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http://scholars.ntou.edu.tw/handle/123456789/212
2024-03-25T23:10:17ZEngine Performance of High-Acid Oil-Biodiesel through Supercritical Transesterification
http://scholars.ntou.edu.tw/handle/123456789/24715
標題: Engine Performance of High-Acid Oil-Biodiesel through Supercritical Transesterification
作者: Lin, Cherng-Yuan; Lin, Yi-Wei
摘要: Relatively cheaper high-acid oil was used to make biodiesel through supercritical methanol transesterification, where high FFA contents in feedstock might conversely enhance the reaction extent. A direct-injection diesel engine and a dynamometer were used to analyze the engine characteristics of the high-acid oil-biodiesel. The experimental results show that the biodiesel made in this study had adequate fuel properties. This present biodiesel from high-acid oil was found to bear a lower heating value and equivalence ratio, with higher exhaust gas temperature, brake-specific fuel consumption (bsfc), and excess air ratio, than super-low sulfur diesel (SLSD). The biodiesel appeared to have larger-sized carbon residue left after the burning process in comparison with that of SLSD. The higher engine speed resulted in higher exhaust gas temperature and equivalence ratio, while lower bsfc, excess air ratio, was observed for the biodiesel. Supercritical methanol transesterification has been successfully proven to convert those low-cost feedstocks to renewable biodiesel products which own competitive engine performance in this study.2024-01-01T00:00:00ZEstimated-State Feedback Fuzzy Compensator Design via a Decentralized Approach for Nonlinear-State-Unmeasured Interconnected Descriptor Systems
http://scholars.ntou.edu.tw/handle/123456789/24707
標題: Estimated-State Feedback Fuzzy Compensator Design via a Decentralized Approach for Nonlinear-State-Unmeasured Interconnected Descriptor Systems
作者: Chang, Wen-Jer; Su, Che-Lun; Lee, Yi-Chen
摘要: This paper investigates the decentralized fuzzy control problems for nonlinear-state-unmeasured interconnected descriptor systems (IDSs) that utilize the observer-based-feedback approach and the proportional-derivative feedback control (PDFC) method. First of all, the IDS is represented as interconnected Takagi-Sugeno (T-S) fuzzy subsystems. These subsystems can effectively capture the dynamic behavior of the system through fuzzy rules. For the stability analysis of the system, this paper uses the free-weighing Lyapunov function (FWLF), which allows the designer to set the weight matrix, to achieve the desired control performance and design the controller more easily. Furthermore, the control problem can be transformed into a set of linear matrix inequalities (LMIs) through the Schur complement, which can be solved using convex optimization methods. Simulation results confirm the effectiveness of the proposed method in achieving the desired control objectives and ensuring system stability.2024-01-01T00:00:00ZRobust Decentralized Fuzzy Control for Large-scale Descriptor Systems With Decay Rate Constraint
http://scholars.ntou.edu.tw/handle/123456789/24702
標題: Robust Decentralized Fuzzy Control for Large-scale Descriptor Systems With Decay Rate Constraint
作者: Su, Che-Lun; Chang, Wen-Jer; Ku, Cheung-Chieh
摘要: This study addresses the control problem of a nonlinear large-scale descriptor system (LSDS) through the use of a decentralized proportional-plus-derivative state feedback fuzzy (DPDF) control strategy. The Takagi-Sugeno (T-S) fuzzy modeling technique, which is widely used by researchers, is used to describe the nonlinear LSDS as a set of linear subsystems with interconnections. Based on the constructed T-S fuzzy LSDS, a DPDF feedback method is proposed to address the limitations of the descriptor matrix of the T-S fuzzy LSDS and to solve the regular and impulse-free problems of systems while providing a more convenient and effective approach for discussing system stability. Additionally, the Lyapunov theory is chosen to analyze the stability conditions. This study uses a quadratic Lyapunov function to provide sufficient criteria to ensure the decay rate performance of the LSDS, which can be transformed into linear matrix inequality (LMI) form. The proposed method is demonstrated through several examples to showcase its effectiveness.2023-01-01T00:00:00ZCrystallization and activator reduction simultaneously for calcium sulfide nanophosphors and evaluation of red-light compensation - Environmental reliability
http://scholars.ntou.edu.tw/handle/123456789/24696
標題: Crystallization and activator reduction simultaneously for calcium sulfide nanophosphors and evaluation of red-light compensation - Environmental reliability
作者: Wu, Chen-Yu; Lei, Chien-Ming; Wu, Rudder T.; Wang, Shing-Hoa; Shih, Jing-Shiang; Chang, Horng-Yi
摘要: Calcium sulfide nanophosphors (CaS:Eu2+) with red emissions were synthesized by hydrothermal-derived 250 nm carbon-sphere templates to induce a reduction atmosphere to activate an activator valence transition and crystallize (Ca,Eu)S simultaneously at 800 degrees C without extra sulfur atmosphere. The cationic concentration z = [Ca2++Eu2+] and ionic ratio y = [S2- ]/[Ca2++Eu2+] were controlled in an innovative chemical solution reflux process to synthesize a sulfide nanophosphor precursor on carbon-sphere template. The particle size and crystallinity of the prepared nanophosphors increased with the "y" value increase. The photoluminescence (PL) intensity of the 652 nm emission excited by 450 nm increased to y = 1 and kept nearly constant to y = 20. High PL intensity was achieved by 0.025CaS-1 and 0.025CaS-10 samples with individually sphere-like nanoparticles, enough crystallinity and homogeneous Eu doping as well as fully reduced Eu2+ in the nanophosphors. The CaS: Eu2+ nanoparticles prepared by carbon-sphere templates showed thermal quenching with temperature. The Eu2+-doped CaS emitted 652 nm red light by 450 nm but not by 380 nm excitation that was only for CaS host at 555 nm emission. The prepared 0.025CaS-10 paste of only 7 wt% was individually coated on a blue-light LED and commercially available YAG-LED. The red emission intensity was enhanced and broadened by the prepared sulfide nanophosphor compared to a commercially available red LED. The CRI value for R9 increased to higher than 90, and the measured Ra was higher than 95 for the prepared sulfide nanophosphor-coated commercial WLED. The prepared sulfide nanophosphors could keep the red-light brightness over six months' exposure at rainy marina to show the environmental reliability.2023-01-01T00:00:00Z