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A symmetric experimental study of the interaction between regular waves and a pontoon breakwater with novel fin attachments
Get PDFFloating breakwaters are widely applied on the ocean water surface to protect human infrastructure from the destructive power of waves. This study designs and investigates the performance of a novel symmetric-pontoon floating breakwater with a symmetric pair of hydrofoils. Based at the Cranfield Ocean Systems Laboratory, the system was constructed and tested in various wave conditions using different fin configurations. The floating structure was anchored using a symmetric four-point mooring system. The tested waves were regular and symmetric perpendicular to the propagating direction. Key parameters, including the attenuated wave amplitude, motions of the breakwater, and the mooring forces, were measured. The wave parameters utilised for testing covered 1.61–5.42 relative wavelength to structural length, with wave heights of 3 cm and 5 cm. Results showed the 90° fin configuration can reduce wave transmission by up to 74%, with the lowest mooring forces at 3.05 relative wavelength, enhancing the performance of wave energy dissipation and structural seakeeping. At 90° setup, the mooring force was lowest at 2.41 relative wavelength. This research can inform novel designs of breakwaters to improve protection abilities for coastal cities and offshore infrastructures, especially renewable energy systems.L.H. acknowledges grants received from Innovate UK (No. 10048187, 10079774, 10081314), the Royal Society (IEC\NSFC\223253, RG R2 232462), and UK Department for Transport (TRIG2023—No. 30066).Symmetr
Design of super wide band 3‐way power divider/combiner
Get PDFA 1:3‐way power divider/combiner has been proposed for much improved bandwidth and isolation between output ports. The matching network for the super wide bandwidth frequency range is designed using a combination of the Klopfenstein taper and the triangular taper. The proposed design yields bandwidth from 1.5 to 20 GHz (18.5 GHz) for return loss better than 15 dB and isolation better than 20 dB. The insertion loss for the entire frequency band is 0.8 dB which is only 0.34 dB for the ultra‐wide bandwidth (3.1–10.6 GHz). The maximum phase imbalance of 3.32° and amplitude imbalance of 0.199 dB between all the output ports have been achieved over the entire bandwidth. The simulated results have been validated experimentally.IET Microwaves, Antennas & Propagatio
Ambidextrous innovation in project management: a systematic literature review
Get PDFProjects work under constant pressure of resource and time constraints. In order to perform effectively and efficiently, innovation seems to be a significant factor. However, due to the different nature of projects as compared to the organization, projects have been finding it difficult to undertake such innovation. However, ambidextrous innovation, which seeks to balance exploratory and exploitative innovation, offers a possible solution. However, research on the relationship between ambidextrous innovation and project management is at an early stage. The purpose of the present research is to undertake a systematic review of the literature to build and synthesize the understanding of innovation ambidexterity at the project level. Following the Preferred Reporting Items for Systematic Reviews and Meta Analysis (PRISMA) guidelines, our research collected data from the Web of Science and SCOPUS databases. By adhering to the PRISMA approach, we ensured a rigorous and transparent approach to the systematic review study, allowing for comprehensive data collection and analysis. The results of the present review study suggest that interest is building rapidly to incorporate ambidextrous innovation into project management. Ambidextrous innovation seemed to positively impact both the performance and capability of projects to undertake the innovation. Further, important drivers such as organizational culture, knowledge management, innovation activities, and agility play key roles in undertaking ambidextrous innovation at the project level. Further, elements of the team such as team integration, alignment, and knowledge utilization also play key roles. Finally, the avenue of future research has also been highlighted
Biodegradation of (Aminomethyl)phosphonic acid (AMPA) by isolated microbial consortia extracted from biological filters at drinking water treatment plants
Get PDFThe widespread use of glyphosate has significantly increased its presence in drinking water sources. Aminomethylphosphonic Acid (AMPA), a breakdown product of glyphosate, is challenging to remove from water using conventional treatment methods, posing risks to public health and environmental safety. This work investigates the biodegradation of AMPA by bacteria isolated from three environmental sources, with a focus on determining their potential application in water treatment systems. Two samples were collected from granular activated carbon (GAC) filters of different operational durations at a water treatment facility, and one sample was taken from soil that had historically been treated with glyphosate-based herbicides. Bacterial isolates capable of degrading AMPA were identified from these samples through selective enrichment, and kinetic degradation experiments were then conducted to assess their effectiveness. In environmental samples, after 48 hrs AMPA removal was > 70 % using GAC from an active treatment plant and soil samples removed 19 %. After bacterial isolation a consortium was isolated and from these four isolates were identified, comprising three species, including novel AMPA degraders M−S3 and M−SS (Myroides sp. mNGS23), and P-S92 (Pseudochrobactrum saccharolyticum). Within both minimal media supplemented with AMPA and raw untreated showing substrate concentrations above 10 mg/L whilst the specific degradation rates saw a decrease in substrate concentrations above 100 mg/L. AMPA removal occured in pilot scale sand filters augmented with P-S92 but removal was inconsistent. These findings show the potential of using biodegradation as an effective treatment strategy for AMPA removal from water. The identification of AMPA-degrading bacteria offers a promising solution for enhancing the removal of this persistent pollutant from contaminated waters. Further research is recommended to explore the full-scale application of these isolates in water treatment processes. This study contributes to the development of sustainable water treatment technologies by harnessing the natural degradative capacities of environmental bacteria.The authors gratefully acknowledge financial support from the Engineering and Physical Sciences Research Council (ESPRC), United Kingdom through their funding of a Doctoral Training Allocation Award to LP (EP/R513027/1) and from the project sponsors UKWIR Ltd.Current Research in Biotechnolog
Comparison of Performance of NiCr2O4 and Cr2O3 Formed on the Ni-Based Superalloy RR1000 Under Corrosive Conditions
Get PDFSamples of the Ni-based superalloy, RR1000, were exposed to 98% Na2SO4/2% NaCl salts at 700 °C with a flux of 1.5 µg cm−2 h−1 in flowing air + 300 ppm SO2 for a total of 250 h. Three pre-exposure conditions were studied: a bare reference alloy; fast heating to the test temperature followed by a 100 h hold; heating at a rate of 5 °C min−1 to the test temperature following by a 100 h hold. The surface oxide formed under the latter two conditions were Cr2O3 or NiCr2O4, respectively. The results show corrosion pit formation on the surface of the base, reference sample, and no pits present on the sample with the preformed Cr2O3. Some protection was found for the sample heated at 5 °C min−1 with a delay in the progression to accelerated corrosion attack. Additional testing under moisture containing air was also conducted. This showed no obvious difference in surface oxide morphology under the two tested heating rates for the short-term exposures examined but a difference was noted to be dependent on the moisture content of the air.Engineering and Physical Sciences Research CouncilThis work was supported by the Rolls-Royce/EPSRC Strategic Partnership under EP/H022309/1High Temperature Corrosion of Material
Dual model sensors for viral RNA and protein detection for SARS- CoV-2 in saliva
Get PDFChianella, Iva - Associate SupervisorThe coronavirus disease 2019 (Covid-19) pandemic emerged as an infection by
severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) over the past 3
years, causing enormous threats to humans and economic loss. It was reported
that currently, nearly 68% of the population shows a degree of immunity to the
disease. Though vaccine has played a critical role to protect the population,
people are at risk of second or third infections with fading antibody titers against
the virus. The detection of the viral load was crucial for monitoring the spread of
this disease, and the detection of the antibody concentration to the virus was
significant as well to understand the neutralization activity and vaccine response.
This thesis reports the development of a rapid paper-based platform, which
provides nucleic acid detection and immunoassay to test both active infections
and body immunity. The project focused on a non-invasive sample, human saliva,
as an alternative to nasopharyngeal swabs for diagnosis. The nucleic acid test,
employing reverse transcription loop-mediated isothermal mediated amplification
(RT-LAMP), was further integrated into a novel paper microfluidic platform, where
the result could be reported within 30 mins. Under the optimized conditions, RT-
LAMP assay correctly detects above 135 copies µL⁻¹ of synthetic SARS-CoV-2
sequence. Moreover, a paper-based immunoassay was devised and constructed,
following meticulous refinement of detection parameters and comparative
analysis against a conventional 96-well plate assay for the identification of
immunoglobulin G (IgG) targeting the SARS-CoV-2 spike protein. For the paper-
based immunoassay, the dynamic range of the IgG was 0.5 μg mL⁻¹ to 50 μg mL⁻¹
, which was sensitive enough compared to clinical values. It should be noted that
only commercially available artificial saliva was utilized to test the analytical
performance of the developed assay. In conclusion, these results demonstrated
a rapid and easy-to-use paper microfluidics platform with the potential to be
further implemented as a comprehensive detection tool for monitoring both
pathogenetic infection and immune levels.MSc by Research in Wate
Real-life resilience in international water utilities
Get PDFJude, Simon - Associate SupervisorResilience is a highly aspired capability for the water sector. Whilst the concept has been
vastly utilised in technocentric and engineering objectives, few studies have investigated
the human dimensions of resilience in the context of international water utilities.
Specifically, little is known about how the organisational environment, organisational
culture and engagement with water customers may contribute to the resilience of the water
sector and the challenges and opportunities of building resilience capabilities in these
domains.
As the central context for this research, water utilities provide critical socio-economic
utility to society. Disruptions felt by water utilities can negatively impact multiple
communities, regional prosperity, and national security. However, water utilities
monopoly nature may insulate them from the new and evolving demands derived from
the free market, thus delaying the organic development of adaptive and agile capabilities.
In addition, given that the infrastructure of water utilities tends to be ‘locked-in’ to a fail-
safe stance, this bleeds through the organisation’s norms and beliefs, thus further
perpetuating previous paths and hindering experimentation and transformative change.
This is problematic because water utilities are more sensitive to local shocks and stresses
as they are bound to local catchments and providing services to local communities, as
opposed to energy utilities that may source energy from a wide range of geographical
locations. All these factors make water utilities an interesting population of research from
the lenses of Organisational Resilience.
Therefore, this thesis aims to understand the current stance and context within
international water utilities in relation adaptability and Organisational Resilience –
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spanning the organisational environment, culture, and interactions with customers. This
work seeks to critically evaluate how the organisational and human capabilities may be
shaped to enhance water sector resilience and the challenges and opportunities of doing
so. Through semi-structured interviews and an iterative survey with international water
utilities this qualitative research captures perceptions from water managers on embedding
Organisational Resilience properties.
This research provides several contributions to the current body of knowledge. Primarily,
the findings empirically identified novel challenges utilities face - spanning the cognitive
frame, behaviour of individuals, and the context of the organisational environment -
which flagged some key developmental areas to establish an organisational setting
conducive of resilience.
For instance, chapter 2 delves deep into the organisational environment in water utilities.
and identifies a need to broaden the cognitive frame of utilities to account for flexible
concepts for enhanced sense-making and proposes novel categories of organisational silos
and a set of cultural attributes that contribute to organisational resilience.
Moreover, chapter 3 explores the contextual property of organisational resilience, based
on external relationships, to examine how customers may influence the resilience of water
utilities. Although it was recognised a role of customers as passive beneficiaries of
resilience, positive roles were also identified, such as: facilitators of more targeted
initiatives, contributors to higher tolerance levels and positive behaviour-change, and
resilience advocates.
An additional contribution of this research is the creation of a framework of an
organisational culture of organisational resilience for the water sector in chapter 4. A
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novel set of cultural attributes that were validated as conducive to the Organisational
Resilience of water utilities were appraised from relevant literature. Derived based on the
perspectives of utility managers, the set of cultural attributes clarifies Organisational
Resilience beliefs and values that should shape individuals’ behaviour and the
organisational environment. Thematic analysis identified an over-emphasis on standards
and procedures that may hinder positive changes towards a culture of organisational
resilience. In addition, addressing organisational barriers perceived as a pre-requisite to
cultural changes, which may lead to inaction. However, the water sector’s impetus for
talent recruitment and staff retention translated as an appetite to foment deeper relational
ties with personnel.
Finally, this study highlights a real need for transforming the beliefs, values, and
behaviour in water utilities to implement and sustain efforts in the human and
organisational dimensions that are conducive of Organisational Resilience. Such
resilience transformation will entail efforts in the cognitive, behavioural, and contextual
aspects within utilities to address current challenges and leverage identified opportunities.PhD in Environment and Agrifoo
A two-stage classification method for improved positioning using low-cost inertial sensors
Get PDFThe two-stage subtractive clustering Takagi-Sugeno (2SC-TS) method is proposed which completely replaces the established method of inertial navigation with classification models. The classifiers are designed by the subtractive clustering algorithm, an unsupervised learning method. The accuracy of the trajectories is compared against three competitive data-driven methods on three independent experimental datasets. The results show how 2SC-TS generates trajectories with approximately 20% lower positional error compared with the single-stage version (SC-TS), and halves the error produced by competitive deep learning methods. The proposed method may help improve the positioning of people and robots carrying low-cost inertial sensors.Engineering and Physical Sciences Research Council (EPSRC)This work was supported by the EPSRC iCASE grant reference EP/S513623/1 and BAE Systems19th IEEE Conference on Industrial Electronics and Applications (ICIEA 2024
COSTA: a multi-center TOF-MRA dataset and a style self-consistency network for cerebrovascular segmentation
Get PDFTime-of-flight magnetic resonance angiography (TOF-MRA) is the least invasive and ionizing radiation-free approach for cerebrovascular imaging, but variations in imaging artifacts across different clinical centers and imaging vendors result in inter-site and inter-vendor heterogeneity, making its accurate and robust cerebrovascular segmentation challenging. Moreover, the limited availability and quality of annotated data pose further challenges for segmentation methods to generalize well to unseen datasets. In this paper, we construct the largest and most diverse TOF-MRA dataset (COSTA) from 8 individual imaging centers, with all the volumes manually annotated. Then we propose a novel network for cerebrovascular segmentation, namely CESAR, with the ability to tackle feature granularity and image style heterogeneity issues. Specifically, a coarse-to-fine architecture is implemented to refine cerebrovascular segmentation in an iterative manner. An automatic feature selection module is proposed to selectively fuse global long-range dependencies and local contextual information of cerebrovascular structures. A style self-consistency loss is then introduced to explicitly align diverse styles of TOF-MRA images to a standardized one. Extensive experimental results on the COSTA dataset demonstrate the effectiveness of our CESAR network against state-of-the-art methods. We have made 6 subsets of COSTA with the source code online available, in order to promote relevant research in the community.IEEE Transactions on Medical Imagin
Architecting CubeSat constellations for messaging service, Part I
Get PDFIn today's modern and globalized world, connectivity is a key factor for businesses, production facilities, sensor networks, and ordinary people. However, there are still populated areas which are not covered by ground-based telecommunications infrastructure. This is where telecommunication satellite constellations come in, as they can provide coverage to remote and uninhabited regions and fill existing connectivity gaps to ensure data transfer. LoRa is one of the technologies designed for data transmissions over long distances with low power consumption. Alongside with other technologies of the Low-Power Wide Area Network family, it is widely used for Internet of Things applications. LoRa chirp spread spectrum modulation is robust against the Doppler frequency shifts encountered in low earth orbits, and it has already been used in IoT satellite communications. Due to the low transmitted signal power, the achieved data rate is not high, making it a suitable technology for telecommunications payloads on CubeSat platforms for messaging services. As compared to existing traditional communication satellite systems, CubeSat constellations are low-cost and may offer an affordable connectivity service to developing regions. This study is divided in two parts. In Part I the demand model is built based on the population distribution not covered by cell towers. The LoRa link performance is analyzed, considering the impact of LoRa channel parameters variation, such as spreading factor and channel bandwidth, while satellite orbital height, transmission antenna beamwidth, and transmitter peak power have a direct impact on the payload mass. Among thousands of possible configurations, 73 feasible payload designs have been downselected. In Part II of the study, the satellite mass and the total system cost are estimated based on the payload parameters obtained. Messages transmission simulation via a constellation is conducted in order to identify optimal constellation architectures for messaging service, as well as the main drivers of the system economic profitability. The presented analysis results provide a deeper understanding of LoRa connectivity advantages and limitations together with the performance drivers, which will support the optimization of future LoRa-based satellite communication systems and other IoT satellite constellations.European Commission, Government of CataloniaThis has been supported by the predoctoral program AGAUR-FI ajuts (2023 FI-1 00477) Joan Oró of the Secretariat of Universities and Research of the Department of Research and Universities of the Generalitat of Catalonia and the European Social Plus Fund.This project was also sponsored in part by the project “GENESIS: GNSS Environmental and Societal Missions – Subproject UPC”, Grant PID2021-126436OB-C21, sponsored by MCIN/AEI/10.13039/ 501100011033/ and EU ERDF “A way to do Europe”.This study would also not have been possible without the support of the Skolkovo Institute of Science and Technology, whose funding enabled the international collaboration through its Academic Mobility program.Acta Astronautic