Perspectives of UK housebuilders on the use of offsite modern methods of construction

Despite an increasing demand for housing and wider concerns over the need to improve performance, the industry seems to be reluctant to adopt offsite technologies. Many studies have attempted to scrutinize the barriers and seek ways forward, but the perspectives of housebuilders remain unclear. This research aims to investigate UK housebuilders’ views on the use of offsite Modern Methods of Construction (offsite-MMC). This was carried out through a combination of personal interviews and a questionnaire survey of the top 100 housebuilders by unit completion. Results suggest that the traditional drivers of time, cost, quality and productivity are still driving the industry in deciding whether to use offsite technologies. Nearly two thirds of the firms believed that there needs to be an increase in the take-up of such technologies. However, current barriers relate to a perceived higher capital cost, complex interfacing, long lead-in time and delayed planning process. Strategies recommended centred on changing peoples’ perceptions, improving procurement, providing better cost data, tackling planning and regulations, encouraging political levers and providing practical guidance. The suggestions present a model for encouraging the take-up of offsite-MMC in the future

Leading UK housebuilders’ utilisation of offsite modern methods of construction

In recent years the industry has been exhorted to increase its utilisation of offsite technologies, or ‘Modern Methods of Construction’, in order to address the under-supply and poor build quality of housing. Despite the well-rehearsed benefits of such technologies, the take-up within the industry has been slow. This paper reports on research which examined housebuilders’ practices and strategies regarding the use of offsite-Modern Methods of Construction (offsite-MMC). A questionnaire survey of the top 100 housebuilders in the UK and a series of interviews were used to reveal the extent to which such technologies are being utilised and the factors which impinge on their popularity. The findings suggest that current offsite-MMC usage in large housebuilders is low, but that the level is likely to increase, given the pressures to improve quality, time, cost, productivity and health and safety. The wider take-up of offsite-MMC is, however, inhibited by perceived higher capital costs, interfacing problems, long lead-in time, delayed planning process and current manufacturing capacity. Based on these findings, the paper provides a set of strategies for improving offsite-MMC practices amongst housebuilders. It is hoped that will help deliver an improvement of housing supply in the UK

Interacting agegraphic dark energy model in tachyon cosmology coupled to matter

Scalar-field dark energy models for tachyon fields are often regarded as an effective description of an underlying theory of dark energy. In this paper, we propose the agegraphic dark energy model in tachyon cosmology by interaction between the components of the dark sectors. In the formalism, the interaction term emerges from the tachyon field nonminimally coupled to the matter Lagrangian in the model rather than being inserted into the formalism as an external source. The model is constrained by the observational data. Based on the best fitted parameters in both original and new agegraphic dark energy scenarios, the model is tested by Sne Ia data. The tachyon potential and tachyon field are reconstructed and coincidence problem is revisited.Comment: 11 pages, 10 figures. Published in PLB (contains some changes in the text with respect to the first version); arXiv admin note: text overlap with arXiv:1106.2659 by same author

Baryon Number Fluctuation and the Quark-Gluon Plasma

We show that $\omega_B$ or $\omega_{\bar B}$, the squared baryon or antibaryon number fluctuation per baryon or antibaryon, is a possible signature for the quark-gluon plasma that is expected to be created in relativistic heavy ion collisions, as it is a factor of three smaller than in an equilibrated hadronic matter due to the fractional baryon number of quarks. Using kinetic equations with exact baryon number conservation, we find that their values in an equilibrated matter are half of those expected from a Poisson distribution. Effects due to finite acceptance and non-zero net baryon number are also studied.Comment: discussion and references added, version to appear in PR

Hard-core Yukawa model for two-dimensional charge stabilized colloids

The hyper-netted chain (HNC) and Percus-Yevick (PY) approximations are used to study the phase diagram of a simple hard-core Yukawa model of charge-stabilized colloidal particles in a two-dimensional system. We calculate the static structure factor and the pair distribution function over a wide range of parameters. Using the statics correlation functions we present an estimate for the liquid-solid phase diagram for the wide range of the parameters.Comment: 7 pages, 9figure

Optical transmission losses in materials due to repeated impacts of liquid droplets

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76812/1/AIAA-7018-720.pd

High Pressure Thermoelasticity of Body-centered Cubic Tantalum

We have investigated the thermoelasticity of body-centered cubic (bcc) tantalum from first principles by using the linearized augmented plane wave (LAPW) and mixed--basis pseudopotential methods for pressures up to 400 GPa and temperatures up to 10000 K. Electronic excitation contributions to the free energy were included from the band structures, and phonon contributions were included using the particle-in-a-cell (PIC) model. The computed elastic constants agree well with available ultrasonic and diamond anvil cell data at low pressures, and shock data at high pressures. The shear modulus $c_{44}$ and the anisotropy change behavior with increasing pressure around 150 GPa because of an electronic topological transition. We find that the main contribution of temperature to the elastic constants is from the thermal expansivity. The PIC model in conjunction with fast self-consistent techniques is shown to be a tractable approach to studying thermoelasticity.Comment: To be appear in Physical Review

Hadronic observables from SIS to SPS energies - anything strange with strangeness ?

We calculate $p, \pi^\pm, K^\pm$ and $\Lambda$(+$\Sigma^0$) rapidity distributions and compare to experimental data from SIS to SPS energies within the UrQMD and HSD transport approaches that are both based on string, quark, diquark ($q, \bar{q}, qq, \bar{q}\bar{q}$) and hadronic degrees of freedom. The two transport models do not include any explicit phase transition to a quark-gluon plasma (QGP). It is found that both approaches agree rather well with each other and with the experimental rapidity distributions for protons, $\Lambda$'s, $\pi^\pm$ and $K^\pm$. Inspite of this apparent agreement both transport models fail to reproduce the maximum in the excitation function for the ratio $K^+/\pi^+$ found experimentally between 11 and 40 A$\cdot$GeV. A comparison to the various experimental data shows that this 'failure' is dominantly due to an insufficient description of pion rapidity distributions rather than missing 'strangeness'. The modest differences in the transport model results -- on the other hand -- can be attributed to different implementations of string formation and fragmentation, that are not sufficiently controlled by experimental data for the 'elementary' reactions in vacuum.Comment: 46 pages, including 15 eps figures, to be published in Phys. Rev.