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Integrating remote sensing and geospatial big data for urban land use mapping: a review
Get PDFRemote Sensing (RS) has been used in urban mapping for a long time; however, the complexity and diversity of urban functional patterns are difficult to be captured by RS only. Emerging Geospatial Big Data (GBD) are considered as the supplement to RS data, and help to contribute to our understanding of urban lands from physical aspects (i.e., urban land cover) to socioeconomic aspects (i.e., urban land use). Integrating RS and GBD could be an effective way to combine physical and socioeconomic aspects with great potential for high-quality urban land use classification. In this study, we reviewed the existing literature and focused on the state-of-the-art and perspective of the urban land use categorization by integrating RS and GBD. Specifically, the commonly used RS features (e.g., spectral, textural, temporal, and spatial features) and GBD features (e.g., spatial, temporal, semantic, and sequence features) were identified and analyzed in urban land use classification. The integration strategies for RS and GBD features were categorized into feature-level integration (FI) and decision-level integration (DI). To be more specific, the FI method integrates the RS and GBD features and classifies urban land use types using the integrated feature sets; the DI method processes RS and GBD independently and then merges the classification results based on decision rules. We also discussed other critical issues, including analysis unit setting, parcel segmentation, parcel labeling of land use types, and data integration. Our findings provide a retrospect of different features from RS and GBD, strategies of RS and GBD integration, and their pros and cons, which could help to define the framework for future urban land use mapping and better support urban planning, urban environment assessment, urban disaster monitoring and urban traffic analysis
Rheological study and printability investigation of titania inks for direct ink writing process
Get PDFTitanium dioxide is widely used in numerous industries and with the newly developed titanium manufacturing technique, referred to as the Near-net-shape Electrochemical Metallisation (NEM) Process, the rapid and precise production of titanium dioxide components is highly sought-after. This manuscript presents the rheological investigation and extrudability tests of titania inks, to establish the improved production of titanium dioxide components via Direct Ink Writing. The extrudability tests indicated that despite an unfavourable increase in viscosity during the high shear rates (dilatancy peaks), the best-performing ink had a weight ratio of 1:0.8:0.1 TiO2:H2O:PEG, and the dilatancy peaks were smoothed out with the addition of 0.1 wt ratio of oleic acid to the ink, dramatically improving the quality of the product. To further improve the green bodies a new printing approach was also introduced, removing the necessity for specialised printing bed, by printing a removable support into the green body and allowing for drying without any cracks and warping
Surface integrity in metal machining - Part II: Functional performance
Get PDFMaterial removal operations play a pivotal role in the manufacture of key components, required for engineering systems to operate safely and efficiently under ever more advanced functional requirements and over extended life cycles. To further step up the loading capability of machined parts, fundamental understanding of how of machining-induced features can influence the performance of advanced materials under complex service conditions is necessary over finer temporal and spatial scales. As discussed in Part I of this review, when engineering surfaces are generated by material removal processes, a wide range of physical mechanisms (e.g. mechanical, thermal, chemical and their combinations) drive the characteristics of workpiece surface integrity. In Part II of this review, the interplay between the metallurgical and micro-mechanical condition induced by material removal processes and their in-service response will be thoroughly explored, by a critical analysis of the state-of-the-art in the field. Specifically, attention is focused on recent advances made towards the understanding of the mechanisms determining the resistance of machined surface to fatigue crack nucleation (Section 2), corrosion and stress-corrosion cracking (Section 3), and wear (Section 4). Furthermore, the impact of relevant post-machining treatments on the in-service behaviour of machined surfaces is analysed, and the possible strategies for the enhancement of the functional performance of machined surfaces are presented (Section 5). Finally, the current research gaps and the prospective challenges in understanding the in-service behaviour of machined surfaces are critically discussed, providing an interpretation of the possible directions of future scientific development of this field
Influence of environmental values on the typhoon risk perceptions of high school students: a case study in Ningbo, China
Get PDFTyphoon is a severe natural disaster that would bring huge economic losses and casualties to society. High school students are more vulnerable compared with adults during typhoon. Improving risk perception of typhoon can assist high school students effectively respond to typhoon and reduce related losses. Environmental values play an important role in human’s perceptions and actions. Although typhoon is related with environment, few studies have investigated the influence of environmental values on typhoon risk perception of high school students. This study investigates typhoon risk perception of high school students in Ningbo, China, and further analyzes the influence of environmental values on the perception with structural equations model. Results reveal that environmental values have significantly positive impacts on the typhoon risk perception. The findings also demonstrate that disaster threats and the disaster management ability of the government have significant positive impacts on the typhoon risk perception. This study proposes suggestions and measures to improve the typhoon risk perception among high school students and provides a reference for typhoon prevention and reduction education in China
A genetic optimization resampling based particle filtering algorithm for indoor target tracking
Get PDFIn indoor target tracking based on wireless sensor networks, the particle filtering algorithm
has been widely used because of its outstanding performance in coping with highly non-linear
problems. Resampling is generally required to address the inherent particle degeneracy problem in
the particle filter. However, traditional resampling methods cause the problem of particle impoverishment.
This problem degrades positioning accuracy and robustness and sometimes may even
result in filtering divergence and tracking failure. In order to mitigate the particle impoverishment
and improve positioning accuracy, this paper proposes an improved genetic optimization based
resampling method. This resampling method optimizes the distribution of resampled particles by
the five operators, i.e., selection, roughening, classification, crossover, and mutation. The proposed
resampling method is then integrated into the particle filtering framework to form a genetic optimization
resampling based particle filtering (GORPF) algorithm. The performance of the GORPF
algorithm is tested by a one-dimensional tracking simulation and a three-dimensional indoor tracking
experiment. Both test results show that with the aid of the proposed resampling method, the GORPF
has better robustness against particle impoverishment and achieves better positioning accuracy than
several existing target tracking algorithms. Moreover, the GORPF algorithm owns an affordable
computation load for real-time applications
A new approach to high value conversion of phosphogypsum from phosphate rock to catalyst for glycerol carbonate synthesis
Get PDFThis paper reports a new process of using phosphate rock as the precursor to prepare a high performance catalyst for glycerol carbonate synthesis. The reported technical route will create a new opportunity to synthesis the active chemical intermediate that can be used for energy generation. Three important preparation parameters were investigated to find out both singular and binary effects upon the statistical significances of prepared glycerol carbonate conversion using response surface methodology (RSM) approach. The optimal condition with the goal of maximizing the glycerol carbonate was set and achieved. The obtained catalyst prepared at the optimal condition was characterized. The proposed process offers a rosy prospect for high value conversion of colossal by-product phosphogypsum generated from phosphorous acid manufacturing industry
Chinese students and personal tutorials in a British overseas campus: the strategic choices of emerging adults
Get PDFPersonal tutorials are an essential feature of student support in British universities, therefore they are duplicated on British overseas campuses. It appears that Chinese students are reluctant to seek help when they experience personal difficulties that affect their engagement with learning and their academic performance. Limited literature explores this phenomenon with relevant studies only focusing on Chinese students’ experiences abroad. Furthermore, these studies mainly refer to cultural factors related to traditional Confucianism to explain why these students do not engage with support structures.
Drawing on the theory of Emerging Adulthood, this paper analyses the experiences of students on a Chinese branch campus of a British university. A mixed methods research approach was considered the most appropriate means of engaging with the participants; a quantitative study was used in an exploratory fashion to provide unbiased insight into student opinion and experience, and a qualitative content analysis was used to analyse participants’ comments in the open field questions.
The findings reveal an alternative portrayal of the “Chinese Personal Tutee”, distant from the traditional Confucian model still predominantly used as an analytical tool in research on Chinese youth. Chinese students on an international campus strategically select their sources of help and prefer to build symmetrical relationships with personal tutors based on personal goals rather than asymmetrical relationships based on ‘care’ provided by adults. Consequently, ‘transnational’ personal tutorial systems pursuing Chinese students’ successful engagement ought to be conceptualised by considering their emerging adulthoods and by respecting their sense of agency
Recovery of carbon fibre from waste prepreg via microwave pyrolysis
Get PDFManagement of waste from carbon fibre composites has become a significant societal issue as the application of composite grows across many industries. In this study, carbon fibres (CF) were successfully recovered from cured carbon fibre/epoxy (CF/EP) prepreg under microwave pyrolysis at 450, 550 and 650◦ C followed by oxidation of any residual char. The recovered fibres were investigated for their tensile properties, surface morphologies and the elements/functional groups presented on the surface. The chemical compositions of gaseous and oil pyrolysis products were also analysed. The microwave pyrolysis effectively pyrolyzed the epoxy (EP) resin. Char residue remained on the fibre surface and the amount of char reduced as the pyrolysis temperature increased. Compared to virgin fibres, the recovered fibre suffered from a strength reduction by less than 20%, and this reduction could be mitigated by reducing the pyrolysis temperature. The surface of recovered fibre remained clean and smooth, while the profile of elements and functional groups at the surface were similar to those of virgin fibres. The main gaseous products were CO, H2, CO2 and CH4, whilst the liquid product stream included phenolic and aromatic compounds
Revisiting the built environment: 10 potential development changes and paradigm shifts due to COVID-19
Get PDFThis study explores potential development and paradigm shifts in two main sectors of construction and the built environment due to COVID-19. These development changes are discussed based on evidence from previous pandemics, current and expected impacts on both industries, and how they are likely to shape the next policy, practices, and perspectives. By assessing the primary areas of both sectors through an expert-led analysis, this study suggests 10 potential development changes that we could expect in the post-COVID time. These potential changes are discussed as possible new practices, empowered regulations, or adaptive measures; and eventually towards paradigm shifts. A total of 50 participants contributed to the selection, identification, and assessment of these potential changes. The findings from this study feed into the assessment of ongoing and forthcoming changes as a result of the current pandemic, specifically on two sectors of ‘construction’ and ‘the built environment’. These will include paradigm shifts in architecture practices, civil engineering practices, project management, and urbanism. Some of the suggestions in this study may harness shared practices, and some may simply develop into new forms of development practices in both sectors
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