Performance Assessment of The Solid Waste Containment System at Transfer Depo (TPS) in Mulyorejo District, Surabaya City, Using Multi-Criteria Decision Making (MCDM) Method

Mulyorejo District contributes approximately 3% of Surabaya’s total solid waste (SW) generation, with a total population of 86,545 in 2020. Therefore, a proper solid waste management (SWM) system is required. A transfer depo (TPS) is a facility to temporarily accommodate SW before being transferred to a landfill (TPA). Communal SW containers play a significant role in accommodating SW in TPS, but problems are often found. This research aims to (1) determine the current condition of the SW containment system at TPS in Mulyorejo District, (2) determine the recommended alternative of the SW containment system at TPS in Mulyorejo District based on expert judgment, and (3) determine the most suitable SW containment system alternative for TPS in Mulyorejo District. This research used the load count analysis method to determine the SW volume in each TPS. Furthermore, observation of the SW containment system in each TPS was done. In selecting the preferable alternative, the Multi-Criteria Decision Making (MCDM) – Analytic Hierarchy Process (AHP) method and Expert Choice 11 software were used to determine experts' tendency to prioritize parameters, criteria, and the preference toward SW containment alternatives. Operational cost analysis using Pacific Consultant International (PCI) and SWOT was used to select the most suitable alternative. Results of the research show that the use of 660 L containers at TPS in Mulyorejo District is inappropriately operated with the enacted regulations. The expert's preference for SW containment system alternatives at TPS in Mulyorejo District was smart container system with a weight of 0.389, prioritizing technical aspect parameters with a weight of 0.817 and operational criteria with a weight of 0.336 and operational cost criteria of 0.418. HCS was the most suitable SW containment system alternative for TPS in Mulyorejo District with an operational cost of IDR 152,676 /m3, followed by an SCS of IDR 231,633 /m3, and smart container system of IDR 115,816 /m3

Verification of the Influence of Processing History through Comparing High-Speed Melt Spinning Behavior of Virgin and Recycled Polypropylene

A ‘model’ material of recycled polypropylene (PP) was prepared through the injection molding process, and the effect of processing history on the polymer characteristics was investigated through the high-speed melt spinning of virgin and recycled PP. On-line measurement of the thinning behavior of the spin-line revealed the downstream shift of solidification point for the recycled PP at the take-up velocity of 1.0 km/min, indicating the suppression of flow-induced crystallization. The difference was not clear at higher take-up velocities of up to 5 km/min. For any identical take-up velocity, no clear difference in the stress-strain curves and birefringence of the fibers from virgin and recycled PP could be observed, whereas the detailed investigation on the variation of relative amount of c-axis and a*-axis oriented crystals in the fibers prepared at varied take-up velocities suggested the deterioration of flow-induced crystallization at 1.0 km/min. It was speculated that the processing history induced the lowering of the entanglement density, which affected the melt spinning and crystallization behavior. An undistinguishable difference between the virgin and recycled PP at increased take-up velocities suggested the existence of an optimum elongational strain rate for the detection of the different states of molecular entanglement

Effect of Elevated Temperatures on the States of Water and Their Correlation with the Proton Conductivity of Nafion

For the first time, we report the effects of elevated temperatures, from 80 to 100 °C, on the changes in the states of water and ion–water channels and their correlation with the proton conductivity of Nafion NR212, which was investigated using a Fourier transform infrared spectroscopy study. Experimentally, three types of water aggregates, protonated water (H⁺(H₂O)_<i>n</i>), nonprotonated hydrogen (H)-bonded water (H₂O···H₂O), and non-H-bonded water, were found in Nafion, and the existence of those three types of water was confirmed through ab initio molecular dynamics simulation. We found that the proton conductivity of Nafion increased for up to 80 °C, but from 80 to 100 °C, the conductivity did not increase; rather, all of those elevated temperatures showed identical conductivity values. The proton conductivities at lower relative humidities (RHs) (up to 50%) remained nearly identical for all elevated temperatures (80, 90, and 100 °C); however, from 60% RH (over λ = 4), the conductivity remarkably jumped for all elevated temperatures. The results indicated that the amount of randomly arranged water gradually increased and created more H-bonded water networks in Nafion at above 60% RH. From the deconvolution of the O–H bending band, it was found that the volume fraction <i>f</i>_{<i>i</i> (<i>i</i>=each deconvoluted band)} of H-bonded water for elevated temperatures (>80–100 °C) increased remarkably higher than for 60 °C

Crystalline structure and the unusual dielectric behavior of nylon 93

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