Control system design using frequency domain models and parameter optimization, with application to supersonic inlet controls

A technique is described for designing feedback control systems using frequency domain models, a quadratic cost function, and a parameter optimization computer program. FORTRAN listings for the computer program are included. The approach is applied to the design of shock position controllers for a supersonic inlet. Deterministic or random system disturbances, and the presence of random measurement noise are considered. The cost function minimization is formulated in the time domain, but the problem solution is obtained using a frequency domain system description. A scaled and constrained conjugate gradient algorithm is used for the minimization. The approach to a supersonic inlet included the calculations of the optimal proportional-plus integral (PI) and proportional-plus-integral-plus-derivative controllers. A single-loop PI controller was the most desirable of the designs considered

Space shuttle pogo active controller design using frequency domain optimization

A frequency domain parameter optimization technique was used to design active pogo suppression controls for the space shuttle. The technique uses a conjugate gradient search procedure and is well suited for designing low-order controllers for higher order systems. The shuttle model was a two-pump and six-structural-mode linear model representing a worst-case condition. A promising feedback controller structure was found to be a lead-lag design

A digital computer propulsion control facility: Description of capabilities and summary of experimental program results

Flight weight digital computers are being used today to carry out many of the propulsion system control functions previously delegated exclusively to hydromechanical controllers. An operational digital computer facility for propulsion control mode studies has been used successfully in several experimental programs. This paper describes the system and some of the results concerned with engine control, inlet control, and inlet engine integrated control. Analytical designs for the digital propulsion control modes include both classical and modern/optimal techniques

Customer relationship management: creating competitive advantage through win-win relationship strategies

CRM is not about hardware and software; it is the heartware – the way we organize ourselves to work together with the customer to build a longlasting, mutually rewarding relationship. This lates contribution of Jarmo and Kaj on CRM offers you the insight, step and tips on how to strategize your direct relationship with your customers. There are plenty of pragmatic examples you can use immediately to energize your CRM initiatives. This book explains the intentions, process, creativity and dedication needed to win customers hearts and patronage. The authors bridge the high-tech disconnections with high touch CRM strategies that work. A must read for all customer builder. Dr Charlie In, President, Asian Direct Marketing Centre. At the start, the author say reading this book will demand thinking. Their clear definitions of the acts, knowledge, and emotion involved in everything the customers and the provider do together as the basis for win-win relationship strategies makes the thinking well wrote the effort

The Spectral Energy Distribution of Self-gravitating Interstellar Clouds I. Spheres

We derive the spectral energy distribution (SED) of dusty, isothermal, self gravitating, stable and spherical clouds externally heated by the ambient interstellar radiation field. For a given radiation field and dust properties, the radiative transfer problem is determined by the pressure of the surrounding medium and the cloud mass expressed as a fraction of the maximum stable cloud mass above which the clouds become gravitational unstable. To solve the radiative transfer problem a ray-tracing code is used to accurately derive the light distribution inside the cloud. This code considers both non isotropic scattering on dust grains and multiple scattering events. The dust properties inside the clouds are assumed to be the same as in the diffuse interstellar medium in our galaxy. We analyse the effect of the pressure, the critical mass fraction, and the ISRF on the SED and present brightness profiles in the visible, the IR/FIR and the submm/mm regime with the focus on the scattered emission and the thermal emission from PAH-molecules and dust grains.Comment: accepted for publication in ApJS, May 2008, v176n1 issu

Control technology for future aircraft propulsion systems

The need for a more sophisticated engine control system is discussed. The improvements in better thrust-to-weight ratios demand the manipulation of more control inputs. New technological solutions to the engine control problem are practiced. The digital electronic engine control (DEEC) system is a step in the evolution to digital electronic engine control. Technology issues are addressed to ensure a growth in confidence in sophisticated electronic controls for aircraft turbine engines. The need of a control system architecture which permits propulsion controls to be functionally integrated with other aircraft systems is established. Areas of technology studied include: (1) control design methodology; (2) improved modeling and simulation methods; and (3) implementation technologies. Objectives, results and future thrusts are summarized

Laterality of motor activity during normal and disturbed sleep

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Relativistic electrons from sparks in the laboratory

Discharge experiments were carried out at the Eindhoven University of Technology in 2013. The experimental setup was designed to search for electrons produced in meter-scale sparks using a 1 MV Marx generator. Negative voltage was applied to the high voltage (HV) electrode. Five thin (1 mm) plastic detectors (5 $\rm cm^2$ each) were distributed in various configurations close to the spark gap. Earlier studies have shown (for HV negative) that X-rays are produced when a cloud of streamers is developed 30-60 cm from the negative electrode. This indicates that the electrons producing the X-rays are also accelerated at this location, that could be in the strong electric field from counterstreamers of opposite polarity. Comparing our measurements with modeling results, we find that $\sim$300 keV electrons produced about 30-60 cm from the negative electrode are the most likely source of our measurements. A statistical analysis of expected detection of photon bursts by these fiber detectors indicates that only 20%-45% of the detected bursts could be from soft ($\sim$10 keV) photons, which further supports that the majority of detected bursts are produced by relativistic electrons

X-ray Halos and Large Grains in the Diffuse Interstellar Medium

Recent observations with dust detectors on board the interplanetary spacecraft Ulysses and Galileo have recorded a substantial flux of large interstellar grains with radii between 0.25 and 2.0 mu entering the solar system from the local interstellar cloud. The most commonly used interstellar grain size distribution is characterized by a a^-3.5 power law in grain radii a, and extends to a maximum grain radius of 0.25 mu. The extension of the interstellar grain size distribution to such large radii will have a major effect on the median grain size, and on the amount of mass needed to be tied up in dust for a given visual optical depth. It is therefore important to investigate whether this population of larger dust particles prevails in the general interstellar medium, or if it is merely a local phenomenon. The presence of large interstellar grains can be mainly inferred from their effect on the intensity and radial profiles of scattering halos around X-ray sources. In this paper we examine the grain size distribution that gives rise to the X-ray halo around Nova Cygni 1992. The results of our study confirm the need to extend the interstellar grain size distribution in the direction of this source to and possibly beyond 2.0 mu. The model that gives the best fit to the halo data is characterized by: (1) a grain size distribution that follows an a^-3.5 power law up to 0.50 mu, followed by an a^-4.0 extension from 0.50 mu to 2.0 mu; and (2) silicate and graphite (carbon) dust-to-gas mass ratios of 0.0044 and 0.0022, respectively, consistent with solar abundances constraints. Additional observations of X-ray halos probing other spatial directions are badly needed to test the general validity of this result.Comment: 17 pages, incl. 1 figure, accepted for publ. by ApJ Letter