Clyde tributaries : report of urban stream sediment and surface water geochemistry for Glasgow

This report presents the results of an urban drainage geochemical survey carried out jointly by the British Geological Survey (BGS) and Glasgow City Council (GCC) during June 2003. 118 stream sediment and 122 surface water samples were collected at a sample density of 1 per 1 km2 from all tributaries draining into the River Clyde within the GCC administrative area. The study was carried out as part of the BGS systematic Geochemical Surveys of Urban Environments (GSUE) programme. Stream sediment and surface water samples underwent analysis for approximately 46 chemical elements including contaminants such as As, Al, Cd, Cu, Cr, Ni, Pb, Se, V and Zn according to standard GSUE procedures. In addition, parameters such as ammonium, asbestos and Hg as well as organic contaminants such as total petroleum hydrocarbons (TPH), polycyclic aromatic hydrocarbons (PAH), poly-chlorinated biphenyls (PCB) and organo-tin compounds were assessed. The aim of the project was to provide an overview of urban drainage geochemistry in Glasgow to link to an on-going sister project, which is investigating the geochemistry of the Clyde estuary. This report presents the initial findings of the Clyde tributaries survey but it is envisaged that the data will be interpreted in more detail as part of a wider Clyde basin study once the Clyde estuary survey is completed

Neutron beam test of CsI crystal for dark matter search

We have studied the response of Tl-doped and Na-doped CsI crystals to nuclear recoils and $\gamma$'s below 10 keV. The response of CsI crystals to nuclear recoil was studied with mono-energetic neutrons produced by the $^3$H(p,n)$^3$He reaction. This was compared to the response to Compton electrons scattered by 662 keV $\gamma$-ray. Pulse shape discrimination between the response to these $\gamma$'s and nuclear recoils was studied, and quality factors were estimated. The quenching factors for nuclear recoils were derived for both CsI(Na) and CsI(Tl) crystals.Comment: 21pages, 14figures, submitted to NIM

Electromagnetic properties of graphene junctions

A resonant chiral tunneling (CT) across a graphene junction (GJ) induced by an external electromagnetic field (EF) is studied. Modulation of the electron and hole wavefunction phases $\varphi$ by the external EF during the CT processes strongly impacts the CT directional diagram. Therefore the a.c. transport characteristics of GJs depend on the EF polarization and frequency considerably. The GJ shows great promises for various nanoelectronic applications working in the THz diapason.Comment: 4 pages 3 figure

Generation of entangled coherent states via cross phase modulation in a double electromagnetically induced transparency regime

The generation of an entangled coherent state is one of the most important ingredients of quantum information processing using coherent states. Recently, numerous schemes to achieve this task have been proposed. In order to generate travelling-wave entangled coherent states, cross phase modulation, optimized by optical Kerr effect enhancement in a dense medium in an electromagnetically induced transparency (EIT) regime, seems to be very promising. In this scenario, we propose a fully quantized model of a double-EIT scheme recently proposed [D. Petrosyan and G. Kurizki, {\sl Phys. Rev. A} {\bf 65}, 33833 (2002)]: the quantization step is performed adopting a fully Hamiltonian approach. This allows us to write effective equations of motion for two interacting quantum fields of light that show how the dynamics of one field depends on the photon-number operator of the other. The preparation of a Schr\"odinger cat state, which is a superposition of two distinct coherent states, is briefly exposed. This is based on non-linear interaction via double-EIT of two light fields (initially prepared in coherent states) and on a detection step performed using a $50:50$ beam splitter and two photodetectors. In order to show the entanglement of a generated entangled coherent state, we suggest to measure the joint quadrature variance of the field. We show that the entangled coherent states satisfy the sufficient condition for entanglement based on quadrature variance measurement. We also show how robust our scheme is against a low detection efficiency of homodyne detectors.Comment: 15 pages, 9 figures; extensively revised version; added Section

The influence of nonlinearities on the symmetric hydrodynamic response of a 10,000 TEU Container ship

The prediction of wave-induced motions and loads is of great importance for the design of marine structures. Linear potential flow hydrodynamic models are already used in different parts of the ship design development and appraisal process. However, the industry demands for design innovation and the possibilities offered by modern technology imply the need to also understand the modelling assumptions and associated influences of nonlinear hydrodynamic actions on ship response. At first instance, this paper presents the taxonomy of different Fluid Structure Interaction (FSI) methods that may be used for the assessment of ship motions and loads. Consequently, it documents in a practical way the effects of weakly nonlinear hydrodynamics on the symmetric wave-induced responses for a 10,000TEU Container ship. It is shown that the weakly nonlinear FSI models may be useful for the prediction of symmetric wave-induced loads and responses of such ship not only in way of amidships but also at the extremities of the hull. It is concluded that validation of hydrodynamic radiation and diffraction forces and their respective influence on ship response should be especially considered for those cases where the variations of the hull wetted surface in time may be noticeable

Survey of Sensor Technology for Aircraft Cabin Environment Sensing

The aircraft cabin environment is unique due to the proximity of the passengers, the need for cabin pressurization, and the low humidity. All of these aspects are complicated by the fact that the aircraft is a semi-enclosed structure. There is an increased desire to monitor the aircraft cabin environment with various sensors for comfort and safety. However, the aircraft cabin environment is composed of a large number of factors. Some of these factors can include air quality, temperature, level of pressurization, and motion of the aircraft. Therefore, many types of sensors must be used to monitor aircraft environments. A variety of technology options are often available for each sensor. Consequently, a fair number of tradeoffs need to be carefully considered when designing a sensor monitoring system for the aircraft cabin environment. For instance, a system designer may need to decide if the increased accuracy of a sensor using a particular technology is worth the increased power consumption over a similar sensor employing a more efficient, less accurate technology. In order to achieve a good solution, a designer needs to understand the tradeoffs and general operation for all of the different sensor technologies that could be used in the design. The purpose of this paper is to provide a survey of the current sensor technology. The primary focus of this paper is on sensors and technologies that cover the most common aspects of aircraft cabin environment monitoring. The first half of this paper details the basic operation of different sensor technologies. The second half covers the individual environmental conditions which need to be sensed. This will include the benefits, limitations, and applications of the different technologies available for each particular type of sensor

Globular cluster systems of early-type galaxies in low-density environments

Deep images of 10 early-type galaxies in low-density environments have been obtained with the Advanced Camera for Surveys (ACS) aboard the Hubble Space Telescope. The global properties of the globular cluster (GC) systems of the galaxies have been derived in order to investigate the role of the environment in galaxy formation and evolution. Using the ACS Virgo Cluster Survey as a high-density counterpart, the similarities and differences between the GC properties in high- and low-density environments are presented. We find a strong correlation of the GC mean colours and the degree of colour bimodality with the host galaxy luminosity in low-density environments, in good agreement with high-density environments. In contrast, the GC mean colours at a given host luminosity are somewhat bluer [Δ(g−z) ∼ 0.05] than those for cluster galaxies, indicating more metal poor (Δ[Fe/H] ∼ 0.10 − 0.15) and/or younger (Δage > 2 Gyr) GC systems than those in dense environments. Furthermore, with decreasing host luminosity, the colour bimodality disappears faster, when compared to galaxies in cluster environments. Our results suggest that: (1) in both high- and low-density environments, the mass of the host galaxy has the dominant effect on GC system properties; (2) the local environment has only a secondary effect on the history of GC system formation; and (3) GC formation must be governed by common physical processes across a range of environments

Giant Shapiro steps for two-dimensional Josephson-junction arrays with time-dependent Ginzburg-Landau dynamics

Two-dimensional Josephson junction arrays at zero temperature are investigated numerically within the resistively shunted junction (RSJ) model and the time-dependent Ginzburg-Landau (TDGL) model with global conservation of current implemented through the fluctuating twist boundary condition (FTBC). Fractional giant Shapiro steps are found for {\em both} the RSJ and TDGL cases. This implies that the local current conservation, on which the RSJ model is based, can be relaxed to the TDGL dynamics with only global current conservation, without changing the sequence of Shapiro steps. However, when the maximum widths of the steps are compared for the two models some qualitative differences are found at higher frequencies. The critical current is also calculated and comparisons with earlier results are made. It is found that the FTBC is a more adequate boundary condition than the conventional uniform current injection method because it minimizes the influence of the boundary.Comment: 6 pages including 4 figures in two columns, final versio

BCC vs. HCP - The Effect of Crystal Symmetry on the High Temperature Mobility of Solid 4^4He

We report results of torsional oscillator (TO) experiments on solid $^4$He at temperatures above 1K. We have previously found that single crystals, once disordered, show some mobility (decoupled mass) even at these rather high temperatures. The decoupled mass fraction with single crystals is typically 20- 30%. In the present work we performed similar measurements on polycrystalline solid samples. The decoupled mass with polycrystals is much smaller, $\sim$ 1%, similar to what is observed by other groups. In particular, we compared the properties of samples grown with the TO's rotation axis at different orientations with respect to gravity. We found that the decoupled mass fraction of bcc samples is independent of the angle between the rotation axis and gravity. In contrast, hcp samples showed a significant difference in the fraction of decoupled mass as the angle between the rotation axis and gravity was varied between zero and 85 degrees. Dislocation dynamics in the solid offers one possible explanation of this anisotropy.Comment: 10 pages, 5 figures, to appear in Journal of Low Temperature Physics - special issue on Supersolidit