MRC Laboratory of Molecular Biology
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Improving thermal comfort in refugee shelters in desert environments
No full textEmpirical studies have shown that internal temperatures in refugee shelters are impacting morbidity, and possibly mortality. Within a displacement setting, solutions are often constrained by time, cost, material availability and local requirements. This often results in “deemed suitable” designs rather than optimal solutions. In this study, we ask which route is most appropriate to optimise thermal comfort: prototyping design improvements, which requires time but may not require significant domain expertise, or thermal modelling, which can be quickly carried out if there is expertise. In a unique experiment, a laboratory of 12 shelters, built in a desert refugee camp, was adapted by the refugees themselves with variants to improve thermal comfort. Thermal modelling and field results were compared. Prototyping, though requiring additional time, was found to offer several advantages over modelling: (a) it gives a more visceral answer, in that the agency staff and refugees can experience the improvement - this could be important as most people might not be able to relate to a numeric statement about temperature; (b) the difficulty of constructing variants can be compared; (c) the financial and time costs are identified accurately. This suggests that such prototyping experiments have great utility, conferring substantial advantages over computer-based modelling. Significantly, we show that simple adaptations can improve conditions by up to 6 °C, and that the skills exist in camps to complete such improvements
How do technology strategies affect the catch-up progress of high-tech latecomers? Evidence from two Chinese research-institute-transformed telecommunications firms
No full textThis paper explores the effects of technology strategies (TSs) on latecomer firms’ catch-up progress. Based on the proposed typology, this work investigates catch-up theories by (1) comparing performance among different TS types and analyzing the causes of these differences and (2) exploring the impact of TS implementation during earlier phases on the firms’ later development. Findings reveal the following trends: (1) a progressive TS is more likely to achieve market success compared to a more radical TS when a firm's internal capabilities are inadequate and external ecosystem are immature; (2) the implementation of TS in earlier phases substantially influences later TS formation; (3) a self-developing TS is more likely to enhance catch-up performance in the long run compared to a co-developing TS; and (4) organizational transformation plays an essential supporting role in strategy implementation
Quantum networks in the UK
No full textWe describe recent progress in quantum secured optical networks in the UK. The Cambridge Quantum Network has been operating for several years with 3 nodes separated by between 5-10 km of installed fibre. All links are secured by QKD systems operating with secure key rates in excess of 1 Mb/s, the highest recorded long term key rates in a deployed network. The network operates in the presence of 100Gb/s classical traffic with no significant reduction of secure key generation rate. In addition, the Bristol Quantum Network has four nodes 1-3km apart connected in a mesh protected by two pairs of QKD systems. The network is designed to be very dynamic, switching both QKD and WDM classical traffic to enable rapid reconfiguration and is used as a testbed for QKD protected dynamic applications. The two metropolitan networks are being connected by a 410 km QKD link, with 4 spans, the longest of which operates over 129km of fibre with an attenuation of 28dB achieving secure key rates of 2.7kb/s, the longest and highest loss QKD field trial to date. A 120km extension of the UK quantum network from Cambridge to BT Labs, Adastral Park operates with fully commercially available components and is an important testbed comprising 3 intermediate nodes and operates with 5 x 100Gb/s classical channels. This helps determine how to proceed with a large-scale commercial deployment of QKD
A computationally efficient framework for modelling energy consumption of ice and electric vehicles
No full textThis article proposes a novel framework to develop computationally efficient energy consumption models of electric and internal combustion engine vehicles. The number of calculations in a conventional energy consumption model prevents the model’s usage in applications where time is limited. As many fleet operators around the world are in the process of transitioning towards electric vehicles, a computationally efficient energy consumption model will be valuable to analyse the vehicles they trial. A vehicle’s energy consumption depends on the vehicle characteristics, drive cycles and vehicle mass. The proposed modelling framework considers these aspects, is computationally efficient, and can be run using open source software packages. The framework is validated through two use cases: an electric bus and a diesel truck. The model error’s standard deviation is less 5% and its mean is less than 2%. The proposed model’s mean computation time is less than 20 ms, which is two orders of magnitude lower than that of the baseline model. Finally, a case study was performed to illustrate the usefulness of the modelling framework for a fleet operator
Analysis of the stress distribution in a laminar direct simple shear device and implications for test data interpretation
No full textDirect simple shear (DSS) testing allows observation of load-deformation response under rotation of the major principal stress plane, which is descriptive of many actual field problems. While the simplicity of the test configuration makes its use popular in research and industry, key uncertainties still remain regarding the interpretation of the laboratory data. This study uses laboratory validated discrete element method (DEM) models to examine the stress transmission in laminar-type direct simple shear devices under drained constant effective stress conditions. The DEM models (comprised of spheres) closely replicate physical specimens of precision chrome steel ball bearings for which the properties (e.g., shape, surface friction, and stiffness) were measured directly. The DEM models were also validated using experimental tests, so that conclusions regarding the system response can be derived with confidence from the available DEM data. The testing program included both loose and dense specimens, allowing for a comparison of the influence of density on stress state which has not been examined in previous simple shear DEM studies. Differences were observed between vertical effective stresses and shear stresses derived from boundary measurements (as commonly carried out in experimental programs) and those derived from force measurements within the DEM specimens. The failure state of the material in simple shear was also examined through Mohr’s circles of stress. The evolution of stresses on both the horizontally and vertically oriented planes were considered so that established methods of direct simple shear interpretation could be critically assessed. For the loose specimens, the angle of shearing resistance can be confidently estimated considering the maximum shear stress acting on the horizontal plane, which is easily inferred from measurements of the shear force during the physical test. This was true considering both internal and boundary calculated stresses. This approach, however, is inaccurate for the dense specimens. Analysis of the particle-scale kinematics of the response illustrates that the deformation field within the central portion of the specimen is in simple shear, although the magnitude of this shearing was significantly larger than what was measured on the boundary. This study and the conclusions derived focus on smooth spherical particle specimens; the objective was to examine the stress distribution within DSS devices and the implications for test interpretation using DEM models that more closely matched the physical laboratory specimens tested than in previous studies. When considered alongside the existing studies, the findings show that there is no broad conclusion that can be applied for all materials and all conditions in simple shear and that interpretation should be carefully tied to the physical conditions simulated
What does operational excellence mean in the Fourth Industrial Revolution era?
No full textAlthough the term Operational Excellence (OE) has been widely applied over the past few decades, its meaning is still ill-defined. This issue may be especially aggravated after the advent of the Industry 4.0 (I4.0), which introduces disruptive digital technologies that may help to overcome traditional barriers in operations management. This paper examines the concept of OE in the Fourth Industrial Revolution. For that, we conducted semi-structured interviews with experts from both academia and manufacturing companies, focusing on the shifts in OE's concepts implied by the I4.0 with regards to four key aspects (people, partnerships, processes, and products and services). Experts’ responses had their content analysed through the lens of General Systems Theory, which allowed the formulation of propositions towards the conceptualization of OE in the digital transformation era. Our findings indicated that, although some attributes may remain the same, the emphasis of OE in the Fourth Industrial Revolution is likely to change. The extensive integration of digital technologies into manufacturing companies tends to entail different expectations in terms of excellence in people, partnerships, processes, and products and services. As interconnectivity and cyber-physical systems gain prominence, a more integrative and systemic perspective of OE is facilitated, expanding its meaning and understanding
Steady-state growth of an interfacial crack by corrosion
No full textThe Wiener–Hopf technique is used to obtain a 2D steady-state solution for the progressive conversion of a pristine interface into a corroded interface between two dissimilar solids. The interface is of infinite extent, and comprises a semi-infinite pristine portion and a semi-infinite corroded portion. Fickian diffusion of the active species (solute) occurs in the upper half-space, with no diffusion in the lower half-space. Corrosion occurs by chemical reaction between the solute and the top surface of the lower half-space, and the path of solute diffusion involves 3 stages. The solute (i) leaves a solute-rich zone of disbonded and previously corroded interface, (ii) enters into and diffuses through the upper half-space, and (iii) leaves the upper half-space and enters the upstream pristine interface where it reacts with the surface of the lower half-space to produce the corrosion product. A steady state is established: the corrosion front moves at a constant velocity V which is dictated by the critical value of accumulated solute on the interface that is needed to form corrosion product and disbond the interface. The reaction zone directly ahead of the corrosion front has a characteristic length that depends upon the diffusion parameters and front velocity V. An asymptotic solution by the Wiener–Hopf analysis is obtained for the diffusion problem at large V. Scaling laws emerge and support the predictions of a much simpler 1D physical model
Nonlinear hydrodynamic analysis of an offshore oscillating water column wave energy converter
No full textThe hydrodynamic performance of a floating cylindrical oscillating water column (OWC) wave energy converter is investigated experimentally and numerically. The physical experiment is carried out in a wave flume at Dalian University of Technology. The floating cylindrical OWC device is constrained by springs and only moves vertically. A second-order time-domain Higher-Order Boundary Element Method, based on the perturbation expansion technique, is used to simulate the nonlinear wave interaction with the floating OWC device. The nonlinear terms concerning the pneumatic and viscous damping are introduced to the free surface boundary conditions inside the OWC chamber. The chamber surface elevation and air pressure, the hydrodynamic efficiency, and the vertical displacement of the OWC device are examined in detail. Good agreements are obtained between experimental data and numerical results. Then, the effects of opening ratio, wave steepness, mooring stiffness and chamber draft on the hydrodynamic performance are then investigated. It is found that the optimal opening ratio is between 0.02 and 0.03. The mooring stiffness plays an important role on the hydrodynamic response of the OWC device. The hydrodynamic efficiency and effective frequency bandwidth increase with the mooring stiffness
Industrial Internet of Things enabled supply-side energy modelling for refined energy management in aluminium extrusions manufacturing
No full textTo improve industrial sustainability performance in manufacturing, energy management and optimisation are key levers. This is particularly true for aluminium extrusions manufacturing —an energy-intensive production system with considerable environmental impacts. Many energy management and optimisation approaches have been studied to relieve such negative impact. However, the effectiveness of these approaches is compromised without the support of refined supply-side energy consumption information. Industrial internet of things provides opportunities to acquire refined energy consumption information in its data-rich environment but also poses a range of difficulties in implementation. The existing sensors cannot directly obtain the energy consumption at the granularity of a specific job. To acquire that refined energy consumption information, a supply-side energy modelling method based on existing industrial internet of things devices for energy-intensive production systems is proposed in this paper. First, the job-specified production event concept is proposed, and the layout of the data acquisition network is designed to obtain the event elements. Second, the mathematical models are developed to calculate the energy consumption of the production event in three process modes. Third, the energy consumption information of multiple manufacturing element dimensions can be derived from the mathematical models, and therefore, the energy consumption information on multiple dimensions is easily scaled. Finally, a case of refined energy cost accounting is studied to demonstrate the feasibility of the proposed models
Digital interoperability and transformation in logistics and supply chain management: Editorial
No full textThis editorial introduces this Special Issue on advances in research on digital interoperability and transformation in logistics and supply chain management. Eleven high-quality and original research works from both researchers and practitioners in the area have been selected to compose this Special Issue. This editorial first introduces the scientific context relevant to the Special Issue, then presents each of the eleven papers. From these papers, this editorial identifies several interesting prospective works, which are finally presented