Egg cartons have popularly been used as sound absorbers because they are inexpensive, easy to install and easily available. However, acoustic experts have demonstrated that egg cartons are bad sound absorbers. This study developed Enhanced Egg Carton-Dry and Enhanced Egg Carton-Wet using additional recycled materials (shredded rice straw paper, textile waste, 2-cm cut rice straws) to improve the cartons' sound absorption coefficient while retaining their original advantages. Enhanced Egg Carton-Dry and Enhanced Egg Carton-Wet were tested based on the ASTM C423-02 method of sound absorption measurement. Enhanced Egg Carton-Dry has a noise reduction coefficient of 0.6 and a sound absorption average of 0.59, while Enhanced Egg Carton-Wet has a noise reduction coefficient of 0.54 and sound absorption average of 0.54. The maximum sound absorption coefficients of Enhanced Egg Carton-Dry and Enhanced Egg Carton-Wet are, respectively, 0.77 at 500 Hz and 0.67 at 630 Hz. Enhanced Egg Carton-Dry has a sound absorption coefficient ⩾0.5, between 315 and 2500 Hz, which makes it able to absorb sound energy of the lower to upper mid-range frequencies. With their high sound absorptivity at mid-range frequencies, Enhanced Egg Carton-Dry and Enhanced Egg Carton-Wet are suitable for mosques and auditoriums, where the human voice is the dominant noise source and where an inexpensive sound absorber is needed. The production of Enhanced Egg Carton-Dry and Enhanced Egg Carton-Wet is so simple that users can do it themselves using basic home tools.

Abstract. This paper describes how collective memory and level of place attachment can be explored using social media data to develop a sustainable travel destination in the city of Yogyakarta. Yogyakarta is famous as a tourist destination city for tourism in Indonesia. One of the reasons why people visit an object at travel destination is to recall the memory of the place. Memory is important for creating memorable space and places as it differentiates one place to another. Memorable places could grow as a symbol and an identity of a district in the city. This paper explores the collective memories recorded as status in the social media. The study identifies the distribution of such locations or nodes representing the memory footprint of the city of Yogyakarta, which can be achieved by determining the quality level of nodes based on the level of place attachment. Analysis is done by looking at the number of caption status by location and time. Qualitative description is used to present the level of place attachment based on the content of the status captioned. The study shows that level of place attachment seems not to be influenced by the popularity of an object. However it affects how strong a travel destination might be sustainable in future development.