Control means for a gas turbine engine

A means is provided for developing a signal representative of the actual compressor casing temperature, a second signal representative of compressor inlet gas temperature, and a third signal representative of compressor speed. Another means is provided for receiving the gas temperature and compressor speed signals and developing a schedule output signal which is a representative of a reference casing temperature at which a predetermined compressor blade stabilized clearance is provided. A means is also provided for comparing the actual compressor casing temperature signal and the reference casing temperature signal and developing a clearance control system representative of the difference. The clearance control signal is coupled to a control valve which controls a flow of air to the compressor casing to control the clearance between the compressor blades and the compressor casing. The clearance control signal can be modified to accommodate transient characteristics. Other embodiments are disclosed

Analysis of control concepts for gas and shaft-coupled V/STOL aircraft lift fan systems

For lift-fan powered V/STOL aircraft, two unconventional propulsion system types were proposed. The first type uses fans connected by hot gas ducting, and the second type uses fans connected by cross shafting. An analytical study identified the basic steady-state and dynamic characteristics for each type of system. For the gas-coupled system, the control concepts analyzed were variable-area fan turbines and throttling valves in the ducting. For the shaft-coupled system, the control concepts analyzed were variable-pitch fans and variable fan inlet guide vanes. All of these concepts are capable of meeting V/STOL aircraft control moment and transient response requirements when appropriate propulsion controls are used

Mr. and Mrs. R. J. Sellers to James Meredith (Undated)

https://egrove.olemiss.edu/mercorr_pro/1902/thumbnail.jp

α_1L-adrenoceptors mediate contraction of human erectile tissue

α1-adrenoceptor antagonists can impact upon sexual function and have potential in the treatment of erectile dysfunction. Human erectile tissue contains predominantly α1A-adrenoceptors, and here we examined whether contractions of this tissue are mediated by the functional phenotype, the α1L-adrenoceptor. Functional experiments using subtype selective agonists and antagonists, along with radioligand ([3H]tamsulosin) binding assays, were used to determine the α1-adrenoceptor population. A61603, a α1A-adrenoceptor agonist, was a full agonist with a potency 21-fold greater than that of noradrenaline. The α1A- and α1D-adrenoceptor antagonist tamsulosin antagonized noradrenaline responses with high affinity (pKD = 9.7 ± 0.3), whilst BMY7378 (100 nM) (α1D-adrenoceptor antagonist) failed to antagonize responses. In contrast, relatively low affinity estimates were obtained for both prazosin (pKD = 8.2 ± 0.1) and RS17053 (pKD = 6.9 ± 0.2), antagonists which discriminate between the α1A- and α1L-adrenoceptors. [3H]Tamsulosin bound with high affinity to the receptors of human erectile tissue (pKD = 10.3 ± 0.1) with a receptor density of 28.1 ± 1.4 fmol mg−1 protein. Prazosin displacement of [3H]tamsulosin binding revealed a single homogenous population of binding sites with a relatively low affinity for prazosin (pKi = 8.9). Taken together these data confirm that the receptor mediating contraction in human erectile tissue has the pharmacological properties of the α1L-adrenoceptor. Keywords: Erectile tissue, α1-adrenoceptor subtypes, α1L-adrenoceptor, Tamsulosin, Prazosi

Perception of Grazing to Promote Ecological Services in Recreational and Government Contracted Grasslands

Managed grazing in grasslands not currently grazed such as those enrolled in the Conservation Reserve Program or used for recreational activities has the potential to improve plant community diversity and soil quality thus enhancing many grassland ecological services including wildlife habitat, carbon sequestration, and preserving water quality. Grazing in grasslands not currently grazed increases the available forage for grazing cattle to reduce the pressure on current pasturelands. However, introducing managed grazing into grasslands not currently grazed poses unique challenges including repairing or installing infrastructure, movement of cattle to new grazing areas, and developing agreements to ensure grazing management meets the goals of both the land owner and cattle producer. To determine the potential for integration of managed grazing into perennial grassland landscapes, a survey was made available to cattle producers and grassland owners throughout the Midwest. Results from 65 respondents throughout the Midwest indicate grassland owners and cattle producers recognize that grazing has potential to enhance the ecological value of grasslands; however, a majority of cattle producers (53%) feel grassland owners don’t want to allow grazing on their land. Of the grassland owners surveyed, 63% wanted to attract wildlife for hunting and 87% would allow short duration grazing to enhance wildlife habitat. If grazing was allowed on government contracted grasslands, 79% of cattle producers were willing to move cattle up to 10 miles for less than 45 days of grazing. Both grassland owners and cattle producers in the survey were most likely to install infrastructure when grazing contracts lasted at least 5 years. The results of this survey indicate both cattle producers and grassland owners are willing to graze grasslands not currently grazed; however, payments would be required by more than 70% of grassland owners to compensate for lost government payments or at a rate equal to current pasture rent

Strong light-matter coupling in bulk GaN-microcavities with double dielectric mirrors fabricated by two different methods

Two routes for the fabrication of bulk GaN microcavities embedded between two dielectric mirrors are described, and the optical properties of the microcavities thus obtained are compared. In both cases, the GaN active layer is grown by molecular beam epitaxy on (111) Si, allowing use of selective etching to remove the substrate. In the first case, a three period Al0.2Ga0.8N / AlN Bragg mirror followed by a lambda/2 GaN cavity are grown directly on the Si. In the second case, a crack-free 2,mu m thick GaN layer is grown, and progressively thinned to a final thickness of lambda. Both devices work in the strong coupling regime at low temperature, as evidenced by angle-dependent reflectivity or transmission experiments. However, strong light-matter coupling in emission at room temperature is observed only for the second one. This is related to the poor optoelectronic quality of the active layer of the first device, due to its growth only 250 nm above the Si substrate and its related high defect density. The reflectivity spectra of the microcavities are well accounted for by using transfer matrix calculations. (C) 2010 American Institute of Physics. [doi:10.1063/1.3477450

Banking from Leeds, not London: regional strategy and structure at the Yorkshire Bank, 1859–1952

Industrial philanthropist Edward Akroyd created the Yorkshire Penny Savings Bank in 1859. Despite competition from the Post Office Savings Bank after 1861 and a serious reserve problem in 1911, it sustained his overall strategy to become a successful regional bank. Using archival and contemporary sources to build on recent scholarship illustrating how savings banks were integrated into local economies and the complementary roles of philanthropy and paternalism, we analyse an English regional bank's strategy, including an assessment of strategic innovation, ownership changes and management structure. This will demonstrate that the founder's vision continued, even though the 1911 crisis radically altered both strategy and structure

A Nanosatellite Mission to Investigate Equatorial Ionospheric Plasma Depletions: The U. S. Air Force Academy’s FalconSat-2

An overview of the United States Air Force Academy’s (USAFA’s) FalconSat-2, a nanosatellite designed to investigate F region ionospheric plasma depletions, is presented. Instruments aboard FalconSat-2 will sample in situ plasma density and temperature at a rate of 10 Hz and 1.0 Hz, respectively. The choice of sampling rate provides for resolution of 2-10 km plasma depletions, important since plasma anisotropies of this scale size are known to disrupt Ultra High Frequency (UHF) radio transmissions. A novel sensor, the Miniature Electrostatic Analyzer (MESA), is presently under development by USAFA faculty and will be used to measure plasma density with its heritage flight aboard FalconSat-2. In addition, a traditional electron Retarding Potential Analyzer (RPA) will be used to measure plasma temperature and density, the latter of which will be used to validate the MESA performance on orbit. The mission’s scientific objectives require a low altitude (300-500 km), medium inclination (45 degrees) orbit; these requirements, coupled with the availability of launch opportunities through the Space Shuttle’s Hitchhiker Program, provide motivation to develop the FalconSat-2 mission for launch via the Hitchhiker’s Palette Ejection System (PES). The satellite bus design consists of a mixture of Commercial Off-The-Shelf (COTS) hardware and original design by USAFA cadets and faculty. Details of the mission and satellite design, as well as key challenges uniquely pertinent to undergraduate satellite programs, are addressed

Improved Approximate String Matching and Regular Expression Matching on Ziv-Lempel Compressed Texts

We study the approximate string matching and regular expression matching problem for the case when the text to be searched is compressed with the Ziv-Lempel adaptive dictionary compression schemes. We present a time-space trade-off that leads to algorithms improving the previously known complexities for both problems. In particular, we significantly improve the space bounds, which in practical applications are likely to be a bottleneck