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This research aimed to enhance the quality of hydrochar produced by the hydrothermal carbonization (HTC) process of waste oily sludge (WOS) during the physicochemical properties study. This study was conducted under the influence of changing the temperature and reaction time (210 °C to 290 °C and reaction time 30 to 90 min) with fixed parameters WOS feed amount a 10 g, 5 MPa of N2 pressure. The characterization of this study included proximate analysis, fuel ratio, ultimate analysis, Van Krevelen Diagram, FTIR spectrum, SEM images, and XRD diffraction. This study relied on developing the produced hydrochar by improving its approximate and ultimate specifications, whereby the percentage of fixed carbon (FC%) was improved from 33.1 for WOS to 38.4 for the fuel produced. Regarding the atomic ratio was enhanced and shifted from WOS to HTC-620 C, and HTC-min respectively. Hence, the economic recycling of carbon material via the production of valuable fuel will contribute to environmental cleanups, significantly reduce CO2 gas emissions, minimize financial costs, and increase NRC Baiji's profits. [ABSTRACT FROM AUTHOR]

This work investigates a multi-objective functions for machine scheduling problems. The objective is to find the optimal schedule for n jobs to minimize the total cost of sum weighted earliness, the weighted tardiness, the weighted completion time, the weighted late work and the number of weighted late jobs where the problem is 1 // ∑ i = 1 n (α j E j + β j T j + θ j C j + γ j U j + ω j V j). For this problem, several special cases and dominance rules are proven to decrease the branching nodes which are applied to solve the suggested problem in reasonable time. [ABSTRACT FROM AUTHOR]