1,805 research outputs found
Probabilistic soil moisture projections to assess Great Britain's future clay-related subsidence hazard
Clay-related subsidence is Great Britainâs (GB) most damaging soil-related geohazard, costing the economy up to ÂŁ500 million per annum. Soil-related geohazard models based on mineralogy and potential soil moisture deficit (PSMD) derived from historic weather data have been used in risk management since the 1990s. United Kingdom Climate Projections (UKCP09) suggest that regions of GB will experience hotter, drier summers and warmer, wetter winters through to 2050. As a result, PSMD fluctuations are expected to increase, exacerbating the shrinkage and swelling of clay soils. A forward-looking approach is now required to mitigate the impacts of future climate on GBâs built environment. We present a framework for incorporating probabilistic projections of PSMD, derived from a version of the UKCP09 stochastic weather generator, into a clay subsidence model. This provides a novel, national-scale thematic model of the likelihood of clay-related subsidence, related to the top 1-1.5m soil layer, for three time periods; baseline (1961-1990), 2030 (2020-2049) and 2050 (2040-2069). Results indicate that much of GB, with the exception of upland areas, will witness significantly higher PSMDs through to the 2050âs. As a result, areas with swelling clay soils will be subject to proportionately increased subsidence hazard. South-east England will likely incur the highest hazard exposure to clay-related subsidence through to 2050. Potential impacts include increased incidence of property foundation subsidence, alongside deterioration and increased failure rates of GBâs infrastructure networks. Future clay-subsidence hazard scenarios provide benefit to many sectors, including: finance, central and local government, residential property markets, utilities and infrastructure operators.EPSR
Soil geohazard mapping for improved asset management of UK local roads
Unclassified roads comprise 60% of the road network
in the United Kingdom (UK). The resilience of this locally
important network is declining. It is considered by the
Institution of Civil Engineers to be âat riskâ and is ranked
26th in the world. Many factors contribute to the degradation
and ultimate failure of particular road sections. However,
several UK local authorities have identified that in drought
conditions, road sections founded upon shrinkâswell susceptible
clay soils undergo significant deterioration compared
with sections on non-susceptible soils. This arises from the
local road network having little, if any, structural foundations.
Consequently, droughts in East Anglia have resulted
in millions of pounds of damage, leading authorities to seek
emergency governmental funding.
This paper assesses the use of soil-related geohazard assessments
in providing soil-informed maintenance strategies
for the asset management of the locally important road network
of the UK. A case study draws upon the UK administrative
county of Lincolnshire, where road assessment data have
been analysed against mapped clay-subsidence risk. This reveals
a statistically significant relationship between road condition
and susceptible clay soils. Furthermore, incorporation
of UKCP09 future climate projections within the geohazard
models has highlighted roads likely to be at future risk of
clay-related subsidence
Enhanced visualization of the flat landscape of the Cambridgeshire Fenlands
The Fenlands of East Anglia, England, represent a subtle landscape, where topographic highs rarely exceed 30 m above sea level. However, the fens represent an almost full sequence of Quaternary deposits which, together with islands of Cretaceous and Jurassic outcrops, make the area of geological importance. This feature discusses the advantages of using 3D visualization coupled with high-resolution topographical data, over traditional 2D techniques, when undertaking an analysis of the landscape. Conclusions suggest that the use of 3D visualization will result in a higher level of engagement, particularly when communicating geological information to a wider public
The price of sex: condom use and the determinants of the price of sex among female sex workers in eastern zimbabwe.
Background.âHigher prices for unprotected sex threaten the high levels of condom use that contributed to the decline in Zimbabwe's human immunodeficiency virus (HIV) epidemic. To improve understanding of financial pressures competing against safer sex, we explore factors associated with the price of commercial sex in rural eastern Zimbabwe. Methods.âWe collected and analyzed cross-sectional data on 311 women, recruited during OctoberâDecember 2010, who reported that they received payment for their most-recent or second-most-recent sex acts in the past year. Zero-inflated negative binomial models with robust standard errors clustered on female sex worker (FSW) were used to explore social and behavioral determinants of price. Results.âThe median price of sex was 5â10 (IQR, 15) per act. Amounts paid in cash and commodities did not differ significantly. At the most-recent sex act, more-educated FSWs received 30%â74% higher payments. Client requests for condom use significantly predicted protected sex (P < .01), but clients paid on average 42.9% more for unprotected sex. Conclusions.âWithin a work environment where clients' preferences determine condom use, FSWs effectively use their individual capital to negotiate the terms of condom use. Strengthening FSWs' preferences for protected sex could help maintain high levels of condom use
Off-grid solar-hydrogen generation by passive electrolysis
A novel embodiment of a polymer electrolyte membrane (PEM) electrolyser is presented as a means for producing hydrogen off-grid by the efficient absorption of the time-varying power output of a solar photovoltaic (PV) panel or array. The balance-of-plant power load was minimised using passive design principles to ensure efficient operation under cloudy, sunset and wintry conditions. Heat generated during the electrolysis process is stored when appropriate to significantly enhance the efficiency of hydrogen production after a period of darkness. A prototype field trial demonstrated the electrolyser's ability to track closely the highly variable output of the PV year-round under a wide range of operating conditions. Hydrogen yields for various geographical locations were estimated to vary from 25 to 65 kg p.a. for a 1.6 kW electrolyser with fixed-tilt PV panels depending on local levels of solar insolation. This could be increased to over 100 kg p.a. by employing a PV panel of greater capacity and a battery for absorbing the peak generation and then discharging it overnight to the electrolyser
Soil moisture content measurement using optical fiber long period gratings
The use of an optical fibre long period grating (LPG) as a soil moisture sensor is reported. Characterization of the device in both clay and sandy soils revealed a sensitivity to moisture levels in the range 10-50%, and the results were compared with the output from a Theta probe, the standard soil moisture sensor, which measures the impedance of the soil. © (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only
Experimental study of laminated composites containing manufacturing defects under combined stress states
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