Effect of fuel molecular structure on soot formation in gas turbine combustion

The effect of fuel variations at the same hydrogen content on the formation of soot in a gas turbine combustor was studied. Six fuels were burned to a combustor over a matrix of about 50 test conditions with test conditions ranging over 500-1800 kPa (5-18 atm) pressure and 500-1000 K burner inlet temperature; fuel-air ratios were varied from 0.008-0.024. Flame radiation measurements were made through a sapphire window toward the end of the primary zone. The hydrogen content of the six test fuels ranged from 12.80 to 12.88%. Five fuels emphasized hydrocarbon types: (mono, di, and tricyclic), naphthenes (decalin) and partially hydrogenated aromatics (tetralin); the sixth fuel emphasized final boiling point

Fuel quality combustion analysis

A high pressure research combustor operating over a wide range of burner inlet conditions was used to determine the effects of fuel molecular structure on soot formation. Six test fuels with equal hydrogen content (12.8%) were blended to stress different molecular components and final boiling points. The fuels containing high concentrations (20%) of polycyclic aromatics and partially saturated polycyclic structures such as tetralin, produced more soot than would be expected from a hydrogen content correlation for typical petroleum based fuels. Fuels containing naphthenes such as decalin agreed with the hydrogen content correlation. The contribution of polycyclic aromatics to soot formation was equivalent to a reduction in fuel hydrogen content of about one percent. The fuel sensitivity to soot formation due to the polycyclic aromatic contribution decreased as burner inlet pressure and fuel/air ratio increased

Low-perigee aerodynamic heating during orbital flight of an atmosphere Explorer

An extensive, low-perigee orbital aerodynamic heating study was undertaken in support of the Atmosphere Explorer-C Temperature Alarm. State of the art of low-density, high-speed flows, some models of the earth's atmosphere, external flow-field definition, thermodynamic and transport properties of atmospheric gases, the accommodation coefficient orbital thermal environment, and correlation of theory and measurements are discussed. Aerodynamic heating rates are determined for eight selected orbits by means of a reduced, analytical model verified by both ground test and flight data. These heating rates are compared with classical free-molecule and first-order collision regime values

Hope in Addiction Recovery: Eschatological Foundations in Celebrate Recovery and The Genesis Process

This project attempts to understand the theological foundations of two nationally known Christian addiction recovery programs currently operating in Seattle, Washington: Celebrate Recovery and The Genesis Process. Of particular focus is the presence or absence of Christianity’s unique sense of hope for the future, using eschatological themes of hope, resurrection, and shalom. The participant materials of each program were analyzed for their use of these themes, using Richard Osmer\u27s framework of the four tasks of practical theology

Thermal Stability of Jet Fuels: Kinetics of Forming Deposit Precursors

The focus of this study was on the autoxidation kinetics of deposit precursor formation in jet fuels. The objectives were: (1) to demonstrate that laser-induced fluorescence is a viable kinetic tool for measuring rates of deposit precursor formation in jet fuels; (2) to determine global rate expressions for the formation of thermal deposit precursors in jet fuels; and (3) to better understand the chemical mechanism of thermal stability. The fuels were isothermally stressed in small glass ampules in the 120 to 180 C range. Concentrations of deposit precursor, hydroperoxide and oxygen consumption were measured over time in the thermally stressed fuels. Deposit precursors were measured using laser-induced fluorescence (LIF), hydroperoxides using a spectrophotometric technique, and oxygen consumption by the pressure loss in the ampule. The expressions, I.P. = 1.278 x 10(exp -11)exp(28,517.9/RT) and R(sub dp) = 2.382 x 10(exp 17)exp(-34,369.2/RT) for the induction period, I.P. and rate of deposit precursor formation R(sub dp), were determined for Jet A fuel. The results of the study support a new theory of deposit formation in jet fuels, which suggest that acid catalyzed ionic reactions compete with free radical reactions to form deposit precursors. The results indicate that deposit precursors form only when aromatics are present in the fuel. Traces of sulfur reduce the rate of autoxidation but increase the yield of deposit precursor. Free radical chemistry is responsible for hydroperoxide formation and the oxidation of sulfur compounds to sulfonic acids. Phenols are then formed by the acid catalyzed decomposition of benzylic hydroperoxides, and deposit precursors are produced by the reaction of phenols with aldehydes, which forms a polymer similar to Bakelite. Deposit precursors appear to have a phenolic resin-like structure because the LIF spectra of the deposit precursors were similar to that of phenolic resin dissolved in TAM

Convergent transcriptional profiles induced by endogenous estrogen and distinct xenoestrogens in breast cancer cells

Estrogen receptors display high levels of promiscuity in accommodating a wide range of ligand structures, but the functional consequence of changing receptor conformations in complex with distinct agonists is highly controversial. To determine variations in the transactivation capacity induced by different estrogenic agonists, we assessed global transcriptional profiles elicited by natural or synthetic xenoestrogens in comparison with the endogenous hormone 17β-estradiol. Human MCF7 and T47D carcinoma cells, representing the most frequently used model systems for tumorigenic responses in the mammary gland, were synchronized by hormone starvation during 48 h. Subsequently, a 24 h exposure was carried out with equipotent concentrations of the selected xenoestrogens or 17β-estradiol. Analysis of messenger RNA was performed on high-density oligonucleotide microarrays that display the sequences of 33 000 human transcripts, yielding a total of 181 gene products that are regulated upon estrogenic stimulation. Surprisingly, genistein (a phytoestrogen), bisphenol-A and polychlorinated biphenyl congener 54 (two synthetic xenoestrogens) produced highly congruent genomic fingerprints by regulating the same range of human genes. Also, the monotonous genomic signature observed in response to xenoestrogens is identical to the transcriptional effects induced by physiological concentrations of 17β-estradiol. This striking functional convergence indicates that the transcription machinery is largely insensitive to the particular structure of estrogen receptor agonists. The occurrence of such converging transcriptional programs reinforces the hypothesis that multiple xenoestrogenic contaminants, of natural or anthropogenic origin, may act in conjunction with the endogenous hormone to induce additive effects in target tissue

The Effect of Lactation Consultation on the Duration of Breastfeeding in New Mothers: A Systematic Review

In the United States, 3.978 million babies were born in the year 2015 (U.S. Department of Health & Human Services, 2016). Statistics show that less than 25% of newborns in the United States are breastfed for half of the recommended time by The American Academy of Pediatrics. There are many benefits to breastfeeding, but babies are not receiving these benefits. This systematic review identifies, reviews, and critically appraises the evidence regarding the effect of lactation consultation on duration of breastfeeding in new mothers. Literature was retrieved from CINAHL and Google Scholar. Each study was vetted based on criteria to fully describe the current state of the science. The researchers from the studies reported mixed results. Most studies found that lactation consultants do increase the duration of breastfeeding, while other studies claimed the results were not significant enough to make a definite conclusion

Investigating word order emergence:Constraints from cognition and communication

How do cognitive biases and mechanisms from learning and use interact when a system of language conventions emerges? We investigate this question by focusing on how transitive events are conveyed in silent gesture production and interaction. Silent gesture experiments (in which participants improvise to use gesture but no speech) have been used to investigate cognitive biases that shape utterances produced in the absence of a conventional language system. In this mode of communication, participants do not follow the dominant order of their native language (e.g., Subject-Verb-Object), and instead condition the structure on the semantic properties of the events they are conveying. An important source of variability in structure in silent gesture is the property of reversibility. Reversible events typically have two animate participants whose roles can be reversed (girl kicks boy). Without a syntactic/conventional means of conveying who does what to whom, there is inherent unclarity about the agent and patient roles in the event (by contrast, this is less pressing for non-reversible events like girl kicks ball). In experiment 1 we test a novel, fine-grained analysis of reversibility. Presenting a silent gesture production experiment, we show that the variability in word order depends on two factors (properties of the verb and properties of the direct object) that together determine how reversible an event is. We relate our experimental results to principles from information theory, showing that our data support the “noisy channel” account of constituent order. In experiment 2, we focus on the influence of interaction on word order variability for reversible and non-reversible events. We show that when participants use silent gesture for communicative interaction, they become more consistent in their usage of word order over time, however, this pattern less pronounced for events that are classified as strongly non-reversible. We conclude that full consistency in word order is theoretically a good strategy, but word order use in practice is a more complex phenomenon

Assessment of slope failures off Vancouver Island revealed in EM300 multibeam bathymetry data

Multibeam bathymetric data acquired off Vancouver Island across the accretionary prism of the Cascadia subduction zone reveal a prominent segmentation of the deformation front with dominant azimuths of the ridges at ~120° and ~150° and abundant submarine landslides. Both these ridge-orientations are oblique to the direction of subduction (~45°). Ridges at a strike of ~120° show dominantly rectangular-shaped failure head-scarps and intact blocks of sediments within the failed sediment mass, whereas ridges with an azimuth of ~150° show curved head-scarps and incoherent debris in the failure mass. We propose that this systematic change in failure-style is related to the underlying thrust fault system producing steeper and taller ridges for azimuths around 150°, but less steep and tall ridges at 120°. Thus, debris-flow style failure is simply a result of higher kinetic forcing of the down-sliding sediment mass: more mixing and destruction of the coherent blocks for taller and steeper ridges, and blocks of intact sediment for gentle slopes and less elevated ridges. A segmentation of the deformation front and ridge alignment into two dominant azimuths could be a result of: a) complex interaction and competing forces from overall slab-pull (45°), b) re-activated faults orientated almost N-S (~175°) on the oceanic plate and overlying sediment cover (reflected in the magnetic stripes and abyssal plain strike-slip faulting), and c) relative orientation of the back-stop off Vancouver Island and accreted terranes (at ~127° following the coastline between Nootka Island and Port Renfrew). Extensional faulting is observed only at ridges with debris-flow style failure, which also are the ridges with larger height and steeper slopes. These extensional faults may be the result of over-steepening of the ridges and collapse of the sediment pile that can no longer withstand its own weight due to limited internal shear strength