Уточнить поиск
Результаты 2841-2850 из 5,014
An experimental investigation of performance and emission of thumba biodiesel using butanol as an additive in an IDI CI engine and analysis of results using multi-objective fuzzy-based genetic algorithm Полный текст
2019
Debnath, Rabisankar | Sastry, Gadepalli Ravi Kiran | Rai, Ram Naresh
The present work studies the effect of butanol in thumba (Citrullus colocynthis) biodiesel in an IDI CI engine at varying percentages of 5 and 10% in 15 and 10% thumba biodiesel respectively with 80% diesel in each blend. Another blend was introduced with 80% diesel and 20% biodiesel without any additive. The experiment was conducted in a single cylinder four-stroke IDI CI engine at 1500 rpm varying from 25% to full-load (100%) conditions. The results showed diesel with less bio diesel and higher butanol in percentage gives good performance and emission compared to diesel at higher loads. Blend containing 10% bio diesel, 10% butanol, and 80% diesel (D80B10Bu10) showed higher cylinder pressure, heat release rate, BThE, and less NOₓ. Biodiesels gave less UHC, CO emissions. In this work, multi-objective fuzzy-based genetic algorithm was introduced for the best fit result. Four parameters were used for optimization (BSFC, BThE, CO, NOₓ). The result from genetic algorithm was taken for validation and the optimized result was found adequate after validation.
Показать больше [+] Меньше [-]Photocatalytic porcelain grés large slabs digitally coated with AgNPs-TiO2 Полный текст
2019
Bianchi, Claudia L. | Cerrato, Giuseppina | Pirola, Carlo | Galli, Federico | Capucci, Valentino
TiO₂ is employed as both photocatalytic and structural materials, leading to its applications in external coatings or in interior furnishing devices, including cement mortar, tiles, floorings, and glass supports. The authors have already demonstrated the efficiency of photoactive micro-sized TiO₂ and here its industrial use is reported using the digital printing to coat porcelain grés slabs. Many advantages are immediately evident, namely rapid and precise deposition, no waste of raw materials, thus positively affecting the economy of the process. Data for the thin films deposited by digital printing were compared with those obtained for the conventional spray method. The use of metal-doped TiO₂ is also reported so that the photoactivity of these materials can be exploited even under LED light. The digital inkjet printed coatings exhibited superior photocatalytic performance owing to both higher exposed surface area and greater volume of deposited anatase, as well as the greater areal distribution density of thinly and thickly coated regions. Moreover, the presence of TiO₂ doped silver increased the efficiency of the materials in NOx degradation both under UVA and LED lights.
Показать больше [+] Меньше [-]Study of the adsorption of endocrine disruptor compounds on typical filter materials using a quartz crystal microbalance Полный текст
2019
Guo, Jun-Xiong | Pan, Jie | Wang, Jing | Wang, Fei | Shi, Hong-Xin
Drinking water containing environmental endocrine disruptor compounds (EDCs) endangers human health, and researching the purification process of drinking water for the effective removal of EDCs is vitally important. Filtering plays a crucial role in the bio-adsorption of EDCs, but the adsorption mechanism that occurs between the EDCs and filters remains unclear. In this study, a quartz crystal microbalance (QCM) was employed to elucidate the adsorption mechanism because QCM is a label-free method that possesses high selectivity, high stability, and high sensitivity. The results indicated that a pseudo-first-order kinetic model best fits the adsorption process of four different EDCs, which included bisphenol A (BPA), estrone (E1), estradiol (E2), and sulfamethoxazole (SMZ), on silica (quartz sand), a typical filter material surface. The order of the amount of individual EDCs absorbed on the silica surface was qE₂ > qE₁ > qSMZ > qBPA and related to their molecular structure, polarity, and chargeability. As the initial EDC concentration increased, the adsorbed amount of the four EDCs on the silica surface increased; however, the initial concentration had little effect on removal efficiency. The calculated Freundlich exponent (1/n) demonstrated SMZ and BPA showed a greater tendency for adsorption than E1 and E2. The mass response time on the surface of the silica gradually increased as the pH increased (from 5.5 to 8.5), indicating the adsorption rate was inhibited by the increase in pH. The addition of electrolytes shortened the mass response time of EDCs on the QCM chip. The pH and ionic strength produced no significant effects on adsorption because hydrophobicity was the primary contributor to adsorption. This study facilitated a better understanding of the interaction between EDCs and filters in water treatment.
Показать больше [+] Меньше [-]Numerical model of aerobic bioreactor landfill considering aerobic-anaerobic condition and bio-stable zone development Полный текст
2019
Feng, Shi-Jin | Li, An-Zheng | Zheng, Qi-Teng | Cao, Ben-Yi | Chen, Hong-Xin
Aeration by airflow technology is a reliable method to accelerate waste biodegradation and stabilization and hence shorten the aftercare period of a landfill. To simulate hydro-biochemical behaviors in this type of landfills, this study develops a model coupling multi-phase flow, multi-component transport and aerobic-anaerobic biodegradation using a computational fluid dynamics (CFD) method. The uniqueness of the model is that it can well describe the evolution of aerobic zone, anaerobic zone, and temperature during aeration and evaluate aeration efficiency considering aerobic and anaerobic biodegradation processes. After being verified using existing in situ and laboratory test results, the model is then employed to reveal the bio-stable zone development, aerobic biochemical reactions around vertical well (VW), and anaerobic reactions away from VW. With an increase in the initial organic matter content (0.1 to 0.4), the bio-stable zone expands at a decreasing speed but with all the horizontal ranges larger than 17 m after an intermittent aeration for 1000 days. When waste intrinsic permeability is equal or greater than 10⁻¹¹ m², aeration using a low pressure between 4 and 8 kPa is appropriate. The aeration efficiency would be underestimated if anaerobic biodegradation is neglected because products of anaerobic biodegradation would be oxidized more easily. A horizontal spacing of 17 m is suggested for aeration VWs with a vertical spacing of 10 m for screens. Since a lower aeration frequency can give greater aeration efficiency, a 20-day aeration/20-day leachate recirculation scenario is recommended considering the maximum temperature over a reasonable range. For wet landfills with low temperature, the proportion of aeration can be increased to 0.67 (20-day aeration/10-day leachate recirculation) or an even higher value.
Показать больше [+] Меньше [-]Biochemical, molecular, and elemental profiling of Withania somnifera L. with response to zinc stress Полный текст
2019
Rout, Jyoti Ranjan | Kerry, Rout George | Panigrahi, Debasna | Sahoo, Santi Lata | Pradhan, Chinmay | Ram, Shidharth Sankar | Chakraborty, Anindita | Sudarshan, Mathummal
Zn stress seriously induces various toxic responses in Withania somnifera L., when accumulated above the threshold level which was confirmed by investigating the responses of protein, expression of antioxidant enzymes, and elemental profiling on accumulation of Zn. Zn was supplemented in the form of ZnSO₄ (0, 25, 50, 100, and 200 μM) through MS liquid medium and allowed to grow the in vitro germinated plants for 7 and 14 days. The study revealed that when the application of Zn increased, a significant reduction of growth characteristics was noticed with alterations of proteins (both disappearance and de novo synthesis). The activity of CAT, SOD, and GPX were increased up to certain concentrations and then declined, which confirmed through in-gel activity under different treatments. RT-PCR was conducted by taking three sets of genes from CAT (RsCat, Catalase1, Cat1) and SOD (SodCp, TaSOD1.2, MnSOD) and found that gene RsCat from CAT and MnSOD from SOD have shown maximum expression of desired genes under Zn stress, which indicate plant’s stress tolerance mechanisms. The proton-induced X-ray emission study confirmed an increasing order of uptake of Zn in plants by suppressing and expressing other elemental constituents which cause metal homeostasis. This study provides insights into molecular mechanisms associated with Zn causing toxicity to plants; however, cellular and subcellular studies are essential to explore molecule-molecule interaction during Zn stress in plants.
Показать больше [+] Меньше [-]Sorption of iodine in soils: insight from selective sequential extractions and X-ray absorption spectroscopy Полный текст
2019
Köhler, Fabian | Riebe, Beate | Scheinost, Andreas C. | König, Claudia | Hölzer, Alex | Walther, Clemens
The environmental fate of iodine is of general geochemical interest as well as of substantial concern in the context of nuclear waste repositories and reprocessing plants. Soils, and in particular soil organic matter (SOM), are known to play a major role in retaining and storing iodine. Therefore, we investigated iodide and iodate sorption by four different reference soils for contact times up to 30 days. Selective sequential extractions and X-ray absorption spectroscopy (XAS) were used to characterize binding behavior to different soil components, and the oxidation state and local structure of iodine. For iodide, sorption was fast with 73 to 96% being sorbed within the first 24 h, whereas iodate sorption increased from 11–41% to 62–85% after 30 days. The organic fraction contained most of the adsorbed iodide and iodate. XAS revealed a rapid change of iodide into organically bound iodine when exposed to soil, while iodate did not change its speciation. Migration behavior of both iodine species has to be considered as iodide appears to be the less mobile species due to fast binding to SOM, but with the potential risk of mobilization when oxidized to iodate.
Показать больше [+] Меньше [-]Short-term exposure to ambient air pollution and daily atherosclerotic heart disease mortality in a cool climate Полный текст
2019
Liu, Guangcong | Sun, Baijun | Yu, Lianzheng | Chen, Jianping | Han, Bing | Liu, Bo | Chen, Jie
The associations between exposure to short-term ambient air pollution and daily atherosclerotic heart disease (ASHD) mortality in cool climate have not been established. We performed a time-series analysis in Shenyang, the largest city of Northeastern China. We identified 7659 ASHD deaths and obtained deaths, ambient air pollution levels, and meteorological data for Shenyang during 2014–2017. The impact of ambient air pollution on daily ASHD deaths was analyzed using generalized additive models (GAMs). Cumulative lag effects were investigated using distributed lag non-linear models (DLNM). We found ASHD deaths significantly increased during days with higher air pollution. Particulate matter with diameter < 2.5 μm (PM₂.₅), PM₁₀, and sulfur dioxide (SO₂) were positively associated with ASHD deaths among the total population. Both single- and multi-pollutants models indicated that PM₂.₅, PM₁₀, and sulfur dioxide (SO₂) were positively associated with the deaths of women with AHSD, whereas only SO₂ was significant in men. This suggests significant gender-based differences in the fatal effects of ambient air pollution. Up to 28 days of single-day lag effects were observed for PM₂.₅ and PM₁₀ in women. The cumulative lag effects of PM₂.₅ and PM₁₀ showed increasing trends in both men and women; however, exposure to higher pollutant concentrations did not necessarily translate to greater risks. The ERRs differences between women and men were larger in cold days than in hot days, suggesting that lower temperature may exacerbate the adverse effects of air pollution on vulnerable women.
Показать больше [+] Меньше [-]Effects of mercury on the germination and growth of Quercus ilex L. seedlings Полный текст
2019
Rodríguez-Alonso, Javier | Sierra, María José | Lominchar, Miguel Ángel | Millán, Rocío
While it is well-known that the toxicity of mercury for plants is related to its bioavailability in the environment in which the plant lives, few studies have addressed Hg effects under controlled conditions of life-limiting available Hg concentrations. This study examines the effects of Hg on the holm oak (Quercus ilex L.) exposed to medium-high available Hg concentrations. Holm oak seeds were sown in a perlite substrate and grown in the presence of a nutrient solution containing 0, 5, 25, or 50 μM Hg. The variables determined as outcome measures were impacts on germination, growth, and nutrient accumulation along with Hg concentration in leaves, stems, and roots at different growth stages. Our findings suggest no overall detrimental effects of the metal on germination, nutrient accumulation, and plant growth, although root morphology was clearly modified. Mercury accumulation in the plant varied according to time, organ, Hg treatment dose, and plant growth stage. When comparing Hg build-up in the different organs, highest concentrations of the metal were detected in the roots, followed by the leaves and stems. The Hg accumulation pattern was positively correlated with time and Hg dose, whereas negative correlation was observed with growth stage. The impacts of all these factors on Hg accumulation were not additive pointing to interesting interaction effects that should be explored in future work.
Показать больше [+] Меньше [-]Interaction of cyanate uptake by rice seedlings with nitrate assimilation: gene expression analysis Полный текст
2019
Yu, Xiao-Zhang | Lei, Sheng-Yu | Lin, Yu-Juan | Zhang, Qing
Cyanate (CNO⁻) has been produced in the environment through either natural or anthropogenic sources. However, due to industrialization, it has been led more over-loads. In this study, interaction of CNO⁻ uptake by rice seedlings with nitrate assimilation was investigated using gene expression analysis after an acute phytotoxicity assay. Our results showed that CNO⁻ exposure caused inhibition on relative growth rates of plants. CNO⁻ analysis demonstrated that rice seedlings had higher potential for CNO⁻ uptake and the removal rates showed a zero-order kinetic. PCR analysis exposed that OsCYN transcript was not significantly induced by CNO⁻ treatments in rice tissues and CNO⁻ exposure also repressed gene expression of the collaborative enzyme carbonic anhydrase (CA), suggesting that assimilation of CNO⁻ initiated by the enzyme cyanase (CYN) in rice seedlings was an enzyme-limitation reaction. Gene expression of other enzymes involved in nitrate metabolism was tissue-specific under CNO⁻ exposure, suggesting that rice seedlings were able to trigger its intrinsic regulative and responsive mechanisms to cope up with uneven N conditions. Significant upregulation of three OsGDH isogenes, except for OsGDH1 in roots, was detected in both rice materials with enhancing CNO⁻ concentrations, suggesting that GDH may play a primary role to maintain the balance of C and N in plants under CNO⁻ exposure. In conclusion, because the innate pool of CYN activity was non-sufficient to degrade exogenous CNO⁻ by rice seedlings, CNO-derived ammonium only can serve as a supporting N source to support growth of rice seedling under non-effective doses of CNO⁻ exposure.
Показать больше [+] Меньше [-]Spatial distribution and pollution assessment of metals in intertidal sediments, Korea Полный текст
2019
Hwang, Dong-Woon | Kim, Pyoung-Joong | Kim, Seong-Gil | Sun, Chul-In | Koh, Byoung-Seol | Ryu, Sang-Ok | Kim, Tae-Hoon
We measured the concentrations of acid volatile sulfide (AVS), chemical oxygen demand (COD), and metals (As, Cd, Cu, Hg, Pb, and Zn) in surface sediments of 74 intertidal sectors along the western and southern coasts of Korea to determine their spatial distribution and pollution status. The concentrations of AVS, COD, and metals were relatively higher in northwestern and southeastern coasts due to human and industrial activities around metropolitan, industrial complexes, and large-scale farms. The results of the sediment quality guidelines and geoaccumulation index for organic matter and metal revealed that almost all intertidal sediments were unpolluted with regard to AVS, COD, Cd, Cu, Hg, Pb, and Zn and some intertidal sediments in northwestern and southeastern coasts were moderately polluted with regard to As. However, the results of pollution load index and ecological risk index for metal showed that intertidal sediments in the southeastern coast are significantly polluted and could have an adverse effect on benthic organisms. Thus, the appropriate management policy and restoration plan for intertidal sectors with high metal pollution level in Korea is necessary to improve the quality of intertidal sediment.
Показать больше [+] Меньше [-]