► We review the technologies for condition assessment of underground utilities. ► We concentrate on the assessment of water and sewage pipelines. ► We compare current technologies and discuss ...limitations. ► We discuss asset management methods, and provide support to another companion paper.
An extensive array of utility networks are buried underneath the ground surface and provide essential services for society’s daily life in terms of water, natural gas, electricity, telecommunications, sewerage, etc. All utilities have a limited service life and it is crucial to assess their condition throughout their life cycles to avoid potential catastrophic failure due to their deterioration. This paper reviews current state-of-the-art technologies for condition assessment of underground utilities (especially water and sewage pipelines) and their advantages and technical challenges for different application areas. Recommendations on how to address these challenges are made and it is highlighted that the system of combined sensor technologies being developed by the Mapping the Underworld (MTU) project may provide a valuable addition to the street works engineer’s armoury in determining the condition of the buried infrastructure. Moreover the ground in which the utility services infrastructure is buried supports the pipes and cables and prevents their permanent or transient displacement under static and dynamic loads, or lateral stress relief associated with adjacent trenching. The ability of the MTU sensing technologies to determine also the condition of the ground is thus equally relevant and is discussed.
The aim of this study was to establish whether abnormal signal intensity in the posterior limb of the internal capsule (PLIC) on magnetic resonance imaging is an accurate predictor of ...neurodevelopmental outcome at 1 year of age in infants with hypoxic-ischemic encephalopathy (HIE).
We have examined 73 term neonates with HIE between 1 and 17 days after birth with cranial magnetic resonance imaging and related the magnetic resonance imaging findings to neurodevelopmental outcome at 1 year of age.
All infants with an abnormal signal intensity in the PLIC developed neurodevelopmental impairment although in 4 infants with very early scans the abnormal signal was not apparent until up to 4 days after birth. A normal signal intensity was associated with a normal outcome in all but 4 cases; 3 of these infants had minor impairments and all had persistent imaging changes within the white matter. The 4th infant with a normal signal intensity on day 2 died before a further image could be obtained. The absence of normal signal predicted abnormal outcome in term infants with HIE with a sensitivity of 0.90, a specificity of 1.0, a positive predictive value of 1.0, and a negative predictive value of 0.87. The test correctly predicted outcome in 93% of infants with grade II HIE, according to the Sarnat system. Applying a Bayesian approach, the predictive probability of the test (the probability that the test would predict an outcome correctly) was distributed with a mean of 0.94 and 95% confidence limits of 0.89 to 1.0.
Abnormal signal intensity in the PLIC is an accurate predictor of neurodevelopmental outcome in term infants suffering HIE.
The surface urban transport infrastructures, which are interpreted widely herein to encompass roads, cycle ways, pedestrian areas and railway foundations, are supported by the ground and hence their ...structural performance is inevitably to some degree controlled by the ground. Since the utility services infrastructure that supports city living is typically buried beneath the surface transport infrastructure, street works activities to install, replace, repair or maintain the utility infrastructure using traditional techniques disrupts, and often significantly damages, the transport infrastructure and the ground on which it bears. As a consequence of this latter argument, the ground and the associated physical infrastructure, whether buried utility service infrastructure or the surface transport infrastructure, exist according to a symbiotic relationship: intervene physically in one and the other is almost inevitably affected in some way, whether immediately or in the future. The physical condition of these assets is therefore of crucial importance in determining what, and how severe, the inevitable impact on each other will be, and the close link between them (i.e. that they are both intimately linked to and to some degree controlled by the ground) must be carefully considered. This paper proposes and discusses the establishment of a universal platform in which the physical infrastructure and the ground, and their conditions, can be mapped.
A major UK initiative, entitled Mapping the Underworld (MTU), is seeking to address the serious social, environmental and economic consequences arising from an inability to locate accurately and ...completely the buried utility service infrastructure without resorting to excavations. One of the four MTU projects aims to develop and prove the efficacy of a multi-sensor device for accurate remote buried utility service detection, location and, where possible, utility identification. This paper aims to introduce the MTU programme followed by a state-of-the-art review of the three essential technologies that are to be combined in the device – ground penetrating radar (GPR), low-frequency quasi-static electromagnetic fields and acoustics – and a summary of the influence of different soil types and states on the transmission of the various signals, and therefore how the techniques might be optimised from a knowledge of the ground instead of using very broad simplifying assumptions. The latest developments in impulse GPR, frequency modulated continuous waveform (FMCW) GPR and stepped frequency continuous waveform (SFCW) GPR are described and previous attempts to combine GPR with other sensing technologies are introduced. The work on quasi-static fields explores the ‘fields-of-opportunity’ related to the 50
Hz currents flowing in existing underground power circuits and the electric field variations when low-frequency current in actively induced into the ground. Acoustic techniques have been primarily used for leak detection and the review focuses on the potential for their application to buried utility service location. The paper concludes with a discussion of the facilities required, and currently available, for comprehensive assessment and independent verification of the performance of both existing devices/technologies and of the multi-sensor device under development.
The purpose of this study was to investigate the relationship between femoral neck version and pre- and intraoperative findings in hips with femoroacetabular impingement (FAI). The authors ...retrospectively reviewed prospectively collected data on 188 patients (204 hips) who underwent hip arthroscopy for FAI and labral pathology. Femoral version was measured on magnetic resonance imaging by a fellowship-trained musculoskeletal radiologist. The study group comprised 100 men and 88 women with a mean age of 35 years (range, 18 to 62 years). Mean femoral version was 9° (range, -10° to 27°). No relationship was found between femoral version and patient demographics (ie, age, sex, weight, height, and body mass index). A significant correlation was found between version and degrees of external rotation (r=-0.208; P=.027) and internal rotation (r=0.231; P=.002) on physical examination. Patients with femoral version less than 5° had significantly increased external rotation (P=.027). Intraoperative findings demonstrated that femoral version greater than 15° was related to larger labral tears that averaged approximately 38 mm in size, whereas patients with anteversion less than 5° had tear sizes measuring 30 mm and patients with angles between 5° and 15° had tear sizes averaging 34 mm (P=.008). Hips with femoral version greater than 15° were 2.2 times more likely (95% confidence interval, 1.2 to 4.1) to have labral tears that extended beyond the 3 o'clock position, denoting more anterior tears. Hips in which a psoas release was performed had higher version angles (8° vs 11°; P=.023).
Prevalence rates of excess weight, tobacco smoking and physical inactivity vary substantially by geographical region within British Columbia (B.C.). The purpose of this study is to determine the ...potential reduction in economic burden in B.C. if all regions in the province achieved prevalence rates of these three risk factors equivalent to those of the region with the lowest rates.
We used a previously developed approach based on population-attributable fractions to estimate the economic burden associated with the various risk factors. Sex-specific relative risk and age/sex-specific prevalence data was used in the modelling.
The annual economic burden attributable to the three risk factors in B.C. was about $5.6 billion in 2013, with a higher proportion of this total attributable to excess weight ($2.6 billion) than to tobacco smoking ($2.0 billion). While B.C. has lower prevalence rates of the risk factors than any other Canadian province, there is significant variation within the province. If each region in the province were to achieve the best prevalence rates for the three risk factors, then $1.4 billion (24% of the $5.6 billion) in economic burden could be avoided annually.
There are notable disparities in the prevalence of each risk factor across health regions within B.C., which were mirrored in each region's attributable economic burden. A variety of social, environmental and economic factors likely drive some of this geographical variation and these underlying factors should be considered when developing prevention programs.
Ecosystem carbon densities (aboveground vegetation plus soil organic carbon (SOC) to 45
cm depth) were compared for forested and deforested sites on hummocky glacial till landforms in central ...Saskatchewan. Six forest sites in Prince Albert National Park, six pasture sites in or near the Cookson Community Pasture, and six privately owned cultivated fields were sampled across a 30
000
ha study area (53°34′N, 106°20′W). The median ecosystem C density for forests (158
Mg
C
ha
−1) was significantly greater (
P<0.05) than the median for pastures (63
Mg
C
ha
−1) and the median for cultivated fields (81
Mg
C
ha
−1). For soil organic carbon alone, significant differences were not detected between forested and deforested sites. The range for SOC density across the study area was 51
Mg
C
ha
−1 for natural forest sites, 54
Mg
C
ha
−1 for pastures and 92
Mg
C
ha
−1 for cultivated fields. Spatial variation in SOC densities within each treatment group precluded detection of land-use effects on SOC densities (expected to be ≤25
Mg
C
ha
−1) with this research design. SOC may have been elevated at sites with shallower groundwater, but further research is required to confirm this and to identify the responsible processes. Differences in ecosystem C densities between the forested and deforested sites were primarily the result of differences in vegetation biomass. Median live plus dead vegetation C density for the forest group was 60
Mg
C
ha
−1 greater than the pasture group (
P<0.05) and 56
Mg
C
ha
−1 greater than the cultivated group (
P<0.15). Including estimated C in coarse roots and lesser vegetation at the forest sites would increase these differences by approximately 15
Mg
C
ha
−1. Accounting for disturbance processes such as forest fires, differences in vegetation carbon between forested and deforested sites in this study area are estimated to vary between 30 to 75
Mg
C
ha
−1 over time. Continued agricultural expansion within the study area would result in losses of at least 30
Mg
C
ha
−1. Recent ratification of the Kyoto protocol by Canada provides an incentive to curtail deforestation and initiate reforestation actions. Future reforestation with trembling aspen dominated vegetation in central Saskatchewan has the potential to sequester 30–75
Mg
C
ha
−1 over the next 50–100 years. However, legislative protection or strong financial incentives will be required to secure long-term carbon gains through reforestation.
Bierman, S. M., Dickey-Collas, M., van Damme, C. J. G., van Overzee, H. M. J., Pennock-Vos, M. G., Tribuhl, S. V., and Clausen, L. A. W. 2010. Between-year variability in the mixing of North Sea ...herring spawning components leads to pronounced variation in the composition of the catch. – ICES Journal of Marine Science, 67: 885–896. North Sea herring (Clupea harengus) are managed as a single stock, but maintaining a diversity of spawning components is considered important. However, the total catch from each of these components cannot be estimated easily because the components mix during the summer feeding season. The spawning origin of herring is determined from patterns in the microstructure of the otolith core, from samples taken in the central and northern North Sea during summer of 2004–2007. The annual catch composition of Dutch vessels is determined within a statistical framework that takes account of the spatial patterns in mixing of spawning components and the classification success of the method. Mixing of components varied between years, with steep latitudinal gradients in compositions in some years, resulting in pronounced between-year differences in estimated catch compositions. Differences in lengths-at-age between spawning components, in particular of the 2000 year class, may have caused the observed between-year changes in mixing of components. Our results indicate that estimates of compositions change when assumptions of perfect spatial mixing and perfect classification are relaxed, and can be uncertain in particular as a result of misclassifications, and that it may not be appropriate to assume that ratios between components are constant through time.
In paleomagnetic and environmental magnetic studies the magnetomineralogical identification is usually based on a set of rock magnetic parameters, complemented by crystallographic and chemical ...information retrieved from X-ray diffraction (XRD), (electron) microscopy or energy dispersive spectroscopy (EDS) of selected samples. While very useful, each of these supplementary techniques has its limitations when applied to natural sample material which are related to low particle concentrations (down to the ppm range in marine sediments) and very fine grain sizes (down to the nm scale). Therefore, meaningful application of such techniques depends on sample quality. Electron backscatter diffraction (EBSD) of individual grains in scanning electron microscopy (SEM) enables mineralogical identification of grains down to ∼0.2 micrometer and is particularly powerful when combined with EDS. In this study, we show the merits of EBSD for rock magnetic investigations by analyzing titanomagnetites and hemoilmenites of various compositions and submicron lamella of titanomagnetite-hemoilmenite intergrowths. Such particles often occur in natural marine sediments where EDS often has a semi-quantitative character and compositionally similar intergrowths may be difficult to distinguish. With the mineralogical information provided by EBSD unambiguous identification of spinel-type and trigonal oxides is obtained. Optimal EBSD patterns are gathered from smooth, polished surfaces, but here we show that interpretable EBSD patterns can be obtained directly from the surface of unconsolidated, so called ‘non-embedded’ particles from marine sediments. This information enhances the interpretative value of rock magnetic parameters.
Twelve newborn infants with clinical evidence of hypoxic ischemic brain injury had conventional and diffusion-weighted magnetic resonance imaging (MRI) performed one to six (median two) days and 7-42 ...days after birth. The extent and conspicuity of the early abnormalities was greater with diffusion-weighted than with conventional imaging in each of the four infants with neonatal infarction and in four of the infants with Grades II or III hypoxic ischemic encephalopathy (HIE). No abnormality was seen with either technique in the other four infants who had Grades I or II HIE. Diffusion weighted MRI may be important for the early diagnosis and grading of infants with hypoxic ischemic brain injury.
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