W-band waveguide-packaged InP HEMT reflection grid amplifier

This letter presents a 79-GHz broadband reflection-type grid amplifier using spatial power combining to combine the power of 64 unit cells. Each unit cell uses a two-stage cascade configuration with InP HEMTs arranged as a differential pair. A broadband orthogonal mode transducer (OMT) separates two orthogonally polarized input and output signals over a 75 to 85GHz range. In conjunction with the OMT, a mode converter with quadruple-ridged apertures was designed to enhance the field uniformity over the active grid. Measurements show 5-dB small signal gain at 79GHz and an 800-MHz 3-dB bandwidth. The amplifier generates an output power of 264mW with little evidence of saturation

A 100-Element MODFET Grid Amplifier

A 100-element quasi-optical amplifier is presented. The active devices are custom-fabricated modulation-doped field-effect transistors (MODFETs). Common-mode oscillations were suppressed using resistors in the input gate leads. The grid has 9 dB of gain at 10.1 GHz. The 3-dB bandwidth is 1.2 GHz. We present a model for the gain of the grid versus frequency and compare measurement with theory

Gain and Stability Models for HBT Grid Amplifiers

A 16-element heterojunction bipolar transistor (HBT) grid amplifier has been fabricated with a peak gain of 11 dB at 9.9 GHz with a 3-dB bandwidth of 350 MHz. We report a gain analysis model for the grid and give a comparison of the measurement and theory. The measured patterns show the evidence of a common-mode oscillation. A stability model for the common-mode oscillation is developed. Based on the stability model, a lumped capacitor gives suitable phase shift of the circular function, thus stabilizing the grid. A second 18-element grid was fabricated, using this theory, with improved stability

Effects of a Graphic Organizer Intervention Package on the Mathematics Word Problem Solving Abilities of Students with Autism Spectrum Disorders

Many of the top 21 st century careers require advanced mathematics skills. However, mathematics is a known area of difficulty for students with disabilities (SWD), as they struggle in this area at a higher rate than peers without disabilities (O’Brien, 2016). Mathematical word problems incorporate comprehension of written language, an area known to pose additional challenges for SWD identified as having autism spectrum disorders (ASD; Smith-Myles, Simpson, & Becker, 1995). The authors describe an intervention involving the K-N-W-S graphic organizer, studied for the first time with the intent of examining its effect on mathematical word problem solving of students with ASD. In addition to the background, methods, and results of the current study, the authors discuss implications and future directions of this research

Foreign Language Education as a Means towards Cosmopolitanism

In this thesis, I propose foreign language education as one approach for fostering the development of a cosmopolitan spirit in students which, I believe, is a practical worldview in light of the complex realities brought about by an increasingly mobile and interconnected world. Once I provide rationale for the promotion of cosmopolitanism, I engage in a three-fold discussion on the relationship between the place and purpose of foreign language education, of attitude in language development, and cosmopolitanism. Specifically, I first explore the place and purpose of foreign language education in secondary schooling within the past 100 years in order to establish background necessary to understand the trajectory of language instruction. The following section will be an exploration of the purpose and importance of language attitudes as they relate to language learning. It is appropriate to analyze attitudes as they have repeatedly been shown to exist in direct relationship with classroom achievement, language acquisition and retention. Thirdly, I introduce cosmopolitan philosophy and provide rationale for promoting this worldview. Having established the linkage between cosmopolitanism and language proficiency, I argue that in order for individuals to have positive interactions with those from other cultures, to overcome negative attitudes towards those who are different from themselves, educators can utilize the space provided in a foreign language classroom to instill cosmopolitan values, imbed in students a sense of shared identity and common ground with those outside national borders, and promote the sense that we have a shared future together. By tying together all three pillars of discussion, I establish that the foreign language classroom is naturally a catalyst for a cosmopolitan conversation – it provides space in each educational day for students to speak, engage, and explore different languages and cultures

Understanding the Relationships Between Architecture, Chemistry, and Energy Release of Energetic Nanocomposites

Energetic nanocomposites are a class of reactive material that incorporate nanosized materials or features in order to enhance reaction kinetics and energy densities. Typically, these systems employ metal nanoparticles as the fuel source and have demonstrated reactivities orders of magnitude larger than more traditionally used micron-sized metal fuels. One drawback of using nanosized metals is that the nascent oxide shell comprises a significant weight percent as the particle size decreases. This shell also complicates the understanding of oxidation mechanisms of nanosized metal fuels. In this dissertation, I apply a two-fold approach to understanding the relationships between architecture, chemistry, and energy release of energetic nanocomposites by 1) investigating alternative metal fuels to develop a deeper understanding of the reaction mechanisms of energetic nanocomposites and 2) creating unique microstructures to tailor macroscopic properties allowing for customizability of energetic performance. In order to accurately study these systems, new analytical techniques capable of high heating rate analysis were developed. The oxidation mechanisms of tantalum nanoparticles was first probed using high heating rate TEM and Temperature-Jump Time-of-Flight Mass Spectrometry (T-Jump TOFMS) and shell crystallization was found to plan an important role in the mechanism. An air-sensitive sample holder was developed and employed to analyze the decomposition and oxidation of molecular aluminum compounds, which theoretically can achieve similar energy release rates to monomolecular explosives in addition to much higher energy densities. In order to obtain simultaneous thermal and speciation data at high heating rates, a nanocalorimeter was integrated into the TOFMS system and measurements were performed on Al/CuO nanolaminates to probe the effect of bilayer thickness on energy release. An electrospray based approach to creating energetic nanocomposites with tunable architectures is also described. An in depth study on the electrospray synthesized nAl/PVDF thin film reaction mechanism was performed using T-Jump TOFMS. The nAl/PVDF system was also studied using a Molecular Beam Sampling Time-of-Flight Mass Spectrometer designed and built primarily to investigate the reaction mechanisms of energetic nanocomposites at 1 atm in both aerobic and anaerobic environments

Sediment Control from Surface Facility Construction

published or submitted for publicationis peer reviewedOpe

Sediment Transport and Water Quality Characteristics of Two Streams in Kane County

published or submitted for publicationis peer reviewedOpe