1-(3-Phenyl­prop-2-yn­yl)pyrrolidinium chloride

The title compound C13H16N+·Cl−, an achiral salt, was synthesized by a three-component coupling reaction in the presence of copper(I) iodide. The configuration of five-membered ring is close to an envelope conformation. The crystal structure is stabilized by inter­molecular C—H⋯Cl and N—H⋯Cl inter­actions

Quasi-static responses of marine mussel plaques attached to deformable wet substrates under directional tensions

Quantifying the response of marine mussel plaque attachment on wet surfaces remains a significant challenge to a mechanistic understanding of plaque adhesion. Here, we developed a customised microscopy system combined with two-dimensional (2D) in-situ digital image correlation (DIC) to quantify the in-plane deformation of a deformable substrate that interacts with a mussel plaque while under directional tension. By analysing the strain field in the substrate, we gained insight into how in-plane traction forces are transmitted from the mussel plaque to the underlying substrate. Finite element (FE) models were developed to assist the interpretation of the experimental measurement. Our study revealed a synergistic effect of pulling angle and substrate stiffness on plaque detachment, with mussel plaques anchoring to a 'stiff' substrate at a smaller pulling angle having mechanical advantages with higher load-bearing capacity and less plaque deformation. We identified two distinct failure modes, i.e., shear traction-governed failure (STGF) mode and normal traction-governed failure (NTGF). It was found that increasing the substrate stiffness or reducing the pulling angle resulted in a failure mode change from NTGF to STGF. Our findings offer new insights into the mechanistic understanding of plaque and substrate interaction, which provides a general plaque-inspired strategy for wet adhesion.Comment: 19 page

4,4′-[8b,8c-Bis(ethoxycarbonyl)-4,8-dioxo-2,3,5,6-tetra­hydro-1H,4H-2,3a,4a,6,7a,8a-hexa­azacyclo­penta­[def]fluorene-2,6-diyl]dipyridinium bis­(tetra­fluorido­borate)

In the title compound, C26H32N8O6 2+·2BF4 −, the cation is built up from four fused rings, viz. two nearly planar imidazole rings and two triazine rings exhibiting chair conformations. One eth­oxy group is disordered between two positions in an approximate ratio 3:2. The F atoms of the two anions are each rotationally disordered between two orientations in the same 3:2 ratio. The crystal structure is stabilized by inter­molecular N—H⋯O, C—H⋯F and N—H⋯F inter­actions

An investigation on plant cell walls during biomass pyrolysis: A histochemical perspective on engineering applications

publishedVersio

Nuclear Criticality Analyses of Separations Processes for the Transmutation Fuel Cycle

The separation and partitioning of used commercial reactor fuel is a vital component of any reprocessing or transmutation strategy. To process the high actinide fuels required for a transmutation effort, the Chemical Technology Division (CMT) at Argonne National Laboratory (ANL) is developing a pyrochemical separations process. Currently, this work is being done via small experiments. While this is more than sufficient to develop the technologies required to process actinide-bearing fuels, it does not allow for the direct investigation of criticality concerns that would be present in larger systems. As the volume of waste to be treated increases, a higher probability exists that fissionable isotopes of plutonium, americium, and curium can accumulate, forming a critical mass. These criticality events can be avoided by ensuring the effective neutron multiplication factor, keff, remains below a safe level. Monte Carlo simulations to evaluate keff are the best way to examine the criticality safety of the proposed separation processes, and will allow engineers to develop proper safety measures for the reprocessing and fabrication of high actinide fuels. A related problem for handling high actinide fuels is the heat generated by the decay of the higher actinides. In particular, the presence of curium in transuranic wastes poses a significant problem. To minimize the impact of curium on the fabrication of actinide-bearing fuels, the process engineers and chemists would like to remove the curium from the fuel. Curium, however, not only poses a criticality concern, but also includes isotopes that generate a great deal of decay heat. This heat generation creates safety problems with regards to handling and storing curium. The decay heat can cause samples to melt very quickly if excessive quantities of curium are present. SCALE, a Monte Carlo code, simulates the scattering and absorption of neutrons. This technique permits assessment of what quantities of curium will result in a critical mass. This information is then combined with thermal transfer models to examine the decay heat issue, and evaluate thermally and critically safe storage configurations for curium-rich waste streams