Modeling Solder Ball Array Interconnects for Power Module Optimization

PowerSynth is a software platform that can co-optimize power modules utilizing a 2D topology and wire bond interconnects. The novel 3D architectures being proposed at the University of Arkansas utilize solder ball interconnects instead of wire bonds. Therefore, they currently cannot be optimized using PowerSynth. This paper examines methods to accurately model the parasitic inductance of solder balls and ball grid arrays so they may be implemented into software for optimization. Proposed mathematical models are validated against ANSYS Electromagnetics Suite simulations. A comparison of the simulated data shows that mathematical models are well suited for implementation into optimization software platforms. Experimental measurements proved to be inconclusive and necessitate future work

Four Preservice Teachers\u27 Use of Mathematical Knowledge during Lesson Planning and Instruction in the Field Experience

The field experience of a teacher education program offers the opportunity for authentic practice in lesson planning and instruction for preservice teachers prior to their transition into their teaching career. However, preservice teachers often struggle applying their developing knowledge and skills because of the multifaceted nature of the field experience context. This complexity is particularly true in mathematics instruction since it includes simultaneously understanding mathematical concepts and mathematical procedure standards during instruction. This study used mini-case studies to examine how four preservice teachers used their developing mathematical knowledge learned in the teacher education program while lesson planning and teaching within the context of the culminating field experience. Data were collected about the preservice teachers\u27 use of mathematical knowledge and the influence of personal background, prior mathematical knowledge, and the field experience context on their instructional choices. The instrumentation for data collection included two questionnaires, lesson plan analyses, interviews, observations, field notes, and student assessment. The results from this study revealed that preservice teachers used their mathematical knowledge developed in the teacher education program during lesson planning and instruction at varying levels. One prevalent influence on lesson planning and instructional decisions was the learning needs of students. The most prominent influence on the preservice teachers was the mentor teachers\u27 educational philosophies and perceptions that determined the amount and type of opportunities the preservice teachers had to practice instructional strategies. Two preservice teachers were observed comfortably using their mathematical knowledge and several instructional strategies after receiving encouragement and guidance from the mentor teachers. Two preservice teachers used their mathematical knowledge, but were limited in their use of instructional strategies by the mentor teachers

The Role of Lipin 1 in Cardiac Metabolism and Function

From the Washington University Office of Undergraduate Research Digest (WUURD), Vol. 12, 05-01-2017. Published by the Office of Undergraduate Research. Joy Zalis Kiefer, Director of Undergraduate Research and Associate Dean in the College of Arts & Sciences; Lindsey Paunovich, Editor; Helen Human, Programs Manager and Assistant Dean in the College of Arts and Sciences. Mentor: Dr. Brian Finc

Proportionality and Punishment: Double Counting under the Federal Sentencing Guidelines

The Federal Sentencing Guidelines enhance sentences when the commission of a crime includes certain kinds of egregious conduct. The guidelines define such egregious conduct in a way that allows the sentencing judge to enhance the defendant\u27s sentence twice for the same conduct—once as a characteristic of the specific offense for which the defendant is convicted and again under a general adjustments section. The federal circuit courts are divided concerning whether the guidelines permit double counting. This Comment examines the courts\u27 differing interpretations of the governing statutes and concludes that the guidelines do not permit double counting unless explicitly stated in the sentencing guidelines

How to walk on water

PodcastEvery year, thanks to the generosity of Jeffrey E. Smith, The Missouri Review is able to bring all of our Jeffrey E. Smith Editor's Prize winners to Columbia for the weekend to celebrate with the staff and to read their award winning works. The Missouri Review will begin this week with it's current Editor's Prize winner in Fiction, Rachel Swearingen, reading her award winning short story, "How to walk on water.

History, Heritage, or Propaganda: Should Confederate Monuments Come Down?

Why did Charlottesville’s confederate monuments, which had been of little interest to white nationalists, suddenly become a rallying ground for them, neo-Confederates and alt-right activists? And why are others demanding these monuments be removed? Are they history worth preserving, or are they white nationalist propaganda packaged as heritage that distorts history for the sake of social control? This teach-in will explore the political, economic, historical and cultural meaning of confederate monuments so that you can better understand the deeper issues underlying this debate and decide for yourself

Mechanical vibration of vacuum tubes

Since the beginning of the art of vacuum tube building, vacuum tube engineers have been faced with many mechanical problems as well as electrical problems. Early mechanical problems were comparatively small because most of the tubes were used in stationary apparatus where little or no vibration was envolved. As time went on, vacuum tubes were placed in portable equipment and this useage established the need for a tube that was mechanically strong enough to give reliable electrical behavior where the tube was subjected to considerable vibration…. Recently it has been shown that vacuum tubes operating in the instrument cabins of jet-powered aircraft have shown malfunction in flight because of the very high levels of sound vibration which the tube is subjected to. Since this vibration condition caused by jet turbines and other moving apparatus of aircraft causes problems in tube failure and circuit misbehavior, the author became interested in the measurement of unwanted internally generated voltages in these vacuum tubes that were caused by the vibration of the tube elements when the tube operates under mechanical vibration. To be able to utilize the findings of such an investigation it was felt desirable to establish a term in the equivalent circuit of the vacuum tube which would represent the internally generated voltages when the tube is operated under a given range of mechanical vibration frequencies. When this equivalent circuit is established for a given tube type, allowances for these voltages can be made in designing the circuitry that goes with the tube. Also it is of particular interest to observe the effect on the normal output voltages that this new term has and establish a means of finding out the components or the output voltage which can be attributed to the mechanical vibration. Knowing these things, circuit designers who are designing circuits for airborne and other equipment that is known to operate under vibration will be able to calculate more workable designs with fewer malfunctions --Introduction, pages 1-2

Out of the Rubble and Towards a Sustainable Future: The “Greening” of Greensburg, Kansas

This is the publisher's version, also available electronically from http://www.mdpi.com/2071-1050/2/7/2302Following a devastating tornado there in 2007, the tiny city of Greensburg, Kansas has engaged in a sustainability-oriented recovery process through which it hopes to serve as a model for other communities planning for a sustainable future. This article uses innovation theory to consider how and why the sustainability focus emerged in Greensburg and to explore the potential transferability of those factors to other contexts. An analysis of 535 newspaper articles reveals key factors as: the shared vision of persistent local leaders, the framing of sustainability as an “opportunity” with an energy efficiency focus, community pride and resilience, and a “clean slate” rebuilding effort with substantial available funding. While Greensburg’s future is intimately connected to the specifics of its recent past, the analysis does reveal lessons that other communities can draw from in crafting sustainability plans of their own