Flow modifying device

A swirler for a gas turbine engine combustor is disclosed for simultaneously controlling combustor flow rate, swirl angle, residence time and fuel-air ratio to provide three regimes of operation. A first regime is provided in which fuel-air ratio is less than stoichiometric, NOx is produced at one level, and combustor flow rate is high. In a second regime, fuel-air ratio is nearly stoichiometric, NOx production is less than that of the first regime, and combustor flow rate is low. In a third regime, used for example at highoff, fuel-air ratio is greater than stoichiometric and the combustor flow rate is less than in either of the other regimes

Test results and facility description for a 40-kilowatt stirling engine

A 40 kilowatt Stirling engine, its test support facilities, and the experimental procedures used for these tests are described. Operating experience with the engine is discussed, and some initial test results are presente

Small scale systems of galaxies I. Photometric and spectroscopic properties of members

This paper is the first of a series addressed to the investigation of galaxy formation/evolution in small scale systems of galaxies (SSSGs) which are located in low density cosmic environments. Our algorithm for SSSG selection includes galaxy systems of 2 or more galaxies lying within 1000 km/s and a 200 h_{100}^{-1} kpc radius volume. We present the analysis of the photometric and spectroscopic properties of 19 member galaxies belonging to a sample of 11 SSSGs. In the $\mu_e - r_e$ plane, early-type members may be considered "ordinary", not "bright" galaxies in the definition given by Capaccioli et al.(1992) with a significant fraction of galaxies having a disk or disky isophotes. We do not detect fine structure and signatures of recent interaction events in the early-type galaxy population, a picture also confirmed by the spectroscopy. At odd, there are several spiral members with open arm configurations as expected in interacting systems. At the same time, emission lines in the spectra of spiral members fall in the HII regions regime defined with diagnostic diagrams (Veilleux & Osterbrock 1987). None of the objects displays unambiguous indication of nuclear activity, although fourspiral nuclei could be ascribed to the class of Seyferts. The star formation rate seems enhanced over the average expected in spiral galaxies only for poorer SSSGs in particular pairs (<50 solar masses per year) but without being in the range of starburst systems.Comment: 24 pages, including 6 figures and 6 tables. Accepted for publication in A

The Seyfert Population in the Local Universe

The magnitude-limited catalog of the Southern Sky Redshift Survey (SSRS2), is used to characterize the properties of galaxies hosting Active Galactic Nuclei. Using emission-line ratios, we identify a total of 162 (3%) Seyfert galaxies out of the parent sample with 5399 galaxies. The sample contains 121 Seyfert 2 galaxies and 41 Seyfert 1. The SSRS2 Seyfert galaxies are predominantly in spirals of types Sb and earlier, or in galaxies with perturbed appearance as the result of strong interactions or mergers. Seyfert galaxies in this sample are twice as common in barred hosts than the non-Seyferts. By assigning galaxies to groups using a percolation algorithm we find that the Seyfert galaxies in the SSRS2 are more likely to be found in binary systems, when compared to galaxies in the SSRS2 parent sample. However, there is no statistically significant difference between the Seyfert and SSRS2 parent sample when systems with more than 2 galaxies are considered. The analysis of the present sample suggests that there is a stronger correlation between the presence of the AGN phenomenon with internal properties of galaxies (morphology, presence of bar, luminosity) than with environmental effects (local galaxy density, group velocity dispersion, nearest neighbor distance).Comment: 35 pages, 13 figures, Accepted to be publised in Astronomical Journa

An orifice shape-based reduced order model of patient-specific mitral valve regurgitation

Mitral valve regurgitation (MR) is one of the most prevalent valvular heart diseases. Its quantitative assessment is challenging but crucial for treatment decisions. Using computational fluid dynamics (CFD), we developed a reduced order model (ROM) describing the relationship between MR flow rates, transvalvular pressure differences, and the size and shape of the regurgitant valve orifice. Due to its low computational cost, this ROM could easily be implemented into clinical workflows to support the assessment of MR. We reconstructed mitral valves of 43 patients from 3D transesophageal echocardiographic images and estimated the 3D anatomic regurgitant orifice areas using a shrink-wrap algorithm. The orifice shapes were quantified with three dimensionless shape parameters. Steady-state CFD simulations in the reconstructed mitral valves were performed to analyse the relationship between the regurgitant orifice geometry and the regurgitant hemodynamics. Based on the results, three ROMs with increasing complexity were defined, all of which revealed very good agreement with CFD results with a mean bias below 3% for the MR flow rate. Classifying orifices into two shape groups and assigning group-specific flow coefficients in the ROM reduced the limit of agreement predicting regurgitant volumes from 9.0 ml to 5.7 ml at a mean regurgitant volume of 57 ml

The PLC/IP3R/PKC pathway is required for ethanol-enhanced GABA release

Research on the actions of ethanol at the GABAergic synapse has traditionally focused on postsynaptic mechanisms, but recent data demonstrate that ethanol also increases both evoked and spontaneous GABA release in many brain regions. Using whole-cell voltage-clamp recordings, we previously showed that ethanol increases spontaneous GABA release at the rat interneuron-Purkinje cell synapse. This presynaptic ethanol effect is dependent on calcium release from internal stores, possibly through activation of inositol 1,4,5-trisphosphate receptors (IP3Rs). After confirming that ethanol targets vesicular GABA release, in the present study we used electron microscopic immunohistochemistry to demonstrate that IP3Rs are located in presynaptic terminals of cerebellar interneurons. Activation of IP3Rs requires binding of IP3, generated through activation of phospholipase C (PLC). We find that the PLC antagonist edelfosine prevents ethanol from increasing spontaneous GABA release. Diacylglycerol generated by PLC and calcium released by activation of the IP3R activate protein kinase C (PKC). Ethanol-enhanced GABA release was blocked by two PKC antagonists, chelerythrine and calphostin C. When a membrane impermeable PKC antagonist, PKC (19-36), was delivered intracellularly to the postsynaptic neuron, ethanol continued to increase spontaneous GABA release. Overall, these results suggest that activation of the PLC/IP3R/PKC pathway is necessary for ethanol to increase spontaneous GABA release from presynaptic terminals onto Purkinje cells

Мониторинг и оптимизация технологических параметров работы скважин, оборудованных установкой электроцентробежных насосов на нефтяном месторождении "Х" (Томская область)

Цель работы – анализ технологической и экономической эффективности применения режима периодического кратковременного включения, а также разработка рекомендаций по времени цикла работы скважины и подбору погружного оборудования на примере Х нефтяного месторождения.The purpose of the work is the analysis of the technological and economic efficiency of the use of the regime of periodic short-term switching on, as well as the development of recommendations for the well cycle time and selection of the submersible equipment using the example of the X oil field

Levosimendan increases brain tissue oxygen levels after cardiopulmonary resuscitation independent of cardiac function and cerebral perfusion

Prompt reperfusion is important to rescue ischemic tissue; however, the process itself presents a key pathomechanism that contributes to a poor outcome following cardiac arrest. Experimental data have suggested the use of levosimendan to limit ischemia–reperfusion injury by improving cerebral microcirculation. However, recent studies have questioned this effect. The present study aimed to investigate the influence on hemodynamic parameters, cerebral perfusion and oxygenation following cardiac arrest by ventricular fibrillation in juvenile male pigs. Following the return of spontaneous circulation (ROSC), animals were randomly assigned to levosimendan (12 µg/kg, followed by 0.3 µg/kg/min) or vehicle treatment for 6 h. Levosimendan-treated animals showed significantly higher brain PbtO(2) levels. This effect was not accompanied by changes in cardiac output, preload and afterload, arterial blood pressure, or cerebral microcirculation indicating a local effect. Cerebral oxygenation is key to minimizing damage, and thus, current concepts are aimed at improving impaired cardiac output or cerebral perfusion. In the present study, we showed that NIRS does not reliably detect low PbtO(2) levels and that levosimendan increases brain oxygen content. Thus, levosimendan may present a promising therapeutic approach to rescue brain tissue at risk following cardiac arrest or ischemic events such as stroke or traumatic brain injury