1,028 research outputs found
JT9D jet engine diagnostics program
Performance deterioration in the JT9D-7 is a flight sensitive phenomenon caused by one short term and two long term wear modes. The short term deterioration occurs primarily during airplane acceptance testing and therefore does not affect airline operation. The long term wear takes place continuously over the engine life so that the performance loss can be minimized by a sound maintenance program. Short term deterioration is primarily due to flight load induced blade and gas path seal wear which result in increased gas path running clearances. The wear occurs in all engine modules but has the most deleterious effect on the low pressure compressor and high pressure turbine performance. The wear occurs during conditions that combine minimum axisymmetric running clearances and maximum engine distortion or asymmetric closure
JT9D performance deterioration results from a simulated aerodynamic load test
The results of testing to identify the effects of simulated aerodynamic flight loads on JT9D engine performance are presented. The test results were also used to refine previous analytical studies on the impact of aerodynamic flight loads on performance losses. To accomplish these objectives, a JT9D-7AH engine was assembled with average production clearances and new seals as well as extensive instrumentation to monitor engine performance, case temperatures, and blade tip clearance changes. A special loading device was designed and constructed to permit application of known moments and shear forces to the engine by the use of cables placed around the flight inlet. The test was conducted in the Pratt & Whitney Aircraft X-Ray Test Facility to permit the use of X-ray techniques in conjunction with laser blade tip proximity probes to monitor important engine clearance changes. Upon completion of the test program, the test engine was disassembled, and the condition of gas path parts and final clearances were documented. The test results indicate that the engine lost 1.1 percent in thrust specific fuel consumption (TSFC), as measured under sea level static conditions, due to increased operating clearances caused by simulated flight loads. This compares with 0.9 percent predicted by the analytical model and previous study efforts
Performance deterioration based on simulated aerodynamic loads test, JT9D jet engine diagnostics program
An engine was specially prepared with extensive instrumentation to monitor performance, case temperatures, and clearance changes. A special loading device was used to apply known loads on the engine by the use of cables placed around the flight inlet. These loads simulated the estimated aerodynamic pressure distributions that occur on the inlet in various segments of a typical airplane flight. Test results indicate that the engine lost 1.3 percent in take-off thrust specific fuel consumption (TSFC) during the course of the test effort. Permanent clearance changes due to the loads accounted for 1.1 percent; increase in low pressure compressor airfoil roughness and thermal distortion in the high pressure turbine accounted for 0.2 percent. Pretest predicted performance loss due to clearance changes was 0.9 percent in TSFC. Therefore, the agreement between measurement and prediction is considered to be excellent
Merry Masquerade
The song, Merry Masquerade, was developed by the fifth-grade students of Martin Luther King Elementary School during the 2015 spring semester as part of the America’s Civil War through Music sessions developed by Scott Schwartz and Marten Stromberg. This is the fourth year the students helped write a new song building on the knowledge that they have acquired through weekly history lessons and music performances by Scott and Marten, and copies of primary
source documents pulled from the University’s Illinois History and Lincoln Collections. The students’ song this year builds on some of the more unusual stories about the mad-capped adventures of Abraham Lincoln, Jefferson Davis, Confederate General Stonewall Jackson, Union
General George McClellan, and the many soldiers who fought during America’s Civil War.Ope
Application of multispectral radar and LANDSAT imagery to geologic mapping in death valley
Side-Looking Airborne Radar (SLAR) images, acquired by JPL and Strategic Air Command Systems, and visible and near-infrared LANDSAT imagery were applied to studies of the Quaternary alluvial and evaporite deposits in Death Valley, California. Unprocessed radar imagery revealed considerable variation in microwave backscatter, generally correlated with surface roughness. For Death Valley, LANDSAT imagery is of limited value in discriminating the Quaternary units except for alluvial units distinguishable by presence or absence of desert varnish or evaporite units whose extremely rough surfaces are strongly shadowed. In contrast, radar returns are most strongly dependent on surface roughness, a property more strongly correlated with surficial geology than is surface chemistry
Forehead Skin Blood Flow in Normal Neonates during Active and Quiet Sleep, Measured with a Diode Laser Doppler Instrument
Changes in forehead skin blood flow during active and quiet sleep were determined in 16 healthy neonates using a recently developed semi-conductor laser Doppler flow meter without light conducting fibres. Measurements were carried out at a postnatal age varying from 5 hours to 7 days. The two sleep states could be distinguished in 17 recordings. The mean skin blood flow values during active sleep were significantly higher (p<0.01) than those during quiet sleep, the mean increase being 28.1%. The variability of the flow signal, expressed as the coefficient of variation, changed significantly from 23.1% during active sleep to 18.2% during quiet sleep
Preparation and structural investigation of epitaxially grown antiferromagnetic FeSn2(001) thin films on InSb(001)
On non-measurable sets and invariant tori
The question: "How many different trajectories are there on a single
invariant torus within the phase space of an integrable Hamiltonian system?" is
posed. A rigorous answer to the question is found both for the rational and the
irrational tori. The relevant notion of non-measurable sets is discussed.Comment: 8 pages, 1 figur
Experimental Observation of Earth's Rotation with Quantum Entanglement
Precision interferometry with quantum states has emerged as an essential tool
for experimentally answering fundamental questions in physics. Optical quantum
interferometers are of particular interest due to mature methods for generating
and manipulating quantum states of light. The increased sensitivity offered by
these states promises to enable quantum phenomena, such as entanglement, to be
tested in unprecedented regimes where tiny effects due to gravity come into
play. However, this requires long and decoherence-free processing of quantum
entanglement, which has not yet been explored for large interferometric areas.
Here we present a table-top experiment using maximally path-entangled quantum
states of light in an interferometer with an area of 715 m, sensitive
enough to measure the rotation rate of Earth. A rotatable setup and an active
area switching technique allow us to control the coupling of Earth's rotation
to an entangled pair of single photons. The achieved sensitivity of 5
rad/s constitutes the highest rotation resolution ever achieved with
optical quantum interferometers, surpassing previous work by three orders of
magnitude. Our result demonstrates the feasibility of extending the utilization
of maximally entangled quantum states to large-scale interferometers. Further
improvements to our methodology will enable measurements of
general-relativistic effects on entangled photons opening the way to further
enhance the precision of fundamental measurements to explore the interplay
between quantum mechanics and general relativity along with searches for new
physics
Membrane Insertion for the Detection of Lipopolysaccharides: Exploring the Dynamics of Amphiphile-in-Lipid Assays
Shiga toxin-producing Escherichia coli is an important cause of foodborne illness, with cases attributable to beef, fresh produce and other sources. Many serotypes of the pathogen cause disease, and differentiating one serotype from another requires specific identification of the O antigen located on the lipopolysaccharide (LPS) molecule. The amphiphilic structure of LPS poses a challenge when using classical detection methods, which do not take into account its lipoglycan biochemistry. Typically, detection of LPS requires heat or chemical treatment of samples and relies on bioactivity assays for the conserved lipid A portion of the molecule. Our goal was to develop assays to facilitate the direct and discriminative detection of the entire LPS molecule and its O antigen in complex matrices using minimal sample processing. To perform serogroup identification of LPS, we used a method called membrane insertion on a waveguide biosensor, and tested three serogroups of LPS. The membrane insertion technique allows for the hydrophobic association of LPS with a lipid bilayer, where the exposed O antigen can be targeted for specific detection. Samples of beef lysate were spiked with LPS to perform O antigen specific detection of LPS from E. coli O157. To validate assay performance, we evaluated the biophysical interactions of LPS with lipid bilayers both in- and outside of a flow cell using fluorescence microscopy and fluorescently doped lipids. Our results indicate that membrane insertion allows for the qualitative and reliable identification of amphiphilic LPS in complex samples like beef homogenates. We also demonstrated that LPS-induced hole formation does not occur under the conditions of the membrane insertion assays. Together, these findings describe for the first time the serogroup-specific detection of amphiphilic LPS in complex samples using a membrane insertion assay, and highlight the importance of LPS molecular conformations in detection architectures
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