Reliability analysis for multiple-stage solid waste management systems.

Solid waste management (SWM) is a key issue for sustainable development and environment protection, and waste collection and transportation (WCT) is one of the most important steps in managing solid waste. A well-designed SWM system with optimised location and capacity of waste transfer stations (WTSs) and final disposal facilities (FDFs) plays a critical role in waste management. However, uncertainties are inevitable in a general SWM system, which could involve in any stage of the waste management. In this paper, we propose to use the reliability analysis method to manage the uncertainties for the multiple-stage SWM system. Furthermore, an optimisation model is developed to maximise the reliability of SWM systems by optimising the allocation of waste treatment demand between facilities. We also generated an event-tree to analyse the failure mode of the whole system. Finally, a case study was undertaken in Hong Kong to demonstrate the effectiveness of the methodology. The case study results indicate that the proposed method can: (i) estate the risk level of a SWM system, (ii) provide a solution to improve the system reliability or reduce the risk level, (iii) analyse the potential contributions of different policies on the reliability index, (iv) identify the critical facilities in a SWM system.

Incorporating global components into ethics education.

Ethics is central to science and engineering. Young engineers need to be grounded in how corporate social responsibility principles can be applied to engineering organizations to better serve the broader community. This is crucial in times of climate change and ecological challenges where the vulnerable can be impacted by engineering activities. Taking a global perspective in ethics education will help ensure that scientists and engineers can make a more substantial contribution to development throughout the world. This paper presents the importance of incorporating the global and cross culture components in the ethic education. The authors bring up a question to educators on ethics education in science and engineering in the globalized world, and its importance, necessity, and impendency. The paper presents several methods for discussion that can be used to identify the differences in ethics standards and practices in different countries; enhance the student's knowledge of ethics in a global arena.

Measuring physical activity during pregnancy.

BACKGROUND: Currently, little is known about physical activity patterns in pregnancy with prior estimates predominantly based on subjective assessment measures that are prone to error. Given the increasing obesity rates and the importance of physical activity in pregnancy, we evaluated the relationship and agreement between subjective and objective physical activity assessment tools to inform researchers and clinicians on optimal assessment of physical activity in pregnancy. METHODS: 48 pregnant women between 26-28 weeks gestation were recruited. The Yamax pedometer and Actigraph accelerometer were worn for 5-7 days under free living conditions and thereafter the International Physical Activity Questionnaire (IPAQ) was completed. IPAQ and pedometer estimates of activity were compared to the more robust and accurate accelerometer data. RESULTS: Of 48 women recruited, 30 women completed the study (mean age: 33.6 ± 4.7 years; mean BMI: 31.2 ± 5.1 kg/m(2)) and 18 were excluded (failure to wear [n = 8] and incomplete data [n = 10]). The accelerometer and pedometer correlated significantly on estimation of daily steps (ρ = 0.69, p < 0.01) and had good absolute agreement with low systematic error (mean difference: 505 ± 1498 steps/day). Accelerometer and IPAQ estimates of total, light and moderate Metabolic Equivalent minutes/day (MET min(-1) day(-1)) were not significantly correlated and there was poor absolute agreement. Relative to the accelerometer, the IPAQ under predicted daily total METs (105.76 ± 259.13 min(-1) day(-1)) and light METs (255.55 ± 128.41 min(-1) day(-1)) and over predicted moderate METs (-112.25 ± 166.41 min(-1) day(-1)). CONCLUSION: Compared with the accelerometer, the pedometer appears to provide a reliable estimate of physical activity in pregnancy, whereas the subjective IPAQ measure performed less accurately in this setting. Future research measuring activity in pregnancy should optimally encompass objective measures of physical activity. TRIAL REGISTRATION: Australian New Zealand Clinical Trial Registry Number: ACTRN12608000233325. Registered 7/5/2008.