The attention in natural fiber reinforced biopolymer composite materials has been rapidly growing both in terms of industrial applications and basic research. This study investigated on the effect of aging time on mechanical properties and morphological structure of thermoset protein-based composites from egg albumen reinforced by natural cotton fibres. The cotton/albumen composites (CAC) were fabricated by hands lay-up technique with 10 w/w % of fiber content. The samples were cured and aged at room temperature for different aging time from 7 to 32 days. The cotton fibres have contributed in a significant improvement in mechanical strength and toughness of the composites. Tensile strength of the composites achieved the optimum strength of 9 MPa after 21 days of aging time and constant till 32 days. As the aging time increased, impact strength of the composites also improved to some value of 20 kJ/m2. Thereby after 21 days observation, the composites show an equilibrium moisture content of 6-9 wt%, and the strength remains stable at room condition with 50-60% relative humidity (RH). Morphology studied using SEM justify that the moisture content after aging time influenced mechanical properties of the composites.

Split Mastic Asphalt (SMA) mixture is one of the favored materials for flexible pavement in Indonesia. Due to the limitation of fine aggregate products from stone crusher, therefore, an alternative sand beach is used. This paper presents the results of determining the influence of the use of coastal sand as fine aggregate substitution on the Split mastic asphalt (SMA). This research has four phases, first testing of aggregate and asphalt properties, then the determination of optimum asphalt content 0%, 25%, 50%, 75%, and 100%. The next step was testing Marshall, Immersion, Indirect Tensile Strength, and Cantabro loss. The results showed that the use of Indrayanti's sand beach as a substituted fine aggregate on the Split Mastic Asphalt 0/11 mixture meets the standard. Based on Marshall's test stability and flexibility of all the mixture was higher, the Bina Marga specification. Indirect Tensile Strength increase in each addition of Indrayanti's sand beach. Cantabro Loss and Index Retained Strength on all specimens of Indrayanti's sand beach qualify Bina Marga standard.

Improving public transport (PT) services is critical to maintaining resilient and sustainable transportation. While the investment in PT (i.e., buses) has not been able to shift private vehicle users, especially motorcyclists, to buses, the emergence of motorcycle-based ride-sourcing (MBRS) has become a popular travel mode that threatens the existing bus demand. Due to this, this study aimed to investigate the factors affecting the choice of buses over private motorcycles and MBRS among high school and university students in Yogyakarta, Indonesia, through the hybrid choice model. The explored variables include sociodemographic characteristics, travel time, travel cost, and latent variables of travel mode perceptions. By involving 527 respondents, the analysis showed that travel time, travel cost, and sociodemographic factors, including education level, income, and motorcycle ownership, significantly impacted travel mode choices. The findings also revealed that convenience causes buses to be the chosen transport means among students, while lifestyle generates students to choose MBRS services. Based on findings, this study proposed some policies to increase bus demand, especially related to the identified convenience factors and travel time.

Research on the production of composites from natural fibers has an enormous attention from researchers due to environmental awareness, which focusing to produce compostable bio-based composites and renewable raw materials that can be safely disposed after their use without polluting the environment. This paper reports the study on the effect of the ultraviolet (UV) to the cotton/albumen composites (CAC). The CAC were prepared by using hands lay-up technique with 10 w/w % of cotton content and cured at room temperature for 14 days. The cured samples were cut before exposing to UV light up to 20 days. The increase in tensile strength was observed up-to 10 days of exposure before it is decreasing to about 15% after 20 days of exposure to UV. The morphological study through SEM micrograph shows that fibers breakage and the biopolymer matrix loss is more with longer duration of UV exposure.

No abstract