Physical Sciences and Mathematics Commons^™

Zenneck Waves In Decision Agriculture: An Empirical Verification And Application In Em-Based Underground Wireless Power Transfer, Usman Raza, Abdul Salam

Faculty Publications

In this article, the results of experiments for the observation of Zenneck surface waves in sub GHz frequency range using dipole antennas are presented. Experiments are conducted over three different soils for communications distances of up to 1 m. This empirical analysis confirms the existence of Zenneck waves over the soil surface. Through the power delay profile (PDP) analysis, it has been shown that other subsurface components exhibit rapid decay as compared to the Zenneck waves. A potential application of the Zenneck waves for energy transmission in the area of decision agriculture is explored. Accordingly, a novel wireless through-the-soil power …

On-Site And External Energy Harvesting In Underground Wireless, Usman Raza, Abdul Salam

Faculty Publications

Energy efficiency is vital for uninterrupted long-term operation of wireless underground communication nodes in the field of decision agriculture. In this paper, energy harvesting and wireless power transfer techniques are discussed with applications in underground wireless communications (UWC). Various external wireless power transfer techniques are explored. Moreover, key energy harvesting technologies are presented that utilize available energy sources in the field such as vibration, solar, and wind. In this regard, the Electromagnetic(EM)- and Magnetic Induction(MI)-based approaches are explained. Furthermore, the vibration-based energy harvesting models are reviewed as well. These energy harvesting approaches lead to design of an efficient wireless underground …

Advanced Iii-V / Si Nano-Scale Transistors And Contacts: Modeling And Analysis, Seung Hyun Park

Open Access Dissertations

The exponential miniaturization of Si CMOS technology has been a key to the electronics revolution. However, the continuous downscaling of the gate length becomes the biggest challenge to maintain higher speed, lower power, and better electrostatic integrity for each following generation. Hence, novel devices and better channel materials than Si are considered to improve the metal-oxide-semiconductor field-effect transistors (MOSFETs) device performance. III-V compound semiconductors and multi-gate structures are being considered as promising candidates in the next CMOS technology. III-V and Si nano-scale transistors in different architectures are investigated (1) to compare the performance between InGaAs of III-V compound semiconductors and …

Image Analysis Using Visual Saliency With Applications In Hazmat Sign Detection And Recognition, Bin Zhao

Open Access Dissertations

Visual saliency is the perceptual process that makes attractive objects "stand out" from their surroundings in the low-level human visual system. Visual saliency has been modeled as a preprocessing step of the human visual system for selecting the important visual information from a scene. We investigate bottom-up visual saliency using spectral analysis approaches. We present separate and composite model families that generalize existing frequency domain visual saliency models. We propose several frequency domain visual saliency models to generate saliency maps using new spectrum processing methods and an entropy-based saliency map selection approach. A group of saliency map candidates are then …

Theory Of Topological Insulators And Its Applications, Parijat Sengupta

Open Access Dissertations

An important pursuit in semiconductor physics is to discover new materials to sustain the continuous progress and improvements in the current electronic devices. Traditionally, three material types are in use: 1) Metals 2) Semiconductors 3) Insulators. All the three material types are classified according to the energy gap between conduction and valence bands derived from band theory of solids. Recent theoretical predictions and confirmed by experimental observations have provided evidence that there exists materials which behave as insulators in the bulk but possess gapless conducting states on the surface. These new class of materials are called topological insulators (TI). In …

Tracking Dynamic Construction Objects ---A Key Node Modeling Approach Using Color-Depth Cameras, Chenxi Yuan

Open Access Theses

A construction site presents a dynamic scenario. Locations of multiple objects are continuously changing and a lot of objects enter and exit the site in high frequencies. Meanwhile a construction activity consists of a large amount of stochastic operations, many uncertainties occur when making decisions. Believing that detecting, locating and tracking dynamic construction objects in real time improve construction productivity and enhance construction safety, a large number of studies have applied a variety of sensing technologies to construction sites. Hybrid image-point cloud sensing technologies, such as color-depth cameras, have a great potential in achieving real time object recognition and tracking …

Solar Cell Temperature Dependent Efficiency And Very High Temperature Efficiency Limits, John Robert Wilcox

Open Access Dissertations

Clean renewable solar energy is and will continue to be a critically important source of electrical energy. Solar energy has the potential of meeting all of the world's energy needs, and has seen substantial growth in recent years. Solar cells can convert sun light directly into electrical energy, and much progress has been made in making them less expensive and more efficient. Solar cells are often characterized and modeled at 25 °C, which is significantly lower than their peak operating temperature. In some thermal concentrating systems, solar cells operate above 300 °C. Since increasing the temperature drastically affects the terminal …

Information Measures For Statistical Orbit Determination, Alinda Kenyana Mashiku

Open Access Dissertations

The current Situational Space Awareness (SSA) is faced with a huge task of tracking the increasing number of space objects. The tracking of space objects requires frequent and accurate monitoring for orbit maintenance and collision avoidance using methods for statistical orbit determination. Statistical orbit determination enables us to obtain estimates of the state and the statistical information of its region of uncertainty given by the probability density function (PDF). As even collision events with very low probability are important, accurate prediction of collisions require the representation of the full PDF of the random orbit state. Through representing the full PDF …

Miniature Mass Spectrometry: Rf Amplitude Control System Design, Matthew Allen Kirleis

Purdue Polytechnic Masters Theses

This thesis covers the methods used to construct and characterize a custom digital RF amplitude control system. Many types of mass spectrometers exist, but few have been miniaturized as much as the Mini instruments developed at Purdue University. The goal of this research was to improve upon an earlier amplitude control system consisting of analog circuits first implemented in the Mini 11.5 mass spectrometer developed at Purdue University.

A custom set of control and data acquisition electronics were developed for testing the digital and analog control systems in a Mini 11.5 mass spectrometer chassis. A MATLAB Simulink simulation was done …