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Item Open Access 2016 British Crystallographic Association (BCA) Spring Meeting, April 4–7, 2016(Cambridge University Press, 2016-12) Rendle, DReview of the 2016 British Crystallographic Association (BCA) Spring Meeting, April 4–7, 2016Item Open Access 3D Lagrangian particle tracking of a subsonic jet using multi-pulse Shake-The-Box(Elsevier, 2021-01-19) Manovski, Peter; Novara, Matteo; Karthik, Nagendra; Mohan, Depuru; Geisler, Reinhard; Schanz, Daniel; Agocs, Janos; Godbersen, Philipp; Schröder, AndreasThree-dimensional (3D) Lagrangian Particle Tracking (LPT) was performed on a subsonic jet flow at Mach 0.506 and 0.845 generated by a round nozzle with diameter-based Reynolds numbers of 1.7×105 and 3.1×105, respectively. The Multi-Pulse Shake-The-Box (MP-STB) technique was employed to reconstruct particle tracks along the four-pulse sequences, which were obtained by using orthogonally polarised light to separate the pulses on camera images. The MP-STB method applied here has a number of differences compared to previous publications, in particular, a new adaptive search radii approach and an iterative strategy and particle track validation criteria that have been customised for high subsonic/transonic flows. A description of this methodology is given followed by presentation of the instantaneous 3D flow velocity and material acceleration particle tracks. By ensemble-averaging the scattered instantaneous measurements extracted from individual particle tracks into small volumetric bins, highly resolved statistical quantities were obtained. The performance of MP-STB was assessed by comparing velocity profiles with published particle image velocimetry (PIV) data-sets. MP-STB was better able to resolve the steep velocity gradients, in particular the thin jet shear layer near the nozzle exit. At this location the MP-STB results also yielded higher turbulence intensities compared with the reported studies for similar flow conditions. The MP-STB acceleration flow statistics were compared for the two Mach numbers, and for the Mach 0.506 case, higher levels of normalised acceleration and fluctuations were found. The position accuracy of the 3D imaging system was quantified and it was found that the use of two different states of polarisation had a direct impact on the accuracy and the amount successfully tracked particles. Further assessment of the particle imaging quality of each camera revealed a significant disparity between cameras. This was attributed to the particle light scattering intensity variations, which were highly dependent on the particle size, camera angles and different states of polarised light. Despite these challenges, an average of40,000 individual particle tracks could be reconstructed from a typical particle image density of 0.02 particles per px (and an active sensor area of 1800×2200 px2). Furthermore, the accuracy of the measurement was shown to be relatively high, with respect to PIV.Item Open Access 5 year public health impacts of an urban greenway, Belfast, Northern Ireland: Causal Loop Diagram (Abstract no diagram)(Oxford University Press, 2023-10-24) Hunter, R.; Garcia, L.; Clewley, Natalie; Hafezi, Mehdi; Hilton, JeremyBackground The development of large scale urban green space infrastructure, such as a new urban greenway, provokes a cascade of changes abating a series of public health impacts, in the realms of: health, society, economy and the environment. The relationships between these factors sustain reciprocal and dynamic influence with potential to generate a virtuous cycle. However, such long-term impacts and their inter-relationships are poorly understood. Methods We aimed to co-develop a shared understanding of the public health impacts of the Connswater Community Greenway with multi-sectoral stakeholders 5 years post-implementation. Objectives were to (a) build shared understanding of the complex system influencing the public health impact of the Connswater Community Greenway, and (b) identify and explore priorities, opportunities, and actions to improve future impacts. We undertook Group Model Building workshops with people representing relevant stakeholders involved in the development and/or maintenance of the Connswater Community Greenway, and local residents living on or along the greenway. Results 23 participants were involved in the workshop included local governmental agencies, local residents, advocacy groups, private sector, and researchers. Stakeholders produced a systems map detailing the public health impacts of the Connswater Community Greenway 5 years post-implementation. Key impacts included increased in mental wellbeing, sense of community pride, increased biodiversity, increased economic investment in the local area. Participants identified a range of priority actions that, in their view, could impact and help reshape the system and influence the future impacts of the greenway. Conclusions The CLD was reflective of the various stakeholders’ experience, knowledge, perceptions, and views about the factors, and the inter-relationships between these factors, of the public health impact of the Connswater Community Greenway at 5 years post-implementation. Key messages • Systems thinking approaches can help identify the public health impacts and plausible causal pathways of green space interventions. • 5 year impacts of an urban greenway included improvements in the realms of health, wellbeing, the environment, the economy and society.Item Open Access 6 Shipwreck archaeology in the past 10 years(Cambridge University Press (CUP), 2023-12-08) Briggs, Lisa; Campbell, Peter B.This paper reviews the trends, topics, and research directions in shipwreck archaeology over the past decade. As archaeology increasingly embraces advances in technological methods that can aid our research, the so-called ‘digital turn’, it behoves maritime archaeologists, and archaeologists more broadly, to consider how collaborative utilization of specialized fields including biomolecular archaeology, geophysics, and contemporary philosophy have spurred on a rapid modernization of our field in recent times. Archaeological research, both terrestrial and underwater, has long been a collaborative discipline. However, we argue here that difficulties in working underwater have encouraged maritime and underwater archaeologists to embrace technological developments at a rapid pace. An explicit theoretical framework and the incorporation of contemporary philosophy in the field of underwater archaeology was, until recently, largely lacking in the discipline’s discourse. The incorporation and advancement of adjacent disciplines within the field of underwater archaeology mark the most relevant changes within the shifting tides of shipwreck research.Item Open Access AD Tools and Prospects for Optimal AD in CFD Flux Jacobian Calculations.(2002-01-01T00:00:00Z) Tadjouddine, Mohamed; Forth, Shaun A.; Pryce, John D.We consider the problem of linearising the short (approximately 100 lines of) code that defines the numerical fluxes of mass, energy and momentum across a cell face in a finite volume compressible flow calculation. Typical of such formulations is the numerical flux due to Roe, widely used in the numerical approximation of flow fields containing moderate to strong shocks. Roe's flux takes as input 10 variables describing the flow either side of a cell face and returns as output the 5 variables for the numerical flux. We present results concerning the efficiency of derivative calculations for Roe's flux using several currently available AD tools. We also present preliminary work on deriving near optimal differentiated code using the node elimination approach. We show that such techniques, within a source transformation approach, will yield substantial gains for application code such as the Roe flux.Item Open Access ADAMS model validation for an all terrain vehicle using test track data(Sage, 2019-07-15) Kanchwala, Husain; Chatterjee, AnindyaMD ADAMS R is widely used for vehicle suspension modeling. In this paper we present modeling, simulation, and test track evaluation of an all terrain recreational vehicle. Our intention is to study the degree to which simplified ADAMS modeling actually matches human-driven vehicle response. For suspension model validation, a vehicle is generally tested on a four-post test rig and base-excitation is applied at four ground-wheel contacts. However, actual driving experience does not match idealized testing conditions. In this work the vehicle is manually driven on a variety of tracks at different speeds, and the vertical accelerations at four axle locations and four body points are measured. The same are then compared in detail against predictions from ADAMS simulation with vertical base excitation. The contribution of this paper is in identifying those aspects of the simulation results that match experiments well, and identifying possible sources for the observed mismatch, especially under more severe test conditions.Item Open Access Adjoint Differentiation of a Structural Dynamics Solver.(2006-12-01T00:00:00Z) Tadjouddine, Mohamed; Forth, Shaun A.; Keane, Andy J.The design of a satellite boom using passive vibration control by Keane [J. of Sound and Vibration, 1995, 185(3),441-453] has previously been carried out using an energy function of the design geometry aimed at minimising mechanical noise and vibrations. To minimise this cost function, a Genetic Algorithm (GA) was used, enabling modification of the initial geometry for a better design. To improve efficiency, it is proposed to couple the GA with a local search method involving the gradient of the cost function. In this paper, we detail the generation of an adjoint solver by automatic differentiation via ADIFOR. This has resulted in a gradient code that runs in 7.4 times the time of the function evaluation. This should reduce the rather time-consuming process (over 10 CPU days by using parallel processing) of the GA optimiser for this problem.Item Open Access Adopting the bottom-up approach and cluster analysis on North American and European male serial killers(JSciMed Central, 2017-11-23) Taylor, Sadie; Cahillane, Marie; Workman, LanceThis study explores the application of the FBI’s organised-disorganised classification to North-American and European male serial killers. Adopting the same method as Taylor, Lambeth, Green, Bone and Cahillane’s 2012 study, 52 crime scene criteria were used to categorise the murders committed by 25 male European and 25 male North-American serial killers. Applying content analysis, murders committed were dichotomously coded for the presence or absence of crime scene criteria using numerous secondary sources. Two separate agglomerative hierarchical cluster analyses using Ward’s method as the clustering algorithm formed two clusters for the North-American and two for the European serial killers. There were differences in the crime scene criteria for clusters between North-American and European serial murders. The ‘bottom-up’ approach resulted in clusters from the crime scene criteria demonstrating that there are problems associated with classifying traits as simply organised and disorganised. All clusters comprised of a degree of core organised traits -consistent with Canter, Alison, Alison and Wentink’s (2004) assumption that all serial killings require a degree of organisation. Further examination of frequency of occurrence measures suggests there are subtle but inherent differences between the MO of North American and European serial killers.Item Open Access Adult fly age estimations using cuticular hydrocarbons and Artificial Neural Networks in forensically important Calliphoridae species(Elsevier, 2017-10-08) Moore, Hannah E.; Butcher, John B.; Day, Charles R.; Drijfhout, Falko P.Blowflies (Diptera: Calliphoridae) are forensically important as they are known to be one of the first to colonise human remains. The larval stage is typically used to assist a forensic entomologists with adult flies rarely used as they are difficult to age because they remain morphologically similar once they have gone through the initial transformation upon hatching. However, being able to age them is of interest and importance within the field. This study examined the cuticular hydrocarbons (CHC) of Diptera: Calliphoridae species Lucilia sericata, Calliphora vicina and Calliphora vomitoria. The CHSs were extracted from the cuticles of adult flies and analysed using Gas Chromatography-Mass Spectrometry (GC-MS). The chemical profiles were examined for the two Calliphora species at intervals of day 1, 5, 10, 20 and 30 and up to day 10 for L. sericata. The results show significant chemical changes occurring between the immature and mature adult flies over the extraction period examined in this study. With the aid of a Principal Component Analysis (PCA) and Artificial Neural Networks (ANN), samples were seen to cluster, allowing for the age to be established within the aforementioned time frames. The use of ANNs allowed for the automatic classification of novel samples with very good performance. This was a proof of concept study, which developed a method allowing to age post-emergence adults by using their chemical profilesItem Open Access Aerodynamic characteristics of a wing-and-flap configuration in ground effect and yaw(IMechE, 2015-08-11) Roberts, L.; Correia, J.; Finnis, Mark V.; Knowles, KevinThe influence of the yaw angle on a model representative of a monoposto racing car’s front wing and nose section operating in close proximity to the ground is discussed. The yawed condition is representative of a car operating in a crosswind or with side-slip while cornering. Because of the need for downforce in corners rather than on a straight, it is standard practice to test a racing car at various orientations of yaw, pitch and roll quasi-statically. Wind tunnel testing with a 50%-scale model at a unit Reynolds number of 1.69 × 106 was used to investigate the forces and the surface flow structures. The results were then used to validate simulations with the three-equation k–kL–ω transitional turbulence model to observe the surface pressures and the wake structures. It was found that a change in the surface pressure caused asymmetric loading of the wing, the strengthening or inhibiting of vortices depending on their rotational sense and an overall reduction in both the downforce and the drag of the wing; all these were amplified as the yaw angle was increased or the ground clearance reduced. The fundamental aerodynamic flow features of a racing car’s front wing operating at yaw are established.Item Open Access Aerodynamics of a convex bump on a ground-effect diffuser(Journal of Fluids Engineering, 2018-04-19) Ehirim, Obinna; Knowles, Kevin; Saddington, A. J.; Finnis, Mark V.A ground-effect diffuser is an upward-sloping section of the underbody of a racing car that enhances aerodynamic performance by increasing the downforce, thus improving tire grip. The downforce generated by a diffuser can be increased by geometric modifications that facilitate passive flow control. Here we modified a bluff body equipped with a 17° diffuser ramp surface (the baseline/plane diffuser) to introduce a convex bump near the end of the ramp surface. The flow features, force and surface pressure measurements determined in wind-tunnel experiments agreed with previous studies but the bump favorably altered the overall diffuser pressure recovery curve by increasing the flow velocity near the diffuser exit. This resulted in a static pressure drop near the diffuser exit followed by an increase to freestream static pressure, thus increasing the downforce across most of the ride heights we tested. We observed a maximum 4.9% increase in downforce when the modified diffuser was compared to the plane diffuser. The downforce increment declined as the ride height was gradually reduced to the low-downforce diffuser flow regime.Item Open Access Aerofoil Optimisation via AD of a Multigrid Cell-Vertex Euler Flow Solver.(2002-01-01T00:00:00Z) Forth, Shaun A.; Evans, Trevor P.We report preliminary results in the use of ADIFOR 2.0 to determine aerodynamic sensitivities of a 2-D airfoil with respect to geometrical variables. Meshes are produced with a hyperbolic interpolation technique. The flow field is calculated using the cell-vertex method of Hall, which incorporates local time-stepping, mesh sequencing and multigrid. We present results and timings using both Finite Differences (FD) and Automatic Differentiation (AD). We investigate the effect of starting the perturbed calculation for FD and the derivative calculation for AD from either the current or freestream conditions and highlight the need for careful implementation of convergence criteria. We attempt to make a comparative study of AD and FD gradients in an aerofoil optimisation, using the DERA CODAS method from the perspective of DERA's eventual aim, 3D viscous optimisation of wing-body configurations.Item Open Access Age estimation of Calliphora (Diptera: Calliphoridae) larvae using cuticular hydrocarbon analysis and Artificial Neural Networks(Elsevier, 2016-09-20) Moore, H. E.; Butcher, J. B.; Adam, C. D.; Day, C. R.; Falko, P. D.Cuticular hydrocarbons were extracted daily from the larvae of two closely related blowflies Calliphora vicina and Calliphora vomitoria (Diptera: Calliphoridae). The hydrocarbons were then analysed using Gas Chromatography–Mass Spectrometry (GC–MS), with the aim of observing changes within their chemical profiles in order to determine the larval age. The hydrocarbons were examined daily for each species from 1 day old larvae until pupariation. The results show significant chemical changes occurring from the younger larvae to the post-feeding larvae. With the aid of a multivariate statistical method (Principal Component Analysis and Artificial Neural Networks), samples were clustered and classified, allowing for the larval age to be established. Results from this study allowed larvae to be aged to the day with at worst, 87% accuracy, which suggests there is great potential for the use of cuticular hydrocarbons present on larvae to give an indication of their age and hence potentially a valuable tool for minimum PMI estimations.Item Open Access Age related changes of rib cortical bone matrix and the application to forensicage-at-death estimation(Nature Publishing Group, 2021-01-22) Bonicelli, Andrea; Zioupos, Peter; Arnold, Emily; Rogers, Keith D.; Xhemali, Bledar; Kranioti, Elena F.Forensic anthropology includes, amongst other applications, the positive identification of unknown human skeletal remains. The first step in this process is an assessment of the biological profile, that is: sex, age, stature and ancestry. In forensic contexts, age estimation is one of the main challenges in the process of identification. Recently established admissibility criteria are driving researchers towards standardisation of methodological procedures. Despite these changes, experience still plays a central role in anthropological examinations. In order to avoid this issue, age estimation procedures (i) must be presented to the scientific community and published in peer reviewed journals, (ii) accurately explained in terms of procedure and (iii) present clear information about the accuracy of the estimation and possible error rates. In order to fulfil all these requirements, a number of methods based on physiological processes which result in biochemical changes in various tissue structures at the molecular level, such as modifications in DNA-methylation and telomere shortening, racemization of proteins and stable isotopes analysis, have been developed. The current work proposes a new systematic approach in age estimation based on tracing physicochemical and mechanical degeneration of the rib cortical bone matrix. This study used autopsy material from 113 rib specimens. A set of 33 parameters were measured by standard bio-mechanical (nanoindentation and microindentation), physical (TGA/DSC, XRD and FTIR) and histomorphometry (porosity-ImageJ) methods. Stepwise regressions were used to create equations that would produce the best ‘estimates of age at death’ vs real age of the cadavers. Five equations were produced; in the best of cases an equation counting 7 parameters had an R2 = 0.863 and mean absolute error of 4.64 years. The present method meets all the admissibility criteria previously described. Furthermore, the method is experience-independent and as such can be performed without previous expert knowledge of forensic anthropology and human anatomy.Item Open Access Age-related changes in femoral head trabecular microarchitecture(Buck Institute for Age Research, 2017-10-11) Greenwood, Charlene; Clement, John; Dicken, Anthony; Evans, Paul; Lyburn, Iain Douglas; Martin, Richard M.; Stone, Nick; Zioupos, Peter; Rogers, KeithOsteoporosis is a prevalent bone condition, characterised by low bone mineral density and increased fracture risk. Currently, the gold standard for identifying osteoporosis and increased fracture risk is through quantification of bone mineral density using dual energy X-ray absorption. However, many studies have shown that bone strength, and consequently the probability of fracture, is a combination of both bone mass and bone ‘quality’ (architecture and material chemistry). Although the microarchitecture of both non-fracture and osteoporotic bone has been previously investigated, many of the osteoporotic studies are constrained by factors such as limited sample number, use of ovariectomised animal models, and lack of male and female discrimination. This study reports significant differences in bone quality with respect to the microarchitecture between fractured and non-fractured human femur specimens. Micro-computed tomography was utilised to investigate the microarchitecture of femoral head trabecular bone from a relatively large cohort of non-fracture and fracture human donors. Various microarchitectural parameters have been determined for both groups, providing an understanding of the differences between fracture and non -fracture material. The microarchitecture of non-fracture and fracture bone tissue is shown to be significantly different for many parameters. Differences between sexes also exist, suggesting differences in remodelling between males and females in the fracture group. The results from this study will, in the future, be applied to develop a fracture model which encompasses bone density, architecture and material chemical properties for both female and male tissues.Item Open Access Age-related trends in the trabecular micro-architecture of the medial clavicle: is it of use in forensic science?(Frontiers, 2020-01-22) McGivern, Hannah; Greenwood, Charlene; Márquez-Grant, Nicholas; Kranioti, Elena F.; Xhemali, Bledar; Zioupos, PeterThe mechanical and structural properties of bone are known to change significantly with age. Within forensic and archaeological investigations, the medial end of the clavicle is typically used for estimating the age-at-death of an unknown individual. Although, this region of the skeleton is of interest to forensic and clinical domains, alterations beyond the macro-scale have not been fully explored. For this study, non-destructive micro-computed tomography (µ-CT) was employed to characterize structural alterations to the cancellous bone of the medial clavicle. Fresh human cadaveric specimens (12-59 years) obtained at autopsy were utilized for this study, and were scanned with a voxel size of ∼83µm. Morphometric properties were quantified and indicated that the bone volume, connectivity density, mineral density, and number of trabeculae decreased with age, while the spacing between the trabeculae increased with age. In contrast to other sub-regions of the skeleton, trabecular thickness, and degree of anisotropy did not correlate with age. Collectively, this could suggest that the network is becoming increasingly perforated with age rather than exhibiting trabecular thinning. These results are used in the context of deriving a potential protocol for forensic investigations by using this particular and largely unexplored region of the skeleton, and provide inspiration for future experiments concerning micro-architectural and small scale changes in other regions of the human skeleton.Item Open Access Ageing bone fractures: the case of a ductile to brittle transition that shifts with age(Elsevier, 2019-12-03) Zioupos, Peter; Kirchner, Helmut O. K.; Peterlik, HerwigHuman bone becomes increasingly brittle with ageing. Bones also fracture differently under slow and fast loadings, being ductile and brittle, respectively. The effects of a combination of these two factors have never been examined before. Here we show that cortical bone is most fracture-resistant at the physiologically prevalent intermediate strain rates of 10−3 s−1 to 10−2 s−1 such as they occur in walking or running, slightly weaker at slower quasistatic and much weaker at fast impact loading rates. In young cortical bone (15 years of age) the ductile-to-brittle transition (DBT) occurs at strain rates of 10−2 s−1, in old cortical bone (85 yrs) at speeds lower by a factor of 10 to 40. Other research has shown that the energy required to break bone (per unit of fracture surface) drops as much as 60% between these two ages. Therefore, DBT seems to compound the well-known phenomenon of ‘brittle old bones’. Old bones can only cope with slow movement, young ones with both slow and fast movement. These observed material characteristics of (i) a shift of the DBT and (ii) a reduced energy absorption capacity appear to contribute at least as much to the loss of bone quality as the various quantity based (lowered bone density and mineral content) explanations of the past. They also provide a new powerful paradigm, which allows us to demonstrate mechanically, and uniquely, how human bone becomes increasingly brittle with age.Item Open Access Airborne behaviour monitoring using Gaussian processes with map information(Institution of Engineering and Technology, 2013-07-31T00:00:00Z) Oh, Hyondong; Shin, Hyo-Sang; Kim, Seungkeun; Tsourdos, Antonios; White, Brian A.This paper proposes an airborne behaviour monitoring methodology of ground vehicles based on a statistical learning approach with domain knowledge given by road map information. To monitor and track the moving ground target using UAVs aboard a moving target indicator, an interactive multiple model (IMM) filter is firstly applied. {\color{red}The IMM filter consists of an on-road moving mode using a road-constrained filter and an off-road moving mode using a conventional filter.} Mode probability is also calculated from the IMM filter, and it provides deviation of the vehicle from the road. Then, a novel hybrid algorithm for anomalous behaviour recognition is developed using a Gaussian process regression on velocity profile along the one-dimensionalised position of the vehicle, as well as the deviation of the vehicle. To verify the feasibility and benefits of the proposed approach, a numerical simulation is performed using realistic car trajectory data in a city traffic.Item Open Access Airborne S-Band SAR for forest biophysical retrieval in temperate mixed forests of the UK(MDPI, 2016-07-20) Ningthoujam, Ramesh K.; Balzter, Heiko; Tansey, Kevin; Morrison, Keith; Johnson, Sarah C. M.; Gerard, France; George, Charles; Malhi, Yadvinder; Burbidge, Geoff; Doody, Sam; Veck, Nick; Llewellyn, Gary M.; Blythe, Thomas; Rodriguez-Vega, Pedro; van Beijma, Sybrand; Spies, Bernard; Barnes, Chloe; Padilla-Parellada, Mark; Wheeler, James E. M.; Louis, Valentin; Potter, Tom; Edwards-Smith, Alexander; Polo Bermejo, JamieRadar backscatter from forest canopies is related to forest cover, canopy structure and aboveground biomass (AGB). The S-band frequency (3.1–3.3 GHz) lies between the longer L-band (1–2 GHz) and the shorter C-band (5–6 GHz) and has been insufficiently studied for forest applications due to limited data availability. In anticipation of the British built NovaSAR-S satellite mission, this study evaluates the benefits of polarimetric S-band SAR for forest biophysical properties. To understand the scattering mechanisms in forest canopies at S-band the Michigan Microwave Canopy Scattering (MIMICS-I) radiative transfer model was used. S-band backscatter was found to have high sensitivity to the forest canopy characteristics across all polarisations and incidence angles. This sensitivity originates from ground/trunk interaction as the dominant scattering mechanism related to broadleaved species for co-polarised mode and specific incidence angles. The study was carried out in the temperate mixed forest at Savernake Forest and Wytham Woods in southern England, where airborne S-band SAR imagery and field data are available from the recent AirSAR campaign. Field data from the test sites revealed wide ranges of forest parameters, including average canopy height (6–23 m), diameter at breast-height (7–42 cm), basal area (0.2–56 m2/ha), stem density (20–350 trees/ha) and woody biomass density (31–520 t/ha). S-band backscatter-biomass relationships suggest increasing backscatter sensitivity to forest AGB with least error between 90.63 and 99.39 t/ha and coefficient of determination (r2) between 0.42 and 0.47 for the co-polarised channel at 0.25 ha resolution. The conclusion is that S-band SAR data such as from NovaSAR-S is suitable for monitoring forest aboveground biomass less than 100 t/ha at 25 m resolution in low to medium incidence angle range.Item Open Access All-sky search for long-duration gravitational wave transients with initial LIGO(American Physical Society, 2016-02-12) Abbott, B. P.; Davies, G. S.; LIGO Scientific Collaboration and Virgo CollaborationWe present the results of a search for long-duration gravitational wave transients in two sets of data collected by the LIGO Hanford and LIGO Livingston detectors between November 5, 2005 and September 30, 2007, and July 7, 2009 and October 20, 2010, with a total observational time of 283.0 days and 132.9 days, respectively. The search targets gravitational wave transients of duration 10–500 s in a frequency band of 40–1000 Hz, with minimal assumptions about the signal waveform, polarization, source direction, or time of occurrence. All candidate triggers were consistent with the expected background; as a result we set 90% confidence upper limits on the rate of long-duration gravitational wave transients for different types of gravitational wave signals. For signals from black hole accretion disk instabilities, we set upper limits on the source rate density between 3.4 × 10−5 and 9.4 × 10−4 Mpc−3 yr−1 at 90% confidence. These are the first results from an all-sky search for unmodeled long-duration transient gravitational waves.