Low NOx heavy fuel combustor concept program addendum: Low/mid heating value gaseous fuel evaluation

The combustion performance of a rich/quench/lean (RQL) combustor was evaluated when operated on low and mid heating value gaseous fuels. Two synthesized fuels were prepared having lower heating values of 10.2 MJ/cu m. (274 Btu/scf) and 6.6 MJ/cu m (176 Btu/scf). These fuels were configured to be representative of actual fuels, being composed primarily of nitrogen, hydrogen, carbon monoxide, and carbon dioxide. A liquid fuel air assist fuel nozzle was modified to inject both of the gaseous fuels. The RQL combustor liner was not changed from the configuration used when the liquid fuels were tested. Both gaseous fuels were tested over a range of power levels from 50 percent load to maximum rated power of the DDN Model 570-K industrial gas turbine engine. Exhaust emissions were recorded for four power level at several rich zone equivalence ratios to determine NOx sensitivity to the rich zone operating point. For the mid Btu heating value gas, ammonia was added to the fuel to simulate a fuel bound nitrogen type gaseous fuel. Results at the testing showed that for the low heating value fuel NOx emissions were all below 20 ppmc and smoke was below a 10 smoke number. For the mid heating value fuel, NOx emissions were in the 50 to 70 ppmc range with the smoke below a 10 smoke number

Low NOx Heavy Fuel Combustor Concept Program

The development of the technology required to operate an industrial gas turbine combustion system on minimally processed, heavy petroleum or residual fuels having high levels of fuel-bound nitrogen (FBN) while producing acceptable levels of exhaust emissions is discussed. Three combustor concepts were designed and fabricated. Three fuels were supplied for the combustor test demonstrations: a typical middle distillate fuel, a heavy residual fuel, and a synthetic coal-derived fuel. The primary concept was an air staged, variable-geometry combustor designed to produce low emissions from fuels having high levels of FBN. This combustor used a long residence time, fuel-rich primary combustion zone followed by a quick-quench air mixer to rapidly dilute the fuel rich products for the fuel-lean final burnout of the fuel. This combustor, called the rich quench lean (RQL) combustor, was extensively tested using each fuel over the entire power range of the model 570 K engine. Also, a series of parameteric tests was conducted to determine the combustor's sensitivity to rich-zone equivalence ratio, lean-zone equivalence ratio, rich-zone residence time, and overall system pressure drop. Minimum nitrogen oxide emissions were measured at 50 to 55 ppmv at maximum continuous power for all three fuels. Smoke was less than a 10 SAE smoke number

Spectroscopy from 2 to 200 keV

The astrophysical processes responsible for line and continuum emission in the spectra range 2 keV to 200 keV are examined from the viewpoint of designing a spectrometer which would operate in this regime. Phenomena considered include fluorescent line radiation in X-ray binaries, magnetically shifted iron lines and cyclotron emission from neutron star surfaces, line emission from cosmically abundant elements in thermal plasmas, and nuclear deexcitation lines in fresh nucleosynthetically produced matter. An instrument consisting of a approximately 10 sq cm array of planar germanium detectors surrounded by a large sodium-iodide anticoincidence shield is described and projected background rates and sensitivities are considered. A sample observing program for a two-day shuttle-based mission is included as an example of the wide range of scientific questions which could be addressed by such an instrument

Physicochemical characterization of traditional Ghanaian cooking oils, derived from seeds of Egusi (Citrullus colocynthis) and Werewere (Cucumeropsis manni)

Traditional vegetable oils derived from Egusi (Citrullus colocynthis) and Werewere (Cucumeropsis manni) could prove to be an important commodity for Ghanaians, serving as a potential alternative source of common cooking oils. This study measured several physicochemical properties of Egusi and Werewere oils to describe and assess their nutritional quality, susceptibility to rancidity, and potential industrial applications. Physicochemical measurements were also taken on olive oil and coconut oil for comparative analysis and method validation. The solvent extraction yield of oil from seed of Egusi (39.94%) and Werewere (28.82%) fares well against the yields of common cooking oil seeds. Refractive index and iodine value tests for Egusi (1.471, 122.94) and Werewere (1.470, 106.134) reveal that the oils are likely rich in  unsaturated fats compared to olive and coconut oil. These measurements also suggest the traditional oils are susceptible to oxidative rancidity. Both Egusi and Werewere oils exceeded the FAO/WHO standards for permissible levels of impurity in edible oils. A high acid value (6.9) was measured for Egusi, suggesting the presence of free fatty acids. A high iodine value (122.9) was also measured for Egusi which suggests high unsaturation, likelihood to oxidation and susceptibility to rancidity. Overall, rigorous extraction and screening processes and additives may be required to produce Egusi and Werewere oils that are aligned with industry standards. The high extraction yield and prospective nutritional benefits of the oils are cause to explore further the use of these vegetable oils. © 2013 International Formulae Group. All rights reserved.Keywords: Vegetable oil, physicochemical properties, unsaturated fats, nutritional qualit

Interleukin-6 and interleukin-6 receptor secretion by chronic lymphatic leukaemia and normal B lymphocytes: effect of PMA and PWM

Interleukin-6 (IL-6) and soluble interleukin-6 receptor (sIL-6R) were detected in supernatants of cultures of B chronic lymphatic leukaemia (CLL) lymphocytes. Phorbol-12-myristate 13 acetate (PMA) caused a decrease in the levels of IL-6 in 14 out of 16 cultures and an increase in levels of sIL6R in all 15 cases. The effect of pokeweed mitogen (PWM) was variable and not significant. The levels of IL-6 were below the detection limit (60 pg/ml) in sera of 13 CLL patients whereas sIL-6R was detected (13 ng/ml to 97 ng/ml) in the 13 sera. IL6 was not detected in cultures of unstimulated or stimulated with PMA or PWM normal human B cells. Levels of sIL-6R were minimal in cultures of normal B lymphocytes and were increased in PMA stimulated cultures. The results are consistent with the view that B-CLL cells produce spontaneously IL-6 which could act in an autocrine fashion to cause shedding of surface IL-6R and account for the correlation found between serum levels of sIL-6R and B-CLL lymphocyte numbers. The fall in levels of IL-6 in PMA stimulated CLL cultures might express masking or degradation of IL-6 after combination with the receptor

The Evolution and Diversity of DNA Transposons in the Genome of the Lizard Anolis carolinensis

DNA transposons have considerably affected the size and structure of eukaryotic genomes and have been an important source of evolutionary novelties. In vertebrates, DNA transposons are discontinuously distributed due to the frequent extinction and recolonization of these genomes by active elements. We performed a detailed analysis of the DNA transposons in the genome of the lizard Anolis carolinensis, the first non-avian reptile to have its genome sequenced. Elements belonging to six of the previously recognized superfamilies of elements (hAT, Tc1/Mariner, Helitron, PIF/Harbinger, Polinton/Maverick, and Chapaev) were identified. However, only four (hAT, Tc1/Mariner, Helitron, and Chapaev) of these superfamilies have successfully amplified in the anole genome, producing 67 distinct families. The majority (57/67) are nonautonomous and demonstrate an extraordinary diversity of structure, resulting from frequent interelement recombination and incorporation of extraneous DNA sequences. The age distribution of transposon families differs among superfamilies and reveals different dynamics of amplification. Chapaev is the only superfamily to be extinct and is represented only by old copies. The hAT, Tc1/Mariner, and Helitron superfamilies show different pattern of amplification, yet they are predominantly represented by young families, whereas divergent families are exceedingly rare. Although it is likely that some elements, in particular long ones, are subjected to purifying selection and do not reach fixation, the majority of families are neutral and accumulate in the anole genome in large numbers. We propose that the scarcity of old copies in the anole genome results from the rapid decay of elements, caused by a high rate of DNA loss

On the principal bifurcation branch of a third order nonlinear long-wave equation

We study the principal bifurcation curve of a third order equation which describes the nonlinear evolution of several systems with a long--wavelength instability. We show that the main bifurcation branch can be derived from a variational principle. This allows to obtain a close estimate of the complete branch. In particular, when the bifurcation is subcritical, the large amplitude stable branch can be found in a simple manner.Comment: 11 pages, 3 figure

High atmospheric demand for water can limit forest carbon uptake and transpiration as severely as dry soil

When stressed by low soil water content (SWC) or high vapor pressure deficit (VPD), plants close stomata, reducing transpiration and photosynthesis. However, it has historically been difficult to disentangle the magnitudes of VPD compared to SWC limitations on ecosystem-scale fluxes. We used a 13 year record of eddy covariance measurements from a forest in south central Indiana, USA, to quantify how transpiration and photosynthesis respond to fluctuations in VPD versus SWC. High VPD and low SWC both explained reductions in photosynthesis relative to its long-term mean, as well as reductions in transpiration relative to potential transpiration estimated with the Penman-Monteith equation. Flux responses to typical fluctuations in SWC and VPD had similar magnitudes. Integrated over the year, VPD fluctuations accounted for significant reductions of GPP in both nondrought and drought years. Our results suggest that increasing VPD under climatic warming could reduce forest CO2 uptake regardless of changes in SWC