Temperature control system with a pulse width modulated bridge

A temperature control system, which includes a modified wheatstone bridge with a resistive-capacitive (RC) circuit in one leg of the bridge, is disclosed. The RC circuit includes a resistor which provides an effective resistance as a function of its absolute resistance and the on-time to off-time ratio of pulses supplied to a switch connected across it. A sawtooth voltage is produced across the RC circuit. The voltage is compared with the voltage across a temperature sensor with heat being applied during each pulse period portion when the sawtooth voltage exceeds the voltage across the temperature sensor

Method for shaping and aiming narrow beams

A sonar method and apparatus is discribed which utilizes a linear frequency chirp in a transmitter/receiver having a correlator to synthesize a narrow beamwidth pattern from otherwise broadbeam transducers when there is relative velocity between the transmitter/receiver and the target. The chirp is so produced in a generator in bandwidth, B, and time, T, as to produce a time bandwidth product, TB, that is increased for a narrower angle. A replica of the chirp produced in a generator is time delayed and Doppler shifted for use as a reference in the receiver for correlation of received chirps from targets. This reference is Doppler shifted to select targets preferentially, thereby to not only synthesize a narrow beam but also aim the beam in azimuth and elevation

Time-adjusted variable resistor

Timing mechanism was developed effecting extremely precisioned highly resistant fixed resistor. Switches shunt all or portion of resistor; effective resistance is varied over time interval by adjusting switch closure rate

Pulse-width-modulated device for precision temperature control

Temperature controller is described which reduces difference between temperature oscillations about control point. Standard temperature-sensitive resistor element is utilized which is highly stable and reproducible. Temperature sensing circuitry is conventional dc bridge with power supplied by battery or highly regulated supply source

Digital Bridges: How Art Educators Build Professional Learning Networks on Twitter

This qualitative case study explores the experiences of K-12 art teachers in the United States who participate in the #K12ArtChat, as a form of professional learning. Grounded in social constructivist learning, connectivism, and informal learning, this study addressed how and why art educators use Twitter Chats for professional growth and the potential impact of participation on their teaching practices. Five themes emerged from this study: Twitter\u27s role as a professional development art education platform, the fostering of personal relationships and support, active community participation and advocacy, continuous professional development, and any perceived pedagogical shifts. With a significant emphasis on combatting the pervasive issue of teacher isolation, especially for those educators positioned as singletons without access to content-specific professional learning opportunities, the findings advocate for a shift in the perceptions and practices surrounding professional development for K-12 art educators

Audio Magazine: proposed series Chapter 09 - Geometry

Richard C. Heyser prepared this chapter as part of a series originally intended for AUDIO magazine in an effort to find an objective way of dealing with the subjective perception of sound. Through the implementation of the time delay spectrometry (TDS) method, Heyser was able to explore the mathematical analysis of audio and the philosophical principles of audio measurement. Chapter 9 discusses the geometric measuring of sound and the existence of a sound image

Audio Magazine: proposed series Chapter 11 - Conclusion

Richard C. Heyser prepared this chapter as part of a series originally intended for AUDIO magazine in an effort to find an objective way of dealing with the subjective perception of sound. Through the implementation of the time delay spectrometry (TDS) method, Heyser was able to explore the mathematical analysis of audio and the philosophical principles of audio measurement. Chapter 11 concludes the series and summaries the purpose of this study

The Pattern of Twos

Rather than explaining the meanings behind the phases of sound measurement, Richard C. Heyser explains the relationships between these phases, which he calls the Pattern of Twos

Audio Magazine: proposed series Chapter 06 - Measurement and Listening

Richard C. Heyser prepared this chapter as part of a series originally intended for AUDIO magazine in an effort to find an objective way of dealing with the subjective perception of sound. Through the implementation of the time delay spectrometry (TDS) method, Heyser was able to explore the mathematical analysis of audio and the philosophical principles of audio measurement. Chapter 6 demonstrates the second prediction of the new paradigm

Brief Theory of Coherent Processor

The particular coherent data processor which is to be discussed relies heavily upon several basic concepts. These concepts represent a departure from conventional practice and hence the theoretical description must await their presentation in order to gain some continuity. We will accordingly present the underlying assumptions and signal physics prior to description of the processor itself