Engineering Collected Works - Research Publications
Now showing items 1-12 of 294
Designing Virtual Avatars to Empower Social Participation among Older Adults
(ACM Press, 2017)
Social participation among older adults improves quality of life, reducing negative emotions that may lead to depression or premature death. The use of virtual avatars (self representations of the user) in online environments can support social participation by providing opportunities for enjoyment. These new online self-representations can affect the behavior of users in both the digital and the physical world. However, further study is needed to identify how to promote social participation for older adults through appropriate design of avatars.
Mitigating punch-through on sand-over-clay using skirted foundations
This paper investigates the potential for using skirted foundations as an alternative to spudcans in an attempt to mitigate punch-through failure of jack-up rigs during installation and preloading in sand-over-clay deposits. The results from a series of numerical analyses on the skirt length were presented in combination with different conditions of sand-over-clay deposit. Three-dimensional large deformation finite element (LDFE) analyses were carried out using the coupled Eulerian-Lagrangian approach. The sand was represented with a modified Mohr-Coulomb model and the clay with an extended Tresca model. The results showed that the likelihood and severity of punch-through increased with (i) increasing the thickness of the sand layer, (ii) increasing the strength of the clay layer, and (iii) reducing the strength non-homogeneity of the clay layer. The degree of mitigation was increased with increasing the skirt length. An optimal skirt length of 0.25D was suggested accounting for the rig towing constraint. Prediction models have been proposed for assessing (i) the potential for punch-through failure, and (ii) the resistance profile for skirted foundations penetrating sand-over-clay deposits.
Projections of global-scale extreme sea levels and resulting episodic coastal flooding over the 21st Century
(Springer Science and Business Media LLC, 2020-07-30)
Global models of tide, storm surge, and wave setup are used to obtain projections of episodic coastal flooding over the coming century. The models are extensively validated against tide gauge data and the impact of uncertainties and assumptions on projections estimated in detail. Global “hotspots” where there is projected to be a significant change in episodic flooding by the end of the century are identified and found to be mostly concentrated in north western Europe and Asia. Results show that for the case of, no coastal protection or adaptation, and a mean RCP8.5 scenario, there will be an increase of 48% of the world’s land area, 52% of the global population and 46% of global assets at risk of flooding by 2100. A total of 68% of the global coastal area flooded will be caused by tide and storm events with 32% due to projected regional sea level rise.
Breakout force required for jack-up spudcan extraction from sand-over-clay seabeds
Spudcan retrieval from clay soils remains a major concern offshore as the extraction force required to overcome suction and soil resistance often exceeds the pulling capacity available on the mobile jack-up, causing extensive delays. Although methods to calculate extraction resistance have been recently suggested for seabeds of pure clay, to date there is no guidance available for the commonly encountered sand-over-clays. Based on failure mechanisms observed in half-spudcan visualisation tests, and calibrated against an extensive geotechnical centrifuge database of precisely measured extractions, this paper presents a method for calculating the force required to extract the spudcan foundations of mobile jack-up platforms after they have penetrated through a sand layer into underlying clay. Complexities, such as the strength degradation and strength recovery of the underlying clay soil, that occurs during spudcan installation and jack-up operations, are accounted for. Validation of the proposed method is demonstrated by retrospective prediction of the centrifuge testing database. The method outlined will allow operators of jack-up platforms to assess the extraction force prior to jack-up installation and to plan operational scenarios based on seabed conditions.
An East German Chile in Bulgaria: Notions of Longing and Displacement
The long-lasting relationship of the East German production company DEFA with Eastern European cinemas is documented by the great number of co-productions undertaken over the years of its existence. In a canon of DEFA films shot on location in Bulgaria, the ‘Chile films’ appear as interesting example of cultural hybridity and transnational filmmaking, which have yet to receive scholarly attention. The features Der Übergang/The Passage (1978), Die Spur des Vermiβten/Trace of the Disappeared (1980) and Blonder Tango/Blond Tango (1985), presenting East German views about human rights violations that occurred in Chile during the Pinochet regime, were made with Bulgarian, German and Chilean casts and crews. This paper examines the Eastern European physiognomies in these films and their meaning as conflation between East and South in the Cold War dynamics of the late 1970s to mid-1980s. While the films propagate notions of Third World solidarity and fascist denunciation in narrative terms, Eastern European natural and urban landscapes produce feelings of displacement and yearning for an intact place remote from East German reality.
Observations during suction bucket installation in sand
(ICE Publishing, 2020-05-01)
Suction buckets represent a viable solution as foundations for offshore wind turbines. Installation in sand is relatively straightforward, albeit with limited understanding of the resulting changes in soil state. This paper describes an experimental methodology that allows for visualisation and quantification of changes in soil state during suction bucket installation, validated in sand. Insights obtained from particle image velocimetry analyses, performed on images of a half-bucket installing against a Perspex window taken in a geotechnical centrifuge are discussed. Compared with the initial self-weight penetration, the deformation mechanism governing the suction-assisted phase shows a preference for the soil below the skirt tips to move inwards and upwards inside the bucket. The installation process is responsible for changes in relative density and permeability within the bucket. In these experiments, the majority of the soil plug heave can be attributed to the soil displaced inwards by the advancing skirts, with a minor contribution caused by dilation. The confidence in the experimental methodology provided through the results of suction bucket installation in sand discussed herein now enables suction bucket installation in more complex seabeds to be investigated.
Observations of the Effects of a Clay Layer on Suction Bucket Installation in Sand
(American Society of Civil Engineers, 2020-05-01)
Suction buckets are becoming established as a viable foundation solution for offshore wind turbines. In sand, suction-induced seepage flow reduces effective stresses at the skirt tips, which decreases penetration resistance. However, layered seabeds are often encountered in areas of offshore wind farm development. The effect of the presence of a clay layer on the suction-induced seepage flow in the sand layer is not well understood. Therefore in this study, the effects of a clay layer on suction bucket installation in dense sand was investigated. This was achieved by analyzing images of a half-bucket installed against a Perspex window. The images were captured during tests performed in a geotechnical centrifuge, such that the stress levels are realistic and relevant to field conditions. Installations in sand-over-clay were unproblematic and characterized by deformation of the sand-clay interface, with no clear interruption of the seepage flow. Installations in clay-over-sand were also successful. Uplift of the clay plug was identified as the mechanism to transfer suction to the underlying sand, creating seepage flow and thus facilitating further skirt penetration rather than terminating the installation.
Polyphenol-Mediated Assembly for Particle Engineering.
(American Chemical Society, 2020-06-22)
ConspectusPolyphenols are naturally occurring compounds that are ubiquitous in plants and display a spectrum of physical, chemical, and biological properties. For example, they are antioxidants, have therapeutic properties, absorb UV radiation, and complex with metal ions. Additionally, polyphenols display high adherence, which has been exploited for assembling nanostructured materials. We previously reviewed the assembly of different phenolic materials and their applications (Angew. Chem. Int. Ed. 2019, 58, 1904-1927); however, there is a need for a summary of the fundamental interactions that govern the assembly, stability, and function of polyphenol-based materials. A detailed understanding of interactions between polyphenols and various other building blocks will facilitate the rational design and assembly of advanced polyphenol particles for specific applications. This Account discusses how different interactions and bonding (i.e., hydrogen, π, hydrophobic, metal coordination, covalent, and electrostatic) can be leveraged to assemble and stabilize polyphenol-based particles for diverse applications. In polyphenol-mediated assembly strategies, the polyphenols typically exert more than one type of stabilizing attractive force. However, one interaction often dominates the assembly process and dictates the physicochemical behavior of the particles, which in turn influences potential applications. This Account is thus divided into sections that each focus on a key interaction with relevant examples of applications to highlight structure-function relationships. For example, metal coordination generally becomes weaker at lower pH, which makes it possible to engineer metal-phenolic materials with a pH-responsive disassembly profile suitable for drug delivery. Engineered particles, such as hollow capsules, mesoporous and core-shell particles, and self-assembled nanoparticles are some of the systems that are covered to highlight how polyphenols interact with other building blocks and therefore make up the major focus of this Account. Some of the applications of these materials exemplified in this Account include drug delivery, catalysis, environmental remediation, and forensics. Finally, a perspective is provided on the current challenges and trends in polyphenol-mediated particle assembly, and viable near-term strategies for further elucidating the interplay of various competing interactions in particle formation are discussed. This Account is also expected to serve as a reference to guide fundamental research and facilitate the rational design of polyphenol-based materials for diverse emerging applications.
Detect adverse drug reactions for the drug Pravastatin
Adverse drug reaction (ADR) is widely concerned for public health issue. ADRs are one of most common causes to withdraw some drugs from market. Prescription event monitoring (PEM) is an important approach to detect the adverse drug reactions. The main problem to deal with this method is how to automatically extract the medical events or side effects from high-throughput medical data, which are collected from day to day clinical practice. In this study we propose an original approach to detect the ADRs using feature matrix and feature selection. The experiments are carried out on the drug Pravastatin. Major side effects for the drug are detected. The detected ADRs are based on computerized method, further investigation is needed.
Detect adverse drug reactions for drug Alendronate
Adverse drug reaction (ADR) is widely concerned for public health issue. In this study we propose an original approach to detect the ADRs using feature matrix and feature selection. The experiments are carried out on the drug Alendronate. Major side effects for the drug are detected and better performance is achieved compared to other computerized methods. The detected ADRs are based on the computerized method, further investigation is needed.
Detect adverse drug reactions for drug Simvastatin
Adverse drug reaction (ADR) is widely concerned for public health issue. In this study we propose an original approach to detect the ADRs using feature matrix and feature selection. The experiments are carried out on the drug Simvastatin. Major side effects for the drug are detected and better performance is achieved compared to other computerized methods. The detected ADRs are based on the computerized method, further investigation is needed.
Detect adverse drug reactions for drug Pioglitazone
Adverse drug reaction (ADR) is widely concerned for public health issue. In this study we propose an original approach to detect the ADRs using feature matrix and feature selection. The experiments are carried out on the drug Pioglitazone. Major side effects for the drug are detected and better performance is achieved compared to other computerized methods. The detected ADRs are based on the computerized method, further investigation is needed.