Optimised acoustic cavitation for the efficient liquid phase exfoliation of graphene.

As there are many different graphene production methods which vary in terms of quality, cost, production rate, yield, scalability, post-processing requirements, flake size distribution, and batch-to-batch repeatability, it has been challenging to develop commercial applications that exploit the extraordinary properties of graphene rather than purely using it as a marketing tool. This thesis reports on the study of ultrasonication, which is an established method to exfoliate graphene in the liquid phase, as well as a pre/post-processing technique in other graphene production methods. Due to a poor understanding of inertial cavitation, which is the fundamental mechanism driving graphene exfoliation during ultrasonication, this production method is commonly characterised by low exfoliation rates, reduced yields and limited scalability/controllability. By optimising the inertial cavitation dose, graphene yields of up to 19 ± 4 % can be exfoliated over just 3 hours of sonication at room temperature. Furthermore, inertial cavitation preferentially exfoliates larger flakes during ultrasonication and the size of the graphene flakes is correlated with, and therefore can be controlled by, inertial cavitation dose. Alongside small-scale exfoliation studies, a scalable graphene sonoreactor proof-of-concept (patent pending), has been designed and tested to generate high exfoliation rates and allow for in-situ size distribution control. More generally it is shown cavitation metrology is critical in developing efficient, controllable and repeatable ultrasonication strategies for the liquid phase exfoliation of 2D nanomaterials, and the many applications and industries in which ultrasonication is employed

Data-driven resilience assessment for transport nfrastructure exposed to multiple hazards

The exposure of critical transport infrastructure to natural hazards and climate change effects has severe consequences on world economies and societies and, thus, safety and resiliency of transport networks are of paramount importance. The currently available frameworks for quantitative risk and resiliencebased design and assessment have been mainly developed for bridges exposed to earthquakes. However, there is an absence of well-informed exposure, vulnerability, functionality and recovery models, which are the main components in the quantification of resilience. The present paper proposes an integrated framework for the data- driven resilience assessment of transport infrastructure exposed to multiple hazards by using multiscale monitoring data, such as terrestrial and airborne data, as well as open-access crowd data and environmental measurements. Monitoring and early warnings are expected to produce accurate and rapidly informed quantitative risk and resilience assessments for transport infrastructure and to enhance asset management. Therefore, this framework aims to facilitate stakeholders’ decision-making for daily and catastrophic events and to support adaptation and preparedness with preventive and/or retrofitting measures against multiple hazards

Numerical simulation on the combustion and NO_X emission characteristics of a turbocharged opposed rotary piston engine fuelled with hydrogen under wide open throttle conditions

Under the stress of environmental pollutions and fossil fuel consumption caused by on-road transport, hybrid vehicles are attracting much attention. Opposed rotary piston (ORP) engines are a promising power source for hybrid vehicles, due to their compact designs and high power density. In this paper, combustion and emission characteristics of a turbocharged ORP engine fuelled with hydrogen were investigated to evaluate the overall performance of this engine. The results indicated that volumetric efficiency of this ORP engine was higher than 89.0% for all the given cases. Peak in-cylinder pressure was in the range of 51.0 ~ 69.0 bar; and 4000 RPM scenario had the maximum value, being benefitted from high intake temperature and pressure, and high volumetric efficiency. Combustion duration of this engine ranged 27 ~ 43° crank angle (CA), and combustion phase happened at 7.5 ~ 13°CA after top dead centre (TDC). Peak nitrogen monoxide (NO) formation rates were corresponding to 5 ~ 13°CA after TDC; accumulated NO decreased slightly after reaching the peak value for low engine speed conditions. Discharge pressure at the start of the exhaust stroke was higher than 6.0 bar, especially for 5000 RPM case whose value was approximately 11.0 bar. This ORP engine presented excellent torque characteristics, and the maximum indicated power density was approximately 104.0 kW·L−1 which was much higher than turbocharged four-stroke reciprocating engines fuelled with gasoline

Resilient Monitoring of the Structural Performance of Reinforced Concrete Bridges using Guided Waves

Structural Health Monitoring of the deflections of a reinforced concrete bridge deck strengthened with Fibre Reinforced Polymers (FRP) or composite materials can help towards obtaining predictions of fail-ures. Data regarding spam deflection, FRP debondings or failures and concrete crack patterns, acquired by guided waves on interfaces of concrete substrate and FRP measures are used in order to represent the damage propagation of the strengthened bridge deck over time. The failure indexes of the interfaces help towards a strategy for maintenance and asset management based on potential risk that derives from structural data. This resilient strategic monitoring of interfaces is a practical, expedient, long-distant tool to estimate the efficiency of the interfaces (Interface Efficiency Indices-InterFeis) and the risk level of the asset with no disruption of traffic or in nonapproachable areas. The monitoring of the time history of data concerning the structural integ-rity, assesses the structural performance of the bridge against critical loads, combined phenomena, extreme events, climate change or other uncertainties of design or of its life-cycle and can be integrated in bridge design guidelines towards infrastructural safety and resilience of the transportation network, saving valuable time and resources

Do Travelers Trust Intelligent Service Robots?

This research investigates travelers' trust in intelligent autonomous technologies based on two studies involving self-driving transportation and robot bartenders. Targeting travelers residing in the United States, online questionnaire was distributed to test the relationships between trusting beliefs in intelligent robots, its antecedents, and its outcomes. The results demonstrate that the cognitive trust formation process holds in situations involving intelligent robots as objects of trust. Trust in intelligent machines is influenced by negative attitude toward technology and propensity to trust technology. Surprisingly, the physical form of robots does not affect trust. Finally, trust leads to adoption intention in both studies. The contribution of this research is in elucidating consumer trust in intelligent robots designed for socially-driven interactions in travel settings

Data-driven resilience assessment for transport infrastructure exposed to multiple hazards by integrating multiscale terrestrial and airborne monitoring systems

The exposure of critical transport infrastructure to natural hazards and climate change effects has severe consequences on world economies and societies and, thus, safety and resiliency of transport networks are of paramount importance. The currently available frameworks for quantitative risk and resiliencebased design and assessment have been mainly developed for bridges exposed to earthquakes. However, there is an absence of well-informed exposure, vulnerability, functionality and recovery models, which are the main components in the quantification of resilience. The present paper proposes an integrated framework for the data- driven resilience assessment of transport infrastructure exposed to multiple hazards by using multiscale monitoring data, such as terrestrial and airborne data, as well as open-access crowd data and environmental measurements. Monitoring and early warnings are expected to produce accurate and rapidly informed quantitative risk and resilience assessments for transport infrastructure and to enhance asset management. Therefore, this framework aims to facilitate stakeholders’ decision-making for daily and catastrophic events and to support adaptation and preparedness with preventive and/or retrofitting measures against multiple hazards

Engineering Ni/SiO₂ catalysts for enhanced CO₂ methanation

The CO₂ methanation is an important process in coal-to-gas, power-to-gas and CO₂ removal for spacecraft. Recently, metal-organic framework (MOF) derivatives have been demonstrated as high-performance catalysts for CO₂ upgrading processes. However, due to the high costs and low stability of MOF derivatives, it still remains challenge for the development of alternative synthesis methods avoiding MOF precursors. In this work, we present the sol-gel method for loading Ni-MOF to silica support in two-steps. Upon modifying the procedure, a more simplified one-step sol-gel method has been developed. Furthermore, the obtained Ni/SiO₂ catalyst still exhibits great catalytic performance with a CO₂ conversion of 77.2% and considerable CH4 selectivity of ~100% during a stability test for 52 h under a low temperature of 310 °C and high GHSV of 20,000 mL·g−1·h−1. Therefore, this work provides a ground-breaking direct strategy for loading MOF derived catalysts, and might shed a light on the preparation of highly dispersed Ni/SiO₂ catalyst

Hotel work-family support policies and employees' needs, concerns and Challenges—The Case of Working Mothers’ maternity leave experience

Based on in-depth interviews conducted with working mothers in the U.S. hotels' industry, the current research developed a process model depicting working mothers’ maternity leave and transition experiences under the current framework of maternity leave and other family and work support policies. Drawing on prior theories and interview findings, our research elucidates the process of how female hospitality professionals cope with challenges and strive to navigate post-maternity life while re-adapting to their professional roles and work-life balance. The model developed from our interview findings brings to light the pivotal role maternity leave and other family support policies play in enabling or inhibiting hospitality working mothers to re-adapt during the post-maternity life stage. Based on such findings, we provide discussions on the theoretical and managerial implications as well as future research agendas related to this topic

Climate change implications of gaming products and services

There is increasing concern over the climate change impact of games consoles. There is, however, little research on the life cycle carbon impact of consoles and existing research (the majority of which is focused on usage) is outdated. This study uses life cycle assessment (LCA) methodology to compare the climate change impact of different console-based gaming methods (i.e. games played from a disc, a down-loaded file, or streamed from the cloud). Console usage and Internet usage were identified as life cycle stages where data were unknown or uncertain. Two studies to improve the understanding of these areas were undertaken in this research and used to complete a cradle-to-grave carbon footprint study of gaming (compared using a functional unit of carbon equivalent emissions per hour of gameplay). Results estimated that, for average cases, download is the lowest carbon method of gaming at 0.047 kgCO2e/h, followed by disc at 0.055 kgCO2e/h. Cloud gaming has higher estimated carbon emissions at 0.149 kgCO2e/h, largely due to the additional energy consumed during use in the Internet, gaming servers, and home router equip-ment. These findings only represent average cases and the size of game files and length of gameplay time were found to be key variables significantly impacting the results. For example, for games played for under 8 hours, cloud gaming was found to have lower carbon emissions than downloads (up to 24 hours when compared to disc). In order to analyse these results, a new method for identifying which gaming method has the lowest carbon emissions with variation in both file size and gameplay time was developed. This has allowed for the identification of the thresholds in which different gaming methods have lowest carbon emissions, for any given range of input variables. The carbon emissions of gaming are highly dependent on consumer behav-iour (which game method is used, how long games are played for, and the type and size of those games) and therefore LCA based on average assumptions for these variables has limited application

Antecedents and Outcomes of Emotional Labour in Hospitality and Tourism: A Meta-Analysis

This paper meta-analytically investigates a theoretical framework of emotional labour and its antecedents and outcomes in the hospitality and tourism literature with 57 correlation matrices from published journal papers. Adopting the psychometric meta-analytical methods and meta-structural equation modelling (meta-SEM) methods, the study finds that emotional labour is related to antecedents including personality, emotional intelligence, customer orientation, social support and display rules, as well as related to attitudinal, behavioural, and customer-related outcomes. In addition, strain mediates the relations between emotional labour and its outcomes. This paper is the first meta-analysis on the relations between emotional labour and the antecedents and outcomes in hospitality and tourism management