Selecting Metal Alloy Electric Contact Materials for MEMS Switches

This paper presents a method for selecting metal alloys as the electric contact materials for microelectromechanical systems (MEMS) metal contact switches. This procedure consists of reviewing macro-switch lessons learned, utilizing equilibrium binary alloy phase diagrams, obtaining thin film material properties and, based on a suitable model, predicting contact resistance performance. After determining a candidate alloy material, MEMS switches were designed, fabricated and tested to validate the alloy selection methodology. Minimum average contact resistance values of 1.17 and 1.87 Ω were measured for micro-switches with gold (Au) and gold–platinum (Au–(6.3%)Pt) alloy electric contacts, respectively. In addition, \u27hot-switched\u27 life cycle test results of 1.02 × 108 and 2.70 × 108 cycles were collected for micro-switches with Au and Au–(6.3%)Pt contacts, respectively. These results indicate increased wear with a small increase in contact resistance for MEMS switches with metal alloy electric contacts

Beyond Data Capture: Using REDCap™ to Facilitate Web-Based Therapeutic Intervention Research

Background Limited guidelines to assist nurse researchers who use web-based interventions are available. Nurses must develop the supporting technology enabling participants to complete study activities and collected data while maintaining data security and participant confidentiality. Objectives To describe how the authors used advanced Research Electronic Data Capture (REDCapTM) functionality to support the data management infrastructure of an interactive, web-based therapeutic intervention. Methods The data management infrastructure for the WISER intervention pilot study consisted of two components: a website for presentation of the intervention and participant account management and a REDCap project for data capture and storage. REDCap application programming interface (API) connected these two components using HTML links and data exchanges. Results We completed an initial pilot study of WISER with 14 participants using the REDCap-based infrastructure. Minimal technical difficulties were encountered. Discussion REDCap is cost-effective, readily available, and through its advanced functionality is able to facilitate confidential, secure interactions with participants, robust data management, and seamless participant progression in web-based intervention research

ACTS Propagation Experiment: Experiment Design, Calibration, and Data Preparation and Archival

The National Aeronautics and Space Administration Advanced Communications Technology Satellite (ACTS) propagation experiment was designed to obtain slant-path attenuation statistics for locations within the United States and Canada for use in the design of low-margin Ka-band satellite communication systems. Experimenters at seven different locations have collected propagation data for more than two years. The propagation terminals used for the experiment were identical. A single preprocessing program was used by the experimenters to provide for automatic calibration, generation of attenuation histograms, and data archival. In this paper, the calibration procedures are described and estimates given for measurement accuracy. ACTS provided beacons at 20.2 and 27.5 GHz for use in making attenuation measurements. In addition to the beacon receivers, each ACTS propagation terminal has two total power radiometers with center frequencies at the beacon frequencies. The radiometers are used to establish the beacon signal reference levels needed for calculating beacon attenuation values. For the combined radiometer and beacon measurement system, the attenuation measurement error was less than a maximum of 1.0 dB and was generally less than 0.3 dB. The dynamic range for attenuation measurement varied from site to site depending on location relative to the peak of the satellite beacon antenna pattern. For locations within the continental United States, the dynamic range was better than 20 dB

Algorithm Development and Computer Graphic Simulation of an Articulated Transporter/ Manipulator System

The University of Florida is part of a multi-university research effort, sponsored by the U.S. Department of Energy, which is underway to develop and deploy an advanced semi-autonomous robotic system for use in nuclear power stations. The robotic system being designed by the Florida/Odetics team can be described . as an Articulated Transporter/Manipulator System (ATMS) which has several unique motion and transport capabilities. The ATMS will be capable of performing tasks in radioactive hazardous environments to reduce occupational radiation exposure of plant personnel and to increase the availability of the plant. This paper will describe the key design and control features of the ATMS with emphasis placed on the implementation of specific motion control algorithms

Radio Frequency MEMS Switch Contact Metal Selection

A method for selecting metal alloys as the electric contact materials for microelectromechanical systems (MEMS) metal contact switches. This method includes a review of alloy experience, consideration of equilibrium binary alloy phase diagrams, obtaining thin film material properties and, based on a suitable model, predicting contact electrical resistance performance. After determination of a candidate alloy material, MEMS switches are conceptualized, fabricated and tested to validate the alloy selection methodology. Minimum average contact resistance values of 1.17 and 1.87 ohms are achieved for micro-switches with gold (Au) and gold-platinum (Au-(6.3 at %)Pt) alloy contacts. In addition, `hot-switched` life cycle test results of 1.02.x108 and 2.70.x108 cycles may be realized for micro-switches with Au and Au-(6.3 at %)Pt contacts. These results indicate increased wear with a small increase in contact resistance for MEMS switches with metal alloy electric contacts

The Effects of Combined Aquatic and Occupational Therapy in Stroke Patients: A Retrospective Study

The purpose of this retrospective pilot study was to determine if aquatic therapy (AT) intervention concurrent with occupational therapy (OT) yielded greater functional gains in stroke patients than OT treatment alone. A retrospective chart review was conducted evaluating subjective data from an inpatient rehabilitation hospital in Morgantown, WV. Thirty-nine stroke survivor charts were examined. Patients who received OT with or without concurrent aquatic therapy were included. Differences in the Functional Independence Measure (FIM) scores in stroke patients who received (a) AT plus conventional OT or (b) conventional OT alone. Discharge bed/chair transfer (p = 0.009) and locomotion (p = 0.01) scores were higher for people who received OT and AT versus patients only receiving OT. Linear regression indicated that use of AT treatment predicted discharge bed/chair transfer FIM score (p = 0.02), discharge locomotion FIM score (p = 0.002), discharge stairs FIM score (p = 0.04), and change in bed/chair transfer FIM score (p = 0.02). These findings indicate that AT, combined with OT, may predict success on specific FIM outcomes (e.g., bed/chair transfer FIM score, locomotion [walking] FIM score) in stroke patients

A detailed analysis of the HD 73526 2:1 resonant planetary system

We present six years of new radial velocity data from the Anglo-Australian and Magellan Telescopes on the HD 73526 2:1 resonant planetary system. We investigate both Keplerian and dynamical ( interacting) fits to these data, yielding four possible configurations for the system. The new data now show that both resonance angles are librating, with amplitudes of 40 degrees and 60 degrees, respectively. We then perform long-term dynamical stability tests to differentiate these solutions, which only differ significantly in the masses of the planets. We show that while there is no clearly preferred system inclination, the dynamical fit with i = 90 degrees provides the best combination of goodness-of-fit and long-term dynamical stability.Peer reviewe

A High Stellar Obliquity in the WASP-7 Exoplanetary System

We measure a tilt of 86+-6 deg between the sky projections of the rotation axis of the WASP-7 star, and the orbital axis of its close-in giant planet. This measurement is based on observations of the Rossiter-McLaughlin (RM) effect with the Planet Finder Spectrograph on the Magellan II telescope. The result conforms with the previously noted pattern among hot-Jupiter hosts, namely, that the hosts lacking thick convective envelopes have high obliquities. Because the planet's trajectory crosses a wide range of stellar latitudes, observations of the RM effect can in principle reveal the stellar differential rotation profile; however, with the present data the signal of differential rotation could not be detected. The host star is found to exhibit radial-velocity noise (``stellar jitter') with an amplitude of ~30m/s over a timescale of days.Comment: ApJ accepted, 9 pages, 9 figure

Book Reviews

Among all the writings that have appeared on the problem of preserving the order of world society, the most searching and the most illuminating is Hart\u27s Bulwarks of Peace. Particularly in connection with any consideration of the plan of the Paris Covenant of the League of Nations, it compellingly arrests attention