewatering and treatment. A few studies have already examined the effect of earthworms on the treatment of wastewater by vertical flow constructed wetlands (VFCWs), but none of them have provided a yearlong research result from an open-air system or compared the effect that different seasons in a temperate climate area can have on these invertebrates. The goal of this research was to estimate the effect that earthworms and plants have on VFCW’s operation. Four mesocosms (a filter, a filter with earthworms, a VFCW and a VFCW with earthworms) were built and their influent and effluent water quality was monitored for a period of 1 year. They were fed with wastewater coming from a building of the University of Bologna (Italy). The results have shown that the presence of earthworms in this specific system did not reduce the organic matter content of the substrate, but it has positively influenced plants’ growth. However, since neither earthworms nor plants had a statistically significant effect on the effluent quality, it can be concluded that the integration of these invertebrates cannot improve wastewater treatment of vertical flow filters or constructed wetlands.
Afficher plus [+] Moins [-]Technoeconomic modelling and environmental assessment of a modern PEMFC CHP system: a case study of an eco-house at University of Nottingham
2019
Sui, Sheng | Rasheed, Rizwan | Li, Qinglin | Su, Yuehong | Riffat, Saffa
This simulation study is aimed to model a contemporary Proton Exchange Membrane fuel cell (PEMFC) CHP system having a ‘heat and power’ autonomy as well as a provision of demand-driven electrical supply to the grid. A novel nanowire-electrode PEMFC stack is adopted within this PEMFC CHP system so to effectively replace the existing natural gas fuelled durable solid oxide fuel cell (SOFC) CHP system installed at David Wilson Millennium Eco-house at University of Nottingham. The energy savings, environmental, and economic performances of the proposed PEMFC system are determined and compared to the base case (SOFC) which is operated continuously to maintain a 1.5 kWe. While to meetup the highly fluctuating and seasonal demands of heating and power like in the UK, a PEMFC is more productive and advantageous over a SOFC. The proposed PEMFC unlike to the SOFC will be able to operate and adjust its output and turn down instantly as per changing conditions of ambient temperatures and loads in terms of electricity and heat. The results of the modelling predicted that as compared to the base case scenario, this PEMFC CHP system will efficiently reduce an annual CO₂ emission by 65.99% and fiscal costs by 66.74% with a viable internal rate of return as 8.93% and benefit to cost ratio as 1.02.
Afficher plus [+] Moins [-]Evaluation of the bioremediation potential of mud polychaete Marphysa sp. in aquaculture pond sediments
2019
Mandario, Mary Anne E. | Alava, Veronica R. | Añasco, Nathaniel C.
Organic enrichment from aquaculture could alter the chemical composition of the fishpond bottom by increasing the levels of organic matter (OM), sulfur (S), iron (Fe), and lower pH of the sediment. Polychaetes can contribute to the nutrient cycling and remediation of polluted sediment. A laboratory experiment was conducted to test the remediation potential of small and large mud polychaete Marphysa sp. introduced to two types of fishpond sediment. Initially, Sediment A had lower OM, S, Fe, and higher pH than Sediment B. After 30 days, in Sediment B, large polychaetes significantly decreased the OM level (27%) while both small and large polychaetes promoted significant decreases of S (71%) and Fe (70–73%) in both sediment types. The increase of sediment pH was promoted by the presence of polychaetes (0.53–0.69) although pH level in small polychaete was not significantly different with the no polychaete treatment. Regardless of polychaete treatment, the pH level of Sediment B (1.04 ± 0.10) was significantly improved than that of Sediment A (0.17 ± 0.02). In both sediments, large polychaetes (95%) had better survival rates than small polychaetes (73%). These findings reveal that large Marphysa sp. can significantly improve sediment quality by decreasing the levels of OM, S, and Fe and improve pH level to a more basic form without compromising its survival. Large polychaetes are recommended to be used as bioremediators of organically enriched aquaculture pond sediment.
Afficher plus [+] Moins [-]Photodegradation using TiO2-activated borosilicate tubes
2019
Khalaf, Samer | Shoqeir, Jawad H. | Scrano, Laura | Karaman, Rafik | Bufo, Sabino A.
This study examines the photocatalytic activity of titanium dioxide (TiO₂) semiconductor supported on borosilicate tubes (cut-off 290 nm) towards removal of a mix of persistent organic pollutants (POPs) from water. For this purpose, two widely used analgesic and anti-inflammatory drugs (NSAIDs), ibuprofen (IBU) and mefenamic acid, along with MCPA sodium monohydrate, which is a common herbicide frequently used in the agricultural activities, were selected as a case study. Borosilicate tubes were coated with titanium oxide through two different approaches: sol-gel dip-coating and a hybrid nanoparticle dip-coating and plasma-enhanced chemical vapour deposition (PECVD) process. The photochemical reactor that hosts the titania-coated tubes was designed to permit continuous throughput of liquid feed stream. The photodegradation experiments were performed in laboratory conditions under artificial irradiation simulating solar light. The efficiency of direct photolysis and heterogeneous photocatalysis (TiO₂) was investigated, and the performance of each coating method was evaluated. Kinetic studies for each experiment were accomplished, the overall results showed poor efficiency and insufficient removal for NSAIDs through direct photolysis, whereas applying heterogeneous photacatalysis with TiO₂ coated on borosilicate tubes was found to accelerate their degradation rate with complete decomposition. Concomitantly, kinetic experimental results showed a critical difference of performance for the two coating methods used; in particular, the degradation rates of pollutants by the sol-gel-coated tubes were much faster than the degradation by the nanoparticle/PECVD-coated tubes. Using TiO₂ supported on borosilicate tubes appears to be a promising alternative to conventional TiO₂ suspension and avoid post-separation stages. The results achieved in this study can be used to optimise large-scale applications, and expanding the study to cover a wide range of pollutants will lead to achieve more representative results.
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