3 research outputs found
DataSheet1_Assessing the interfacial corrosion mechanism of Inconel 617 in chloride molten salt corrosion using multi-modal advanced characterization techniques.DOCX
The United States Department of Energy (DOE) has committed to expanding the domestic clean energy portfolio in response to the rising challenges of energy security in the wake of climate change. Accordingly, the construction of a series of Generation IV reactor technologies are being demonstrated, including sodium-cooled, small modular, and molten chloride fast reactors (MCFRs). To date, there are no fully qualified structural materials for constructing MCFRs. A number of commercial structural alloys have been considered for the construction of MCFRs, including alloys from the Inconel and Hastelloy series. Informed qualification of structural materials for the construction of MCFRs in the future can only be ensured by expanding the current fundamental knowledgebase of information pertaining to material performance under environmental stressors relevant to operation of the reactor, including corrosion susceptibility. The purpose of this investigation is to illustrate how a correlative multi-modal electron microscopy characterization approach, including the novel application of focused-ion beam 3D reconstruction capabilities, can elucidate the corrosion mechanism of a candidate structural material Inconel 617 for MCFR in NaCl-MgCl2 eutectic salt at 700°C for 1,000 h. Evidence of intergranular corrosion, Ni and Fe dealloying, and Cr-O enrichment along the grain boundary, which most likely corresponds to Cr2O3, is a phenomenon that has been documented in other Ni-based superalloys exposed to chloride molten salt systems. Additional corrosion products, including the formation of insoluble MgAl2O4, within the porous network produced by the salt attack is a novel observation. In addition, Mo3Si5 and τ2 precipitates are detected in the alloy bulk and are dissolved by the salt. Furthermore, the lack of detection of design γ′ precipitates in Inconel 617 after 1,000 h could indicate that the molten salt corrosion mechanism has indirectly induced a phase transformation of Al2TiNi (τ2) and Ni3(Al,Ti) (γ’) phase. This investigation provides a comprehensive understanding of molten salt corrosion mechanisms in a complex material system such as a commercial structural alloy for applications in MCFRs.</p
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Glycosylated Peptoid Nanosheets as a Multivalent Scaffold for Protein Recognition
Glycoproteins adhered on the cellular
membrane play a pivotal role
in a wide range of cellular functions. Their importance is particularly
relevant in the recognition process between infectious pathogens (such
as viruses, bacteria, toxins) and their host cells. Multivalent interactions
at the pathogen-cell interfaces govern binding events and can result
in a strong and specific interaction. Here we report an approach to
mimic the cell surface presentation of carbohydrate ligands by the
multivalent display of sugars on the surface of peptoid nanosheets.
The constructs provide a highly organized 2D platform for recognition
of carbohydrate-binding proteins. The sugars were displayed using
different linker lengths or within loops containing 2–6 hydrophilic
peptoid monomers. Both the linkers and the loops contained one alkyne-bearing
monomer, to which different saccharides were attached by copper-catalyzed
azide–alkyne cycloaddition reactions. Peptoid nanosheets functionalized
with different saccharide groups were able to selectively bind multivalent
lectins, Concanavalin A and Wheat Germ Agglutinin, as observed by
fluorescence microscopy and a homogeneous Förster resonance
energy transfer (FRET)-based binding assay. To evaluate the potential
of this system as sensor for threat agents, the ability of functionalized
peptoid nanosheets to bind Shiga toxin was also studied. Peptoid nanosheets
were functionalized with globotriose, the natural ligand of Shiga
toxin, and the effective binding of the nanomaterial was verified
by the FRET-based binding assay. In all cases, evidence for multivalent
binding was observed by systematic variation of the ligand display
density on the nanosheet surface. These cell surface mimetic nanomaterials
may find utility in the inactivation of pathogens or as selective
molecular recognition elements
Large Area Synthesis of a Nanoporous Two-Dimensional Polymer at the Air/Water Interface
We present the synthesis
of a two-dimensional polymer at the air/water interface and its nm-resolution
imaging. Trigonal star, amphiphilic monomers bearing three anthraceno
groups on a central triptycene core are confined at the air/water
interface. Compression followed by photopolymerization on the interface
provides the two-dimensional polymer. Analysis by scanning tunneling
microscopy suggests that the polymer is periodic with ultrahigh pore
density