Renewable hydrocarbons through biomass hydropyrolysis process: challenges and opportunities

Considering the current issues of carbon control and the desire to become less dependent on imported oil, the utilization of renewable hydrocarbons for the reduction of CO₂ emission and production of liquid synthetic fuels/chemicals has been proposed by researchers worldwide. Efforts to make chemicals/fuels from renewable resources have escalated over the past few years. Biomass-based renewable hydrocarbons are considered to be one of the sources with the highest potential to contribute to the energy needs of modern society for both developed and developing economies worldwide. Fast pyrolysis is becoming an important thermal route to convert biomass to liquid fuels; however, the raw bio-oils obtained have a number of negative properties such as high acidity, high water content, and variable viscosity over time. To overcome this problem and produce bio-oil of good quality, process of ‘hyropyrolysis’ has been developed. The scope for using pyrolysis under hydrogen pressure and also by process of hydropyrolysis followed by in situ hydroconversion of vapors to give oils with much lower oxygen contents has been reviewed.     

Bio-efficacy evaluation of nanoformulations of β-cyfluthrin against Callosobruchus maculatus (Coleoptera: Bruchidae)

In the present investigation, bioefficacy of developed β-cyfluthrin formulations, utilizing laboratory synthesized poly(ethylene glycols) based amphiphilic copolymers, were evaluated against Callosobruchus maculatus (Coleoptera: Bruchidae). The bioefficacy data indicated that the formulations developed by utilizing polymers having PEG – 1500 (3c) and PEG – 2000 (3d) as the hydrophilic segment showed greater efficacy after 14 days as evident from EC₅₀ values (2.2 and 1.58 mg L^?1 respectively). Also, release from the commercial SC formulation was faster than developed formulations as the commercial formulation had the lowest EC₅₀ value on the first day (0.51 mg L^?1). The mean EC₅₀ of the commercial formulation against C. maculatus was quite high as compared to those of developed formulations. The results suggest that depending upon the polymer matrix used, the application rate of β-cyfluthrin can be optimized to achieve insect control at the desired level and period. The results described in this paper are promising and provide a comparison of developed formulations with the commercial one showing an earlier degradation of β-cyfluthrin in the latter and relatively prolonged activity in the former.     

Evaluation of the Potential of Laser-Induced Breakdown Spectroscopy for Detection of Trace Element in Liquid

Abstract

The analytical figure of merit of the potential of laser-induced breakdown spectroscopy (LIBS) has been evaluated for detection of trace element in liquid. LIBS data of Mg, Cr, Mn, and Re were studied. Various optical geometries, which produce the laser spark in and at the liquid sample, were tested. The calibration curves for Mg, Cr, Mn, and Re were obtained at the optimized experimental conditions with bulk liquid and in liquid jet. It was found that measurements using a liquid jet provide better detection limits than bulk liquid measurements. The limits of detection (LOD) of Mg, Cr, Mn, and Re in the present liquid jet measurement are found to be 0.1, 0.4, 0.7, and 8 ppm, respectively. The LOD of Mg using Mg 279.55 nm was compared with the values found in other liquid work.     

Biodegradation of endosulfan-contaminated soil in a pilot-scale reactor-bioaugmented with mixed bacterial culture

A novel mixed bacterial culture was enriched from an endosulfan (6, 7, 8, 9, 10, 10 – hexachloro-1, 5, 5a, 6, 9, 9a-hexahydro-6, 9-methano-2, 3, 4-benzo (e) dioxathiepin-3-oxide) processing industrial surface soil. The cultures were successful in the degradation of aqueous phase endosulfan in both aerobic and anaerobic conditions. Using the cultures, endosulfan degradation in silty gravel with sand (GM) was examined via pilot scale reactor at an endosulfan concentration of 0.78 ± 0.01 mg g^{? 1} of soil, and optimized moisture content of 40 ± 1%. During operation, vertical spatial variability in endosulfan degradation was observed within the reactor. At the end of 56 days, maximum endosulfan degradation efficiency of 78 ± 0.2% and 86.91 ± 0.2% was observed in the top and bottom portion of the reactor, respectively. Both aerobic and anaerobic conditions were observed within the reactor. However, endosulfan degradation was predominant in anaerobic condition and the total protein concentration in the reactor was declined progressively down the soil depth. Throughout the study, no known intermediate metabolites of endosulfan reported by previous researchers were observed.     

Reverse phase high performance liquid chromatographic determination of Baygon in water

Abstract

A simple analytical procedure for determination of Baygon in water is described. The Baygon residues are extracted on a C₁₈ SEP‐PAK cartridge and subsequently analyzed by reverse phase high performance liquid chromatography using ultraviolet detection at 272 nm. Water samples spiked with Baygon are found to give greater than 90 percent recoveries.

Concentration levels as low as 20 ppb can be easily detected by this method.     

Distinctive effects of nano-sized permethrin in the environment

Pesticides are an essential tool in integrated pest management. Nanopermethrin was prepared by solvent evaporation from an oil-in-water volatile microemulsion. The efficacy of the formulated nanopermethrin was tested against Aedes aegypti and the results compared to those of regular, microparticular permethrin. The 24 h LC₅₀ for nanopermethrin and permethrin was found to be 0.0063 and 0.0199 mg/L, respectively. The formulated nanopermethrin was tested for toxicity against non-target organisms. Nanopermethrin did not show antibacterial activity against Escherichia coli (ATCC 13534 and 25922) or against Bacillus subtilis. Phytotoxicity studies of nanopermethrin to the seeds of Lycopersicum esculentum, Cucumis sativus, and Zea mays showed no restraint in root length and germination percentage. In the Allium cepa test, regular microparticular permethrin treatment of 0.13 mg/L showed a mitotic index (MI) of 46.8 % and chromosomal aberration of 0.6 %, which was statistically significant (p?<?0.05) compared to control. No significant differences were observed in 0.13 mg/L nanopermethrin exposure as compared to control (MI of 52.0 and 55.03 % and chromosomal aberration of 0.2 and 0 %, respectively). It was concluded that formulated nanopermethrin can be used as a safe and effectual alternative to commercially available permethrin formulation in agricultural practices.     

Synthesis and pesticidal activity of new N-alkyl-N-[1-(2-hydroxyphenyl) ethyl]amines

A series of novel N-alkyl-N-[1-(2-hydroxyphenyl) ethyl]amines were synthesized as potential new agents to control pests. Their structures were confirmed on the basis of IR, NMR and elemental analyses. Six new N-alkyl-N-[1-(2-hydroxyphenyl) ethyl]amines were prepared by reduction of corresponding Schiff bases using sodium borohydride in 80–87 % yields. These compounds were tested for their antifungal activity against two pathogenic fungi viz., Rhizoctonia bataticola ITCC 0482 and Sclerotium rolfsii ITCC 5226 and for insecticidal activity against insects of stored grain pest Callosobruchus analis. Fungicidal bioassay revealed that compound N-Decyl-N-[1-(2-hydroxyphenyl)ethyl]amine, was highly effective against R. bataticola (ED₅₀ 6.86 mg L^?1) which was comparable with that of commercial fungicide hexaconazole (ED₅₀ 6.35 mg L^?1). Also compounds N-Heptyl-N-[1-(2-hydroxyphenyl)ethyl]amine, N-Octyl-N-[1-(2-hydroxyphenyl)ethyl]amine and N-Nonyl-N-[1-(2-hydroxyphenyl)ethyl]amine displayed promising fungitoxicity against same pathogen. However, compound N-Heptyl-N-[1-(2-hydroxyphenyl)ethyl]amine was also found to be effective against S. rolfsii (ED₅₀ 4.92 mg L^?1 as against 1.27 mg L^?1 for hexaconazole). Compound N-Hexyl-N-[1-(2-hydroxyphenyl)ethyl]amine was most effective as insecticide followed by compound N-Octyl-N-[1-(2-hydroxyphenyl)ethyl]amine. LC₅₀ values for these compounds were 155.0 and 275.0 mg L^?1 respectively as against 36.70 mg L^?1 for commercial insecticide dichlorovos. The results obtained from bioassays indicate that this class of compounds can be utilized for the design of new substances endowed with pesticidal activities.     

Artificially roughened solar air heater: A comparative study

Artificially roughened solar air heater has been topic in research for the last 30 years. Prediction of heat transfer and fluid flow processes of an artificially roughened solar air heater can be obtained by three approaches: theoretical, experimental, and computational fluid dynamics (CFD). This article provides a comprehensive review of the published literature on the investigations of artificially roughened solar air heater. In the present article, an attempt has been made to present holistic view of various roughness geometries used for creating artificial roughness in solar air heater for heat transfer enhancement. This extensive review reveals that quite a lot of work has been reported on design of artificially roughened solar air heater by experimental approach but only a few studies have been done by theoretical and CFD approaches. Finally this article presents a comparative study of thermo-hydraulic performance of 21 different types of artificial roughness geometries attached on the absorber plate of solar air heater in terms of thermo-hydraulic performance parameter. Heat transfer and friction factor correlations developed by various investigators for different types of artificially roughened solar air heaters have also been reported in this article.     

A stochastic approach for the operation of a wind and pumped storage plant under a deregulated environment

To improve the competiveness in the energy market, it is necessary that the wind power plants provide guaranteed power generation, although, it is not possible to forecast power availability from wind power plant accurately. This paper presents a stochastic model and solution technique for the combined operation of wind and pumped storage power plants to improve the power availability and increasing the profit considering uncertainties of wind power generation. In this model, uncertainties in wind data have been forecasted for grid connected day-ahead market using Weibull distribution model. The imbalances in the forecasted wind data and the market demand have been reduced by operating the pumped storage power plant. In this stochastic mixed integer problem, pumped storage plant can take the supply either from the grid or from the wind power plant for the pumping operation to store the energy in order to utilize this energy during peak hours for increasing the overall revenue. The reliability of the pumped storage is improved by replacing the conventional unit with the adjustable speed type pumped storage unit. In order to prove the optimality of the solution, two case studies were considered. In case study–I, scheduling is provided by operating the conventional pumped storage unit, whereas in case study–II, adjustable speed pumped storage unit has been used. It has been found that the adjustable speed pumped storage unit has further reduced the imbalance between generated power and demand. The complete approach has been formulated and implemented using AMPL software.     

Allometric models for the estimation of above- and below-ground biomass of Jatropha curcas L. in semi-arid regions of Southern India

Jatropha curcas L. (Jatropha) is an important multipurpose tree valued for oil. In India, plans are underway to bring substantial area under this crop for meeting the biofuel requirements of the country. A study was conducted to develop allometric relationships in Jatropha to predict various biomass-related components (above ground and below ground) using easily measurable attributes, viz. collar diameter, tree height, number of branches, crown diameter, and crown depth. Further, it was aimed to establish the reliability of these relationships using an independent dataset obtained from varied management situations. Destructive sampling was carried out during the rainy season of 2011, when Jatropha plants were eight years old. Highly significant allometric relationships (F-values significant at 1% level) were obtained while predicting various biomass components (above, below, and total) using easily measurable attributes with R² values ranging from 0.89 to 0.98. Of all the predictors, collar diameter exhibited a highly significant relationship with total dry biomass per plant (R² = 0.97). The allometric relationships developed were validated with an independent dataset. The allometric relationships developed would serve as valuable tools for estimating total dry biomass production and carbon sequestration with reasonable accuracy in Jatropha systems, as they are proposed to be taken up in substantial area in the years to come.