In Situ ESEM Examination of Microstructural Changes of an Apple Tissue Sample Undergoing Low-Pressure Air-Drying Followed by Wetting

Low-pressure drying of apple tissue has been visualized in situ using an environmental scanning electron microscope (ESEM). Both freshly cut and pre-boiled sample tissues were tested for drying and followed by wetting processes and the differences between the two types of samples noted. Bubble formation was observed when drying the freshly cut sample and were found to form only around the intact cells (intracellular spaces or channels). Boiling produced a more uniform surface and no bubble formation could be observed. Air-drying of the two tissue samples was conducted as a complementary investigation so that the effect of boiling can be better ascertained.     

CHEMICALLY BONDED CERAMIC TOOLING FOR ADVANCED COMPOSITES

The wide range of advanced composite forming methods has motivated the development of new tooling materials capable of surviving processing extremes. Chemically Bonded Ceramic (CBC) tooling media have been formulated to supply molds with the strength, durability and thermal properties required in these applications. These inorganic materials retain relatively low cost and fabrication times. They incorporate a wide range of aggregates, fibers and inserts, selected to provide tools with desirable thermal and physical properties. CBC tools have been successfully utilized to form parts at temperatures ranging from ambient to 1800° F and at pressures as high as 10,000 psi. Chemically Bonded Ceramic tooting media provide an innovative alternative when more traditional tooling materials lack stability, durability, heat transfer capabilities or formability. This paper presents an overview of some applications in which Chemically Bonded Ceramic tooling have been used, and compares these materials to others which are commonly used in composite forming processes.     

Singular perturbation theory for predicting extravasation of Brownian particles

Motivated by recent studies on tumor treatments using the drug delivery of nanoparticles, we provide a singular perturbation theory and perform Brownian dynamics simulations to quantify the extravasation rate of Brownian particles in a shear flow over a circular pore with a lumped mass transfer resistance. The analytic theory we present is an expansion in the limit of a vanishing Péclet number ( $P$ ), which is the ratio of convective fluxes to diffusive fluxes on the length scale of the pore. We state the concentration of particles near the pore and the extravasation rate (Sherwood number) to $O(P^{1/2})$ . This model improves upon previous studies because the results are valid for all values of the particle mass transfer coefficient across the pore, as modeled by the Damköhler number ( $\kappa $ ), which is the ratio of the reaction rate to the diffusive mass transfer rate at the boundary. Previous studies focused on the adsorption-dominated regime (i.e., $\kappa \rightarrow \infty $ ). Specifically, our work provides a theoretical basis and an interpolation-based approximate method for calculating the Sherwood number (a measure of the extravasation rate) for the case of finite resistance [ $\kappa \sim O(1)$ ] at small Péclet numbers, which are physiologically important in the extravasation of nanoparticles. We compare the predictions of our theory and an approximate method to Brownian dynamics simulations with reflection–reaction boundary conditions as modeled by $\kappa $ . They are found to agree well at small $P$ and for the $\kappa \ll 1$ and $\kappa \gg 1$ asymptotic limits representing the diffusion-dominated and adsorption-dominated regimes, respectively. Although this model neglects the finite size effects of the particles, it provides an important first step toward understanding the physics of extravasation in the tumor vasculature.     

Battery Recycling Challenge Looms as Electric Vehicle Business Booms

In June 2021,the Ontario,Canada-based company Li-Cycle announced plans to,by the end of 2021,begin construction of North America's largest lithium-ion battery(L...