Papers by Keyword: Turbostratic

Abstract: The abundance of waste coffee grounds led to an adverse effect in our environment. This study focuses on generating carbon with conventional microwave for energy efficiency. The carbon result of conventional microwave carbonization is being compared to furnace and microwave-furnace processes. Before the conversion, Thermogravimetric Analysis (TGA) was performed to determine the degradation temperature of the waste coffee grounds. In addition, Fourier Transform Infrared Spectroscopy (FTIR) was employed to elucidate the presence of organic functional groups in the samples. Absence of significant peaks from the carbonized coffees spectrum confirms degradation. X-ray Diffraction (XRD) analysis was also performed to monitor the effect of temperature as shifting, and formation of peaks are seen. Identified peaks with Miller indices of (002), (101), and (004) signifies the presence of carbon. Scanning Electron Microscopy (SEM) paired with Energy Dispersive X-ray spectroscopy (EDX), shows the difference in morphology for the dried coffee and the carbonized coffees as well as the strong presence of carbon from the microwave-assisted carbonization which is about 74%.

Abstract: We propose an atomistic model to study the interface properties of mis-oriented (turbostratic) epitaxial graphene on SiC (000-1) surface. Using calculations from first principles, we compare the energetics, and structural/electronic properties of AB and turbostratic stacking sequences within a model based on the Si adatom surface reconstruction. Our calculations show that the systems with AB and turbostratic sequences are very close in energy, demonstrating the possibility of the observation of Moire patterns in epitaxial graphene on the C-face of SiC. The two-dimensional electron gas behavior is preserved in the epitaxial turbostratic graphene systems. However, there are deviations from the ideal turbostratic epitaxial graphene.

Abstract: We illustrate the x-ray Combined Analysis approach capabilities in characterizing silicates and phyllosilicates for samples exhibiting crystallographic textures. Two mullite composite ceramics, one elaborated under uniaxial pressure the other under centrifugation, and one uniaxially pressed montmorillonite aggregate, are studied in terms of texture, cell parameters and phase contents. Several weak texture components are present in the mullite samples, combinations of planar- and fibre-like textures. The methodology is able to take account of the amorphous silica-like matrix of the composite, and cell parameters and structure of mullite correspond to the commonly modelled used for this phase. The montmorillonite turbostratic phase is correctly reproduced with its fibre texture, eventhough minor phases are also present and modelled in the aggregate.