2,791 research outputs found
Xenon fluorides show potential as fluorinating agents
Xenon fluorides permit the controlled addition of fluorine across an olefinic double bond. They provide a series of fluorinating agents that permit ready separation from the product at a high purity. The reactions may be carried out in the vapor phase
Precise computer controlled positioning of robot end effectors using force sensors
A thorough study of combined position/force control using sensory feedback for a one-dimensional manipulator model, which may count for the spacecraft docking problem or be extended to the multi-joint robot manipulator problem, was performed. The additional degree of freedom introduced by the compliant force sensor is included in the system dynamics in the design of precise position control. State feedback based on the pole placement method and with integral control is used to design the position controller. A simple constant gain force controller is used as an example to illustrate the dependence of the stability and steady-state accuracy of the overall position/force control upon the design of the inner position controller. Supportive simulation results are also provided
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Densely distributed and real-time scour hole monitoring using piezoelectric rod sensors
This study aims to validate a piezoelectric driven-rod scour monitoring system that can sense changes in scour depth along the entire rod at its instrumented location. The proposed sensor is a polymeric slender rod with a thin strip of polyvinylidene fluoride that runs through its midline. Extraction of the fundamental frequency allows the direct calculation of the exposed length (or scour depth) of the slender rod undergoing fluid flow excitation. First, laboratory validation in dry conditions is presented. Second, hydrodynamic testing of the sensor system in a soil-bed flume is discussed. Each rod was installed using a three-dimensional-printed footing designed for ease of installation and stabilization during testing. The sensors were installed in a layout designed to capture symmetric scour conditions around a scaled pier. In order to analyze the system out of steady-state conditions, water velocity was increased in stages during testing to induce different degrees of scour. As ambient water flow excited the portion of the exposed rods, the embedded piezoelectric element outputted a time-varying voltage signal. Different methods were then employed to extract the fundamental frequency of each rod, and the results were compared. Further testing was also performed to characterize the relationship between frequency outputs and flow velocity, which were previously thought to be independent. In general, the proposed driven-rod scour monitoring system successfully captured changing frequencies under varied flow conditions
State-space self-tuner for on-line adaptive control
Dynamic systems, such as flight vehicles, satellites and space stations, operating in real environments, constantly face parameter and/or structural variations owing to nonlinear behavior of actuators, failure of sensors, changes in operating conditions, disturbances acting on the system, etc. In the past three decades, adaptive control has been shown to be effective in dealing with dynamic systems in the presence of parameter uncertainties, structural perturbations, random disturbances and environmental variations. Among the existing adaptive control methodologies, the state-space self-tuning control methods, initially proposed by us, are shown to be effective in designing advanced adaptive controllers for multivariable systems. In our approaches, we have embedded the standard Kalman state-estimation algorithm into an online parameter estimation algorithm. Thus, the advanced state-feedback controllers can be easily established for digital adaptive control of continuous-time stochastic multivariable systems. A state-space self-tuner for a general multivariable stochastic system has been developed and successfully applied to the space station for on-line adaptive control. Also, a technique for multistage design of an optimal momentum management controller for the space station has been developed and reported in. Moreover, we have successfully developed various digital redesign techniques which can convert a continuous-time controller to an equivalent digital controller. As a result, the expensive and unreliable continuous-time controller can be implemented using low-cost and high performance microprocessors. Recently, we have developed a new hybrid state-space self tuner using a new dual-rate sampling scheme for on-line adaptive control of continuous-time uncertain systems
The Indiana University School of Nursing Clinical Faculty Mentoring Initiative: One-Year Outcomes and Lessons Learned
This poster describes the progress and lessons learned as a result of newly implemented Faculty Mentoring Program in the Indiana University School of Nursing
Mentoring Nurse Faculty: Outcomes of a Three-Year Clinical Track Faculty Initiative
Clinical track faculty often lack mentoring opportunities needed to develop their scholarship which may hinder their academic promotion. The Clinical Track Faculty Mentoring Initiative was designed to foster scholarship development and academic promotion of clinical assistant professors. Fifteen clinical assistant professors in two cohorts and their mentors participated in the Initiative. Each Cohort lasted two years with one overlapping year. Participating clinical assistant professors were required to attend five check-in meetings, a summer writing workshop, school and university promotion information sessions, and mentor-protégé meetings. Program outcomes were assessed quarterly and they included knowledge of promotion processes, mentorship quality, scholarship productivity, and academic promotion. Scores on knowledge of promotion processes and perceived mentorship quality among participating clinical assistant professors were significantly increased. Participating clinical assistant professors published, on average, 3.33 papers and delivered 6.4 presentations in two years. The Initiative demonstrated an effective mentoring program that incorporated a multimethod approach with clear program goals, strong systems support, and high mentorship quality
Non-tenured Track Nursing Faculty Mentoring Initiative
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