Apparatus for sensor failure detection and correction in a gas turbine engine control system

A gas turbine engine control system maintains a selected level of engine performance despite the failure or abnormal operation of one or more engine parameter sensors. The control system employs a continuously updated engine model which simulates engine performance and generates signals representing real time estimates of the engine parameter sensor signals. The estimate signals are transmitted to a control computational unit which utilizes them in lieu of the actual engine parameter sensor signals to control the operation of the engine. The estimate signals are also compared with the corresponding actual engine parameter sensor signals and the resulting difference signals are utilized to update the engine model. If a particular difference signal exceeds specific tolerance limits, the difference signal is inhibited from updating the model and a sensor failure indication is provided to the engine operator

Second messenger systems underlying amine and peptide actions on cardiac muscle in the horseshoe crab, Limulus polyphemus

The biochemical mechanisms by which octopamine, catecholamines and the peptide proctolin exert their actions on Limulus cardiac muscle were investigated. Amines produced long-lasting increases in the amplitude of contractions evoked by electrical stimulation. At 10(−5) mol l-1, the apparent order of potency for amine-induced increases in evoked contraction amplitude was dopamine approximately equal to octopamine greater than norepinephrine approximately equal to epinephrine. At this dose, amines produced long-lasting increases in the levels of cyclic AMP (octopamine greater than dopamine approximately equal to norepinephrine approximately equal to epinephrine), but not of cyclic GMP, in Limulus cardiac muscle. Like the amines, the adenylate cyclase activator forskolin enhanced cardiac muscle contractility and increased levels of cyclic AMP, but not of cyclic GMP. The phosphodiesterase inhibitor IBMX produced a transient increase in cardiac muscle contractility, but typically produced long-lasting negative inotropy. This agent increased levels of both cyclic AMP and cyclic GMP in Limulus cardiac muscle. Proctolin and the protein kinase C activator phorbol dB increased the contraction amplitude of the intact heart and the electrically stimulated myocardium. These compounds, as well as dopamine, elicited sustained contractures and rhythmic contractions when applied to deganglionated Limulus cardiac muscle rings. Unlike the amines, proctolin and phorbol dB did not increase cardiac muscle cyclic AMP levels. These results suggest that several second-messenger systems may be utilized by amines and peptides to produce excitatory actions on cardiac muscle fibers of the Limulus heart. Cyclic AMP appears to be an important second messenger underlying the effects of amines to enhance cardiac muscle contractility. Pharmacological data suggest that proctolin may alter cardiac muscle contractility and excitability by a mechanism which involves the phosphatidylinositol pathway. Dopamine, unlike the other amines, produces a number of proctolin-like effects and may activate both the cyclic AMP and the phosphatidylinositol systems in Limulus cardiac muscle

Torsional suspension system for testing space structures

A low frequency torsional suspension system for testing a space structure uses a plurality of suspension stations attached to the space structure along the length thereof in order to suspend the space structure from an overhead support. Each suspension station includes a disk pivotally mounted to the overhead support, and two cables which have upper ends connected to the disk and lower ends connected to the space structure. The two cables define a parallelogram with the center of gravity of the space structure being vertically beneath the pivot axis of the disk. The vertical distance between the points of attachment of the cables to the disk and the pivot axis of the disk is adjusted to lower the frequency of the suspension system to a level which does not interfere with frequency levels of the space structure, thereby enabling accurate measurement

CARETS: A prototype regional environmental information system. Volume 12: User evaluation of experimental land use maps and related products from the central Atlantic test site

The author has identified the following significant results. Recommendations resulting from the CARETS evaluation reflect the need to establish a flexible and reliable system for providing more detailed raw and processed land resource information as well as the need to improve the methods of making information available to users

Involvement of cyclic AMP in multiple, excitatory actions of biogenic amines on the cardiac ganglion of the horseshoe crab Limulus polyphemus

Cyclic AMP appears to be involved in several excitatory actions of amines on neurones of the Limulus cardiac ganglion. Amines selectively increase levels of cardiac ganglion cyclic AMP with a magnitude and time course similar to that observed for amine-induced excitation of cardiac ganglion burst rate. With respect to either the physiological or biochemical effect, the apparent order of potency is octoparnine\u3eepinephrine==dopamine\u3enorepinephrine. Elevation of cardiac ganglion cyclic AMP levels by octopamine or dopamine is dose-dependent and is potentiated by the phosphodiesterase inhibitor 3-isobutyl 1-methylxanthine (IBMX). Several pharmacological agents which influence cyclic nucleotide metabolism, including forskolin, IBMX and 8-substituted cyclic AMP analogues, have amine-like effects on the Limulus cardiac ganglion. These effects include increased burst rate of the isolated cardiac ganglion and decreased burst duration, interburst interval and number of spikes per burst in follower neurones. Forskolin and IBMX increase levels of cardiac ganglion cyclic AMP, and IBMX also increases cyclic GMP levels in this tissue. Amines, forskolin and IBMX have direct effects on follower neurones pharmacologically isolated from pacemaker cell input. Octopamine, forskolin and IBMX depolarize follower neurones, while dopamine hyperpolarizes these cells. Amines, forskolin and IBMX elicit burst-like potentials in follower neurones, and increase the size of evoked, unitary junction potentials recorded in cardiac muscle fibres. These pharmacological and biochemical data suggest that multiple, excitatory effects of biogenic amines on the Limulus cardiac ganglion are mediated by simultaneous increases in cyclic AMP at several loci within this neural network

They (Don't) Care About Education: A Counternarrative on Black Male Students' Responses to Inequitable Schooling

Focus group interviews and systematic content analysis of 304 essays written by black male undergraduates refute the dominant message that black men do not care about education. On the contrary, these students aspire to earn doctoral degrees in education despite acute understanding that the education system is stacked against them. The analysis asks what compels that dedication

Wing/store flutter with nonlinear pylon stiffness

Recent wind tunnel tests and analytical studies show that a store mounted on a pylon with soft pitch stiffness provides substantial increase in flutter speed of fighter aircraft and reduces dependency of flutter on mass and inertia of the store. This concept, termed the decoupler pylon, utilizes a low frequency control system to maintain pitch alignment of the store during maneuvers and changing flight conditions. Under rapidly changing transient loads, however, the alignment control system may allow the store to momentarily bottom against a relatively stiff backup structure in which case the pylon stiffness acts as a hardening nonlinear spring. Such structural nonlinearities are known to affect not only the flutter speed but also the basic behavior of the instability. The influence of pylon stiffness nonlinearities or the flutter characteristics of wing mounted external stores is examined

Experimental X-ray Stress Analysis Procedures for Ultra High Strength Materials

X-ray stress analysis procedures for accurate measurement of elastic strain in high strength steel

CARETS: A prototype regional environmental information system. Volume 10: Environmental problems in the coastal and wetlands ecosystems of Virginia Beach, Virginia

There are no author-identified significant results in this report