Engineering topics

Williams, Ashley

Publications and source records attributed to Williams, Ashley.

3 records

DOE OSTI2024

Structural characterization of a new samarium–sodium heterometallic coordination polymer

Lanthanide-containing materials are of interest in the field of crystal engineering because of their unique properties and distinct structure types. In this context, a new samarium–sodium heterometallic coordination polymer, poly[tetrakis(μ 2 -2-formyl-6-methoxyphenolato)samarium(III)sodium(I)], {[SmNa(C 8 H 7 O 3 ) 4 ]·solvent} n ( Sm-1 ), was synthesized and crystallized via slow evaporation from a mixture of ethanol and acetonitrile. The compound features alternating Sm III and Na I ions, which are linked by ortho -vanillin ( o -vanillin) ligands to form a mono-periodic chain-like coordination polymer. The chains propagate along the [001] direction. Residual electron density of disordered solvent molecules in the void space could not be reasonably modeled, thus the SQUEEZE function was applied. The structural, vibrational, and optical properties are reported.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2022

Dicyanobenzothiadiazole (DCBT) Organic Dye as a Visible Light Absorbing Strong Photoinduced Oxidant with a 16 Microsecond Long–Lived Excited State

Strong photoinduced oxidants are important to organic synthesis and solar energy conversion, to chemical fuels or electric. For these applications, visible light absorption is important to solar energy conversion and long–lived excited states are needed to drive catalysis. With respect to these desirable qualities, a series of five 5,6–dicyano[2,1,3]benzothiadiazole (DCBT) dyes are examined as organic chromophores that can serve as strong photooxidants in catalytic systems. The series utilizes a DCBT core with aryl groups on the periphery with varying electron donation strengths relative to the core. The dyes are studied via both steady–state and transient absorption and emission studies. Additionally, computational analysis, voltammetry, crystallography, and absorption spectroelectrochemistry are also used to better understand the behavior of these dyes. Ultimately, a strong photooxidant is arrived at with an exceptionally long excited state lifetime for an organic chromophore of 16 µs. Finally, the long–lived excited state photosensitizer is well–suited for use in catalysis, and visible light driven photosensitized water oxidation is demonstrated using a water–soluble photosensitizer.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

NASA NTRS2019

Requirements Development and Management on the Psyche Project

In January 2017, Psyche was one of two mission concepts selected by NASA for flight as part of the 14th Discovery mission competition. The project has been staffing up and maturing the spacecraft, instrument and mission system baseline designs on the path towards a 2022 launch. During much of 2018, the Project has been executing the lifecycle stage called Phase B, “Preliminary Design and Technology Completion,” one key element of which is the development and management of requirements at various levels. In the case of the Psyche project, this process has been particularly unique for several reasons. The project utilizes a Solar Electric Propulsion (SEP) Chassis from Space Systems Loral (SSL), a high volume manufacturer of commercial geostationary (GEO) telecom spacecraft based on the 1300 satellite bus. While SSL has an extensive, well-vetted set of requirements based on their very successful Earth-orbiting product line, translating that heritage to a deep space science mission required special care. In addition to the differences associated with the deep space environment and longer communication times, new interfaces had to be incorporated. While a substantial portion of the Flight System consists of the SEP Chassis, there were several new interfaces within various subsystems between SSL components and those provided by JPL and other contractors. Managing these interfaces through requirements at a relatively higher level than normally seen on internal or external builds proved challenging. Finally, the Psyche spacecraft plans to host the flight terminal of the Deep Space Optical Communications (DSOC) technology demonstration, which is itself a separate project with its own requirements that must be flowed down and managed. This paper will present an overview of the requirement development and management process for the Psyche project. It will discuss in detail the various challenges summarized above, the methods and decisions chosen to address them, and evaluate their overall effectiveness at this stage in the project.

Elkins-Tanton, Linda T.↗