Third International Symposium on Magnetic Suspension Technology

In order to examine the state of technology of all areas of magnetic suspension and to review recent developments in sensors, controls, superconducting magnet technology, and design/implementation practices, the Third International Symposium on Magnetic Suspension Technology was held at the Holiday Inn Capital Plaza in Tallahassee, Florida on 13-15 Dec. 1995. The symposium included 19 sessions in which a total of 55 papers were presented. The technical sessions covered the areas of bearings, superconductivity, vibration isolation, maglev, controls, space applications, general applications, bearing/actuator design, modeling, precision applications, electromagnetic launch and hypersonic maglev, applications of superconductivity, and sensors

Control of a magnetically levitated ventricular assist device

This work presents theoretical and experimental means for achieving impeller stability in a magnetically levitated left ventricular assist device (LVAD). These types of medical devices are designed to boost the native heart`s ability to pump blood by means of mechanical energy transfer using a rotating impeller. Magnetic suspension of the impeller eliminates bearing friction and reduces blood damage, but it requires active controls that monitor the impeller`s position and speed in order to generate the forces and torques required to regulate its dynamic behavior. To accomplish this goal, this work includes: 1) a dynamic system model derived using energy and momentum conservation 2) dynamic analysis including stability, controllability and observability, and 3) development of two control algorithms: proportional integral derivative and sliding mode control. Experimental validation included component behavior, model accuracy, and the characterization of controller performance using a physiological simulator. The system model proved to be an adequate representation of the system while levitating in air, but additional research is needed to model hydrodynamic and gyroscopic effects. After the prototype`s subcomponents were tested, calibrated and/or modified to fit the control requirements, both control strategies were successful in controlling the rotor as it spun at 6000 rpm pumping 6L/min of water at 80mmHg. A maximum speed of 6500 rpm was achieved with speed control within 5% over most of the operating range. The control platform and many of the methods presented here are continually being used and improved towards the implantation of the device in a human subject in the future

PI-PD controller design for magnetic levitation systems via weighted geometrical center method

Manyetik levitasyon (Maglev) sistemleri, mühendislik sistemlerinde sürtünmeyi en aza indiren çözümler sunduğundan, güncel mühendislik çalışmalarındandır. Bu çalışmada, yeni bir PI-PD kontrolcü tasarım prosedürü sunulmuştur. PI-PD kontrolcüleri, bir PI (iç döngü) ve bir PD (dış döngü) kombinasyonundan oluşur. İç döngünün amacı, açık döngü kararsız sistemi kararlı kılmaktır. Dış döngünün amacı, kapalı döngü sisteminin toplam performans gereksinimlerini sağlamaktır. Tasarım prosedürü, kontrolcü parametreleri düzleminde kararlılık sınır eğrisi kullanılarak çizilen kararlı bölgenin elde edilmesi ve bu bölgenin ağırlıklı geometrik merkezinin (AGM) hesaplanmasına dayanır. Tasarım prosedüründe, ilk olarak, iç döngü için PD kontrolcü parametrelerinin düzlemindeki kararlı bölge ve bunun ağırlıklı geometrik merkezi hesaplanır. İç döngü, belirtilen AGM kontrol parametreleri kullanılarak tek bir bloğa indirgenir ve ardından prosedür, farklı tasarımlarda faz ve kazanç payı performans gereksinimlerini uygulayan bir test fonksiyonu kullanılarak dış döngü PI denetleyicisi için tekrarlanır. Deneysel çalışma, önerilen metodoloji ile tasarlanan PI-PD kontrolcünün literatürde bulunan alternatiflere göre daha üstün performans sergilediğini göstermektedi

The Fifth National Technology Transfer Conference and Exposition

No abstract availabl

A History of Materials and Technologies Development

The purpose of the book is to provide the students with the text that presents an introductory knowledge about the development of materials and technologies and includes the most commonly available information on human development. The idea of the publication has been generated referring to the materials taken from the organic and non-organic evolution of nature. The suggested texts might be found a purposeful tool for the University students proceeding with studying engineering due to the fact that all subjects in this particular field more or less have to cover the history and development of the studied object. It is expected that studying different materials and technologies will help the students with a better understanding of driving forces, positive and negative consequences of technological development, etc

NASA Tech Briefs, July 2009

Topics covered include: Dual Cryogenic Capacitive Density Sensor; Hail Monitor Sensor; Miniature Six-Axis Load Sensor for Robotic Fingertip; Improved Blackbody Temperature Sensors for a Vacuum Furnace; Wrap-Around Out-the-Window Sensor Fusion System; Wide-Range Temperature Sensors with High-Level Pulse Train Output; Terminal Descent Sensor Simulation; A Robust Mechanical Sensing System for Unmanned Sea Surface Vehicles; Additive for Low-Temperature Operation of Li-(CF)n Cells; Li/CFx Cells Optimized for Low-Temperature Operation; Number Codes Readable by Magnetic-Field-Response Recorders; Determining Locations by Use of Networks of Passive Beacons; Superconducting Hot-Electron Submillimeter-Wave Detector; Large-Aperture Membrane Active Phased-Array Antennas; Optical Injection Locking of a VCSEL in an OEO; Measuring Multiple Resistances Using Single-Point Excitation; Improved-Bandwidth Transimpedance Amplifier; Inter-Symbol Guard Time for Synchronizing Optical PPM; Novel Materials Containing Single-Wall Carbon Nanotubes Wrapped in Polymer Molecules; Light-Curing Adhesive Repair Tapes; Thin-Film Solid Oxide Fuel Cells; Zinc Alloys for the Fabrication of Semiconductor Devices; Small, Lightweight, Collapsible Glove Box; Radial Halbach Magnetic Bearings; Aerial Deployment and Inflation System for Mars Helium Balloons; Steel Primer Chamber Assemblies for Dual Initiated Pyrovalves; Voice Coil Percussive Mechanism Concept for Hammer Drill; Inherently Ducted Propfans and Bi-Props; Silicon Nanowire Growth at Chosen Positions and Orientations; Detecting Airborne Mercury by Use of Gold Nanowires; Detecting Airborne Mercury by Use of Palladium Chloride; Micro Electron MicroProbe and Sample Analyzer; Nanowire Electron Scattering Spectroscopy; Electron-Spin Filters Would Offer Spin Polarization Greater than 1; Subcritical-Water Extraction of Organics from Solid Matrices; A Model for Predicting Thermoelectric Properties of Bi2Te3; Integrated Miniature Arrays of Optical Biomolecule Detectors; A Software Rejuvenation Framework for Distributed Computing; Kurtosis Approach to Solution of a Nonlinear ICA Problem; Robust Software Architecture for Robots; R4SA for Controlling Robots; Bio-Inspired Neural Model for Learning Dynamic Models; Evolutionary Computing Methods for Spectral Retrieval; Monitoring Disasters by Use of Instrumented Robotic Aircraft; Complexity for Survival of Living Systems; Using Drained Spacecraft Propellant Tanks for Habitation; Connecting Node; and Electrolytes for Low-Temperature Operation of Li-CFx Cells