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Anterior mitral valve leaflet (AMVL) elongation is a recognised feature of hypertrophic cardiomyopathy (HCM). However, whether AMVL elongation precedes left ventricular hypertrophy in cats is currently unknown. The aim of this study was to explore the risk of developing an HCM phenotype in cats with an elongated AMVL.FIFTY-FIVE APPARENTLY HEALTHY CATS WITH A NORMAL BASELINE ECHOCARDIOGRAM AND A FOLLOW-UP ECHOCARDIOGRAM ATONE YEAR.This was a retrospective longitudinal study. Cats at the baseline were grouped based on whether or not they developed an HCM phenotype at follow-up. AMVL length and left atrial and left ventricular dimensions were measured from two-dimensional images.The median follow-up period of the study population was 5.4 years (25th and 75th quartile, 2.7-6.7 years). During this time, 17 cats (30.9%) developed an HCM phenotype. At the baseline, cats that subsequently developed an HCM phenotype had greater AMVL length (9.4 mm [25th and 75th quartile, 9.0-10.6 mm] vs. 8.5 mm [25th and 75th quartile, 7.6-9.1 mm], P 0.0001) and maximal left ventricular wall thickness (4.5 mm [25th and 75th quartile, 4.1-4.7 mm] vs. 4.0 mm [25th and 75th quartile, 3.7-4.6 mm], P = 0.007) than those that did not. Multiple logistic regression analysis confirmed that both baseline variables were independent predictors for development of an HCM phenotype.The AMVL length was greater in cats that subsequently developed left ventricular hypertrophy. Further studies investigating the clinical application of AMVL in the natural history of feline HCM are warranted.

Introduction Both paroxysmal high-grade second-degree and persistent third-degree atrioventricular block (AVB) are recognised in cats. Our aim was to document the presentation, echocardiographic data, comorbidities and outcome in affected cats from a single referral hospital, including those that underwent epicardial pacemaker implantation (EPI). Animals, materials and methods This retrospective study included 64 cats diagnosed with persistent third-degree or paroxysmal high-grade AVB, for which detailed patient history was available. Non-parametric testing, Kaplan-Meier curves and Cox proportional hazard testing were performed. Results Atrioventricular block was persistent in 43 cats (67%) and paroxysmal in 21 (33%). Forty-seven cats (74%) were referred for cardiac complaints (e.g. collapse, arrhythmia, tachypnea), 6 (9%) had non-specific complaints and AVB was an incidental finding in 11 cats (17%). Median duration of clinical signs prior to presentation was 21 days (1–1138 days). Thirty-nine (63%) cats had echocardiographic abnormalities; 13 (20%) presented with congestive heart failure. Forty-five (70%) cats had one or more comorbidities. Fifteen cats underwent EPI with immediate resolution of signs in 12 cats. Following EPI, two and four cats experienced major and minor complications, respectively. Forty-seven cats died; median survival time was 799 days (all-cause mortality). Cardiac-related death occurred in 17 cats (36%); median survival in these cats was 132 days. Heart failure on presentation was the only independent risk factor for cardiac death (p=0.002). Conclusions Outcome in cats with AVB was variable, although most had good medium- to long-term survival. Cardiac death occurred in a minority of cats. Pacemaker implantation was effective in relieving clinical signs.

A method to calculate the elastic shakedown limit of transportation systems (e.g. pavements and railways) supported by geogrid reinforced soils is presented. For the first time, lower-bound shakedown theory is combined with a strength-based geogrid simulation approach, resulting in a rapid method to quantify the benefit of geogrids on the elastic shakedown limit. It allows decoupling of elastic stress generation and shakedown calculations, meaning it is straightforward to implement, and requires minimal computational effort. Therefore it presents a useful tool to optimise geogrid design for transportation structures such as highway pavements and railways. To show the capability of the method, shakedown limits are calculated for a variety of geogrid configurations using elastic stresses induced by a moving Hertz load. The effect of geogrid depth, soil cohesion, soil friction angle and loading type (normal versus tangential) are investigated for reinforced and non-reinforced soils. It is found that the optimum depth is sensitive to the soil strength properties. Regarding loading, it is shown that for highly tangential loads, shallower geogrids are effective, while for loads with a minimal tangential component, deeper geogrids are effective.

This paper gives new insights into non-linear subgrade behaviour on high speed railway track dynamics. First, a novel semi-analytical model is developed which allows for soil stiffness and damping to dynamically change as a function of strain. The model uses analytical expressions for the railroad track, coupled to a thin-layer element formulation for the ground. Material non-linearity is accounted for using a ‘linear equivalent’ approach which iteratively updates the soil material properties. It is validated using published datasets and in-situ field data. Four case studies are used to investigate non-linear behaviour, each with contrasting subgrade characteristics. Considering an 18 tonne axle load, the critical velocity is significantly lower than the linear case, and rail deflections are up to 30% higher. Furthermore, at speeds close-to, but below the non-linear critical velocity, dynamic amplification is highly sensitive to small increases in train speed. These findings are dependent upon soil material properties, and are important for railway track-earthwork designers because often 70% of the linear critical velocity is used as a design limit. This work shows that designs close to this limit may be still at risk of high dynamic effects, particularly if line speed is increased in the future.

Railway tracks experience elevated rail deflections when the supporting soil is soft and/or the train speed is greater than approximately 50% of the wave propagation velocity in the track-soil system (i.e. the critical velocity). Such vibrations are undesirable, so soil replacement or soil improvement of the natural soil (or alternatively mini-piles or lime-cement treatment) is often used to increase track-ground stiffness prior to line construction. Although areas of existing soft subgrade might be easily identified on a potential new rail route, it is challenging to determine the type and depth of ground remediation required. Therefore, major cost savings can be made by optimising ground replacement/improvement strategies. This paper presents a numerical railway model, designed for the dynamic analysis of track-ground vibrations induced by high speed rail lines. The model simulates the ground using a thin-layer finite element formulation capable of calculating 3D stresses and strains within the soil during train vehicle passage. The railroad track is modelled using a multi-layered formulation which permits wave propagation in the longitudinal direction, and is coupled with the soil model in the frequency-wavenumber domain. The model is validated using a combination of experimental railway field data, published numerical data and a commercial finite element package. It is shown to predict track and ground behaviour accurately for a range of train speeds. The railway simulation model is computationally efficient and able to quickly assess dynamic, multi-layered soil response in the presence of ballast and slab track structures. Therefore it is well-suited to analysing the effect of different soil replacement strategies on dynamic track behaviour, which is particularly important when close to critical speed. To show this, three soil-embankment examples are used to compare the effect of different combinations of stiffness improvement (stiffness magnitude and remediation depths up to 5 m) on track behaviour. It is found that improvement strategies must be carefully chosen depending upon the track type and existing subgrade layering configuration. Under certain circumstances, soil improvement can have a negligible effect, or possibly even result in elevated track vibration, which may increase long-term settlement. However, large benefits are possible, and if detailed analysis is performed, it is possible to minimise soil improvement depth with respect to construction cost.

Railway lines typically use traditional sloping embankments as the principal means of track support. However, the use of Geosynthetically Reinforced Soil (GRS) systems have gained popularity as alternatives to conventional embankments, particularly for high-speed lines in Japan. This system requires less ground stabilization/improvement and less land take than conventional embankments due to its smaller base area. This research investigates the immediate and long-term settlement behaviour of a Geosynthetically Reinforced Soil with Retaining Wall (GRS-RW) system subject to cyclic loading for two track forms: a concrete slab track and a ballasted track. First, a three-sleeper concrete slab section is constructed at full-scale under controlled laboratory conditions, followed by a ballasted track. Both are supported on a 1.2 m deep subgrade and a frost protection layer in accordance with railway design standards. Two different axle load magnitudes are applied statically, and then cyclically/dynamically, using 6 actuators to replicate moving train axle loads. It is observed that the slab track performs significantly better in terms of elastic and plastic deformation under both static and cyclic loading. Overall, the amplitude of the rail displacement under an individual cycle loading was approximately 25% lower for the slab track and the amplitude of the sleeper displacement on the ballasted track was approximately 6–7 times higher.

Beam on elastic foundation theory is widely employed when studying railway track behaviour, for applications such as track dynamics, and noise and vibration. At a basic level, the use of a single continuous beam resting on a springs-in-series support is straightforward to implement and computationally efficient. However, it can also be extended to simulate the multi-layered and periodic nature of railway tracks, which typically comprise a variety of components. Further, these track models can also be coupled with both vehicle and subgrade models. Therefore, this paper presents a state-of-the-art technical review of beam on elastic foundation theory, including the exploration of recent advancements in the field. Firstly, a variety of modelling strategies and solution methods employed for the computation of track behaviour are reviewed. These include periodic and semi-periodic modelling approaches. Considerations for extending beam on elastic foundation approaches to include train-track interaction and track-ground interaction are then provided. Finally, using the aforementioned theory, benchmark solutions for three common problem types are given: railway noise, railway track dynamics and railway ground-borne vibration.

In 2016 the first Strategy for Heating and Cooling of the European Union has shown that district heating and cooling networks can integrate renewable energies in an increasingly energy-efficient built environment. At the same time, the heating and cooling sector is probably the most diverse and least mapped component of the European energy system. The aim of the Pan-European Thermal Atlas is to improve the knowledge base for the geographical distribution of heat and cooling demands across Europe. Demand densities of the demanded thermal services themselves, the spatial coherence of these demands, and their location relative to sources of heating greatly affect the economy of district heating schemes compared to individual solutions. The objective is therefore to develop a comprehensive model, which can be used to a) quantify heat demands by density, b) group coherent areas with demands into prospective supply zones, c) produce supply curves for these zones, and d) ultimately calculate local energy mixes on the basis of allocated excess heat as well as renewable energy sources. The developed method spatially disaggregates national demand data to high-resolution geospatial data on urban structures. The resulting atlas allows for an advanced quantitative screening process, which can establish the basis for energy systems analyses relying on geographically explicit information on the heating demand and supply volumes and costs. The present paper presents version 4 of the Pan-European Thermal Atlas, which takes another step towards higher spatial resolution and confidence in comparison to its predecessors, version 1 to 3. For the first time, a 100 m resolution heat atlas of Europe is being presented, which may help describing the heating sector in the required spatial resolution. By means of spatial statistical analyses using ordinary least square linear regressions, multiple spatial inputs such as population, degree of built-up and its derivatives are turned into a coherent model of the urban tissue. Plot ratios form the basis of models of heat demand in single and multi-family residential buildings as well as the service sector. Prospective district heating areas have been delineated, and the resulting zoning of heat supply has been linked to a resource-economic analysis, which allows for cost-supply studies in disaggregated form. The present heat atlas version 4 is now available for 14 countries that altogether represent 90% of the heat demand in the 28 European Union member states. First results are being presented with emphasis on the achieved methodological improvements. Moreover, a newly developed online mapping system is being presented, which will assist in mapping the new geography of heating and cooling demands and supplies.

Introduction Hypertrophic cardiomyopathy (HCM) has a variable prognosis; left atrial size, presence of clinical signs and left ventricular systolic function have been shown to predict outcomes. Mitral annular plane systolic excursion (MAPSE) and tricuspid annular plane systolic excursion (TAPSE) assess longitudinal ventricular systolic function and are decreased in cats with HCM. The aim of the study was to ascertain whether MAPSE and TAPSE have prognostic value in HCM and if cats with pleural effusion have lower MAPSE and TAPSE than cats with pulmonary oedema. Animals One hundred eighty-four client-owned cats diagnosed with HCM. Methods This is a retrospective study. Echocardiography was used to diagnose HCM (end-diastolic left ventricular wall thickness ≥ 6 mm) and to measure MAPSE and TAPSE. Survival information was obtained. Results No multivariable model including MAPSE or TAPSE could be generated in this population. Cats with pleural effusion ± pulmonary oedema had lower MAPSE measured at the interventricular septum (MAPSE IVS) and TAPSE, compared with cats with pulmonary oedema only. MAPSE IVS was the only factor predicting pleural effusion on multivariable regression model. Conclusions Lower MAPSE and TAPSE were not independently associated with outcomes on multivariable analysis. Cats with pleural effusion ± pulmonary oedema had lower TAPSE and MAPSE IVS than cats with pulmonary oedema, and MAPSE IVS was the only predictive factor associated with the development of pleural effusion in this population.

Pericardial effusion (PE) is reported in dogs as a consequence of neoplasia, primary cardiac disease or as an idiopathic condition. We describe seven dogs with systemic inflammatory disease, PE without tamponade and increased cardiac troponin I concentrations. Echocardiographic findings and adjunctive testing did not identify other known causes of PE. Resolution of the PE was documented in five of seven dogs in which follow-up echocardiography was performed, often after anti-inflammatory therapy. Resolution of PE was associated with normalisation of cardiac troponin I levels. Clinical signs had not recurred in six dogs with follow-up for more than 12 months and up to 7 years. These findings suggest an association between systemic inflammation and PE in dogs.

AIM To investigate whether computed tomography (CT)/magnetic resonance imaging (MRI) brain imaging is associated with detection of structural causes of a first episode of psychosis (FEP) or first episode of behavioural abnormality (FEB) in the paediatric population, as this has not been previously documented in the literature. MATERIALS AND METHODS Individuals with FEP/FEB but no neurological signs referred to a tertiary children's centre for cerebral MRI or CT were reviewed retrospectively. Individuals were evaluated independently with one technique (CT or MRI) only. RESULTS Thirty-four consecutive cerebral MRI and six consecutive CT examinations were identified between 2017 and 2020. No patients were identified as having an organic cause for the psychosis at MRI or CT. Four patients (9%) had incidental findings on MRI, unrelated to the psychosis, such as prominent perivascular spaces, hypoplastic transverse sinus, and sinonasal mucosal wall thickening. No abnormal findings were seen on CT. There was therefore no obvious difference between MRI and CT imaging in detecting organic disease potentially responsible for FEP. CONCLUSION Routine structural MRI or CT of the brain is unlikely to reveal disease leading to a significant change in management. MRI demonstrated only a few incidental findings, unrelated to the child's clinical history. Therefore, routine brain structural imaging of FEP/FEB in paediatric patients without focal neurology may not be routinely required. If imaging is requested, then there is no significant difference between CT and MRI in detecting clinically significant lesions.

Railway-induced ground vibrations can cause negative effects to people/structures located in urban areas. One of the main sources of these vibrations is from the large vehicle forces generated when train wheels impact local defects (e.g. switches/crossings). The sole use of traditional in-field transfer-mobility approaches is well suited for plain-line assessments, however is more challenging when discontinuities are present, due to the generation of large magnitude impact forces. This paper presents a hybrid experimental-numerical approach that can predict ground-borne vibration levels in the presence of a variety of railroad artefacts such as transition zones, switches, crossings and rail joints on existing networks. Firstly, the experimental procedure is described, which consists of multiple single source transfer mobilities to determine the transmission characteristics between rail and nearby structures. This is then coupled with a combined multibody vehicle and track numerical model, which is capable of simulating vibration generation in the presence of railway discontinuities. The resulting model is advantageous over alternative approaches because it can account for complex railway discontinuities, while at the same time incorporating the large uncertainties associated with different soil configurations. It is used to analyse a case study, where it is shown that vibration levels are strongly dependent on vehicle speed, defect type and defect size.

Railway track is constructed on compacted soil which is, characteristically, unsaturated. The performance of the subgrade, both in the short- and long-term, is dependent on environmental factors, in particular, an increase in subgrade moisture content due to high rainfall can result in subgrade distress or shear failure under cyclic loading (i.e. train passage). Furthermore, due to varying climatic conditions, subgrade soil may fluctuate between a saturated and unsaturated condition. It is necessary, therefore, to understand such soil behaviour to ensure a safe and economical design and in the planning of maintenance work. Previous research has focused on the effect of water on the superstructure, but not the substructure. This paper outlines a full-scale testing programme to study track performance after flooding and, subsequently, during a 2, 4 and 6 week recovery (drying) period. The study investigated the influence of soil suction on subgrade behaviour with measurements made using the filter paper technique, whilst subgrade modulus was measured using the plate load test. The results show that subgrade behaviour is influenced by changes in water content associated with soil suction; particularly, when wetted from a dry state. It is also found that tamping is less effective in the presence of wet/low-stiffness subgrade soil.

A high degree of accuracy is required when using echocardiography to diagnose hypertrophic cardiomyopathy (HCM) in cats, as variation in measurements of 0.5 mm may affect classification of individuals as ‘abnormal’. This study in adult cats examined at different time points inter-observer variability between two Board certified echocardiographers in veterinary cardiology.Twenty-four female European shorthair cats were examined at 12, 18 and 24 months of age by observer 1. Two dimensional (2D) echocardiographic images were collected in conscious cats to measure left ventricular, aortic and left atrial dimensions. Measurements were repeated by observer 2 on stored images, and analysed for effect of time, observer and time-observer interaction. Based on end-diastolic left ventricular wall thickness, cats were diagnosed as ‘normal’ or 'abnormal'. Linear mixed models (generalized when appropriate) were performed.A significant difference between observers was found for all septal (IVSd) and free wall (LVFWd) thickness measurements and left ventricular internal diameters but not for aortic or left atrial measurements. All measurement coefficients of variation (CV) were 5 mm in cats > 6 kg bodyweight) was significantly different between observers for IVSd but not LVFWd.Caution is warranted when diagnosing as ‘abnormal’ or interpreting small changes based on IVSd, due to significant inter-observer differences in this measurement. Keywords: Ultrasound, Reproducibility, Cat, Heart

Purpose The purpose of this study was to compare low-dose-rate prostate brachytherapy treatment plans created using three retrospectively applied planning techniques with plans delivered to patients. Methods and Materials Treatment plans were created retrospectively on transrectal ultrasound (TRUS) scans for 26 patients. The technique dubbed 4D Brachytherapy was applied, using TRUS and MRI to obtain prostatic measurements required for the associated webBXT online nomogram. Using a patient's MRI scan to create a treatment plan involving loose seeds was also explored. Plans delivered to patients were made using an intraoperative loose seed TRUS-based planning technique. Prostate V100 (%), prostate V150 (%), prostate D90 (Gy), rectum D0.1cc (Gy), rectum D2cc (Gy), urethra D10 (%), urethra D30 (%), and prostate volumes were measured for each patient. Statistical analysis was used to assess and compare plans. Results Prostate volumes measured by TRUS and MRI were significantly different. Prostate volumes calculated by the webBXT online nomogram using TRUS- and MRI-based measurements were not significantly different. Compared with delivered plans, TRUS-based 4D Brachytherapy plans showed significantly lower rectum D0.1cc (Gy) values, MRI-based 4D Brachytherapy plans showed significantly higher prostate V100 (%) values and significantly lower rectum D0.1cc (Gy), urethra D10 (%), and urethra D30 (%) values, and loose seed MRI-based plans showed significantly lower prostate V100 (%), prostate D90 (Gy), rectum D0.1cc (Gy), rectum D2cc (Gy), urethra D10 (%), and urethra D30 (%) values. Conclusions TRUS-based 4D Brachytherapy plans showed similar dosimetry to delivered plans; rectal dosimetry was superior. MRI can be integrated into the 4D Brachytherapy workflow. The webBXT online nomogram overestimates the required number of seeds.

The increase in freight and passenger rail travel has driven demand for more efficient and rapid investigation of railway trackbed ballast. One of the current approaches to evaluating the stiffness of railway ballast is to use a falling weight deflectometer (FWD). Whilst this is effective to establish overall track stiffness, it requires the rails to be unclipped from the sleepers – thus, it is very intrusive and expensive. The FWD technique does not measure ballast fouling. This paper focuses on using the impulse response (IR) testing method with a 12 lb instrumented hammer to excite a railway trackbed ballast composed of variously fouled ballast, with response measured using a geophone – in order to estimate ballast fouling. Finally, the impulse response results are successfully correlated with the assessed Fouling Index of the ballast.

Ground-borne noise and vibration from railway lines can cause human distress/annoyance, and also negatively affect real estate property values. Therefore this paper analyses a collection of technical ground-borne noise and vibration reports, detailing commercial vibration assessments undertaken at 1604 railway track sections, in 9 countries across the world. A wide range of rail projects are considered including light rail, tram lines, underground/tunnelled lines, freight, conventional rail and high speed rail. It documents the rise in ground-borne vibration problems and trends in the prediction industry, with the aim of informing the current research area. Firstly, the reports are analysed chronologically and it is found that railway vibration is a growing global concern, and as such, assessments have become more prevalent. International assessment metrics are benchmarked and it is found that velocity decibels (VdB), vibration dose value (VDV) and peak particle velocity (PPV) are the most commonly used methods of assessment. Furthermore, to predict vibration levels, the physical measurement of frequency transfer functions is preferential to numerical modelling. Results from the reports show that ground vibration limits are exceeded in 44% of assessments, and that ground-borne noise limits are exceeded in 31%. Moreover, mitigation measures were required on approximately 50% of projects, revealing that ground-borne noise and vibration is a widespread railroad engineering challenge. To solve these problems, the most commonly used abatement strategy is a modification of the railtrack structure (active mitigation), rather than the implementation of a more passive solution in the far-field.

When high speed trains travel close to the wave propagation velocity of the supporting track-ground system, large amplitude track deflections are generated. This has safety implications, and also results in a significant increase in track maintenance due to subgrade deterioration. Thus, this paper presents a method to rapidly predict the speed at which these ‘critical velocity’ effects occur. The method is based upon a dispersion analysis of both the track (either ballast or non-ballasted/slab track) and the underlying ground, which are treated as uncoupled systems. Unlike previous approaches, the new calculation approach is fully automated thus not requiring any post-processing to extract the soil dispersion curve. It also works for soil layers of arbitrary depth, uses minimal computing power and can calculate critical speeds associated with higher soil modes. The dispersion based method can be deployed on new/existing lines via a drop-weight test, or using existing geotechnical data. Its accuracy is tested by comparing the results against an alternative semi-analytical, quasi-static railtrack model, and found to be 97% accurate. The code is useful for railway track infrastructure design and its short run times mean it can be used as a scoping tool for newly proposed high speed railroad lines. To obtain new insights into the key variables effecting critical velocity, a sensitivity analysis is undertaken using 1000 random soil profiles. It is found that on average, for the same track height, slab tracks are less likely to encounter critical velocity issues than ballasted tracks because their critical speed is typically 11% higher. It is also shown that track height plays an important role with increases in slab track thickness and reductions in ballasted track thickness both causing increases in critical velocity. Furthermore, it is found that soil saturation affects critical speed considerably (by up to 12–17% depending on track type) because changes to Poisson’s ratio alter the dispersion characteristics of layered soils in the mid-frequency range, where critical velocity effects occur. Finally, it is shown that railpad stiffness has a low influence, and that increasing the rail bending stiffness on ballasted tracks increases critical speed.

When constructing a new railway line, its long length means there are significant financial implications associated with determining the geodynamic ground properties. Therefore, this paper presents recommendations to optimize the efficiency and depth of such a geotechnical site investigation. Firstly, a numerical analysis is performed to investigate the effect of soil layering, soil stiffness and track bending stiffness on critical velocity. It is shown that each of these variables play an important role, however for most practical cases, only the top 8 m of soil is influential. Track dynamics are rarely affected by soil properties at depths below this, meaning this is the maximum required depth of soil investigation. Using this knowledge, a hybrid experimental-analytical methodology is presented, based on a geophysical Spectral Analysis of Surface Waves (SASW) experimental setup to compute the ground dispersion curve and an analytical model to compute the track dispersion curve. The experimental and analytical results are combined directly, to accurately compute the critical velocity. This approach is attractive because: 1) SASW tests are typically accurate to ≈8 m (when using a mobile exciter) thus matching the required depth needed for critical velocity computation, 2) soil property uncertainties are inherently accounted for, 3) the uncertainties associated with SASW inversion are avoided. The approach is attractive when constructing new railway lines and upgrading the speed of existing lines because it can potentially yield site investigation cost savings. In-situ field work is performed to show the practical application of the technique., This research was financially supported by: Project POCI-01-0145-FEDER-007457–CONSTRUCT–Institute of R&D InStructures and Construction funded by FEDER funds through COMPETE2020– Programa Operacional Competitividade e Internacionalização (POCI)–and by national funds through FCT–Fundação para a Ciência e a Tecnologia; Project POCI-01-0145-FEDER-029577–funded by FEDER funds through COMPETE2020 – Programa Operacional Competitividade e Internacionalização (POCI), national funds (PIDDAC) through FCT and the Leverhulme Trust (PLP-2016-270). This work was partially carried out under the framework of In2Track2, a research project of Shift2Rail. The financial support provided by University of Leeds Cheney Award Scheme is also appreciated.

This paper aims to demonstrate the anisotropic behaviour of railway ballast via true-triaxial tests. To do so, a novel, large-scale, true-triaxial testing apparatus (GeoTT) is designed and constructed. It consists of six hydraulic actuators, designed to apply a distributed stress to large granular cubic test specimens with dimensions: 500 mm × 500 m × 500 mm. To show the capability of the new facility, crushed granite railway ballast with d50 = 43 mm is tested. Three different confining stresses are applied to determine the Poisson’s ratio and modulus in three dimensions. Anisotropic behaviour is clearly evident, with horizontal directions showing a lower modulus compared to the vertical direction. It is also found that confining stress has an important effect on both Poisson’s ratio and modulus when the primary loading is applied in three orthogonal directions. These results are useful for understanding the behaviour of railway ballast and for the calibration of railroad numerical models.

A rail track system comprises a number of components and, in order to analyse and predict track behaviour, it is essential to understand the function of each component as each will have a major influence on overall track performance. Historically, rail track substructure, particularly the subgrade, has been given less attention than the superstructure despite its importance in track design. This paper presents a full-scale experimental investigation to study the behaviour of subgrade in both saturated and unsaturated conditions, and how this behaviour changes with soil suction. Further, the investigation also studies the role of sand-blanketing during and after repeated flooding events. The results show that as soil suction reduces, flooding results in a continual reduction in both soil stiffness and track stiffness. It is also shown that the introduction of a sand-blanket has limited effectiveness as a drainage material, particularly after prolonged and repeated flooding.

This work reveals the existence of a new dynamic load amplification mechanism due to ground surface loads. It is caused by the interaction between a moving vehicle's axle configuration and the vibration characteristics of the underlying soil-guideway system. It is more dominant than the traditionally considered ‘critical velocity’ dynamic amplification mechanism of the guideway-ground structure, and is of relevance to very high speed transport systems such as high speed rail. To demonstrate the new amplification mechanism, first a numerical model is developed, capable of simulating ground-wave propagation in the presence of a series of discrete high speed loads moving on a soil-guideway system. The model couples analytical equations for the transportation system guideway with the thin-layer element method for ground simulation. As a practical example, it is validated using high speed railroad field data and then used to analyse the response of a generalised single moving load at high speed. Next the effect of multiple discrete vehicle-guideway contact points is studied and it is shown that dynamic amplification is highly sensitive to load spacing when the speed is greater than the critical velocity. In particular, large resonant effects occur when the axle/magnet loading frequency and the propagating wave vibration frequency of the soil-guideway structure are equivalent. As an example, it is shown that for an individual case, although critical velocity might increase displacements by 50–100%, for the same scenario, axle configuration can increase displacements by 400%. It is also shown that resonance is sensitive to the total number of loading points and the individual frequencies excited by various spacings. The findings are important for current (e.g. high speed railway) and potential future (e.g. hyperloop) transport systems required to operate at speeds either close-to, or greater than the critical velocity of their supporting guideway-soil structure. In such situations, it is important to design the vehicle and supporting structure(s) as a combined system, rather than in isolation.

This paper reviews, synthesises and benchmarks new understandings relating to railway vibrations. Firstly, the effect of vibrations on passenger comfort is evaluated, followed by its effect on track performance. Then ground-borne vibration is discussed along with its effect on the structural response of buildings near railway lines. There is discussion of the most suitable mathematical and numerical modelling strategies for railway vibration simulation, along with mitigation strategies. Regarding ground borne vibration, structural amplification is discussed and how vibration mitigation strategies can be implemented. There is also a focus on determining how 'critical velocity' and 'track critical velocity' are evaluated - with the aim of providing clear design guidelines related to Rayleigh wave velocity. To aid this, conventional site investigation data is reviewed and related to critical velocity calculations. The aim is to provide new thinking on how to predict critical velocity from readily available conventional site investigation data.

This paper provides new insights into the characteristics and uncertainties in railway ground-borne vibration prediction. It analyses over 1500 ground-borne vibration records, at 17 high speed rail sites, across 7 European countries. Error quantification tests reveal that existing scoping models, for at-grade tracks, are subject to a mean error of approximately ±4.5 VdB. Furthermore, it is found that seemingly identical train passages are subject to a standard deviation of ±2 VdB, thus providing an indicator of the minimum error potentially achievable in detailed prediction studies. Existing vibration attenuation relationships are also benchmarked and potential new relationships proposed. Furthermore, it is found that soil material properties are the most influential parameter that effect vibration levels while the effect of train speed is low. In addition, sites with train speeds close to the ‘critical velocity’ are examined and it is found that their vibration characteristics differ vastly from non-critical velocity sites. The study presents one of the most comprehensive publications of experimental ground-borne railway vibration data and comprises of datasets from Belgium, France, Spain, Portugal, Sweden, England and Italy. First, several international metrics are used to analyse the data statistically. Then the effect of train speed is investigated, with train speeds ranging from 72 to 314 km/h being considered. Next the effect of train type is analysed, with correlations presented for TGV, Eurostar, Thalys, Pendolino, InterCity, X2000, Alfa Pendular, AVE-S100 and Altaria trains. Then, vibration frequency spectrums are considered and critical speed effects analysed. Finally, an investigation into the typical standard deviation encountered in vibration prediction is undertaken.

Objectives To evaluate vena contracta and other echocardiographic measures of myxomatous mitral valve disease (MMVD) severity in a multivariable analysis of survival in dogs. Animals 70 dogs diagnosed with MMVD from stored echocardiographic images that met study inclusion criteria. Methods Left heart dimensions were measured as well as mitral regurgitant jet area/left atrial area (JAR), early mitral filling velocity (E vel ), extent of mitral valve prolapse in right and left views (Prol R , Prol L ), Prol indexed to aortic diameter (Prol R :Ao, Prol L :Ao), presence of a flail leaflet (Flail R , Flail L ), and mitral regurgitation vena contracta diameter (VC R , VC L ) indexed to aortic diameter (VC R :Ao, VC L :Ao). Follow-up from referring veterinarians was obtained by questionnaire or telephone to determine survival times. Inter- and intra-observer agreement was evaluated with Bland–Altman plots and weighted Kappa analysis. Survival was analyzed using Kaplan–Meier curves, logrank tests and Cox's proportional hazards. Results Logrank analysis showed VC L :Ao, VC R :Ao, Flail L, Prol R :Ao, Prol L :Ao, left ventricular internal dimension in diastole indexed to aortic diameter (LVIDD:Ao) >2.87, left atrium to aorta ratio (LA/Ao) >1.6, and E vel >1.4 m/s were predictors of cardiac mortality. In a multivariable analysis, the independent predictors of cardiac mortality were E vel >1.4 m/s [hazard ratio (HR) 5.0, 95% confidence interval (CI) 2.5–10.3], Flail L (HR 3.1, 95% CI 1.3–7.9), and Prol R :Ao (HR 2.8, 95% CI 1.3–6.3). Conclusions Echocardiographic measures of mitral regurgitation severity and mitral valve pathology provide valuable prognostic information independent of chamber enlargement in dogs with MMVD.

Objectives To compare red cell distribution width (RDW) between dogs with different causes of pulmonary hypertension (PH) and a control dog population to determine whether RDW was correlated with severity of PH as measured by echocardiography. A further aim was to determine the prognostic significance of increased RDW for dogs with PH. Animals Forty-four client-owned dogs with PH and 79 control dogs presented to a single tertiary referral institution. Methods Signalment, clinical pathological and echocardiographic data were obtained retrospectively from the medical records of dogs with PH, and RDW measured on a Cell-Dyn 3500 was compared between dogs with pre- and post-capillary PH and a control population. Referring veterinary surgeons were contacted for follow-up information and Kaplan–Meier analysis was conducted to investigate differences in survival time between affected dogs with different RDW values. Results The RDW was significantly greater in dogs with pre-capillary PH compared to control dogs. There was no difference in median survival times between dogs with PH divided according to RDW values. The RDW was positively correlated with mean corpuscular volume and haematocrit in dogs with PH, but did not correlate with echocardiographic variables. Conclusions An association was found between dogs with PH and increased RDW; however there was considerable overlap in values between control dogs and dogs with PH. The RDW was not associated with survival in this study.

This paper presents the measured results of full-scale testing of railway track under laboratory conditions to examine the effect on the track stiffness when the ballast is reinforced using a urethane cross-linked polymer (polyurethane). The tests are performed in the GRAFT I (Geopavement and Railways Accelerated Fatigue Testing) facility and show that the track stiffness can be significantly enhanced by application of the polymer. The track stiffness is measured at various stages during cyclic loading and compared to the formation stiffness, which is determined prior to testing using plate load tests. The results indicate that the track stiffness increased by approximately 40–50% based on the measured results and from the previously published GRAFT I settlement model. The track stiffness was monitored during loading for a maximum of 500,000 load cycles. The paper concludes by presenting and commenting on, the application of the technique to a real site where the Falling Weight Deflectometer was used before and after polymer treatment to determine the dynamic sleeper support stiffness. The very challenging site conditions are highlighted, in particular the water logged nature of the site, and comment made on the effect of the water on polymer installation. The results of the FWD measurements indicate that a good increase in overall track stiffness was measured. These results are consistent with the laboratory tests which are performed on a different soil and use a different measurement technique and hence confirm that regardless of the soil and measurement system track stiffness increases are observed using this technique.

The purpose of this paper is to provide an overview of fuel production costs for two types of synthetic fuels – methanol and methane, along with comparable costs for first and second generation biodiesel, two types of second generation bioethanol, and biogas. When analysing 100% renewable systems, the intermittent nature of renewable energy sources needs to be taken into consideration, so flexible solutions that can provide an option for regulating the energy system by balancing and storing excess electricity are essential. Coupled with the limitations of biomass resources and the need for the sustainable use of it, the solution that fits both concerns needs to be prioritized. The model analysed in this article is a 100% renewable scenario of Denmark for 2050, where the data for the transport sector has been changed to estimate the fuel production costs for eight different fuel pathways. The results confirm that synthetic fuel pathways reduce the demand for biomass, while simultaneously increasing the flexibility of the energy system by enabling a high share of wind energy. The most interesting finding is that the production costs of synthetic fuels are comparable with petrol production costs once the associated CO2 emissions are included.

Vibration assessments are required for new railroad lines to determine the effect of vibrations on local communities. Low accuracy assessments can significantly increase future project costs in the form of further detailed assessment or unexpected vibration abatement measures.This paper presents a new, high accuracy, initial assessment prediction tool for high speed lines. A key advantage of the new approach is that it is capable of including the effect of soil conditions in its calculation. This is novel because current scoping models ignore soil conditions, despite such characteristics being the most dominant factor in vibration propagation. The model also has zero run times thus allowing for the rapid assessment of vibration levels across rail networks.First, the development of the new tool is outlined. It is founded upon using a fully validated three dimensional finite element model to generate synthetic vibration records for a wide range of soil types. These records are analysed using a machine learning approach to map relationships between soil conditions, train speed and vibration levels. Its performance is tested through the prediction of two independent international vibration metrics on four European high speed lines and it is found to have high prediction accuracy.A key benefit from this increased prediction accuracy is that it potentially reduces the volume of detailed vibration analyses required for a new high speed train line. This avoids costly in-depth studies in the form of field experiments or large numerical models. Therefore the use of the new tool can result in cost savings.

This paper investigates the effect of initial tunnel construction on the future ground vibration levels generated during underground railway line operation. This is important because tunnel construction results in soil disturbance, thus inducing high soil strain levels near the tunnel lining. The resulting soil stiffness degradation impacts the future generation of ground-borne traffic vibration and it's propagation to the foundations of nearby buildings, however has never been investigated. Therefore, to address this, this work develops a novel hybrid modelling approach, consisting of a construction simulation model and an elastodynamics model. First the convergence-confinement method is used to determine the stress state induced during tunnel construction using a tunnel boring machine (TBM). Next a 2.5D FEM-PML model consisting of vehicle-track-tunnel-soil is used to predict the vibration fields induced by underground trains. To link the approaches, the soil stiffness degradation contours computed from the tunnelling simulation act as inputs for the 2.5D underground railway model. This facilitates the assessment of the effect of tunnel construction on vibration levels. It is found that railway ground-borne vibration levels are underestimated if construction effects are ignored, with discrepancies of up to 10 dB found at higher frequencies. Therefore, when estimating future vibration levels during the underground railway design stage (e.g. for subway, metro, high-speed lines … etc), tunnel construction should be considered as an operational source of uncertainty.

This work describes a series of novel experimental tests to determine the potential of geogrids to confine granular layers within ballasted railway lines operating at speeds close to critical velocity. This is important because at low train speeds, vertical stresses are dominant, but when approaching critical velocity conditions, dynamic horizontal stress levels are magnified. Therefore the majority of previous geogrid investigations have been performed assuming constant horizontal stress levels, thus making them more relevant for lower speed lines. To investigate settlement under high relative train speeds, ballasted railway track samples were subject to combined vertical-horizontal cyclic loading. Three areas were explored: (1) the performance benefit from placing geogrid at the ballast-subballast interface, (2) the performance benefit from placing geogrid at the subballast-subgrade interface, (3) the effect of subgrade stiffness on geogrid performance at the subballast-subgrade interface. Testing was performed using a unique large-scale true triaxial apparatus which had the ability to vary stress levels in three Cartesian directions. Compared to the control conditions, the geogrid offered a settlement improvement of approximately 35% when placed at the ballast-subballast interface, and 10–15% when placed at the subballast-subgrade interface. Regarding subgrade CBR, it was found that the geogrid offered the greatest performance benefits when the subgrade was soft. Therefore it was concluded that for the ballasted rail structures under test, when subject to elevated levels of horizontal stress, geogrids reduced settlements compared to non-geogrid solutions.

Ground borne vibrations generated due to high speed train passage can cause undesirable effects on the nearby environment. One approach to mitigate vibration levels is to use “wave barriers”, however their installation cost may be very high. In an attempt to minimize construction costs, numerical modelling and physical experiments are performed to determine guidelines for the optimisation of trench dimensions. Substantial savings are found to be achievable through carefully chosen barrier dimensions. Firstly, for the purposes of testing a numerical model that can be used by railway wave barrier designers, a geophysical investigation is undertaken on a high speed railway line outside Edinburgh, Scotland. The testing schedule consists of vibration measurements adjacent to the line and a multi-channel analysis of surface waves technique to determine the underlying soil properties. An outline is then presented describing a newly developed three dimensional finite element railway model using commercially available software. The resulting model is modified to replicate the track and soil properties at the test site and then it is shown that the model results exhibit a strong correlation in comparison to those collected during the experimental stage. The numerical model is then used to assess the ability of a range of wave barrier configurations to protect nearby sites from railway vibration. It is found that depth and length have a strong influence on the mitigation of vibration levels but the effect of trench width is negligible. Lastly, for a specific example it is shown that cost savings of 95% are achievable if trench dimensions are carefully planned. All of the analyses require that the ratio of the acoustic impedance of soil compared to wave barrier backfill material must be greater than eight.

The utilisation of biomass poses large challenges in renewable energy systems while buildings account for a substantial part of the energy supply even in 100% renewable energy systems. In this paper the focus is on how the heating sector can reduce its consumption of biomass, thus leaving biomass for other sectors, but while still enabling a 100% renewable energy system. The analyses of heating technologies shows that district heating (DH) systems are important in limiting the dependence on biomass and create cost effective solutions. DH systems are especially important in renewable energy systems with large amounts of fluctuating sources as it enables fuel efficient and low cost energy systems with thermal heat storages. DH increases the efficiency with the use of combined heat and power production (CHP), while reducing the biomass demand by enabling the use of other renewable resources such as large-scale solar thermal, large heat pumps, geothermal heat, industrial surplus heat, and waste incineration. Where the energy density in the building stock is not high enough for DH to be economical, geothermal heat pumps can be recommended for individual heating systems, even though biomass consumption is higher than the DH solutions.

The challenge of integrating fluctuating power from renewable energy sources in the electricity grid by the use of smart grids cannot be looked upon as an isolated issue but should be seen as one out of various means and challenges of approaching sustainable energy systems in general. Therefore, electricity smart grids must be coordinated with the utilisation of renewable energy being converted into other forms of carriers than electricity including heat and biofuels as well as energy conservation and efficiency improvements, such as CHP and improved efficiencies e.g. in the form of fuel cells. All such measures have the potential to replace fossil fuels or improve the fuel efficiency of the system. However, they also add to the electricity balancing problem and contribute to the excess electricity production and thereby to the need for electricity smart grids. The long-term relevant systems are those in which such measures are combined with energy conservation and system efficiency improvements. This article illustrates why electricity smart grids should be seen as part of overall smart energy systems and emphasises the inclusion of flexible CHP production in the electricity balancing and grid stabilisation. Furthermore, it highlights some recent developments in the Danish electricity market operation.

Abstract Ireland’s share of electricity generated from RES-E (renewable energy sources) is due to increase from 14.4% in 2009 to 40% in 2020. With this target predominantly fulfilled with wind generated electricity, the need for increased grid flexibility to facilitate this intermittent energy source is becoming ever more significant. As smart metering becomes available, demand side participation will be one option for achieving this flexibility. Using an immersion heated hot water tank as an example, this paper examines the impact that price optimised load scheduling has on the facilitation of wind generated electricity. To replicate real-world data availability, optimisation is performed using day-ahead predicted prices while the results are calculated using final prices and metered generation data. The results demonstrate a correlation between the day-ahead predicted half-hourly price of electricity and real-time wind availability. This supports the use of price as a means of providing an incentive for load response in order to increase the amount of renewable energy that can be facilitated on the electrical grid. Furthermore, various thermal storage efficiencies were examined for the device to reveal that as the energy loss rate of the device is reduced, the financial savings increase, wind generation increases, and conventional generation decreases.

To evaluate whether the addition of a protease inhibitor (PI) to feline plasma improves the temporal stability of N-terminal pro-B-type natriuretic peptide (NT-proBNP).Forty-four EDTA blood samples were collected from 42 cats with cardiac disease or hyperthyroidism. Samples were separated within 15 min of collection and the plasma stored at -80 °C. Samples were thawed and each separated into 2 aliquots, one of which was mixed with PI. Each was subdivided into 5 aliquots, which remained at room temperature (RT) for zero, 24, 48, 96 or 120 h before being returned to storage at -80 °C. NT-proBNP was measured using a commercially-available ELISA.There was no difference in NT-proBNP measurements between plain and PI samples at time zero (P = 0.836) or 24 h (P = 0.293). At subsequent time-points NT-proBNP was higher in the PI than the plain samples (P 0.05). An overall effect of time at RT was detected for plain (P 0.001) and PI samples (P 0.001).The addition of PI to feline plasma significantly reduces, but does not eliminate, degradation of NT-proBNP at RT. This degradation occurs over a time course comparable to postal transportation of samples for laboratory analysis and may alter the clinical interpretation of results.

Pumped hydroelectric energy storage (PHES) is the largest and most mature form of energy storage currently available. However, the capital costs required for PHES are extremely large and the availability of suitable sites is decreasing. Therefore, identifying the remaining sites available for PHES is becoming vital so that the most beneficial location is chosen: in terms of capacity and economics. As a result, the aim of this work is to develop a computer program that will scan a terrain and identify if there are any feasible PHES sites on it. In this paper, a brief description of the program is provided, including the limitations identified during the initial development. Also, the program was used to evaluate a 20 km × 40 km area in the South West of Ireland so the results obtained from this study are discussed. Finally, future improvements to advance the program's capabilities are identified. The program has proven to date that it can identify feasible locations for PHES, however, further investigation is necessary to improve the site selection.

To determine if natriuretic peptide concentrations are increased in cats with systemic hypertension and/or chronic kidney disease (CKD).22 normal cats, 13 normotensive cats with mild-moderate CKD (NT-CKD), 15 hypertensive cats with mild-moderate CKD (HT-CKD) and 8 normotensive cats with severe CKD (NT-CKD-severe).N-terminal pro-B-type (NT-proBNP) and pro-A-type (NT-proANP) natriuretic peptides were measured in plasma samples from all cats using commercially available assays and concentrations in the normal and diseased groups compared using non-parametric statistical tests. Spearman's rank correlation was used to test for an association between natriuretic peptide and creatinine concentrations.NT-proANP was significantly higher in the NT-CKD-severe than the normal group of cats (P=0.006) but there were no other differences between groups. NT-proBNP concentrations were significantly higher in the HT-CKD group than both the normal (P0.001) and the NT-CKD (P0.001) groups. NT-proBNP concentrations were also higher in the NT-CKD-severe (P0.001) and the NT-CKD (P=0.005) groups than the normal group. NT-proANP but not NT-proBNP was significantly and positively associated with plasma creatinine concentration.Measurement of NT-proBNP shows promise as a diagnostic marker for systemic hypertension in the cat. Its concentration is not significantly increased in cats with mild-moderate normotensive CKD.

Objectives: To determine if serum natriuretic peptide (NP) concentrations could distinguish cardiac from non-cardiac causes of respiratory distress (RD) in cats. Animals: Seventy-four cats from 1 university hospital were used. Methods: Serum NP concentrations were measured in 41 cats with non-cardiac respiratory distress (RD-NC) and compared to 33 cats with RD due to congestive heart failure (RD + CHF) using sandwich enzyme immunoassays (ELISA). Results: RD-NC cats had lower (P = 0.0001) median NT-proANP and NT-proBNP concentrations (614 and 45 fmol/mL, respectively) than RD + CHF cats (1690 and 523 fmol/mL, respectively). The area under the curve was 0.88 and 0.96 for the receiver operating curve analysis of the diagnostic accuracy of NT-proANP and NT-proBNP concentrations to discriminate RD + CHF from RD-NC cats (P = 0.036). An optimum cut-off concentration of 986 fmol/mL for NT-proANP and 220 fmol/mL for NT-proBNP accurately discriminated RD-NC from RC + CHF cats with a sensitivity of 93.8% and 93.9% and a specificity of 80.3% and 87.8%, respectively. Conclusions: Serum NP concentrations were different in RD + CHF cats compared to RD-NC cats. Evaluation of circulating NP concentrations may be helpful in the initial approach to cats presenting with respiratory distress, particularly if advances in ELISA technology result in a rapid cage-side test. © 2009 Elsevier B.V. All rights reserved.

Acquired tricuspid valve stenosis (TVS) is a rare complication of endocardial lead placement in humans that has not been described in the veterinary literature. We describe a 6.5-year-old Border terrier that was presented with right-sided congestive heart failure 5.5 years after placement of a transvenous pacemaker. Severe TVS was confirmed by cardiac ultrasonography and appeared to be secondary to excessive endocardial pacemaker lead within the right atrium. Repositioning of the lead proved impossible and subsequent postmortem examination demonstrated fusion of the tricuspid valve (TV) leaflets around the endocardial lead with associated narrowing of the tricuspid valve orifice. In addition, the loop of the endocardial lead was anchored by thick fibrous tissue to the right atrial wall. This case report suggests that if sufficient endocardial lead is left inside the heart, in dogs undergoing transvenous pacemaker therapy, the redundant lead can become adherent to the tricuspid valve apparatus and cause valvular stenosis.

Hypertrophic cardiomyopathy (HCM) is the most commonly inherited cardiomyopathy. In cats it is even more common: 15% of a large population of unselected outbred cats has HCM. HCM-causing mutations in sarcomeric proteins have been proposed to increase myofilament Ca2+-sensitivity but may have additional primary effects.We have previously found that in dilated cardiomyopathy (DCM)-causing mutations in thin filament proteins the relationship between phosphorylation at Ser 22 and 23 of cardiac troponin I (TnI) and Ca2+-sensitivity was abolished. This phenomenon has been termed ‘uncoupling’ and has been found for all thin-filament protein DCM-causing mutations investigated in vitro and in skinned myofibrils. It is associated with a blunted response to β1-adrenergic stimulation and reduced cardiac reserve that is potentially disease-causing.Interestingly, uncoupling might also be a characteristic of HCM. Uncoupling has been demonstrated in a number of HCM mutants in TnI and troponin T. To determine whether either of these phenomena is common to HCM mutations we have studied them using the in vitro motility assay. We have looked at mutations in TPM1 (E180G) and TNNT2 (Δ14, Δ28+7, R92L, R92Q, ΔE160, S179F, K273E and K280N) using recombinant and mutant cardiac troponin. All of these mutations showed uncoupling. The ACTC E99K mutation showed uncoupling in both isolated thin filaments and single myofibrils.Preliminary experiments were carried out with troponin from a Ragdoll cat heart with HCM due to the R820W mutation in MYBPC3 and a non-affected cat as control. The mutant thin filaments showed an increase in Ca2+-sensitivity and were also uncoupled. Thus, troponin from HCM cats was abnormal even though the mutation was in MyBP-C that was not present in the assay.Overall these results suggest the Ca2+-sensitising and uncoupling properties of HCM mutations may be more widely distributed than previously thought.

Understanding the migration of hydrocarbons in the subsurface is of primary importance for oil and gas exploration. Fluid migration structures on reflection seismic data are difficult to map manually and subtle features that are related to hydrocarbon migration are often overlooked. ChimneyCube processing is a new technique in which fluid migration paths are detected in a semi-automated way, using an assemblage of directive, multi-trace seismic attributes, supervised neural networks and the interpreter's insight. Chimney detection results indicate where hydrocarbons originated, how they migrated into a prospect, and how they spilledor leaked from this prospect and created shallow gas pockets, mud volcanoes and pockmarks near and on the seabed. Integration with other geological information is a prerequisite for correct interpretation of the results. Examples show that it provides important information for prospect evaluation, distinguishes between charged and non-charged prospects, detects shallow gas hazards, distinguishes between sealing and non-sealing faults, determines seal quality and helps in the prediction of reservoir hydrocarbon phase in multi-phase basins.

Recently there has been some interest in the use of Simulated Annealing to obtain ‘good’ solutions to a number of combinatorial problems. This paper reports on the use of this method applied to the Quadratic Assignment Problem (i.e. the assignment of inter-communicating objects to locations to minimize the total cost of communication between them). The result is a much-improved annealing scheme for this problem which performs well on a range of examples, finding improved solutions for several of the largest problems available in the literature and requiring only modest amounts of computational effort.