289 research outputs found
On passivity and power-balance inequalities of nonlinear RLC circuits
No full textArbitrary interconnections of passive (possibly nonlinear) resistors, inductors, and capacitors define passive systems, with power port variables the external source voltages and currents, and storage function the total stored energy. In this paper, we identify a class of RLC circuits (with convex energy function and weak electromagnetic coupling), for which it is possible to “add a differentiation” to the port terminals preserving passivity—with a new storage function that is directly related to the circuit power. To establish our results, we exploit the geometric property that voltages and currents in RLC circuits live in orthogonal spaces, i.e., Tellegen’s theorem, and heavily rely on the seminal paper of Brayton and Moser published in the early sixties
Reverse-engineering RLC networks with in-circuit measurement
No full textThesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2015.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.The hands-on side of electrical engineering is still taught using solderless breadboards. To lower the learning curve and improve the utility of solderless breadboards, I have designed and implemented a prototype that draws schematic diagrams of passive circuits that are built on a breadboard. The system reverse engineers circuits by means of a network sensing algorithm, which iteratively grounds and excites nodes with voltage sources, and subsequently measures the resulting currents and voltages in the network. Both a software simulation and a hardware implementation were built to test the network sensing algorithm. The sofware system is capable of reverse-engineering arbitrarily sized RLC networks with some caveats regarding high-q parallel RLC networks. The hardware system is able to accurately detect resistive and capacitive networks with eight nodes, though current hardware limitations significantly reduce the precision of measurment. The performance of the hardware system was analyzed and solutions to many of the measurement issues were found. A technique for surface-mount soldering breadboards to PCBs is presented in this thesis.by Joshua Michael Gordonson.M. Eng
Research learning communities: How the RLC approach enables teachers to use research to improve their practice and the benefits for students that occur as a result
No full textThis article explores the research learning communities (RLC) model that the author has pioneered and its potential to be an effective way of fostering and embedding research-informed practice among teachers. The article begins by setting out the origins of the RLC approach and the
theoretical and conceptual thinking that underpins the model, as well as the practical elements of how RLCs are run and delivered. It then uses the case study of one teaching school alliance – Excellence Together – to illustrate how the RLC approach has led not only to teachers
within this specific alliance engaging in research-informed practice, but also how this practice has begun to transform teaching and improve student outcomes within participating schools. Scales and a methodology for identifying and measuring both research engagement and transformative teaching/improved
student outcomes are presented, along with the results for Excellence Together
Research learning communities:how the RLC approach enables teachers to use research to improve their practice and the benefits for students that occur as a result
No full textThis article explores the research learning communities (RLC) model that the author has pioneered and its potential to be an effective way of fostering and embedding research-informed practice among teachers. The article begins by setting out the origins of the RLC approach and the
theoretical and conceptual thinking that underpins the model, as well as the practical elements of how RLCs are run and delivered. It then uses the case study of one teaching school alliance – Excellence Together – to illustrate how the RLC approach has led not only to teachers
within this specific alliance engaging in research-informed practice, but also how this practice has begun to transform teaching and improve student outcomes within participating schools. Scales and a methodology for identifying and measuring both research engagement and transformative teaching/improved
student outcomes are presented, along with the results for Excellence Together.</ns7:p
Modelling delay and noise in arbitrarily coupled RC trees.
No full textClosed-form equations for second-order transfer functions of general arbitrarily coupled resistance-capacitance (RC) trees with multiple drivers are reported. The models allow precise delay and noise calculations for systems of coupled interconnects with guaranteed stability and represent the minimum complexity associated with this class of circuits. Their accuracy is extensively compared against other relevant models and is found to be better or comparable to more expensive models. All results are derived from a theoretical approach, and their physical basis is examined. The simplicity, accuracy, and generality of the models make them suitable for use in early signal integrity analyses of complex systems and incremental physical optimization
Assessing academic and personal outcomes for men engaged in the Sigma phi Epsilon residential learning community
No full textThe presence of fraternities on college campuses is a topic of controversy among various higher education stakeholders. While fraternity membership has been found to be positively associated with college persistence (Biddix, Matney, Norman, & Martin, 2014; Routon & Walker, 2014), other associations related to academic performance and social behavior are not as positive (Brint & Cantwell, 2008; Whipple & Sullivan, 1998). Though an obvious and longstanding presence on over 800 American campuses, these organizations have been called into question regarding their contributions to the collegiate experience. As a result, the North-American Interfraternity Conference (NIC) and some of its member organizations have developed programs designed to address issues of concern. The purpose of this quantitative study was to evaluate a residential learning community (RLC) program that was developed by a national fraternity, Sigma Phi Epsilon (Sig Ep). Sigma Phi Epsilon fraternity recognizes both RLC and non-RLC chapters. The research questions guiding this study were: (a) do men living in a fraternity house that employs the Sig Ep RLC program report higher levels of social and academic engagement compared to fraternity members in a chapter that does not participate in this program, and (b) are the grade point averages of men in the Sig Ep RLC higher than those of men whose chapter are not designated as a RLC? The National Survey of Student Engagement (NSSE) was completed by 761 undergraduate members of Sig Ep fraternity within 140 chapters. All class years participated in approximately equal percentages. A total of 32% (n = 245) were from a RLC chapter and 68% (n = 516) were from non-RLC chapters. A series of t-tests identified that while grade point averages were positively associated with involvement in an RLC, involvement with faculty and co-curricular opportunities were higher for non-RLC men. Further research is needed to clarify the relationship between student engagement and GPA for students in RLC and non-RLC chapters prior to implementing the Sig Ep RLC program on a wide-scale basis.Ed.D.Includes bibliographical referencesby Thea Zunic
Effect of ageing on the micro-tensile bond strength of resin based composite when bonded with resin luting cement
No full textAbstractObjective: Resin based composite (RBC) restoration, existing at tooth bonding sites can compromise the bond between the framework and the tooth. Therefore, the aim of the study was to evaluate the effect of in vitro ageing of RBC on its micro-tensile bond strength with resin luting cement (RLC).Materials and methods: Forty standardised RBC blocks (4×6×8mm) were fabricated. Twenty blocks were divided into four groups (N=5 per group). Group 1 (control) received no ageing; in group 2, specimens were exposed to 500 cycles of thermocycling (TC) at 5–55°C; in group 3, specimens were exposed to 5000 cycles of TC and in group 4 specimens were placed in Sodium hydroxide (0.1N, NaOH) for one week. Following treatment, RBC blocks were paired with identical untreated RBC blocks and bonded, using RLC (Panavia F 2.0) under constant load. RLC was cured for 160s at the intensity of 650mWcm−2. Bonded blocks were sectioned using a diamond saw at 500rpm and 250 ground force. A total of 160 specimen sticks were subjected to micro-tensile bond strength testing (Bisco Inc., Virginia, USA) at a crosshead speed of 0.5mm/min. Fractographic analysis was performed using a stereomicroscope (63×). Means of micro-tensile bond strength (μ-tbs) were analysed with ANOVA and Tukey-Kramer multiple comparisons test (P=0.05).Results: μ-tbs was significantly higher for group 1 (54.20±7.34MPa) as compared to group 2 (44.17±8.61MPa) and group 3 (20.32±7.91MPa). Specimens in group 4 debonded prior to μ-tbs testing. 77.5% specimens in group1 and 100% specimens in groups 2 and 3 showed adhesive failures at the RBC and RLC bonding interface.Conclusion: RLC showed significantly lower micro tensile bond strengths when bonded to aged RBC as compared to when RLC was bonded to non-aged RBC
A note on the analysis of a heterogeneous rod-like chain in DNA modeling
No full textTwo different results concerning the elastic behavior of the heterogeneous worm-like chain (WLC) [D. Bensimon et al., Europhys. Lett. 42, 97 (1998)] and rod-like chain (RLC) [P. Nelson, Phys. Rev. Lett. 80, 5810 (1998)] are compared. We argue that the RLC is a more suitable model for double-stranded (ds-) DNA. As the hetero-RLC is the basic model for studying sequence-dependent ds-DNA, a rigorous path integral analysis for the effective bending persistence length is performed in the weak disorder limit. The novelty of the paper is in analyzing a path integral on the Lie group SO (3) with random forcing, which supplies a rigorous basis for the analysis of RLC type models.Physics, AppliedPhysics, Condensed MatterPhysics, MathematicalSCI(E)0ARTICLE142213-22242
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