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Monitoring the methanol conversion process in H-ZSM-5 using synchrotron X-ray powder diffraction-mass spectrometry
By monitoring the catalytic conversion of methanol using operando synchrotron powder X-ray diffraction (SXRD) and structure refinement, in combination with theoretical calculations, we demonstrate for the first time, that the concerted associative mechanism is responsible for dimethyl ether production via an activated protonated methanol intermediate species over H-ZSM-5 in an early stage of reaction at 200 °C. The minor contribution from the dissociative mechanism of the adsorbed methoxy intermediate species at Brønsted acid sites, renders their accumulation during the late stage of reaction, which leads to a build-up of the ‘hydrocarbon pool’ and eventually to ‘carbon’ through the formation of C-C bonds.
Decoupling and elucidation of surface-driven processes during inorganic mineralization on virus templates
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Industrial process system assessment: bridging process engineering and life cycle assessment through multiscale modeling
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Experimental and numerical investigation of the horizontal ribbon growth process
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Robust multivariable predictive control for laser-aided powder deposition processes
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Process development of NiTi using binder jetting additive manufacturing: Investigation of the sintering process
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Effects of oil and water contamination on natural gas engine combustion processes
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Evolution of crystalline phase during laser processing of Zr-based metallic glass
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Progress on matrix SiC processing and properties for fully ceramic microencapsulated fuel form
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Processing used nuclear fuel with nanoscale control of uranium and ultrafiltration
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Predictive modeling of crystal accumulation in high-level waste glass melters processing radioactive waste
The effectiveness of HLW vitrification is limited by precipitation/accumulation of spinel crystals [(Fe, Ni, Mn, Zn)(Fe, Cr)2O4] in the glass discharge riser of Joule-heated ceramic melters during idling. These crystals do not affect glass durability; however, if accumulated in thick layer, they can clog the melter and prevent discharge of molten glass into canisters. To address this problem, an empirical model was developed that can predict thicknesses of accumulated layers as a function of glass composition. This model predicts well the accumulation of single crystals and/or small-scale agglomerates, but, excessive agglomeration observed in high-Ni-Fe glass resulted in an under-prediction of accumulated layers, which gradually worsen over time as an increased number of agglomerates formed. Accumulation rate of ~53.8 ± 3.7 µm/h determined for this glass will result in ~26 mm thick layer in 20 days of melter idling.
Processing Strategies for an Organic Photovoltaic Module with over 10% Efficiency
Abstract not provided
Processes for Electrochemical Production of Electrolyte-free Hydrogen Peroxide
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Performance of solid oxide fuel cells operated with coal syngas provided directly from a gasification process
Solid oxide fuel cells (SOFCs) are presently being developed for gasification integrated power plants that generate electricity from coal at 50+% efficiency. The interaction of trace metals in coal syngas with the Ni-based SOFC anodes is being investigated through thermodynamic analyses and in laboratory experiments, but direct test data from coal syngas exposure are sparsely available. This research effort evaluates the significance of SOFC performance losses associated with exposure of a SOFC anode to direct coal syngas. SOFC specimen of industrially relevant composition are operated in a unique mobile test skid that was deployed to the research gasifier at the National Carbon Capture Center (NCCC) in Wilsonville, AL. The mobile test skid interfaces with a gasifier slipstream to deliver hot syngas (up to 300°C) directly to a parallel array of 12 button cell specimen, each of which possesses an active area of approximately 2 cm2. During the 500 hour test period, all twelve cells were monitored for performance at four discrete operating current densities, and all cells maintained contact with a data acquisition system. Of these twelve, nine demonstrated good performance throughout the test, while three of the cells were partially compromised. Degradation associated with the properly functioning cells was attributed to syngas exposure and trace material attack on the anode structure that was accelerated at increasing current densities. Cells that were operated at 0 and 125 mA/cm² degraded at 9.1 and 10.7% per 1000 hours, respectively, while cells operated at 250 and 375 mA/cm² degraded at 18.9 and 16.2% per 1000 hours, respectively. Post-trial spectroscopic analysis of the anodes showed carbon, sulfur, and phosphorus deposits; no secondary Ni-metal phases were found.