Consistency between the radio and MIR faint source counts using the radio-MIR correlation

We show from the recent extrapolation of the radio-FIR correlation to the MIR that the 20 cm and 15 um differential source counts are likely to come from the same parent population.Comment: 2 pages, 2 figures, to appear in proceedings of 'Multi-wavelength AGN surveys', Cozumel, 200

Exact vortex nucleation and cooperative vortex tunneling in dilute BECs

With the imminent advent of mesoscopic rotating BECs in the lowest Landau level (LLL) regime, we explore LLL vortex nucleation. An exact many-body analysis is presented in a weakly elliptical trap for up to 400 particles. Striking non-mean field features are exposed at filling factors >>1 . Eg near the critical rotation frequency pairs of energy levels approach each other with exponential accuracy. A physical interpretation is provided by requantising a mean field theory, where 1/N plays the role of Planck's constant, revealing two vortices cooperatively tunneling between classically degenerate energy minima. The tunnel splitting variation is described in terms of frequency, particle number and ellipticity.Comment: 4 pages,4 figure

Innovative methods of ground improvement for railway embankment Peat Fens foundation soil

The aim of this research was to assess the feasibility of biocementing a problematic foundation soil of railway embankments from Peat Fens in East Anglia, UK. Biocementation of soil is an emerging, novel ground improvement technique. It has recently attracted the interest of researchers worldwide because it has been proposed as potentially environmentally superior to chemical grouts and other common soil stabilisers e.g. cement or lime (linked to high CO2 11 emissions). In this study we screened and isolated non-pathogenic indigenous ureolytic microbial candidates with potential for biocementation from samples originating from Peat Fens in East Anglia, UK. Four strains were selected as the most suitable candidates, based on their growth rate and their viability in a wide range of temperatures, pH and soil moisture contents corresponding to typical seasonal field conditions. After a number of Unconfined Compressive Strength (UCS) tests, one strain (Bacillus licheniformis) was selected as the most promising for this soil treatment and used for further study. Two different methods of implementation of the treatments were considered, namely pressure flow soil column and electrokinetic injection. The UCS results supported by CaCO3 measurements as well as microstructural SEM-EDS analysis proved that biocementation did occur for both implementation methods and for a number of treatment combinations. Ongoing work on optimisation of treatments and implementation methods is carried out towards the upscaling of the techniques for in situ implementation which is planned for the next stage of the research

Deep ROSAT Surveys & the contribution of AGNs to the soft X-ray background

The ROSAT Deep Surveys in the Lockman Hole have revealed that AGNs are the main contributors (~75%) to the soft X-ray background in the 1–2 keV band. Using new optical/infrared and radio observations we have obtained a nearly complete identification (93%) of the 91 X-ray sources down to a limiting flux of 1.2·10^(–15) erg cm^(–2) s^(–1) in the 0.5–2.0 keV band. We present the optical colors and the emission line properties of our AGNs in comparison with other X-ray selected AGN samples. Furthermore we discuss the fraction of red AGNs found in the ROSAT Deep Surveys. From the ROSAT Deep Surveys we see no evidence for a new class of X-ray bright galaxies, which significantly contributes to the soft X-ray background

Performance Enhancement of Urban Ground Source Heat Pumps through Interactions with Underground Railway Tunnels

Ground source heat pumps (GSHPs) can provide an efficient way of heating and cooling buildings due to their high operating efficiencies. The implementation of these systems in urban environments could have further benefits. In such locations the ground source heat is potentially more accessible via alternative sources such as through underground railways (URs). This paper investigates to what extent the heat in the soil surrounding an UR tunnel could enhance the operation of urban GSHPs installations. To address this, a numerical investigation was set out which included a parametric study considering a number of geometrical options of the systems. The results showed that heat extraction rates of GSHPs installed near UR tunnels can be significantly improved by up to ~ 43%

Biocementation of an organic soil using indigenous ureolytic bacteria

This paper describes research aiming at assessing the potential for biocementation of an unsuitable organic foundation soil encountered in the UK railway network. As opposed to the majority of previous studies it focuses on isolation and use of non-pathogenic, indigenous ureolytic bacterial strains from the in situ soil, which are capable of inducing calcite precipitation. The paper describes the procedures for indigenous bacteria isolation and screening, their growth and urease activity and shows results from soil strength and calcite precipitation testing proving biocementation for this type of soil using indigenous bacteria

Implementation of biocementation for a partially saturated problematic soil of the UK railway network

This paper refers to biocementation of a problematic soil of the UK railway network as a potential stabilisation technique of this soil using indigenous ureolytic bacteria. The soil is peat, a soft foundation soil also subject to oxidation wastage. As the peat is under existing embankments, electrokinetics (EK) is proposed as a promising technique to implement treatments. In the context of unsaturated soils the paper thus focuses on two particular aspects relevant for the implementation of treatments and the stability of this soil, namely: a) the effect of degree of saturation of the peat on the bio-electrokinetic treatment ; b) the soil water retention curve of the soil affecting flow and transport; these are relevant as we focus on understanding and modelling the implementation of treatments through electrokinetics; moreover for the peat it is of importance to understand moisture exchange in the vadose zone and control groundwater table levels (e.g. during electrokinetics) in order to prevent further oxidation. After isolation and screening of indigenous microorgansisms Bacillus licheniformis was selected for further testing. The results in terms of unconfined compressive strength, CaCO3 content, swelling and compression behaviour and water retention proved the feasibility of biocementation using this indigenous microorganism. Ongoing work is assessing the required treated soil characteristics and related required biocementation degree to solve UK rail's peat foundation problems. Upscaling of the techniques towards in situ implementation is also planned in the next stage of the research

Developing a sentinel monitoring network for Scotland's rivers and lochs

• The Scottish Environment Protection Agency’s (SEPA) surveillance monitoring networks for rivers and lochs were established over a decade ago to help assess the state of Scotland’s freshwater environment and detect environmental change. This long-term monitoring is integral in formulating evidence-based policy and evaluating whether land and water management aimed at improving environmental quality is effective. • SEPA and Scottish Government have commissioned this review of the surveillance networks to better understand their national representativeness, optimal size and sampling intensities. • The review also considered new and innovative monitoring technologies, and assessed where these may help SEPA to more cost-effectively assess long-term trends in the environment. • The specific aims of this report are: (1) to assess how well the SEPA river surveillance network represents Scotland’s environment; (2) to identify possible changes in the river surveillance network to improve its representativeness; (3) to estimate the ability of the existing river and loch surveillance networks to detect long-term environmental change, and investigate how this might be affected by changes in sampling regimes; (4) to analyse environmental changes detectable since the inception of the surveillance networks; and (5) to analyse the benefits of adopting new sampling methods