Improved control in elimination of white impurities on graphene by chemical vapor deposition (CVD)

Chemical vapor deposition (CVD) is one of the most preferred technique of graphene fabrication. However, it still faces some challenges, such as contamination with white particulate impurities which occurs commonly when furnaces with quartz tubes are used in the process. In this work, the source of contamination on copper substrates was traced and tackled in three stages of the graphene fabrication process. The cleaning, annealing, and finally the fabrication stage was studied. No evidence was found to support that copper foil or cleaning tools were sources of the contamination. XPS, EDS and XRD results reveal that the white impurities are silicates, formed due to the phase transition of quartz at elevated temperatures in presence of copper vapor and oxygen gas. It was evident that due to the appearance of this contamination, quartz tubes are not ideal for use in graphene synthesis. However, if unavoidable this study proposes a special substrate configuration which has been found to suppress the contamination during fabrication

Satisfacción turística con atributos del sitio del patrimonio en el Sultanato de Omán

Tourist satisfaction, as one of the important measures of destination performance, has been widely used by destination managers to improve their service offerings and hence attract more visitors. The present study analyses the level of satisfaction the tourists have with two heritage sites namely Nizwa Fort and Bahla Fort in the Aldhkhiliyah region of the Sultanate of Oman. 162 tourists were surveyed on-site through a bi-lingual (English and Arabic) questionnaire composed of 27 statement, 25 of which were categorized in four major variables as Facilities (9 statements), Appearance and Maintenance (4 statements), Accessibility (8 statements) and Quality of Services (4 items); and 2 statements were used to check overall satisfaction of the tourists. While the respondents were overall satisfied with the two sites, they rated certain dimensions of the two heritage sites higher than the others. It is hoped that the findings will help the site managers and policymakers at the two heritage sites to focus on the visitors' concerns and improve on those components to increase visitor satisfactionLa satisfacción del turista, como una de las medidas importantes del rendimiento del destino, ha sido ampliamente utilizada por los gerentes de destino para mejorar sus ofertas de servicios y, por lo tanto, atraer más visitantes. El presente estudio analiza el nivel de satisfacción que los turistas tienen con dos sitios patrimoniales, a saber, el Fuerte Nizwa y el Fuerte Bahla en la región Aldhkhiliyah del Sultanato de Omán. 162 turistas fueron encuestados en el sitio a través de un cuestionario bilingüe (inglés y árabe) compuesto por 27 declaraciones, 25 de las cuales se clasificaron en cuatro variables principales como Instalaciones (9 declaraciones), Apariencia y mantenimiento (4 declaraciones), Accesibilidad (8 declaraciones) y Calidad de los servicios (4 artículos); y se usaron 2 declaraciones para verificar la satisfacción general de los turistas. Si bien los encuestados estaban en general satisfechos con los dos sitios, calificaron ciertas dimensiones de los dos sitios patrimoniales más que los demás. Se espera que los hallazgos ayuden a los administradores del sitio y los encargados de formular políticas en los dos sitios del patrimonio a centrarse en las preocupaciones de los visitantes y mejorar esos componentes para aumentar la satisfacción de los visitante