Body powered thermoelectric systems

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.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.Includes bibliographical references (p. 107-111).Great interest exists for and progress has be made in the effective utilization of the human body as a possible power supply in hopes of powering such applications as sensors and continuously monitoring medical devices [1]. This report furthers into the area of thermal energy harvesting, which focuses on using the temperature differential generated between the human body and the ambient environment to generate power. More specifically, a body-powered, thermoelectric-based power supply and system will be introduced and examined, with hopes that this technology will be utilized alongside low-power, medical monitoring applications in order to achieve self-sufficiency. This report also analyzes the performance of existing thermoelectric-based body-powered energy harvesting applications and compares that with the new design introduced in this work. The new designs were able to output upwards of 25[mu]W/cm2 or, equivalently, 280µW for the entire heat sink system. Additionally, this report details the physics associated with thermoelectric modules, addresses the issues with modern thermoelectric heat-sinks, introduces two new types of wearable, conformal heat sinks, quantifies the performance of the body-powered thermoelectric supply, tests a flexible EKG processing board, and analyzes future paths for this project.by Krishna Tej Settaluri.M.Eng

Identification of Wheat Varieties with a Parallel-Plate Capacitance Sensor Using Fisher’s Linear Discriminant Analysis

Fisher’s linear discriminant (FLD) models for wheat variety classification were developed and validated. The inputs to the FLD models were the capacitance (C), impedance (Z), and phase angle (θ), measured at two frequencies. Classification of wheat varieties was obtained as output of the FLD models. Z and θ of a parallel-plate capacitance system, holding the wheat samples, were measured using an impedance meter, and the C value was computed. The best model developed classified the wheat varieties, with accuracy of 95.4%, over the six wheat varieties tested. This method is simple, rapid, and nondestructive and would be useful for the breeders and the peanut industry

Photonics Links -- From Theory to Automated Design

Recent advancements in silicon photonics show great promise in meeting the high bandwidth and low energy demands of emerging applications. However, a key gating factor in ensuring this necessity is met is the utilization of a link design method- ology which transcends the various levels in the hierarchy, ranging from the device and platform level up to the systems level. In this dissertation, a comprehensive methodology for link design will be introduced which takes a two-prong approach to tackling the issue of silicon photonic link efficiency. Namely, a fundamentals-based first principles approach to link optimization will be introduced and validated. In addition, physical design trade-offs connecting levels in the architectural hierarchy will also be studied and explored. This culminates in an intermediate goal of this dissertation, which is the first-ever design and verification of a full silicon photonic interconnect on a 3D integrated electronic-photonic platform. To proceed and further enable the rapid exploration of the link design architectural space, the analog macros for a majority of this dissertation were auto-generated using the Berkeley Analog Generator (BAG). With these key design tools and framework, performance bottlenecks and improvements for silicon photonic links will be analyzed and, from this analysis, the motivation for a new, single comparator-based PAM4 receiver architecture shall emerge. This architecture not only showcases the tight bond in dependency between high-level link specifications and low level device parameters, but also shows the im- portance of physical design constraints alongside fundamental theory in influencing end-to-end link performance