Radiation-aware Design for Cubesat Form-Factor Experiment Using Goal Structuring Notation

A Goal Structuring Notation (GSN) model is presented to argue for the radiation reliability of a SEU SCRAM experiment in a CubeSat form-factor for a 1 year old polar LEO mission

Reliability Concerns for Flying SiC Power MOSFETs in Space

SiC power MOSFETs are space-ready in terms of typical reliability measures. However, single event burnout (SEB) often occurs at voltages 50% or lower than specified breakdown. Data illustrating burnout for 1200 V devices is reviewed and the space reliability of SiC MOSFETs is discussed

Goal Structuring Notation in a Radiation Hardening Assurance Case for COTS-Based Spacecraft

A systematic approach is presented to constructing a radiation assurance case using Goal Structuring Notation (GSN) for spacecraft containing COTS parts. The GSN paradigm is applied to an SRAM single-event upset experiment board designed to fly on a CubeSat in January 2017. A custom software language for development of a GSN assurance case is under development at Vanderbilt. Construction of a radiation assurance case without use of hardened parts or extensive radiation testing is discussed

Capturing and Modeling Radiation Hardness Assurance throughout the Project Lifecycle

This presentation describes how assurance arguments for the radiation reliability of a system can be modeled in Goal Structuring Notation over the life-cycle of a project. A practical implementation of the NASA-STD-8729.1 and Model-Based Mission Assurance

Reliability Concerns for Flying SiC Power MOSFETs in Space

SiC power MOSFETs are space-ready in terms of typical reliability measures. However, single event burnout (SEB) often occurs at voltages 50% or lower than specified breakdown. Data illustrating burnout for 1200 V devices is reviewed and the space reliability of SiC MOSFETs is discussed

Gold(I)-Catalyzed Coupling Reactions for the Synthesis of Diverse Small Molecules Using the Build/Couple/Pair Strategy

The build/couple/pair strategy has yielded small molecules with stereochemical and skeletal diversity by using short reaction sequences. Subsequent screening has shown that these compounds can achieve biological tasks considered challenging if not impossible (‘undruggable’) for small molecules. We have developed gold(I)-catalyzed cascade reactions of easily prepared propargyl propiolates as a means to achieve effective intermolecular coupling reactions for this strategy. Sequential alkyne activation of propargyl propiolates by a cationic gold(I) catalyst yields an oxocarbenium ion that we previously showed is trapped by C-based nucleophiles at an extrannular site to yield α-pyrones. Here, we report O-based nucleophiles react by ring opening to afford a novel polyfunctional product. In addition, by coupling suitable building blocks, we subsequently performed intramolecular pairing reactions that yield diverse and complex skeletons. These pairing reactions include one based on a novel aza-Wittig-6π-electrocyclization sequence and others based on ring-closing metathesis reactions.Chemistry and Chemical Biolog

Tomografia komputerowa w neuroradiologii

Obserwując historię tomografii komputerowej, można bez wahania stwierdzić, że to neuroradiologia była stymulatorem powstania i rozwoju TK. Zarówno pierwszy prototyp tomografii, jak i pierwsze komercyjnie dostępne skanery byty przeznaczone do badań głowy. Dopiero w okresie późniejszym rozszerzono zakres możliwości aplikacyjnych tomografów na badania całego ciała