Performance,combustion and emission characteristics of a single-cylinder,four-stroke,direct injection diesel engine operated on a dual-fuel mode using Honge oil methyl ester and producer gas derived from biomass feedstock of different origin

Renewable and alternative fuels have numerous advantages compared with fossil fuels, as they are renewable and biodegradable, and provide food and energy security and foreign exchange savings besides addressing environmental concerns and socio-economic issues. In this context, present work was carried out to investigate the feasibility of alternative and renewable fuels derived from biomass feedstock of different origin for engine applications. The present study was also extended to study the effect of producer gas composition derived from different biomass feedstock on the performance, combustion and emission characteristics of a single-cylinder, four-stroke, direct injection stationary diesel engine operated on a dual-fuel mode using Honge oil methyl ester (HOME) and producer gas induction. The performance of the engine was evaluated with a constant injection timing of 27° before top dead centre, an injection pressure of 205 bar for the diesel–producer gas combination and 230 bar for the HOME–producer gas combination and a compression ratio of 17.5. The results showed that the performance of the dual-fuel engine varies with the composition of the producer gas and depends on the type of biomass feedstock used in the gasifier. Experimental investigations on the dual-fuel engine showed that brake thermal efficiency values for the engine operated using HOME–producer gas derived from babul, neem and honge woods were found to be 17.2, 14.3 and 11.56% respectively, compared to 23.8% for diesel–producer gas operation at 80% load. However, the results showed better engine performance with lower exhaust emission levels for the operation of HOME–producer gas derived from the ordinary or babul wood compared with the operation of that derived from the neem and Honge woods. In view of this, present study reveals that use of alternative and renewable fuels for dual fuel engine can be considered as an immediate solution for the development of rural areas and emergency use in the event of severe diesel fuel shortage.     

Effects of compression ratio,swirl augmentation techniques and ethanol addition on the combustion of CNG–biodiesel in a dual-fuel engine

The diminishing resources and continuously increasing cost of petroleum in association with their alarming pollution levels from diesel engines has led to an interest in finding alternative fuels to diesel. Emission control and engine efficiency are two of the most important parameters in current engine design. The impending introduction of emission standards such as Euro IV and Euro V has forced research towards developing new technologies for combating engine emissions. This paper examines the effects of compression ratio, swirl augmentation techniques and ethanol addition on the combustion of compressed natural gas (CNG) blended with Honge oil methyl esters (HOME) in a dual fuel engine. The present results show that the combustion of HOME and 15% ethanol blend with CNG induction in a dual-fuel engine operated in optimized parameters at an injection timing of 27° Before Top Dead Centre and a compression ratio of 17.5 resulted in acceptable combustion emissions and improved brake thermal efficiencies. The implementation of swirl augmentation techniques increased brake thermal efficiencies (BTEs) and considerably reduced combustion emissions such as smoke, HC, CO and NO_x. The addition of ethanol also increased BTEs. However, at more than 15% of ethanol in HOME, NO_x emissions increased dramatically.     

Dioxin-like activity in sediments from Tai Lake, China determined by use of the H4IIE-luc bioassay and quantification of individual AhR agonists

Deterioration of the general ecosystem and specifically quality of the water in Tai Lake (Ch: Taihu), the third largest freshwater in China, is of great concern. However, knowledge on status and trends of dioxin-like compounds in Tai Lake was limited. This study investigated AhR-mediated potency and quantified potential aryl hydrocarbon receptor (AhR) agonists in sediments from four regions (Meiliang Bay, Zhushan Lake, Lake Center, Corner of Zhushan Lake, and Meiliang Bay) of Tai Lake by use of the in vitro H4IIE-luc, cell-based, transactivation, reporter gene assay, and instrumental analysis. Concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (Bio-TEQs) in sediments ranged from less than the limit of detection to 114.5 pg/g, dry weight, which indicated that organic extracts of sediments exhibited significant AhR-mediated potencies. Results of the potency balance analysis demonstrated that acid-labile, dioxin-like compounds represented a greater proportion of concentrations of Bio-TEQs in sediments from Tai Lake. Concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents calculated as the sum of the product of concentrations of individual congeners and their respective relative potencies (Chem-TEQs) based on polycyclic aromatic hydrocarbons and/or polychlorinated biphenyls represented no more than 10 % of the total concentrations of Bio-TEQs.     

Contamination levels of polychlorinated biphenyls in wild versus cultivated samples of female and male mussels (Mytilus sp.) from the Northwest Coast of Iberian Peninsula—new application for QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) methodology

A newly analytical method based on QuEChERS extraction followed by gas chromatography with mass spectrometry (GC-MS) analysis was developed and validated for the quantification of 18 PCBs in wild (from Matosinhos Beach, Portugal) and cultivated (from Ria de Arousa, Spain) mussel samples, pooled by sex. Wild animals showed higher PCB levels than cultivated mussels, with males from both origins, presenting an upper contamination profile comparing with females. This fact seems to be correlated with few biometric parameters, but other interdependencies, not addressed herein, such as distinct lipid contents between sexes, as a consequence of the gametogenic stage, may also explain this data. Overall, data reiterate the importance of investigating the presence of PCBs in marine biological samples, which can act both as bioindicators of environmental contamination, either as food quality controls for human health.     

Photocatalytic degradation of acetaminophen in modified TiO2 under visible irradiation

This study investigated the photocatalytic degradation of acetaminophen (ACT) in synthetic titanium dioxide (TiO₂) solution under a visible light (λ >440 nm). The TiO₂ photocatalyst used in this study was synthesized via sol–gel method and doped with potassium aluminum sulfate (KAl(SO₄)₂) and sodium aluminate (NaAlO₂). The influence of some parameters on the degradation of acetaminophen was examined, such as initial pH, photocatalyst dosage, and initial ACT concentration. The optimal operational conditions were also determined. Results showed that synthetic TiO₂ catalysts presented mainly as anatase phase and no rutile phase was observed. The results of photocatalytic degradation showed that LED alone degraded negligible amount of ACT but with the presence of TiO₂/KAl(SO₄)₂, 95 % removal of 0.10-mM acetaminophen in 540-min irradiation time was achieved. The synthetic TiO₂/KAl(SO₄)₂ presented better photocatalytic degradation of acetaminophen than commercially available Degussa P-25. The weak crystallinity of synthesized TiO₂/NaAlO₂ photocatalyst showed low photocatalytic degradation than TiO₂/KAl(SO₄)₂. The optimal operational conditions were obtained in pH 6.9 with a dose of 1.0 g/L TiO₂/KAl(SO₄)₂ at 30 °C. Kinetic study illustrated that photocatalytic degradation of acetaminophen fits well in the pseudo-first order model. Competitive reactions from intermediates affected the degradation rate of ACT, and were more obvious as the initial ACT concentration increased.     

Development of aquatic life criteria in China: viewpoint on the challenge

While more developed countries have a well-established systems to develop water quality criteria (WQC), little research has been done on the adequacy of the current WQC to protect endemic species of China. In order to maintain the health of aquatic ecosystems in China, a series of projects to establish national WQC based on regional characteristics has recently been initiated. However, the establishment of a completely novel methodology would be costly and time consuming. Also, due to the similarities in physiologies and natural histories of classes of aquatic organisms, there is no reason to believe that WQC would not be sufficient to protect unique species in China. This review was undertaken to identify key outstanding issues regarding establishment of aquatic life criteria (ALC) to be applied in China, including prioritization of chemicals, test species, mode of action, field/semi-field data, and methods of aggregating the information and calculating the ALC. This was used to identify the principle issues that need to be addressed in order to better understand the methods for development of criteria for the protection of aquatic life and provide a reference to China and other developing countries committed to the establishment of their own WQC system.     

Bioremediation assessment of diesel–biodiesel-contaminated soil using an alternative bioaugmentation strategy

This study investigated the effectiveness of successive bioaugmentation, conventional bioaugmentation, and biostimulation of biodegradation of B10 in soil. In addition, the structure of the soil microbial community was assessed by polymerase chain reaction-denaturing gradient gel electrophoresis. The consortium was inoculated on the initial and the 11th day of incubation for successive bioaugmentation and only on the initial day for bioaugmentation and conventional bioaugmentation. The experiment was conducted for 32 days. The microbial consortium was identified based on sequencing of 16S rRNA gene and consisted as Pseudomonas aeruginosa, Achromobacter xylosoxidans, and Ochrobactrum intermedium. Nutrient introduction (biostimulation) promoted a positive effect on microbial populations. The results indicate that the edaphic community structure and dynamics were different according to the treatments employed. CO₂ evolution demonstrated no significant difference in soil microbial activity between biostimulation and bioaugmentation treatments. The total petroleum hydrocarbon (TPH) analysis indicated a biodegradation level of 35.7 and 32.2 % for the biostimulation and successive bioaugmentation treatments, respectively. Successive bioaugmentation displayed positive effects on biodegradation, with a substantial reduction in TPH levels.     

Use of hairy roots extracts for 2,4-DCP removal and toxicity evaluation by Lactuca sativa test

2,4-Dichlorophenol (2,4-DCP) is widely distributed in wastewaters discharged from several industries, and it is considered as a priority pollutant due to its high toxicity. In this study, the use of different peroxidase extracts for 2,4-DCP removal from aqueous solutions was investigated. Tobacco hairy roots (HRs), wild-type (WT), and double-transgenic (DT) for tomato basic peroxidases (TPX1 and TPX2) were used to obtain different peroxidase extracts: total peroxidases (TPx), soluble peroxidases (SPx), and peroxidases ionically bound to the cell wall (IBPx). All extracts derived from DT HRs exhibited higher peroxidase activity than those obtained from WT HRs. TPx and IBPx DT extracts showed the highest catalytic efficiency values. The optimal conditions for 2,4-DCP oxidation were pH 6.5, H₂O₂ 0.5 mM, and 200 U mL^?1 of enzyme, for all extracts analyzed. Although both TPx extracts were able to oxidize different 2,4-DCP concentrations, the removal efficiency was higher for TPx DT. Polyethylene glycol addition slightly improved 2,4-DCP removal efficiency, and it showed some protective effect on TPx WT after 2,4-DCP oxidation. In addition, using Lactuca sativa test, a reduction of the toxicity of post removal solutions was observed, for both TPx extracts. The results demonstrate that TPx extracts from both tobacco HRs appear to be promising candidate for future applications in removing 2,4-DCP from wastewaters. This is particularly true considering that these peroxidase sources are associated with low costs and are readily available. However, TPx DT has increased peroxidase activity, catalytic efficiency, and higher removal efficiency than TPx WT, probably due to the expression of TPX1 and TPX2 isoenzymes.     

Determination of the utility of groundwater with respect to the geochemical parameters: a case study from Tuticorin District of Tamil Nadu (India)

In modern living, rapid development has created an increase in demand for groundwater. An endeavor has been made to understand the hydrogeochemical parameters to determine the utility of groundwater. This situation is severe in coastal hard rock aquifers due to the influence of salinity ingression and other anthropogenic influence. A total of 135 groundwater samples were collected from the coastal aquifer of the Tuticorin district and analyzed for major cations and anions during premonsoon (PRM) and postmonsoon (POM). The ions analyzed were used to determine the drinking, agricultural and domestic utility of groundwater. The electrical conductivity (EC) contour shows that the groundwater quality is poor along the coast. The parameters were compared with WHO (Guidelines for drinking water quality recommendations, WHO, Geneva, 2004) standard for drinking purpose. A groundwater classification method has been developed for groundwater in the area using a dynamic water quality index (WQI). On the basis of the WQI so computed, groundwater in the area has been spatially classified into “excellent,” “good,” “poor” and “very poor” to “Unsuitable” water types variation lithologywise. Corrosivity ratio and hardness were noted to be higher and found to be unsuitable in majority of the regions for domestic purpose. Higher fluoride concentration was noted in the central part of the study area represented by complex geology comprising of the hornblende biotite gneiss and charnockite. Sodium percentage (Na%), sodium absorption ratio, residual sodium carbonate, Wilcox (Classification and use of irrigation waters, US Department of Agriculture, Washington, 1955), permeability index, residual sodium bicarbonate, magnesium hazard, Kelly’s ratio and potential salinity also indicate that most of the groundwater samples are not suitable for irrigation purposes.     

Pathways of rural change: an integrated assessment of metabolic patterns in emerging ruralities

While rural transformations are nothing new in human history, current processes of rural change occur under multiple forces at an unprecedented pace, involving profound and unexpected changes in land use and users, and rapid transformations in the metabolic patterns of rural systems. The present special section aims to shed light on current drivers and pathways of rural change by analyzing, under a common conceptual and theoretical framework, examples of new ruralities that are emerging as responses across different world regions. Within this context, this introduction presents: (1) common research questions of the six presented cases of rural change; (2) the general theoretical and methodological framework of integrated assessment of societal metabolism adopted to analyze rural systems and (3) the main contributions and conclusions that could be drawn from six context-specific case studies from Asia, Latin America and Europe.