57 research outputs found
Morphology and performance in pentacene
Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1999.Includes bibliographical references (p. 57-60).by Ioannis Kymissis.M.Eng
Movers and Shakers: Kinetic Energy Harvesting for the Internet of Things
Numerous energy harvesting wireless devices that will serve as building
blocks for the Internet of Things (IoT) are currently under development.
However, there is still only limited understanding of the properties of various
energy sources and their impact on energy harvesting adaptive algorithms.
Hence, we focus on characterizing the kinetic (motion) energy that can be
harvested by a wireless node with an IoT form factor and on developing energy
allocation algorithms for such nodes. In this paper, we describe methods for
estimating harvested energy from acceleration traces. To characterize the
energy availability associated with specific human activities (e.g., relaxing,
walking, cycling), we analyze a motion dataset with over 40 participants. Based
on acceleration measurements that we collected for over 200 hours, we study
energy generation processes associated with day-long human routines. We also
briefly summarize our experiments with moving objects. We develop energy
allocation algorithms that take into account practical IoT node design
considerations, and evaluate the algorithms using the collected measurements.
Our observations provide insights into the design of motion energy harvesters,
IoT nodes, and energy harvesting adaptive algorithms.Comment: 15 pages, 11 figure
Project-based Learning within a Large-Scale Interdisciplinary Research Effort
The modern engineering landscape increasingly requires a range of skills to
successfully integrate complex systems. Project-based learning is used to help
students build professional skills. However, it is typically applied to small
teams and small efforts. This paper describes an experience in engaging a large
number of students in research projects within a multi-year interdisciplinary
research effort. The projects expose the students to various disciplines in
Computer Science (embedded systems, algorithm design, networking), Electrical
Engineering (circuit design, wireless communications, hardware prototyping),
and Applied Physics (thin-film battery design, solar cell fabrication). While a
student project is usually focused on one discipline area, it requires
interaction with at least two other areas. Over 5 years, 180 semester-long
projects have been completed. The students were a diverse group of high school,
undergraduate, and M.S. Computer Science, Computer Engineering, and Electrical
Engineering students. Some of the approaches that were taken to facilitate
student learning are real-world system development constraints, regular
cross-group meetings, and extensive involvement of Ph.D. students in student
mentorship and knowledge transfer. To assess the approaches, a survey was
conducted among the participating students. The results demonstrate the
effectiveness of the approaches. For example, 70% of the students surveyed
indicated that working on their research project improved their ability to
function on multidisciplinary teams more than coursework, internships, or any
other activity
Wearable toe band system for monitoring of peripheral artery disease
Approximately 8 to 12 million people in the United States suffer from peripheral artery disease (PAD). PAD causes narrowed arteries and reduces blood flow to the lower extremities. People with PAD begin to experience discomfort and pain while walking. Untreated PAD can lead to ulcers, gangrene, and amputation. Before experiencing those severe conditions, detection of narrowing blood vessel enables early diagnosis and treatment. Therefore, accurate and timely diagnosis is necessary.
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A Lithographic Process for Integrated Organic Field-Effect Transistors
Abstract-This paper reports a photolithographic process for fabricating organic field-effect transistors which provides two layers of metal with arbitrary via placement, and optionally allows for subtractive lithographic patterning of the transistor active layer. The demonstrated pentacene transistors have a field-effect mobility of 0.1 0.05 cm 2 /(V s). Parylene-C is used both as the gate dielectric and an encapsulation layer which allows for subtractive lithographic patterning. Also demonstrated is a PMOS inverter without level shifting circuitry and level-restoring High and Low . This work demonstrates a high definition, multilayer, integrated photolithographic process which creates organic field effect transistors suitable for use in integrated circuit applications such as a display backplanes
An Implantable Piezofilm Middle Ear Microphone: Performance in Human Cadaveric Temporal Bones
Purpose: One of the major reasons that totally implantable cochlear
microphones are not readily available is the lack of good implantable
microphones. An implantable microphone has the potential to provide a range of
benefits over external microphones for cochlear implant users including the
filtering ability of the outer ear, cosmetics, and usability in all situations.
This paper presents results from experiments in human cadaveric ears of a
piezofilm microphone concept under development as a possible component of a
future implantable microphone system for use with cochlear implants. This
microphone is referred to here as a drum microphone (DrumMic) that senses the
robust and predictable motion of the umbo, the tip of the malleus. Methods: The
performance was measured of five DrumMics inserted in four different human
cadaveric temporal bones. Sensitivity, linearity, bandwidth, and equivalent
input noise were measured during these experiments using a sound stimulus and
measurement setup. Results: The sensitivity of the DrumMics was found to be
tightly clustered across different microphones and ears despite differences in
umbo and middle ear anatomy. The DrumMics were shown to behave linearly across
a large dynamic range (46 dB SPL to 100 dB SPL) across a wide bandwidth (100 Hz
to 8 kHz). The equivalent input noise (0.1-10 kHz) of the DrumMic and amplifier
referenced to the ear canal was measured to be 54 dB SPL and estimated to be 46
dB SPL after accounting for the pressure gain of the outer ear. Conclusion: The
results demonstrate that the DrumMic behaves robustly across ears and
fabrication. The equivalent input noise performance was shown to approach that
of commercial hearing aid microphones. To advance this demonstration of the
DrumMic concept to a future prototype implantable in humans, work on
encapsulation, biocompatibility, connectorization will be required
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