Reflective judgment vs. investigation of things – a comparative study of Kant and Zhu Xi

This thesis is devoted to studying two historical philosophical events that happened in the West and the East. A metaphysical crisis stimulated Kant’s writings during his late critical period towards the notion of the supersensible. It further motivated a methodological shift and his coining of reflective judgment, which eventually brought about a systemic unfolding of his critical philosophy via Kantian moral teleology. Zhu Xi and his Neo-Confucian contemporaries confronted a transformed intellectual landscape resulting from the Neo-Daoist and Buddhist discourses of “what is beyond the form”. The revival of Confucianism required a method in order to relocate the formless Dao back into daily life and to reconstruct a meta-ethical foundation within a social context. This led to the Neo-Confucian recasting of “investigation of things” from The Great Learning via complex hermeneutic operations. By the respective investigation on, as well as the comparative analysis of the two events, I reveal the convergence and incommensurability between the two distinct cultural traditions concerning the metaphysical quests, the mechanism of intellectual development, and moral teleology, so as to capture the intrinsic characteristics of philosophical research in general.

Influence of combined fundamental potentials in a nonlinear vibration energy harvester

Ambient mechanical vibrations have emerged as a viable energy source for low-power wireless sensor nodes aiming the upcoming era of the ‘Internet of Things’. Recently, purposefully induced dynamical nonlinearities have been exploited to widen the frequency spectrum of vibration energy harvesters. Here we investigate some critical inconsistencies between the theoretical formulation and applications of the bistable Duffing nonlinearity in vibration energy harvesting. A novel nonlinear vibration energy harvesting device with the capability to switch amidst individually tunable bistable-quadratic, monostable-quartic and bistable-quartic potentials has been designed and characterized. Our study highlights the fundamentally different large deflection behaviors of the theoretical bistable-quartic Duffing oscillator and the experimentally adapted bistable-quadratic systems, and underlines their implications in the respective spectral responses. The results suggest enhanced performance in the bistable-quartic potential in comparison to others, primarily due to lower potential barrier and higher restoring forces facilitating large amplitude inter-well motion at relatively lower accelerations.

Frequency adjustable MEMS vibration energy harvester

Ambient mechanical vibrations offer an attractive solution for powering the wireless sensor nodes of the emerging "Internet-of-Things". However, the wide-ranging variability of the ambient vibration frequencies pose a significant challenge to the efficient transduction of vibration into usable electrical energy. This work reports the development of a MEMS electromagnetic vibration energy harvester where the resonance frequency of the oscillator can be adjusted or tuned to adapt to the ambient vibrational frequency. Micro-fabricated silicon spring and double layer planar micro-coils along with sintered NdFeB micro-magnets are used to construct the electromagnetic transduction mechanism. Furthermore, another NdFeB magnet is adjustably assembled to induce variable magnetic interaction with the transducing magnet, leading to significant change in the spring stiffness and resonance frequency. Finite element analysis and numerical simulations exhibit substantial frequency tuning range (25% of natural resonance frequency) by appropriate adjustment of the repulsive magnetic interaction between the tuning and transducing magnet pair. This demonstrated method of frequency adjustment or tuning have potential applications in other MEMS vibration energy harvesters and micromechanical oscillators.