1,583 research outputs found
ACHILLES: reducing infrastructure whole-life costs
No full textThe ACHILLES research programme is a collaboration between six UK universities and the British Geological Survey, which aims to provide the tools to “assess, monitor, design and repair the performance of the ground” upon which infrastructure depends, to ensure that rail and other linear infrastructure provides “consistent, affordable and safe services, underpinned by intelligent design, management and maintenance.” The research programme addresses three main challenges: (i) improved understanding of material and asset deterioration processes; (ii) improved understanding of asset performance, with and without interventions; and (iii) improved forecasting of asset and network behaviour, and decision support for interventions, identifying best-value intervention strategies. These challenges are met through four complementary workstreams: (i) Performance and Deterioration (PaD); (ii) Monitoring and Measurement (MaM); (iii) Simulation and Modelling (SaM); and (iv) Design and Decisions (DaD). This paper is focussed on the SaM and, especially, DaD workstreams. It describes the development of decision support to identify the earthworks maintenance and renewal strategies, and select the designs required, to reduce and ideally minimise the whole-life costs of individual assets, routes and networks. The work is based initially upon cuttings on Britain’s Great Western Main Line railway between London and Bristol, whose individual and collective whole-life costs are being analysed to develop a route-level whole-life engineering cost model. The workstreams then extend to include the handling of uncertainty, environmental and passenger and freight end-user impacts, and the costs and potential benefits of additional asset condition data
ACHILLES: reducing earthworks failure risks and whole-life costs
No full textVital transport and other linear infrastructure in Britain and elsewhere depends upon an extensive set of earthworks of varying age, condition and engineering quality. These earthworks are subject to normal deterioration, and these processes are exacerbated and complicated by the variable and unpredictable effects of climate change on weather patterns, particularly in the form of increased rainfall intensity and flooding. Railway earthworks are particularly vulnerable to these effects, given their typical age and the comparatively primitive engineering techniques used in their design and construction, as well as the increasing (pre-Covid) traffic levels to which they have been subjected. This paper describes research work being undertaken to improve the understanding of earthworks condition, deterioration and remediation, and to develop methods and tools to assist with the economic assessment of, selection from and prioritisation of alternative design interventions
Direct numerical simulation of turbulent Couette-Poiseuille flow with zero skin friction
No full textThe near-wall scaling of mean velocity U(y) is addressed for the case of zero skin friction on one wall of a fully turbulent channel flow. The present DNS results can be added to the evidence in support of the conjecture that U is proportional to √yw in the region just above the wall at which the mean shear dU/dy = 0
The seasonal ratcheting of clay cut slopes in response to seasonal weather cycles
No full textMany cut slopes in the UK are in the later stages of their operational life but continue to support road and rail transportation networks. Some of these slopes experienced delayed, deep-seated, first-time failures between 10 and 50 years after construction. However, some continue to seasonally deform and then fail at shallow depth due to the process of seasonal, downslope ratcheting. This paper reviews the evidence for seasonally-induced, downslope ratcheting movements in clay cut slopes, gathered from physical model tests, in-situ monitoring and numerical simulations. The evidence shows that seasonal ratcheting is an increasingly dominant mechanism of slope deformation and ultimate failure for some high-plasticity clay cut slopes as they are exposed to many seasonal weather cycles. The rate of downslope ratcheting depends on the slope age (i.e., number of seasonal weather cycles since construction), the slope geometry (i.e., slope height and angle) and the strain-softening behaviour of the slope material (e.g., as observed in stiff, high-plasticity clays). This rate, when measured, can be used to inform monitoring and management strategies for old, clay cut slopes (e.g., ageing railway and highway cuttings) by identifying the slopes that are prone to seasonally-induced, downslope ratcheting towards the end of their operational life
Scaling and intermittency in ocean turbulence: analysis of coastal water optical properties and sea surface temperature (SST)
No full textWe consider here some scaling and intermittency properties of oceanic turbulence, with a general aim of considering the impact of turbulence on the bio-optical dynamics. For that purpose, we tried two different approaches, using in situ and satellite data. For the in situ study we adopted one dimensional and for the satellite two dimensional approaches. Different techniques such as Fourier power spectrum, Empirical mode of decomposition (EMD), Hilbert spectral analysis (HSA) have been used for analyzing the intermittency characteristics of the in situ data. For analyzing the multi-scale properties of the satellite images, we have considered Structure functions (SF) and Fourier power spectrum (1D and 2D). The general objective is to understand the multi-scale oceanic variability using scaling tools developed in the field of intermittent turbulence studies
Book Review: A Competitive Future for Europe? Towards a New European Industrial Policy
No full text A Competitive Future for Europe? Towards a New European Industrial Policy, ed. P.R. Beije, J. Gronewagen, I. Kostoulas, J. Paelink and C. van Paridon. Croom Helm (1987). </jats:p
The organization of industry in the P.R. China: A new start or resort to old concepts?
No full textThe Chinese have let it be known since the death of Mao Zedong and the purge of the “Gang of Four” that they would in future draw on credits from foreign governments as well as other sources to finance imports of technology. According to western conjectures China’s capital requirements may be between US $ 25 and 50 bn or even a good deal higher. Many observers have taken the view that the Chinese have thereby put all their former development principles behind them. The author of the following article was in the P.R. China about the middle of this year at the invitation of the National Planning Commission. His assessment is that the P.R. China is far from embarking on an entirely new course in its development policy
Constant approximation for virtual backbone construction with guaranteed routing cost in wireless sensor networks
No full textEconomic potential of the P.R. Spring oil-impregnated deposit, Uinta Basin, Utah
No full textreportThe P.R. Spring oil-impregnated sandstone (tar sand) deposit is located in the southeastern portion of the Uinta Basin, approximately 50 miles northwest of Grand Junction, Colorado. These oil impregnated sandstones are in the Eocene Green River Formation and five zones have been identified. These zones consist of one or more lenticular beds of lacustrine sandstone, separated by intervals of barren lithologies. The degree of impregnation of individual beds within the five zones is controlled by the lateral extent of the bed, its porosity and permeability, and the distance the oil has migrated within the bed. The degree of saturation varies both laterally and vertically. The purpose of this report was to 1) determine the total hydrocarbon content of each zone in blocks of 640 acres or less, and 2) relate this data to current economic and mining feasibility. This study incorporates the results of 38 measured sections and 26 core holes. The oil extracted from the P.R. Spring tar sands is a naturally occurring, brown to black, highly viscous or solid mixture of hydrocarbons. Its composition indicates that the oil was formed in situ or migrated only a short distance. The author has calculated the total barrels of oil in place for the deposit to be approximately 3.3 billion barrels. This is less than other published calculations of 3.7 and 4.0 to 4.5 billion barrels (Byrd, 1967; Ritzma, 1974). Problems associated with the method of economic recovery of the oil remain to be solved. Only the southeastern corner of the field is strip rninable. Other areas will probably have to be exploited by in situ recovery methods and several are being tested. The only known active operation in P.R. Spring is by Bighorn Oil, located in the southeastern part of the deposit. Their operation consists of an open-pit mine and a 200-barrel-per-day extraction plant utilizing a solvent solution process. Surface water availability in the area is limited, but may be sufficient if storage, reuse and ground-water potential are considered. Oil extraction will require a fuel supply, possibly from generated coke and other byproduct fuels generated by the tar refining process or by local natural gas or coal production. Further work is needed in the area, specifically more core holes and associated analyses. Strategic drilling in T. 11 S., R. 22 and 24 E., and T. 12 S., R. 22 E., could be used to verify assumed saturation
Obivius Nationale Relatietest: Bachelor Eindverslag
No full textBachelor Eindverslag (MKT) over het bouwen van een web-applicatie t.b.v. Nescio's Hermitage bv, onder begeleiding van Peter van NieuwenhuizenMKTMediamaticsElectrical Engineering, Mathematics and Computer Scienc
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