Concept Studies for a Joint Support Ship

While all the major NATO navies have been under considerable pressure to downsize following the end of the post-Cold War, the higher degree of political instability world-wide has led to a desire to increase the deployability of the reduced number of naval assets. Thus there has been an increased interest in providing a new generation of naval support vessels as part of each navy’s contribution to Coalition peacekeeping. These new support ships are often also required to provide a contribution to amphibious capabilities, including humanitarian tasks, in littoral operations. This means there is a challenging combination of capabilities being sought from the current replacements of traditional afloat support ships. This paper describes the design work undertaken by the Design Research Centre at UCL, as part of a bid team responding to a Canadian National Defence Department requirement for feasibility studies into a “Joint Support Ship” programme. The UCL task consisted of designing a range of possible design options, to investigate the impact of capabilities on the configuration of this innovative concept, exploring the requirement’s two levels of capability, namely, “shall” and “should” as part of designing to cost and capability. A range of concepts was designed using the UCL Design Building Block approach, using the SURFCON module of the Graphics Research Corporation PARAMARINE ship design system. The advantage this approach gave in designing these novel solutions is shown through the ability of the DBB concept approach to balance both technical and configurational features, thereby enabling significantly different ship styles to be readily produced and compared

Seeing arrangements as connections: The use of networks in analysing existing and historical ship designs

A growing trend in computer aided ship design, particularly in the early stages, is the utilisation of approaches and numerical methods developed in other disciplines. Examples include genetic algorithms, financial methods of risk assessment and the use of network science. Networks can provide an abstract mathematical representation of many types of connected features, properties and information, such that the associated network analysis metrics and approaches can offer new ways of investigating and evaluating ship designs. This paper reports on ongoing UCL investigations into the application of network science in assisting human analysis of the general arrangements of existing ship designs. This work includes designs of complex service vessels (research vessels) as a comparison with naval ships and makes use of freely available network analysis software. This project makes use of the experience in naval vessel concept design at UCL by enabling a comparison of expert judgement and interpretation of designs with the quantitative network metrics. This paper describes the network analysis approach adopted, the findings for the arrangements analysed, and also discusses the future work required to further the approach

Modelling the operational effects of deploying and retrieving a fleet of uninhabited vehicles on the design of dedicated naval surface ships

Uninhabited vehicles (UXVs) are becoming an important component of naval warfare, providing an entirely new capability. By projecting military power in a more affordable way, through the use of UXVs, exposure of human life to military threats should be significantly reduced. While several navies are employing UXVs for a variety of applications, the concept of operating a fleet of such vehicles from a mothership that supports their overall operations during a mission, is a further challenge. This paper describes the research conducted by University College London (UCL) Design Research Centre (DRC) to develop and demonstrate a relevant analytical approach to design a mothership supporting a fleet of UXVs. This research should provide ship designers with the basis for early stage assessment of the impact of the various facilities seen as appropriate to host and support a substantial fleet of UXVs. It is particularly focused on the Launch and Recovery (LAR) capability of the UXV mothership. The research explored various options to demonstrate the proposed approach, rather than producing a definitive mothership design solution. This was appropriate given the fact that any UXV fleet composition is hard to predict (since mission related) and UXV technology is rapidly developing, so both must be speculative. It was found that the QT tool could provide meaningful investigation into the impact of potential tasks to be undertaken by a fleet of UXVs, addressing the design of mission bays, which were shown to be key to USV mothership design. While more focused simulations could refine subsystem options, this was not pursued, given the technology is still developing. Consequently, at this very early stage of investigating the deployment of a fleet of USVs from surface ships (through case studies), queuing network theory was seen to be more appropriate than a simulation-based analysis for this initial exploratory and investigatory work on future naval deployment of UXVs

Distributed Ship Service Systems Architecture in The Early Stages of Designing Physically Large and Complex Vessels: The Submarine Case

In the initial sizing of complex vessels, where recourse to type ship design can be overly restrictive, one crucial set of design features has traditionally been poorly addressed. This is the estimation of the weight and space demands of the various Distributed Ship Services Systems (DS3), which include different types of commodity services beyond those primarily associated with the ship propulsion system. In general, naval vessels are typified by extensive and densely engineered DS3, with the modern naval submarine being at the extreme of dense outfitting. Despite this, the ability for the concept designer to consider the impact of different configurations for the DS3 arrangements has not been readily addressed in concept design. This paper describes ongoing work at University College London (UCL) to develop a novel DS3 synthesis approach utilising computer tools, such as Paramarine™, MATLAB®, and CPLEX®, which provide the concept designer with a quantitative network-based evaluation to enable DS3 space and weight inputs early in the design process. The results of applying the approach to a conventional submarine case study indicate quantitative insights into early DS3 sizing can be obtained. The paper concludes with likely developments in concluding the research study

A demonstration of an advanced library based approach to the initial design exploration of different hullform configurations

The importance of requirement elucidation, in shaping both the customers' needs and initial solutions during the concept stage of the ship design process, has previously been emphasised in the choice of initial design methods. It is well known that alternative hullform styles can bring distinct performance benefits in certain design investigations. However, current design methods or tools suitable for exploring alternate hullform styles during requirement elucidation do not readily facilitate this. This paper describes a library based ship concept design tool and its ability to include exploration of hullform options in the initial exploratory stage of the ship design process. The library based approach utilises sub-structuring to describe the design in terms of four functional subsets to increase the efficiency of the search process. The example presented looks at monohull, catamaran and trimaran hullform options for a fast naval combatant. The paper concludes with the advantages seen in adopting the tool in concert with a configuration-oriented approach to ship design, namely, the UCL Design Building Block approach. © 2011 Elsevier Ltd. All rights reserved

Genetic evaluation of seedling heat tolerance in sorghum

Surface temperatures of tropical soils at planting time, where sorghum (Sorghum bicolor) is a traditional crop, can exceed 50 oC for hours. Seedling heat tolerance is critical for adequate crop establishment in the semi-arid tropics. Improvement of seedlings heat tolerant genotypes would reduce crop losses due to sufficient plant populations. The objectives of this study were to estimate seedling tolerance to heat, determine individual parental contribution and estimate additive, dominance and epistatic effects for seedling tolerance. In our experiments, seedling heat tolerance termed heat tolerance index (HTI) was defined as a ratio of resumed coleoptile growth after a controlled heat shock, compared to normal growth. Genetic parameters of HTI were determined by crossing four lines with varying HTI, with three tester lines, and deriving F1, F2, F3, BC1 and BC11 families forgeneration means analysis. Line IS20969 from Egypt showed the highest HTI of 0.71, while 290R, an experimental line from the University of Nebraska was the lowest at 0.51. Additive and dominance effects contributed to coleoptile elongation under normal conditions, but only additive effects were significant in recovery growth. Epistatic effects were present in both conditions. General combining ability (GCA) effects for HTI were highly significant in both conditions, but specific combining ability effects were negligible. These results indicate that it is possible to improve seedling heat tolerance and, thus, improve sorghum variety and hybrid plant populations in tropical areas where hot soil temperatures occur

Visualising apoptosis in live zebrafish using fluorescence lifetime imaging with optical projection tomography to map FRET biosensor activity in space and time

Fluorescence lifetime imaging (FLIM) combined with optical projection tomography (OPT) has the potential to map Förster resonant energy transfer (FRET) readouts in space and time in intact transparent or near transparent live organisms such as zebrafish larvae, thereby providing a means to visualise cell signalling processes in their physiological context. Here the first application of FLIM OPT to read out biological function in live transgenic zebrafish larvae using a genetically expressed FRET biosensor is reported. Apoptosis, or programmed cell death, is mapped in 3-D by imaging the activity of a FRET biosensor that is cleaved by Caspase 3, which is a key effector of apoptosis. Although apoptosis is a naturally occurring process during development, it can also be triggered in a variety of ways, including through gamma irradiation. FLIM OPT is shown here to enable apoptosis to be monitored over time, in live zebrafish larvae via changes in Caspase 3 activation following gamma irradiation at 24 hours post fertilisation. Significant apoptosis was observed at 3.5 hours post irradiation, predominantly in the head region

Validity and reliability of the XSENSOR in-shoe pressure measurement system

Background In-shoe pressure measurement systems are used in research and clinical practice to quantify areas and levels of pressure underfoot whilst shod. Their validity and reliability across different pressures, durations of load and contact areas determine their appropriateness to address different research questions or clinical assessments. XSENSOR is a relatively new pressure measurement device and warrants assessment. Research question Does the XSENSOR in-shoe pressure measurement device have sufficient validity and reliability for clinical assessments in diabetes? Methods Two XSENSOR insoles were examined across two days with two lab-based protocols to assess regional and whole insole loading. The whole insole protocol applied 50–600 kPa of pressure across the insole surface for 30 seconds and measured at 0, 2, 10 and 30 seconds. The regional protocol used two (3.14 and 15.9 cm2 surface area) cylinders to apply pressures of 50, 110 and 200 kPa to each insole. Three trials of all conditions were averaged. The validity (% difference and Root Mean Square Error: RMSE) and repeatability (Bland Altman, Intra-Class Correlation Coefficient: ICC) of the target pressures (whole insole) and contact area (regional) were outcome variables. Results Regional results demonstrated mean contact area errors of less than 1 cm2 for both insoles and high repeatability (≥0.939). Whole insole measurement error was higher at higher pressures but resulted in average peak and mean pressures error < 10%. Reliability error was 3–10% for peak pressure, within the 15% defined as an analytical goal. Significance Errors associated with the quantification of pressure are low enough that they are unlikely to influence the assessments of interventions or screening of the at-risk-foot considering clinically relevant thresholds. Contact area is accurate due to a high spatial resolution and the repeatability of the XSENSOR system likely makes it appropriate for clinical applications that require multiple assessments

Prediction of Topside Electromagnetic Compatibility in Concept-Phase Ship Design

An approach for the prediction of topside electromagnetic compatibility in the concept phase of naval ship design is proposed and demonstrated. The approach was developed by utilizing the commercially available numerical computational package, Computer Simulation Technology, to assess the electromagnetic environment of a Royal Navy Type 22 Batch II Frigate. A number of the results of such an assessment were validated using measurements on a 1:50 scale copper model of the Type 22 Batch II Frigate. The approach was then applied to a new concept phase design study for a Future Patrol Ship, produced by UK Ministry of Defence's Naval Design Partnership. This work is expected to be useful in assessing the severity of topside EMI, using numerical modeling and simulations, in Concept-Phase Ship Design

Solar wind interaction with comet 67P: impacts of corotating interaction regions

International audienceWe present observations from the Rosetta Plasma Consortium of the effects of stormy solar wind on comet 67P/Churyumov-Gerasimenko. Four corotating interaction regions (CIRs), where the first event has possibly merged with a coronal mass ejection, are traced from Earth via Mars (using Mars Express and Mars Atmosphere and Volatile EvolutioN mission) to comet 67P from October to December 2014. When the comet is 3.1–2.7 AU from the Sun and the neutral outgassing rate ∼1025–1026 s−1, the CIRs significantly influence the cometary plasma environment at altitudes down to 10–30 km. The ionospheric low-energy (∼5 eV) plasma density increases significantly in all events, by a factor of >2 in events 1 and 2 but less in events 3 and 4. The spacecraft potential drops below −20 V upon impact when the flux of electrons increases. The increased density is likely caused by compression of the plasma environment, increased particle impact ionization, and possibly charge exchange processes and acceleration of mass-loaded plasma back to the comet ionosphere. During all events, the fluxes of suprathermal (∼10–100 eV) electrons increase significantly, suggesting that the heating mechanism of these electrons is coupled to the solar wind energy input. At impact the magnetic field strength in the coma increases by a factor of 2–5 as more interplanetary magnetic field piles up around the comet. During two CIR impact events, we observe possible plasma boundaries forming, or moving past Rosetta, as the strong solar wind compresses the cometary plasma environment. We also discuss the possibility of seeing some signatures of the ionospheric response to tail disconnection events