The reaction between SiO(g) and CO(g) is a relevant intermediate reaction in the silicon production process. One of the products generated from this gas mixture is called by its color, brown condensate. In this paper, SiO(g) and CO(g) are produced from SiO2-SiC pellets. The reaction between the two gases occurred on SiC particles. Inert gas was injected at different flows. The SiC particles were collected, and the brown condensate deposited on them was characterized by electron probe microanalysis, X-ray photoelectron spectroscopy, and focused ion beam preparation samples for transmission electron microscope analysis. The brown condensate consists of a mixture of Si spheres embedded in a SiO2 matrix. The compound generates in the temperature range from 1400 °C to 1780 °C (1673 K to 2053 K), and in the SiO(g) partial pressure range between 0.534 and 0.742, depending on the inert gas flow. SiC crystallites are located at the Si-SiO2 interface. Carbides are believed to generate from the reaction between liquid silicon and CO(g). Carbides may also precipitate from reaction between dissolved carbon and liquid silicon, but to a minor extent. Both mechanisms are believed to happen above the melting point of silicon and in the softening range of silica.

Silicon carbide nanowires are valuable for electronic and optical applications, due to their high mechanical and electrical properties. Previous studies demonstrated that nanowires can be produced easily, by mixing a silicon-based compound (Si or SiO2) with a carbon source (C or SiC), in an inert gas atmosphere (Ar or He). The result of this reaction is an elevated number of core–shell SiC-SiOx nanowires. The mechanism of formation of these wires should be inquired, in order to control the process. In this work, SiO2 and SiC are chosen as raw materials for SiO(g) and CO(g) production. These two gases react at SiC surfaces and generate the core–shell nanowires. SEM, TEM and XPS analyses confirm the composition and the microstructure of the product. A three-step mechanism of formation is proposed. The formation of nanowires is compared with thermodynamics of reactions occurring in the Si-C-O system. It is found that nanowires develop in wide temperature and SiO partial pressure ranges (T: 924 °C to 1750 °C, pSiO = 0.50 to 0.74). Higher He flows will shift the reaction to lower temperatures and pSiO.

BACKGROUND AND AIMS As more therapeutic options with their own characteristics become available for inflammatory bowel disease (IBD), drug development and individual treatment decision-making needs to be tailored towards patients’ preferences and needs. This study aimed to understand patient preferences among IBD patients, and their most important treatment outcomes and unmet needs. METHODS This qualitative study consisted of 1) a scoping literature review, 2) two focus group discussions (FGDs) with IBD patients (n=11) using the nominal group technique, and 3) two expert panel discussions. RESULTS IBD patients discussed a multitude of unmet needs regarding their symptoms, side-effects, psychological and social issues for which they would welcome improved outcomes. Particularly, IBD patients elaborated on the uncertainties and fears they experienced regarding the possible need for surgery or an ostomy, the effectiveness and onset of action of their medication, and its long-term effects. Furthermore, participants extensively discussed the mental impact of IBD and their need for more psychological guidance, support, and improved information and communication with healthcare workers regarding their disease and emotional well-being. The following five characteristics were identified during the attribute grading as most important: prevent surgery, long-term clinical remission, improved quality of life (QoL), occurrence of urgency, and improved labor rate. CONCLUSIONS This study suggests that IBD drug development and treatment decision-making needs to improve IBD symptoms and adverse events that significantly impact IBD patients’ QoL. Furthermore, this study underscores patients need for a shared decision-making process where their desired treatment outcomes and uncertainties are explicitly discussed and considered.

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