On the survivability and pyrosynthesis of PAH during combustion of pulverized coal and tire crumb

Results are presented on the emissions of semivolatile polycyclic aromatic hydrocarbons (PAH) from the combustion of a pulverized bituminous coal and ground waste automobile tires. Streams of fuel particles were injected at steady-state steady-flow conditions, and burned inside an isothermal drop-tube furnace, in air, at a gas temperature and gas residence time of 1150°C and 0.75 s, respectively. Combustion occurred under either very fuel-lean conditions (bulk equivalence ratio, φ < 0.5) or substantially fuel-rich conditions (φ = 1.6–1.9). Emissions from fuel pyrolysis, in the absence of oxygen, were also examined. The survivability of the fuel-PAHs during combustion/pyrolysis was assessed by examining the reactants (fuels) and the products of their oxidation/pyrolysis. The PAH species in the effluent of combustion were: 1) qualitatively compared with indigenous PAH constituents of the input fuels, and 2) quantitatively contrasted with known amounts of deuterium-labeled PAH standards, which were absorbed on the input fuels. No PAHs were detected in the effluent of combustion of either fuel under sufficiently fuel-lean conditions, e.g., φ < 0.5. This indicated that the PAH constituents of the input fuels, either indigenous or adsorbed, as well as those formed by pyrosynthesis in either the diffusion volatile flames or during the heterogeneous oxidation of the chars were destroyed. Significant amounts of PAHs were detected in the effluent of the combustion of both fuels under sufficiently fuel-rich conditions, e.g., φ > 1.6 and, especially, under pyrolytic conditions in N₂. These PAHs were mostly attributed to pyrosynthesis since none of the deuterated PAHs, adsorbed on the fuels, survived the combustion process. Small amounts of the labeled compounds, however, survived under purely pyrolytic conditions. These results were confirmed with separate experiments, where deuterium-labeled PAH standards were adsorbed on highly porous calcium/magnesium oxide or mullite particles. Again, small amounts of some PAHs survived in high-temperature pyrolytic conditions, but none in oxidative environments. These observations suggest that pyrosynthesis is the major contributing mechanism to the PAH emissions from the combustion of these fuels. Survivability of parent PAHs may be a minor mechanism at very high equivalence ratios.

Finally, both fuels were mixed with powders of calcium magnesium acetate (CMA), calcium carbonate (CaCO₃), and calcium oxide (CaO), all of which are known sulfur reduction agents, at a molar Ca/S ratio of 1. Combustion of the fuels mixed with CMA or CaCO₃ generated enhanced amounts of PAHs, while combustion with CaO had no effect on the PAH emissions.     

A hybrid feature extraction and machine learning approaches for epileptic seizure detection

Multidimensional Systems and Signal Processing - Epileptic seizure detection from the brain EEG signals is an essential step for speeding up the diagnosis that assists researchers and medical...     

Comparison of body weight and adipose tissue in male C57BI/6J mice fed diets with and withouttrans fatty acids

The effect of a diet containingtrans-fatty acids (tFA) on the fatty acid composition and fat accumulation in adipose tissue was investigated in mice. Male C57BI/6J mice were fed Control or Trans Diets that were similar, except that 50% of the 18∶1, which was allcis in the Control Diet, was replaced bytFA in the Trans Diet. At selected ages, body weight, epididymal fat pad weight, perirenal fat yield, adipose tissue cellularity and fatty acid composition were examined. Over the time period studied (2–24 mon), the proportion of 18∶0 and 16∶0 tended to decrease whilecis-18∶1 levels increased. Compared to the Control Diet, the Trans Diet resulted in adipose tissue lipids with higher percentages of 14∶0 and 18∶2n−6 and lower percentages ofcis-18∶1 and 20∶4n−6. In polar lipids,tFA replaced saturated fatty acids, whereastFA replacedcis-18∶1 in the nonpolar lipids. Body weights at 16 and 24 mon of age and epididymal fat pad weights at 8–24 mon of age were lower in mice fed the Trans Diet as compared to those fed the Control Diet. At the ages studied, the Trans Diet also resulted in lower values for perirenal fat weights, triacylglycerol to polar lipid ratios, and adipose cell size. The data suggest that chronic consumption oftFA affects lipid metabolism and results in decreased fat accumulation in murine adipose tissue.     

Identifying hazardousness of sewer pipeline gas mixture using classification methods: a comparative study

In this work, we formulated a real-world problem related to sewer pipeline gas detection using the classification-based approaches. The primary goal of this work was to identify the hazardousness of sewer pipeline to offer safe and non-hazardous access to sewer pipeline workers so that the human fatalities, which occurs due to the toxic exposure of sewer gas components, can be avoided. The dataset acquired through laboratory tests, experiments, and various literature sources was organized to design a predictive model that was able to identify/classify hazardous and non-hazardous situation of sewer pipeline. To design such prediction model, several classification algorithms were used and their performances were evaluated and compared, both empirically and statistically, over the collected dataset. In addition, the performances of several ensemble methods were analyzed to understand the extent of improvement offered by these methods. The result of this comprehensive study showed that the instance-based learning algorithm performed better than many other algorithms such as multilayer perceptron, radial basis function network, support vector machine, reduced pruning tree. Similarly, it was observed that multi-scheme ensemble approach enhanced the performance of base predictors.

     

A reversible approach to two’s complement addition using a novel reversible TCG gate and its 4 dot 2 electron QCA architecture

Microsystem Technologies - Classical computers are already facing threshold limitations with CMOS getting restricted to clocking speeds in GHz range and alarming heat dissipation issues. Both these...     

Studies in indian seed oils: VII—Four oils with unusual constituents

The percentages by weight of palmitic, hexadecenoic, stearic, oleic, linoleic, linolenic and arachidic acids were determined in the seed fats fo Bunium cylindricum (Umbelliferae), Euonymus hamiltonianus (Celastraceae), Crotalaria intermedia (Leguminosae)and Solanum khasianum (Solanaceae) by gas-liquid chromatography. An unusual component in the first fat was 38·5% petroselinic acid and in the second 8·5% (by wt.) acetic acid. The other two fats contained higher chain length components: a total of 4·0% of 22:0,24:0 and 26:0 acids and 0·1, 0·3 and 0·1% of 21: 0, 23:0 and 25:0 linear acids in C. Intermedia and 1·5% of a possible 19:0 branched-chain acid and 0·1% of an apparent 22:1 acid in S. khasianum.     

Toffoli Netlist and QCA implementations for existing four variable reversible gates: a comparative analysis

Microsystem Technologies - With CMOS reaching its fundamental physical heat threshold limits, reversible logic has emerged as a viable alternative due to its heat arresting attributes. CMOS started...     

Composition of Cicer soongaricum seeds

The legume, Cicer soongaricum grows wild in high altitude regions of the Himalayas. The seeds are nutritionally rich, containing 19.1% protein, 44.5% starch, 7.2% oil and 3.4% minerals. Glutelin has been found to be the major protein fraction (43.7%) whereas albumin, globulin and prolamin are 11.5, 14.3 and 6.6%, respectively. The oil contains 29.8% phospholipids, wherein palmitic (30.0%), stearic (32.4%) and linolenic acids (13.6%) are the major fatty acids. The phospholipid fraction has an appreciable content of phosphatidyl choline (1.0% in the seed) which is higher than in soya bean, presently the commercial source of its manufacture.