Cryogenic probe station for on-wafer characterization of electrical devices

A probe station, suitable for the electrical characterization of integrated circuits at cryogenic temperatures is presented. The unique design incorporates all moving components inside the cryostat at room temperature, greatly simplifying the design and allowing automated step and repeat testing. The system can characterize wafers up to 100 mm in diameter, at temperatures <20 K. It is capable of highly repeatable measurements at millimeter-wave frequencies, even though it utilizes a Gifford McMahon cryocooler which typically imposes limits due to vibration. Its capabilities are illustrated by noise temperature and S-parameter measurements on low noise amplifiers for radio astronomy, operating at 75–116 GHz

Building Mobile Instruments for Improvised Musical Performance

This paper explores an approach to building electronic musical instruments for use in improvised music that I have found to be particularly effective for developing flexible, dynamic, and versatile instruments well adapted to the improvised context, and a resultant set of suites of solo improvised character pieces. The lessons learned from this research can be useful beyond the scope of this particular instrument design philosophy. In Part I, I present the foundations of my approach to instrument design, based on my past experience and the technological environment in which electronic music has developed. I discuss the values that guide me in the creation of instruments for use in improvised performance, and describe the development tools iRTcmix and Nikl, and Dixey, an instrument I have created with those tools and hardware devices using the Apple iOS operating system. Part II discusses the musical issues related to the creation of Character Weekend, a set of solo recordings produced with the tools described in Part I

Technology Advances for Radio Astronomy

The field of radio astronomy continues to provide fundamental contributions to the understanding of the evolution, and inner workings of, our universe. It has done so from its humble beginnings, where single antennas and receivers were used for observation, to today's focal plane arrays and interferometers. The number of receiving elements (pixels) in these instruments is quickly growing, currently approaching one hundred. For the instruments of tomorrow, the number of receiving elements will be in the thousands. Such instruments will enable researchers to peer deeper into the fabric of our universe and do so at faster survey speeds. They will provide enormous capability, both for unraveling today's mysteries as well as for the discovery of new phenomena. Among other challenges, producing the large numbers of low-noise amplifiers required for these instruments will be no easy task. The work described in this thesis advances the state of the art in three critical areas, technological advancements necessary for the future design and manufacturing of thousands of low-noise amplifiers. These areas being: the automated, cryogenic, probing of \diameter100 mm indium phosphide wafers; a system for measuring the noise parameters of devices at cryogenic temperatures; and the development of low-noise, silicon germanium amplifiers for terahertz mixer receivers. The four chapters that comprise the body of this work detail the background, design, assembly, and testing involved in these contributions. Also included is a brief survey of noise parameters, the knowledge of which is fundamental to the design of low-noise amplifiers and the optimization of the system noise temperature for large, dense, interferometers.</p

The role of Periostin in regulating the biomechanical properties of cushion tissue

Abstract only availableDuring embryonic heart development the atrio-ventricular (AV) cushions swell and fuse to form the valves and septa of the adult heart. Initially, the cushions appear as swellings on the interior wall of the AV canal and eventually fuse to form the septum and valvular leaflets. The morphogenetic event that the cushions undergo during the fusion process is, in part, driven by the cohesive energy of the tissue, which can be described by the tissue's surface tension. It has been shown earlier that many properties of embryonic tissues can be interpreted by using the analogy that they behave as liquids and it is this analogy that gives rise to apparent tissue surface tension. Periostin is hypothesized to affect cushion tissue surface tension, through its possible binding of the extracellular matrix of the tissue. In this study virus containing the sense strand of Periostin DNA is introduced into hanging drops containing living explants of AV cushion tissue. Overnight the tissue explants rounded up to form spheroids allowing their surface tension to be measured and compared to the surface tension of AV cushion tissue explants exposed to a LacZ promoter control virus. The surface tension was determined using a specifically designed apparatus that measures the viscoelastic response of spherical explants due to a compressive force. It was expected that the increased production of Periostin in the cushion explants due to exposure to the virus will result in an increased surface tension compared to that of explants exposed to the control virus. The preliminary results of the experiment have displayed no significant difference of surface tension between the control virus and the Periostin virus. Since earlier research has shown a significant difference in the rate of fusion of cushions exposed to Periostin DNA virus and those exposed to the control virus, and because fusion time is characterized by the ratio of the surface tension and the viscosity of the tissue, we believe that Periostin may be affecting the viscosity of the tissue explants instead of the surface tension.NSF-REU Program in Biosystems Modeling and Analysi

Outcomes of interfacility critical care adult patient transport: a systematic review

INTRODUCTION: We aimed to determine the adverse events and important prognostic factors associated with interfacility transport of intubated and mechanically ventilated adult patients. METHODS: We performed a systematic review of MEDLINE, CENTRAL, EMBASE, CINAHL, HEALTHSTAR, and Web of Science (from inception until 10 January 2005) for all clinical studies describing the incidence and predictors of adverse events in intubated and mechanically ventilated adult patients undergoing interfacility transport. The bibliographies of selected articles were also examined. RESULTS: Five studies (245 patients) met the inclusion criteria. All were case-series and two were prospective in design. Due to the paucity of studies and significant heterogeneity in study population, outcome events, and results, we synthesized data in a qualitative manner. Pre-transport severity of illness was reported in only one study. The most common indication for transport was a need for investigations and/or specialist care (three studies, 220 patients). Transport modalities included air (fixed or rotor wing; 66% of patients) and ground (31%) ambulance, and commercial aircraft (3%). Transport teams included a physician in three studies (220 patients). Death during transfer was rare (n = 1). No other adverse events or significant therapeutic interventions during transport were reported. One study reported a 19% (28/145) incidence of respiratory alkalosis on arrival and another study documented a 30% overall intensive care unit mortality, while no adverse events or outcomes were reported after arrival in the three other studies. CONCLUSION: Insufficient data exist to draw firm conclusions regarding the mortality, morbidity, or risk factors associated with the interfacility transport of intubated and mechanically ventilated adult patients. Further study is required to define the risks and benefits of interfacility transfer in this patient population. Such information is important for the planning and allocation of resources related to transporting critically ill adults

Magnetour: Surfing Planetary Systems on Electromagnetic and Multi-Body Gravity Fields

In this NIAC Phase One study, we propose a new mission concept, named Magnetour, to facilitate the exploration of outer planet systems and address both power and propulsion challenges. Our approach would enable a single spacecraft to orbit and travel between multiple moons of an outer planet, with no propellant required. Our approach would enable a single spacecraft to orbit and travel between multiple moons of an outer planet, with no propellant nor onboard power source required. To achieve this free-lunch _Grand Tour', we exploit the unexplored combination of magnetic and multi-body gravitational fields of planetary systems, with a unique focus on using a bare tether for power and propulsion. The main objective of the study is to develop this conceptually novel mission architecture, explore its design space, and investigate its feasibility and applicability to enhance the exploration of planetary systems within a 10-year timeframe. Propellantless propulsion technology offers enormous potential to transform the way NASA conducts outer planet missions. We hope to demonstrate that our free-lunch tour concept can replace heavy, costly, traditional chemical-based missions and can open up a new variety of trajectories around outer planets. Leveraging the powerful magnetic and multi-body gravity fields of planetary systems to travel freely among planetary moons would allow for long-term missions and provide unique scientific capabilities and flagship-class science for a fraction of the mass and cost of traditional concepts. New mission design techniques are needed to fully exploit the potential of this new concept.This final report contains the results and findings of the Phase One study, and is organized as follows. First, an overview of the Magnetour mission concept is presented. Then, the research methodology adopted for this Phase One study is described, followed by a brief outline of the main findings and their correspondence with the original Phase One task plan. Next, an overview of the environment of outer planets is provided, including magnetosphere, radiation belt and planetary moons. Then performance of electrodynamic tethers is assessed, as well as other electromagnetic systems. A method to exploit multi-body dynamics is given next. These analyses allow us to carry out a Jovian mission design to gain insight in the benefits of Magnetour. In addition, a spacecraft configuration is presented that fully incorporates the tether in the design. Finally technology roadmap considerations are discussed

Synergies of Robotic Asteroid Redirection Technologies and Human Space Exploration

This paper summarizes the results of a 2014 KISS workshop that identified a wide variety of ways that the technologies (and their near-term derivatives) developed for the proposed Asteroid Redirect Mission (ARM) would beneficially impact the Nation’s space interests including: human missions to Mars and its moons, planetary defense, orbital debris removal, robotic deep-space science missions, commercial communication satellites, and commercial asteroid resource utilization missions. This wide applicability of asteroid retrieval technology is, in many ways, is just as surprising as was the initial finding about the feasibility of ARM. The current Asteroid Redirect Mission concept consists of two major parts: the development of an advanced Solar Electric Propulsion (SEP) capability and the retrieval of a near-Earth asteroid. The improvement in SEP technology required by ARM provides an extensible path to support human missions to Mars, is applicable to all planetary defense techniques, could reduce the time required for the LEO-to-GEO transfer of large commercial or military satellites, would enable new deep space robotic science missions, and could enable affordable removal of large orbital debris objects. The asteroid retrieval part of ARM would greatly improve the understanding of the structure of rubble-pile asteroids necessary to evaluate the effectiveness of primary asteroid deflection techniques, demonstrate at least one secondary asteroid deflection technique, greatly accelerate the use of material resources obtained in space to further space exploration and exploitation, and further planetary science

Diversity Plans Can’t Breathe without AIIR: Building a High-Caliber Diversity Initiative

For one intensive month this summer, we participated in an online leadership development program, the National Inclusive Excellence Leadership Academy (NIXLA), with nearly 100 leaders from across the country. The twin goals of the program were to hone our strategic diversity leadership skills and strengthen our best-practice too kit of resources, frameworks, and tactics for leading real change that we can see and feel on our campuses in the area of diversity, equity, and inclusion