697 research outputs found

    Reason, Luck, and Meaning : A Critique of the Moralist View of Meaning in Life

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    Degradation of a Wholly Aromatic Main-Chain Thermotropic Liquid-Crystalline Polymer Mediated by Superbases

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    Plastic circular economy needs to be established to solve environmental issues related to plastic waste. Superengineering plastics such as liquid-crystalline (LC) polymers exhibit excellent thermal and mechanical properties, resulting in poor degradability in natural environment. Herein, we report the degradation of a wholly aromatic thermotropic LC polyester, poly(4-hydroxybenzoic acid-co-6-hydroxy-2-naphthoic acid) (Vectra) mediated by superbases. Methanolysis and hydrolysis of Vectra yield its monomeric compounds, 4-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, and their methyl esters. Among several transesterification catalysts explored, 1,5,7-triazabicylco[4.4.0]dec-5-ene (TBD) is the most suitable for the methanolysis of Vectra. The complete degradation of Vectra is achieved under reflux. The degradation proceeds heterogeneously via a surface erosion mechanism, preferentially starting from less chain-packed regions. Model reactions using aryl arylates reveal that monomeric compound–superbase complexes could mediate the cleavage of the ester bonds in both homogeneous and heterogeneous systems. The ester bonds of Vectra have inherent poor reactivity and are protected by oriented robust structures of the polymer. Nevertheless, the superbases enable the degradation of Vectra via the cleavage of the ester bonds by methanol. These outcomes open the way for recycling high-performance plastics as well as demonstrate the feasibility of recovering precious aromatic compounds from plastic waste as aromatic feedstock

    バーナード・ウィリアムズの功利主義批判再考 (Bernard Williams’ Critique of Utilitarianism Reconsidered)

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    This research discusses Bernard Williams' critique of utilitarianism. I will address Williams' well-known “Integrity Objection” and clarify where his main issue with utilitarianism lies. Through this, I will demonstrate that the separation of the two viewpoints – the “inside viewpoint” and the “impartial viewpoint” - is the issue, as the utilitarian impartial viewpoint does not capture the value of ethical deliberations based on our inside viewpoint in which we presuppose our personal projects. Furthermore, I will argue that this interpretation enables us to place the objection in the context of the critique of impartiality which is one of the central themes of Williams’ ethics

    A Preliminary Test of Measurement of Joint Angles and Stride Length with Wireless Inertial Sensors for Wearable Gait Evaluation System

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    The purpose of this study is to develop wearable sensor system for gait evaluation using gyroscopes and accelerometers for application to rehabilitation, healthcare and so on. In this paper, simultaneous measurement of joint angles of lower limbs and stride length was tested with a prototype of wearable sensor system. The system measured the joint angles using the Kalman filter. Signals from the sensor attached on the foot were used in the stride length estimation detecting foot movement automatically. Joint angles of the lower limbs were measured with stable and reasonable accuracy compared to those values measured with optical motion measurement system with healthy subjects. It was expected that the stride length measurement with the wearable sensor system would be practical by realizing more stable measurement accuracy. Sensor attachment position was suggested not to affect significantly measurement of slow and normal speed movements in a test with the rigid body model. Joint angle patterns measured in 10 m walking with a healthy subject were similar to common patterns. High correlation between joint angles at some characteristic points and stride velocity were also found adequately. These results suggested that the wireless wearable inertial sensor system could detect characteristics of gait

    Compositional Probabilistic Model Checking with String Diagrams of MDPs

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    We present a compositional model checking algorithm for Markov decision processes, in which they are composed in the categorical graphical language of string diagrams. The algorithm computes optimal expected rewards. Our theoretical development of the algorithm is supported by category theory, while what we call decomposition equalities for expected rewards act as a key enabler. Experimental evaluation demonstrates its performance advantages.Comment: 32 pages, Extended version of a paper in CAV 202
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