Low speed phaselock speed control system

A motor speed control system for an electronically commutated brushless dc motor is provided which includes a phaselock loop with bidirectional torque control for locking the frequency output of a high density encoder, responsive to actual speed conditions, to a reference frequency signal, corresponding to the desired speed. The system includes a phase comparator, which produces an output in accordance with the difference in phase between the reference and encoder frequency signals, and an integrator-digital-to-analog converter unit, which converts the comparator output into an analog error signal voltage. Compensation circuitry, including a biasing means, is provided to convert the analog error signal voltage to a bidirectional error signal voltage which is utilized by an absolute value amplifier, rotational decoder, power amplifier-commutators, and an arrangement of commutation circuitry

COVID-19 Modifications to a Service-Learning Project Designed to Prepare Special Education Students to Be Effective Participants in Transdisciplinary Collaborations

This research study examined the impact of COVID-19 on university students’ perceptions about the effectiveness of a community-based service-learning project designed to prepare graduate students in special education and undergraduate students in psychology and speech-language pathology to work in transdisciplinary teams in early childhood settings. Students were placed into transdisciplinary teams and assigned to one of two community-based early childhood programs to administer a universal screening tool that assessed young children in several domains. The project was in its sixth year when the country stood still because of the COVID-19 pandemic. The project was re-envisioned, mid-course, to provide an equitable and rigorous assignment for students who were unable to complete the original assignment due to the lockdown. Student perceptions were compared, pre and post COVID; subsequent results are discussed in alignment with the original four goals of the project. Additionally, suggestions are posed to position this service-learning assignment for remote delivery should the pandemic persist to disrupt higher education

Service Learning in the Time of COVID-19

Excerpt This essay describes a collaborative service-learning project in which psychology and speech-language pathology undergraduate students, along with special education graduate students, completed developmental screenings as part of their training in providing effective services to children. Universal developmental screening is an important tool in the early identification of developmental delays in young children and is increasingly incorporated into early childhood education. However, limited resources make it difficult for educators to routinely screen all young children in their care. Our students were able to meet this need for two local childcare centers by conducting developmental screenings in transdisciplinary groups

Application of Sinboron Fibrous Monoliths for Air Breathing Engine Applications

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76640/1/AIAA-2005-3646-549.pd

Fluorescence Microscopy of Cereals

The fluorescence microscope is one of the most sensitive instruments available for morphological and microchemical analysis of biological material, and especially of cereal grains. Recent innovations in illuminating systems, fluorescence chemistry, and specimen preparation have combined to provide significant improvements over conventional bright-field microscopy in both specificity and sensitivity. A variety of relatively specific fluorescent markers has been devised for routine and high resolution detection of all major cereal components. Several examples of useful fluorescent markers are described, including appropriate methods for specimen preparation, fluorescence analysis, and photography

Thermal Time Scales in a Color Glass Condensate

In a model of relativistic heavy ion collisions wherein the unconfined quark-gluon plasma is condensed into glass, we derive the Vogel-Fulcher-Tammann cooling law. This law is well known to hold true in condensed matter glasses. The high energy plasma is initially created in a very hot negative temperature state and cools down to the Hagedorn glass temperature at an ever decreasing rate. The cooling rate is largely determined by the QCD string tension derived from hadronic Regge trajectories. The ultimately slow relaxation time is a defining characteristic of a color glass condensate.Comment: 5 pages, ReVTeX format, nofigure