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Fast frequency and phase lock of grid-connected TGS based on FIR filter
Get PDFThe thermoelectric generation system (TGS) has many advantages such as clean, no mechanical vibration and high reliability. When TGS is connected to the power grid, it requires that the frequency and phase are same as the power grid. It will take a number of working periods for the response time under the traditional method. A frequency and phase lock method with FIR filter will be introduced in the paper. It is based on the Capture and EPWM module of TMS320F28335. The phase lock can be carried out in one period. And the working frequency of TMS320F28335 is 150MHZ. Therefore, the speed of the whole operation is fast. The experimental results show that the method is feasible
Modeling and stability enhancement of a permanent magnet synchronous generator based DC system for More Electric Aircraft
Get PDFThe concept of the More Electric Aircraft (MEA) is aimed at electrifying the mechanical, hydraulic, and pneumatic subsystems on aircraft. With increasing usage of power electronics, the architecture of on-board electrical power distribution systems (EPDS) becomes more complicated. Therefore, it is necessary to analyze the stability of the system. This paper firstly presents and validates an impedance model of a permanent magnet synchronous generator (PMSG) as a source and dual active bridge (DAB) converter as a load. These models are used for the stability analysis of a simple DC power system. In addition, two new control strategies are proposed to enhance the stability of the system. The stabilization effects of the new control strategies are verified with experimental results
Linking theory with practice on an MA TESOL programme
Get PDFWhile there can be little doubt that taking part in an MA TESOL programme is likely to expose the participants to significant amounts of ELT theory, the learning that ultimately results from this may not always convert very well into ELT practice. This is particularly true for those who join a Masters’ programme with limited previous teaching experience, especially if the programme itself lacks a practical teaching component. In such cases, unless students are encouraged to make their own explicit links between theory and practice, the didactic transmission mode of delivery commonly found in university lectures may further conspire to make the gap even wider. This paper describes an attempt to move beyond such a traditional MA lecture format and discusses an alternative pedagogical means of linking theory with practice on an MA TESOL programme delivered at an EMI branch campus in China
Political and technological changes, glass provenance and a new glass production model along the west Asian Silk Road
Get PDFWe consider some of the social, political, and economic factors that led to the mass production of glass, especially during the ‘Abbasid Caliphate. Scientific analysis is used to investigate glass production, and consider how these factors can be used to interpret the results having defined glass technology and its provenance for glass derived from a 2000-mile area of the Middle East, between Egypt and northern Iran. The results show evidence of production in the Levant, northern Syria, and Iran/Iraq as well as sub-zones associated with cosmopolitan urban centers in Cairo, Beirut, Damascus, Al-Raqqa, Samarra, Ctesiphon, and Nishapur and specialized production of specific vessel types. It is shown that glass trade occurred between these hubs with limited recycling within a decentralized production system forming part of the ‘Abbasid economic boom
Extraction of power lines and pylons from LiDAR point clouds using a GCN-based method
Get PDFThe routine power line inspection is critical to maintain the reliability, availability, and sustainability of electricity supply. As a key part of inspection, power lines and pylons extraction is essential for resource management and power corridor safety, especially in the mountain regions. In this paper, we proposed a deep learning based method to extract power lines and pylons using ALS point clouds. First, a structure information preserved module is designed to mine the relationship of local neighborhood points. Then, a graph convolutional network (GCN) is used as basic module to extract point features. Finally, three categories, power lines, pylons and other objects are segmented from input point clouds. In addition, we provide an effective data enhancement strategy to generate enough samples to train the proposed model. We evaluated our method using a dataset acquired by our ALS scanning system. Experimental results demonstrate that our method is superior to the state-of-the-art methods on descriptiveness and efficiency. The overall accuracy and mean time are 99.1% and 9.3 seconds, respectively
Health knowledge about smoking, role of doctors, and self-perceived health: a cross-sectional study on smokers’ intentions to quit
Get PDFLimited empirical work has been done to compare the effects that health knowledge and advice from doctors have on smokers’ intentions to quit. This paper examines the association of smokers’ intentions to quit with health knowledge, advice from doctors, and self-perceived health. A sample of 2509 smokers aged 15–69 years old in Ningbo was used from China’s National Health Literacy Surveillance survey, conducted in 2018 and 2019. Respondents were asked whether they agree smoking causes stroke, heart attack, lung cancer; and heart diseases in adults, lung illnesses in children, and lung cancer in adults, by secondhand smoke, respectively. Using the logistic model, we found that knowing that smoking causes stroke and lung cancer more than doubles the odds of one’s intention to quit (OR = 2.705, p < 0.01), the effect of which is much greater than knowing that smoking causes lung cancer only (OR = 1.795, p < 0.01). Doctors’ advice to quit is more important than health knowledge, in terms of predicting smokers’ past cessation behaviours. In addition, smokers’ self-perceived health is negatively associated with their decisions to quit. This paper highlights that more resources should be directed towards training health care providers to advise smokers to quit, which might be more effective than health education alone
Big data challenges in overcoming China’s water and air pollution: relevant data and indicators
Get PDFBig data are potentially useful for environmental management planning and actions that can be directed toward pollu-tion control. China is using big data approaches to help reduce its current levels of pollution. However, also needed are better environmental indicators, measurement technologies, data management and reporting, and adaptive manage-ment and enforcement. Based on continental-extent monitoring and assessment programs in Europe and the USA, we recommend three major programmatic changes for China. (1) Establish long-term systemic environmental and human health objectives and indicators. (2) Adopt national standard methods for survey designs, sampling and analytical pro-tocols, statistical analyses, and collaborative sampling programs. (3) Provide a transparent process for reporting and correcting data errors
Impact of CO2 activation on the structure, composition, and performance of Sb/C nanohybrid lithium/sodium-ion battery anodes
Get PDFAntimony (Sb) has been regarded as one of the most promising anode materials for both lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) and attracted much attention in recent years. Alleviating the volumetric effect of Sb during charge and discharge processes is the key point to promote Sb-based anodes to practical applications. Carbon dioxide (CO2) activation is applied to improve the rate performance of the Sb/C nanohybrid anodes caused by the limited diffusion of Li/Na ions in excessive carbon components. Based on the reaction between CO2 and carbon, CO2 activation can not only reduce the excess carbon content of the Sb/C nanohybrid but also create abundant mesopores inside the carbon matrix, leading to enhanced rate performance. Additionally, CO2 activation is also a fast and facile method, which is perfectly suitable for the fabrication system we proposed. As a result, after CO2 activation, the average capacity of the Sb/C nanohybrid LIB anode is increased by about 18 times (from 9 mA h g−1 to 160 mA h g−1) at a current density of 3300 mA g−1. Moreover, the application of the CO2-activated Sb/C nanohybrid as a SIB anode is also demonstrated, showing good electrochemical performance
Probing cultural differences in product design and consumer evaluation using repertory grid analysis
Get PDFCulture plays an essential role in the success of product design, especially in the age of a global economy where there is a high probability of discrepancy between the designer's intention and the consumer's response. However, the role of culture is often challenging to identify and measure. In the current paper, we employed Repertory Grids (RG) to investigate differences in UK and Chinese participants' evaluations of designs, which were themselves from both UK and Chinese students. The techniques of Honey's Content Analysis (HCA) and Principal Components Analysis (PCA) were applied to integrate the analysis of both the collected qualitative and quantitative data. The results show that the two groups tended to focus on a similar range of design aspects (i.e. aesthetics, form/shape, usability, creativity, and functionality), but apply different criteria in evaluating such aspects.The UK and Chinese designs were found to be distinctive from each other and tended to appeal more to the people from the same cultural background. The findings reveal the interplay between culture and design and underline the importance of integrating culture into design education
Public-health-driven microfluidic technologies: from separation to detection
Get PDFSeparation and detection are ubiquitous in our daily life and they are two of the most important steps toward practical biomedical diagnostics and industrial applications. A deep understanding of working principles and examples of separation and detection enables a plethora of applications from blood test and air/water quality monitoring to food safety and biosecurity; none of which are irrelevant to public health. Microfluidics can separate and detect various particles/aerosols as well as cells/viruses in a cost-effective and easy-to-operate manner. There are a number of papers reviewing microfluidic separation and detection, but to the best of our knowledge, the two topics are normally reviewed separately. In fact, these two themes are closely related with each other from the perspectives of public health: understanding separation or sorting technique will lead to the development of new detection methods, thereby providing new paths to guide the separation routes. Therefore, the purpose of this review paper is two-fold: reporting the latest developments in the application of microfluidics for separation and outlining the emerging research in microfluidic detection. The dominating microfluidics-based passive separation methods and detection methods are discussed, along with the future perspectives and challenges being discussed. Our work inspires novel development of separation and detection methods for the benefits of public health
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