197,489 research outputs found
Panel with self-tuning shunted piezoelectric patches for broadband flexural vibration control
No full textA practical approach based on maximisation of vibration power dissipation is proposed for
the self-tuning of single- and multi-resonant shunts connected to piezoelectric patches,
which are bonded on thin rectangular panels to reduce the broadband flexural vibrations
produced by stochastic disturbances at low audio-frequencies. The single- and multiresonant
shunts are formed either by one or by multiple resistance-inductance-capacitance
(RLC) branches connected in parallel. The proposed self-tuning approach sequentially
adapts the RL elements in the branches of each shunt in such a way as to maximise the
vibration power dissipation from the resonant response of the flexural modes of the hosting
structure that resonate in a target frequency band. The vibration power dissipated is
estimated from the measured electric power dissipated by each shunt so that self-tuning
can be implemented locally and independently in each shunt without the need of system
identification or on-line measurement of the vibration response of the hosting structure.
Therefore, on-line tuning can be implemented to control the vibrations of distributed
structures, also in those cases where they are characterised by time-varying dynamics,
generated, for example, by tensioning effects, mass variations, moving loads, uneven constraints,
etc. To start with, the paper presents a parametric study on a thin rectangular
panel with two piezoelectric patches connected to multi-resonant shunts, which shows
that, the time-averaged total flexural kinetic energy of the smart panel and the timeaveraged
electric power dissipated by each shunt are characterised by matching local minima
and maxima, which identify the optimal RL parameters in the branches of each shunt
necessary to control the resonant responses of the panel low order flexural modes. A practical
iterative approach, based on the maximisation of the time-averaged electric power
dissipated by each shunt, is then introduced to find on-line these optimal RL parameters.
Finally, a brief survey is presented to show the flexural vibration control effects produced
in the panel by increasingly larger arrays of piezoelectric patches connected to the proposed
self-tuning multi-resonant shunts
Piezoelectric patches with multi-resonant shunts for multiple frequency band vibration control
No full textDo teachers differ by certification route? novice teachers' sense of self-efficacy, commitment to teaching, and preparedness to teach
No full textAlternative teacher certification (ATC) programs are one method created to help
alleviate teacher shortages (Cox, Matthews, & Assoc, 2001; Hallinan & Khmelkov,
2001). While much debate has arisen over ATC programs, very few have empirically
examined their impact on the teaching pool (Darling-Hammond, Berry, & Thoreson,
2001; Darling-Hammond, Chung, & Frelow, 2002; Goldhaber, 2000; Ingersoll, 1999;
Shen, 1997, 1999). The present study was designed to explore differences by
certification type and program characteristics based on novice teachers' demographics,
educational attainment, sense of self-efficacy, and sense of preparedness to enter the
classroom.
Results from the present study suggest ATC programs are somewhat diversifying
the teaching population by bringing in more minorities and science majors, but do not
appear to be bringing in more experienced scientists and mathematicians nor do they
appear to be alleviating the teacher shortage. In this sample, traditionally certified
teachers felt better prepared than ATC teachers with the biggest differences on
Promoting Student Learning. Regardless of certification route, prior classroom experience was a strong predictor of Overall Preparedness and a teacher's perception of
his or her ability to be an effective teacher. For ATC teachers, a positive mentoring
experience was a strong predictor of Overall Preparedness.
The discussion of whether or not ATC programs should exist should now be
replaced with a discussion of how to ensure that these programs produce better teachers
and improve student learning. The underlying theme from the present study was that, in
order to feel prepared and have high self-efficacy, novice teachers needed instruction in
the majority of the components identified by research and by the National Commission
on Teaching and America's Future (1996), including positive mentoring experiences,
field based experiences, and curriculum based on child development, learning theory,
cognition, motivation, and subject matter pedagogy. Results from the present study
support the assertion that teacher preparation programs, program components, mentoring
experiences, and field-based experiences do impact teacher effectiveness in the
classroom
Piezoelectric patches with multi-resonant shunts for broadband vibration control: practical tuning approach
No full textDr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Dr. Glendon Swarthout
No full textHosted by Roger M. Busfield, MSU Assistant Professor of Speech and Theater, Meet the Author is designed to introduce a general audience to a contemporary author and their work through in-depth interviews. This episode features a conversation between Dr. Glendon Swarthout, prolific author and English professor at MSU, and assistant professors Sam S. Baskett and Theodore B. Strandness
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