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Editorial: ‘One City, Many Tales’: COVID-19, perception, and the importance of contextualization
Full text linkThis introduction to the special issue summarizes the contributions from the five leading scholars in the field—their contribution to the conceptualization of such concepts as soft power, sharp power, image shaping, image reception, as well as methodological approaches. It highlights the importance of contextualizing their findings for a full understanding of the image of China in the media narratives examined. In doing so, the Introduction lays foundation for further investigations on the relationship between media coverage of health crisis and image construction as the world continues to fight against the virus
Investigation of fire protection performance and mechanical properties of thin-ply bio-epoxy composites
Full text linkHybrid composites composed of bio-based thin-ply carbon fibre prepreg and flameretardant mats (E20MI) have been produced to investigate the effects of laminate design on their fire protection performance and mechanical properties. These flame-retardant mats rely primarily on expandable graphite, mineral wool and glass fibre to generate a thermal barrier that releases incombustible gasses and protects the underlying material. A flame retardant (FR) mat is incorporated into the carbon fibre bio-based polymeric laminate and the relationship between the fire protection properties and mechanical properties is investigated. Hybrid composite laminates containing FR mats either at the exterior surfaces or embedded 2-plies deep have been tested by the limited oxygen index (LOI), vertical burning test and cone calorimetry. The addition of the surface or embedded E20MI flame retardant mats resulted in an improvement from a base line of 33.1% to 47.5% and 45.8%, respectively. All laminates passed the vertical burning test standard of FAR 25.853. Cone calorimeter data revealed an increase in the time to ignition (TTI) for the hybrid composites containing the FR mat, while the peak of heat release rate (PHRR) and total heat release (TTR) were greatly reduced. Furthermore, the maximum average rate of heat emission (MARHE) values indicated that both composites with flame retardant mats had achieved the requirements of EN 45545-2. However, the tensile strengths of laminates with surface or embedded flame-retardant mats were reduced from 1215.94 MPa to 885.92 MPa and 975.48 MPa, respectively. Similarly, the bending strength was reduced from 836.41 MPa to 767.03 MPa and 811.36 MPa, respectively
Balancing performance and effort in deep learning via the fusion of real and synthetic cultural heritage photogrammetry training sets
Full text linkCultural heritage presents both challenges and opportunities for the adoption and use of deep learning in 3D digitisation and digitalisation endeavours. While unique features in terms of the identity of artefacts are important factors that can contribute to training performance in deep learning algorithms, challenges remain with regards to the laborious efforts in our ability to obtain adequate datasets that would both provide for the diversity of imageries, and across the range of multi-facet images for each object in use. One solution, and perhaps an important step towards the broader applicability of deep learning in the field of digital heritage is the fusion of both real and virtual datasets via the automated creation of diverse datasets that covers multiple views of individual objects over a range of diversified objects in the training pipeline, all facilitated by closerange photogrammetry generated 3D objects. The question is the ratio of the combination of real and synthetic imageries in which an inflection point occurs whereby performance is reduced. In this research, we attempt to reduce the need for manual labour by leveraging the flexibility provided for in automated data generation via close-range photogrammetry models with a view for future deep learning facilitated cultural heritage activities, such as digital identification, sorting, asset management and categorisation
Do Chinese firms benefit from government ownership following cross-border acquisitions?
Full text linkChinese firms’ increasing cross-border acquisitions (CBAs) in recent years seem to challenge the explanatory power of received theories of multinational enterprise (MNE) due to their relatively unique characteristics and the active role of the Chinese government. In this study, we seek to revisit and contextualize the OLI paradigm in conjunction with the institution-based view and examine how Chinese firms’ post-CBA long term performance is associated with government ownership. Our study shows that Chinese firms with more government ownership demonstrate better post-CBA long term performance. However, the above relationship is differentially moderated by such firm-level boundary conditions as political connections and financial slack, and the country-level institutional boundary conditions (i.e., the host country formal institutions and the home-host country cultural distance). We discuss our findings in detail and explore theoretical and practical implications for both Chinese firms and other emerging economy (EE) firms
Optimal cut-Off values of visceral fat area for predicting metabolic syndrome among type 2 diabetes patients in Ningbo, China
Full text linkObjective: To examine the optimal cut-off values of visceral fat area (VFA) for predicting metabolic syndrome (MetS) among type 2 diabetes (T2D) patients in Ningbo China. Methods: A total of 1017 subjects were selected from T2D patients who accepted standardized management by the National Standardized Metabolic Disease Management Center at Ningbo First Hospital from March 2018 to January 2020. Demography and medical information were collected through questionnaires. Regional adiposity was examined by a visceral fat analyzer using the dual bioelectrical impedance method. Results: Overall, 769 (75.6%) T2D patients were defined to have MetS. Patients with MetS had higher anthropometric values and biomarkers, compared to those without MetS. VFA was significantly correlated with risk factors of MetS. Further logistic regression models showed that VFA was significantly associated with MetS in men (OR=1.02) and in women (OR=1.03) (P<0.001 for both genders) after controlling for related factors. Receiver-operating characteristic curve analysis demonstrated that the optimal cut-off values of VFA were 84.7 cm2 for men and 81.1 cm2 for women to predict MetS in T2D patients. Conclusion: VFA was associated with MetS and could be an independent predictor of MetS in T2D patients. Clinical Trial Registration: Www.ClinicalTrials.gov, number: NCT03811470
Novel two-stage fluidized bed-plasma gasification integrated with SOFC and chemical looping combustion for the high efficiency power generation from MSW: a thermodynamic investigation
Full text linkA novel municipal solid waste (MSW)-based power generation system was proposed in this study, which consists of a bubbling fluidized-bed (BFB)-plasma gasification unit, a high-temperature solid oxide fuel cell (SOFC), a chemical looping combustion (CLC) unit and a heat recovery unit. Process simulation was conducted using Aspen PlusTM and validated by literature data. The energetic and exergetic assessment of the proposed system showed that the net electrical efficiency and exergy efficiency reached 40.9 % and 36.1 %, respectively with 99.3 % of carbon dioxide being captured. It was found that the largest exergy destruction took place in the BFB-Plasma gasification unit (476.5 kW) and accounted for 33.6 % of the total exergy destruction, which is followed by the SOFC (219.1 kW) and then CLC (208.6 kW). Moreover, the effects of key variables, such as steam to fuel ratio (STFR), fuel utilization factor (Uf), current density and air reactor operating temperature, etc., on system performance were carried out and revealed that the system efficiency could be optimized under STFR = 0.5, Uf = 0.8 and air reactor operating temperature of 1000 ºC. Furthermore, the proposed process demonstrated more than 14% improvement in net electrical efficiency in comparison with other MSW incineration and/or gasification to power processes
Cu-ZrO2 catalysts with highly dispersed Cu nanoclusters derived from ZrO2@ HKUST-1 composites for the enhanced CO2 hydrogenation to methanol
Full text linkIn this study, a series of Cu-ZrO2 catalysts with highly dispersed Cu nanoclusters were prepared via the calcination and reduction of ZrO2@HKUST-1 precursors. These catalysts demonstrated an outstanding selectivity in the yield of methanol during CO2 hydrogenation. The space-time yield (STY) of methanol is 5.2 times higher than that of those similar catalysts reported by other researchers, which were prepared using conventional method and tested under the same testing conditions. Density functional theory (DFT) study revealed that the activation of CO2 occurs at the Cu-ZrO2 interfaces and facilitates the hydrogenation of CO2 to methanol. It is concluded that the controlled formation of the highly dispersed Cu nanoclusters not only provides a large number of highly efficient active centers for CO2 hydrogenation, but also leads the generation of more Cu-ZrO2 interfaces. These two effects contribute to the superior catalytic performance of the nano Cu-ZrO2 catalyst in CO2 hydrogenation
Machining-induced thermal damage in cortical bone: necrosis and micro-mechanical integrity
Full text linkIn bone cutting, the tissue is exposed to necrosis due to temperature elevation, which can significantly influence postoperative results in orthopaedic surgeries. This damage is usually revealed through histological analysis to show the necrotic extent; however, this technique does not capture mechanical damage, which is essential for a full material integrity assessment. Here, with micro-mechanics, it is demonstrated that machining-induced damage in bone extends beyond the necrotic region. Drilling with different conditions was performed on ex-vivo bovine cortical bone, inducing different damage degrees. Micro-pillar compression tests were performed in the machined sub-surface to identify changes in properties and failure modes caused by drilling. It was revealed that at high cutting temperatures, the bone near the machined surface suffers from lower modulus (−42%), strength (−41%) and brittle behaviour, whereas the bulk bone remains undamaged with pristine properties and ductile behaviour. Histology was also performed to evaluate necrosis and, surprisingly, it was found that the brittle and weaker bone layer is more than three times larger when compared to the necrotic layer, clearly showing that the drilling thermo-mechanical effect could affect not only biologically, but also micro-mechanically. Consequently, these results reveal another kind of bone damage that has so far been neglected
Fast and simple tuning rules of synchronous reference frame proportional-integral current controller
Full text linkSynchronous reference frame proportional-integral (PI) current controller (CC) is considered the most well-established solution for the current regulation in electrical drives. However, the gain selection of the PI CC is still regarded to be poorly reported, particularly in relation to the effect of the inevitable execution time taken by the controller and inverter. Mostly, tuning process of PI CC is done by trial and error or using simple rules based on pole zero cancelation and pole placement methods which ignore time delays through the controller and inverter. Hence, PI CC delivers significantly different performance compared to the expected one during the digital implementation, especially if high bandwidth or low ratio between the switching and operational frequency are required. Therefore, this paper firstly addresses and analyses the common tuning rules of PI CC which ignore the existence of time delays followed by a rigorous analysis for PI CCs’ robustness to the influence of computational and modulation delays. Based on this analysis, generic recommendations have been proposed to select the PI CCs’ gains as a function of the electrical drive switching frequency considering the delay effect. A set of simple, generic, and fast tuning rules were derived that guarantee fast dynamic performance with reasonable stability margins. Moreover, the effects of model uncertainties on these developed rules have been analyzed and reported. Comprehensive experimental results are provided to prove the key analytical results of this study and to validate the proposed design recommendations
The foreign direct investment-environment nexus: does emission disaggregation matter?
Full text linkThis paper examines the effect of foreign direct investment (FDI) on CO2 emissions by using disaggregated emissions data; territorial-based and consumption-based emissions. FDI is measured in three ways; inflow, net inflow, and stock. Employing data over the period 1995–2014 and a number of estimators, the results indicate FDI (whether measured as inflow or net inflow) has negative impact on emissions (irrespective of the measurement). However, the impact is generally found to be greater for the territorial-based emissions. The results of the FDI flow variables largely support the pollution halo hypothesis. Thus, the results are supportive of the robust effect of FDI’s positive effect. Regarding the stock measure, the negative effect of FDI is only found for the territorial-based CO2 emissions. Since the territorial-based emissions capture emissions in the domestic economy only, it is not surprising that the plausible efficiency of FDI stock is found to reduce these emissions rather the consumption-based. FDI stock is now considered part of the local economy. The results of the paper are largely not parallel with previous studies that did not disaggregate CO2 emissions. This we believe is an indication that the measure of CO2 matters for the analyses of the FDI-emissions nexus
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