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النتائج 4761 - 4770 من 6,558
Emission profiling of CI engine fueled with neem and wintergreen oil blend with hexanol and octanol manifold injection النص الكامل
2020
Swaminathan, Siluvaimuthu | Subramanian, Thiyagarajan | Martin, Leenus Jesu | Beddhannan, Nagalingam
The present work details the effects of injection of higher order alcohols, namely hexanol (Hex) and octanol (Oct) as secondary fuels in a CI engine. The last decade has seen an exponential increase in the carbon emission chief of which have been contributed by fossil fuels. Vegetable oils provide a viable alternative to the current scenario as they can be synthesized easily from nature and can be readily adapted for use in CI engines. Neem oil (NO) is non-edible and widely available and hence taken as a base fuel for this research. The poor properties of neem oil were improved by the addition of novel low viscous biofuel, namely wintergreen oil (WGO). During the course of this research work, a blend containing a mixture of 50% of neat neem oil and 50% of wintergreen oil (NO50-WGO50) was optimized based on trial tests and taken as pilot fuel while Hex and Oct were injected along with intake air as secondary fuels. The alcohols were injected into the engine successively in the 10%, 20%, and 30% (by mass) ratios. Experiments were conducted in a single-cylinder CI engine fabricating 5.2-kW power at a constant speed of 1500 rpm at varying load conditions. It is observed that inferior performance of NO led to more smoke, HC, and CO in comparison to diesel at all the loads and these are improved with NO50-WGO50 blend. Nevertheless, a minor increase in NOx emission was perceived with the blend. Addition of higher order alcohol promoted reduction of both NOx and smoke emission without affecting performance. Among the various combinations, NO50-WGO50 + Hex30 and Oct30 reduced NOx emission by 12% and 9.5% and smoke emission by 13% and 19% respectively. These results are on par with the diesel performance and emission characteristics.
اظهر المزيد [+] اقل [-]A novel thermophilic anaerobic granular sludge membrane distillation bioreactor for wastewater reclamation النص الكامل
2020
Duong, Chinh Cong | Chen, Shiao-Shing | Lê, Huy Quang | Chang, Hau-Ming | Nguyen, Nguyen Cong | Cao, Dan Thanh Ngoc | Chien, I-Chieh
Membrane distillation (MD) has a high heat requirement. Integrating MD with thermophilic bioreactors could remedy this problem. A laboratory-scale thermophilic anaerobic granular sludge membrane distillation bioreactor (ThAGS-MDBR) was used to treat wastewater with a high organic loading rate (OLR). Waste heat from ThAGS was used directly for the MD process to reduce energy consumption. The result demonstrated that the ThAGS-MDBR system achieved a high-efficiency removal of chemical oxygen demand (more 99.5%) and NH₄⁺-N (96.4%). Furthermore, the highest methane production from the proposed system was 332 mL/g CODᵣₑₘₒᵥₑd at OLR of 16 kg COD/m³/day. Specifically, an aggregate of densely packed diverse microbial communities in anaerobic granular sludge was the main mechanism for the enhancement of bioreactor tolerance with environmental changes. High-quality distillate water from ThAGS-MDBR was reclaimed in one step with total organic carbon less than 1.7 mg/L and electrical conductivity less than 120 μS/cm. Furthermore, the result of the DNA extraction kit recorded that Methanosaeta thermophila was a critical archaea for high COD removal and bioreactor stability.
اظهر المزيد [+] اقل [-]Revealing the active period and type of tetracycline stress on Chinese cabbage (Brassica rapa L.) during seed germination and post-germination النص الكامل
2020
Luo, Yuan | Liang, Jie | Zeng, Guangming | Zhang, Yafei | Cheng, Xiaojuan | Jiang, Longbo | Xing, Wenle | Tang, Ning
Stresses of antibiotics can cause strains (i.e. effects) on seed at germination and post-germination stages. But there is a lack of research on the period and type of the effects at present. In this study, Chinese cabbage (Brassica rapa L.), a commonly used crop, was selected to investigate the effect of tetracycline (TC), a major-use antibiotic, on its seed during different periods of the stages. Results showed that there were no significant differences among the germination energy (GE) of control (CK) and treatments, but radicle length (RL) of the treatments, the exposure to TC at post-germination stage (i.e. radicle elongation stage), was all significantly less than that of CK. The initial stage of radicle elongation was the earliest and most sensitive period at which the stress of TC caused the plastic effect on seed. Moreover, the action of TC stress on seed did not have a delayed characteristic. The result of RL was identical to the leakage of intracellular substances at radicle fast elongation stage, but not the Evan’s blue trapped by radicle. We concluded that TC inhibited the elongation of radicle through weakening the cellular metabolic activity rather than leading to the loss of cellular membrane integrity. It should be paid more attention to the phytotoxicity of TC in the field due to its active characteristics revealed in our study.
اظهر المزيد [+] اقل [-]Influence of particle size distribution on anaerobic degradation of phenol and analysis of methanogenic microbial community النص الكامل
2020
Wang, Jing | Wu, Benteng | Sierra, Julian Muñoz | He, Chunhua | Hu, Zhenhu | Wang, Wei
Sludge morphology considerably affects the mechanism underlying microbial anaerobic degradation of phenol. Here, we assessed the phenol degradation rate, specific methanogenic activity, electron transport activity, coenzyme F₄₂₀ concentration, and microbial community structure of five phenol-degrading sludge of varying particle sizes (i.e., < 20, 20–50, 50–100, 100–200, and > 200 μm). The results indicated an increase in phenol degradation rate and microbial community structure that distinctly correlated with an increase in sludge particle size. Although the sludge with the smallest particle size (< 20 μm) showed the lowest phenol degradation rate (9.3 mg COD·gVSS⁻¹ day⁻¹), its methanogenic activity with propionic acid, butyric acid, and H₂/CO₂ as substrates was the best, and the concentration of coenzyme F₄₂₀ was the highest. The small particle size sludge did not contain abundant syntrophic bacteria or hydrogenotrophic methanogens, but contained abundant acetoclastic methanogens. Moreover, the floc sizes of the different sludge varied in important phenol-degrading bacteria and archaea, which may dominate the synergistic mechanism. This study provides a new perspective on the role of sludge floc size on the anaerobic digestion of phenol.
اظهر المزيد [+] اقل [-]Impact of average temperature, energy demand, sectoral value added, and population growth on water resource quality and mortality rate: it is time to stop waiting around النص الكامل
2020
Tehreem, Hafiza Samina | Anser, Muhammad Khalid | Nassani, Abdelmohsen A. | Abro, Muhammad Moinuddin Qazi | Zaman, Khalid
It is an overwhelming concern that increases in global average temperature lead to serious consequences on the natural environment in the form of deteriorating water resource quality and damaging healthcare sustainability agenda. The sustainable innovation forum (COP21) shows a high concern on climate changes and suggested to reduce global average temperature less than 2 °C. The study brings an idea from the stated theme and analyzed the relationship between climate change and water resource quality in order to redesign economic and environmental policies to improve water quality and healthcare sustainability in the context of Pakistan. The country has serious issues regarding the provision of safe drinking water, improved water resource quality, and healthcare sustainability, which can be achieved by sustainable policies to handle the extreme temperature in Pakistan. The study employed simultaneous generalized method of moments (GMM) technique in order to estimate parameters of the study during the period of 1980–2016. The results show that energy demand and industry value added substantially decrease water resource quality (WRQ), while agriculture value added and per capita income significantly increase WRQ in a country. The other regression apparatus, where health expenditures serve as the response variable, shows that average temperature, industry value added, population growth, and foreign direct investment (FDI) inflows significantly increase healthcare expenditures while WRQ has a negative impact on healthcare expenditures in a country. The final regression model shows that average temperature and per capita income decrease, while WRQ and industrial value added increase mortality rate in a country. The overall results confirm that WRQ affected by climate change, energy demand, and population growth that need sustainable water resource policies in order to achieve long-term sustained growth. The climate actions required more policy instruments to combat environmental challenges that should support healthcare sustainability agenda across the globe.
اظهر المزيد [+] اقل [-]Could phthalates exposure contribute to the development of metabolic syndrome and liver disease in humans? النص الكامل
2020
Milošević, Nataša | Milanović, Maja | Sudji, Jan | Bosić Živanović, Dragana | Stojanoski, Stefan | Vuković, Bojan | Milić, Nataša | Medić Stojanoska, Milica
In the study, 305 patients of both genders were enrolled and divided into three groups: obese (BMI > 30 kg/m²), patients who were diagnosed type 2 diabetes mellitus (T2DM), and control, normal weight healthy volunteers. At least one of ten different phthalate metabolites was determined in the urine samples of 49.84% all enrolled participants. In the obese subgroup, the sum of all urinary phthalate metabolites was positively associated with TG levels (p = 0.031) together with derived TC/HDL and TG/HDL ratios (p = 0.023 and 0.015), respectively. Urinary MEP concentration was positively correlated with the HOMA-IR in T2DM subgroup (p = 0.016) while in the control subgroup, log₁₀MEP levels were negatively correlated with total cholesterol (p = 0.0051), and LDL serum levels (p = 0.0015), respectively. Also, in the control subgroup, positive linear correlations between urinary log₁₀MEP levels and TyG and TYG-BMI values (p = 0.028 and p = 0.027), respectively, were determined. Urinary MEHP levels were associated with glucose serum levels (p = 0.02) in T2DM subgroup, while in the control HDL values were negatively associated with log₁₀MEHP (p = 0.0035). Healthy volunteers exposed to phthalates had elevated AST levels in comparison to non-exposed ones (p = 0.023). In control subgroup, ALT and AST values were increased (p = 0.02 and p = 0.01, respectively) in MEP exposed while GGT levels were enhanced (p = 0.017) in MEHP exposed in comparison with non-exposed. Combined phthalates influence on glucose and lipid metabolism may increase the possibility for NAFLD and insulin resistance development among exposed individuals.
اظهر المزيد [+] اقل [-]CeCu composite oxide for chlorophenol effective removal by heterogeneous catalytic wet peroxide oxidation النص الكامل
2020
Xie, Hongmei | Zeng, Jia | Zhou, Guilin
CeCu solid solution oxide catalysts were prepared by the complex method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET), and X-ray photoelectron spectroscopy (XPS). And its activity in the catalytic wet peroxide oxidation (CWPO) of 4-chlorophenol (4-CP) and 2,4-dichlorophenol (2,4-DCP) in water was investigated. The results showed that the Cu²⁺ ions dissolved into the CeO₂ lattice to form CeCu solid solution oxide with a coarse, interconnected, porous, and cotton-like morphology. The metal-oxygen bonds were weakened by the formation of solid solution in the CeCu oxide catalyst. This weakening facilitated the activation and decomposition of the H₂O₂ to form highly oxidative HO· species that can lead to significant chlorophenol mineralization. The formation of CeCu solid solution oxide can effectively inhibit the Cu ions to be leached from the used CeCu oxide catalysts, which can ensure the CeCu oxide catalysts to adapt to a wide pH range of 2.1–7.9 and exhibit good reusability. CWPO reaction of 4-CP and 2,4-DCP molecules on CeCu oxide catalysts conforms to the first-order kinetic equation: y = 6959.3x − 17.2 and y = 9725x − 25.4, respectively. And the reaction activation energies are 57.8 and 80.8 kJ/mol, respectively. The TOC removals of 4-CP and 2,4-DCP can exceed 88 and 82%, and the dechlorination rates of 4-CP and 2,4-DCP are higher than 95 and 99.5%, respectively.
اظهر المزيد [+] اقل [-]Analysis of the influencing factors of energy-related carbon emissions in Kazakhstan at different stages النص الكامل
2020
Xiong, Chuanhe | Chen, Shuang | Gao, Qun | Xu, Liting
This study analyzes Kazakhstan’s influencing factors of energy-related carbon emissions in different stages, and the study period (1992–2014) was divided into four stages by using the logarithmic mean Divisia index (LMDI) method. In the low efficiency and high output stage, Kazakhstan had the most energy-related carbon emissions. The total energy-related carbon emissions might be positive or negative in the high efficiency and high output stage and the low efficiency and low output stage, and this was mainly determined by the energy intensity effect or the economic output effect. Different influencing factors had different effects in the different stages from 1992 to 2014. The economic output effect was the first contributor for promoting energy-related carbon emissions, and the energy intensity factor was the first contributor for suppressing energy-related carbon emissions from 1992 to 2014. Finally, policy recommendations in terms of the main influencing factors are put forward, including the low-carbon economic development mode transformation, technological innovation, and renewable energy development.
اظهر المزيد [+] اقل [-]Chemical characteristics of rainwater in the tropical rainforest region in northwestern Borneo النص الكامل
2020
Valappil, Ninu Krishnan Modon | Viswanathan, Prasanna Mohan | Hamza, Vijith
A comprehensive study of the chemical composition of rainwater was carried out from October 2016 to September 2017 in the equatorial tropical rainforest region of northwestern Borneo. Monthly cumulative rainwater samples were collected from different locations in the Limbang River Basin (LRB) and were later categorized into seasonal samples representing northeast monsoon (NEM), southwest monsoon (SWM), and inter-monsoon (IM) periods. Physical parameters (pH, EC, TDS, DO, and turbidity), major ions (HCO₃⁻, Cl⁻, Ca²⁺, Mg²⁺, Na⁺, and K⁺) and trace metals (Co, Ni, Cd, Fe, Mn, Pb, Zn, and Cu) were analyzed from collected rainwater samples. Rainwater is slightly alkaline with mean pH higher than 5.8. Chloride and bicarbonate are the most abundant ions, and the concentration of major ions in seasonal rainwater has shown slight variation which follows a descending order of HCO₃⁻> Cl⁻> Na⁺ > Ca²⁺ > Mg²⁺ > K⁺ in NEM and Cl⁻ > HCO₃⁻ > Na⁺ > Ca²⁺ > K⁺ > Mg²⁺ in SWM and Cl⁻ > HCO₃⁻ > Na⁺ > Ca²⁺ > Mg²⁺ > K⁺ in IM period. Trace metals such as Fe and Ni have shown dominance in seasonal rainwater samples, and all the metals have shown variation in concentration in different seasons. Variation in chemical characteristic of seasonal rainwater samples identified through piper diagram indicates dominance of Ca²⁺-Mg²⁺-HCO₃⁻ and mixed Ca²⁺-Mg²⁺-Cl⁻ facies during NEM, SWM, and IM periods. Statistical analysis of the results through two-way ANOVA and Pearson’s correlation also indicates significant variation in physico-chemical characteristics. This suggests a variation in contributing sources during the monsoon seasons. Factor analysis confirmed the source variation by explaining the total variance of 79.80%, 90.72%, and 90.52% with three factor components in NEM, SWM, and IM rainwater samples with different loading of parameters. Enrichment factor analysis revealed a combined contribution of marine and crustal sources except K⁺ which was solely from crustal sources. Sample analysis of backward air mass trajectory supports all these findings by explaining seasonal variation in the source of pollutants reaching the study area. Overall, the results show that the chemical composition of seasonal rainwater samples in LRB was significantly influenced by natural as well as anthropogenic processes. These include (long-range and local) industrial activities, fossil fuel combustion, forest burning, transportation activities including road transport and shipping activities, and land-derived soil dust along with chemical constituents carried by seasonal wind.
اظهر المزيد [+] اقل [-]Finding new sources of water for semi-arid cities in unlikely places النص الكامل
2020
Butler, Erick | Howell, Nathan A. | Guerrero, Bridget
Determining alternative water sources to meet municipal water demands is important when availability is limited. The purpose of this study was to demonstrate a means for water planners to estimate the amount of combined sanitary wastewater and storm water that they might already be capturing through open air oxidation ponds. Increased understanding of the quantity of water that is already available could help water planners to better envision optimal water reuse scenarios. Using water and climate data on oxidation ponds in these three cities within the Texas Panhandle from 2010 to 2014, we evaluated water quantities which would be available for potential reuse. From the net monthly wastewater volumes values, the study also considered if per capita demand could have been met by reusing the wastewater. The study found wastewater volumes were lower in fall and winter months and much higher in spring and summer months. If a city considers reusing wastewater, blue water (groundwater) extraction could be reduced by as low as 45–50% in one city to as high as 100% in another. Water planners in similar environments and wastewater treatment systems may find this demonstration of potential reuse water quantity encouraging for better meeting their own water demands and enhancing water supply resiliency.
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