Calculations of the interactions of diatomic molecules with solid surfaces.
Interactions of homonuclear diatomic gas molecules with fcc solid surfaces calculated by digital computer
MOLECULAR COLLISION↗
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Results for “GAS-SOLID INTERFACE”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Detection of the vibrational states of gases adsorbed on tungsten by low-energy electron scattering.
Detection of vibrational structure of gases adsorbed on tungsten by low energy electron scattering
ELECTRON SCATTERING↗
Numerical calculations of gas-surface interactions.
Numerical calculations of interactions of monatomic gas particles with ideal and contaminated crystal surfaces at epithermal energies
CRYSTAL SURFACE↗
Gas-solid interactions and buoyancy.
Gas-solid interactions and buoyancy relation, discussing fluid density effect on Archimedes principle
BUOYANCY↗
Deciphering atomistic mechanisms of the gas-solid interfacial reaction during alloy oxidation
Gas-solid interfacial reaction is critical to many technological applications from heterogeneous catalysis to stress corrosion cracking. A prominent question that remains unclear is how gas and solid interact beyond chemisorption to form a stable interphase for bridging subsequent gas-solid reactions. Here, we report real-time atomic-scale observations of Ni-Al alloy oxidation reaction from initial surface adsorption to interfacial reaction into the bulk. We found distinct atomistic mechanisms for oxide growth in O 2 and H 2 O vapor, featuring a “step-edge” mechanism with severe interfacial strain in O 2 , and a “subsurface” one in H 2 O. Ab initio density functional theory simulations rationalize the H 2 O dissociation to favor the formation of a disordered oxide, which promotes ion diffusion to the oxide-metal interface and leads to an eased interfacial strain, therefore enhancing inward oxidation. Our findings depict a complete pathway for the Ni-Al surface oxidation reaction and delineate the delicate coupling of chemomechanical effect on gas-solid interactions.
36 MATERIALS SCIENCE↗
Mapping the Interfacial Chemistry and Structure of Partially Fluorinated Bottlebrush Polymers and Their Linear Analogues
Polymer interfaces are key to a range of applications including membranes for chemical separations, hydrophobic coatings, and passivating layers for antifouling. While important, challenges remain in probing the interfacial monolayer where the molecular ordering and orientation can change depending on the chemical makeup or processing conditions. In this work, we leverage surface specific vibrational sum frequency generation (SFG) and the associated dependence on molecular symmetry to elucidate the ordering and orientations of key functional groups for poly(2,2,2-trifluoroethyl methacrylate) bottlebrush polymers and their linear polymer analogues. These measurements were framed by atomistic molecular dynamic simulations to provide a complementary physical picture of the gas–polymer interface. Simulations and SFG measurements show that methacrylate backbones are buried beneath a layer of trifluoroethyl containing side groups that result in structurally similar interfaces regardless of the polymer molecular weight or architecture. The average orientational angles of the trifluoroethyl containing side groups differ depending on polymer linear and bottlebrush architectures, suggesting that the surface groups can reorient via available rotational degrees of freedom. Results show that the surfaces of the bottlebrush and linear polymer samples do not strongly depend on molecular weight or architecture. As such, one cannot rely on increasing the molecular weight or altering the architecture to tune surface properties. This insight into the polymer interfacial structure is expected to advance the design of new material interfaces with tailored chemical/functional properties.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Methane Remediation using Biocatalysts in Gas-Solid Reactor – Challenges and Prospects
One of the engineering grand challenges of the 21 st century is to develop carbon sequestration methods due to human activities. Carbon dioxide and methane are the two most abundant greenhouse gases with methane having a higher global warming potential (GWP) than carbon dioxide. Methanotrophs are a time of bacteria that consumes methane and can produce different kinds of organic acids. Wild methanotrophs produce a range of products and can be specifically selected and genetically engineered to produce a specific product. Improvement of bioreactor design for a solid-gas mass transfer is necessary for this technology to move forward. Poor solubility of methane requires high energy input for the conversion of methane. This paper reviews some relevant technology in bioreactor design of gas and liquid/solid interfaces and describes the scope of the project here at LLNL and the objectives it seeks to achieve in the geometric design of reactor of methanotroph.
36 MATERIALS SCIENCE↗