Numerical modeling of the propagation environment in the atmospheric boundary layer over the Persian Gulf

Strong vertical gradients at the top of the atmospheric boundary layer affect the propagation of electromagnetic waves and can produce radar ducts. A three-dimensional, time-dependent, nonhydrostatic numerical model was used to simulate the propagation environment in the atmosphere over the Persian Gulf when aircraft observations of ducting had been made. A division of the observations into high- and low-wind cases was used as a framework for the simulations. Three sets of simulations were conducted with initial conditions of varying degrees of idealization and were compared with the observations taken in the Ship Antisubmarine Warfare Readiness/Effectiveness Measuring (SHAREM-115) program. The best results occurred with the initialization based on a sounding taken over the coast modified by the inclusion of data on low-level atmospheric conditions over the Gulf waters. The development of moist, cool, stable marine internal boundary layers (MIBL) in air flowing from land over the waters of the Gulf was simulated. The MIBLs were capped by temperature inversions and associated lapses of humidity and refractivity. The low-wind MIBL was shallower and the gradients at its top were sharper than in the high-wind case, in agreement with the observations. Because it is also forced by land–sea contrasts, a sea-breeze circulation frequently occurs in association with the MIBL. The size, location, and internal structure of the sea-breeze circulation were realistically simulated. The gradients of temperature and humidity that bound the MIBL cause perturbations in the refractivity distribution that, in turn, lead to trapping layers and ducts. The existence, location, and surface character of the ducts were well captured. Horizontal variations in duct characteristics due to the sea-breeze circulation were also evident. The simulations successfully distinguished between high- and low-wind occasions, a notable feature of the SHAREM-115 observations. The modeled magnitudes of duct depth and strength, although leaving scope for improvement, were most encouraging.

Habitat associations and breeding bird community composition within the city of Bristol, UK

Capsule: Different urban breeding bird communities are associated with different habitat types, but, although community species diversity varies significantly, total bird density does not. Aims: To investigate the association between breeding bird communities and habitats within Bristol, UK and how these communities vary in terms of species diversity and total bird abundance. Methods: Breeding density data for 70 species in the metropolitan area of Bristol, UK were subjected to de-trended correspondence analysis to identify the number of different communities present and their indicator species. These data were then used to identify patterns of habitat association with each community and differences in species richness and total bird density. Results: Three communities were identified: a rural community associated with woodland, managed grassland and inland water; a suburban community associated with buildings and residential gardens; and an intermediate community that shared some of these habitat characteristics. Species richness, but not total bird abundance, was lowest in the suburban community. Conclusion: The diversity of species in urban areas appears to be most dependent upon the availability of patches of natural and semi-natural habitats. Residential gardens support fewer species, but those species that are present may be found at high densities.

A model of intelligent building energy management for the indoor environment

People's interaction with the indoor environment plays a significant role in energy consumption in buildings. Mismatching and delaying occupants' feedback on the indoor environment to the building energy management system is the major barrier to the efficient energy management of buildings. There is an increasing trend towards the application of digital technology to support control systems in order to achieve energy efficiency in buildings. This article introduces a holistic, integrated, building energy management model called `smart sensor, optimum decision and intelligent control' (SMODIC). The model takes into account occupants' responses to the indoor environments in the control system. The model of optimal decision-making based on multiple criteria of indoor environments has been integrated into the whole system. The SMODIC model combines information technology and people centric concepts to achieve energy savings in buildings.

Preliminary results from the infrared multilayer filters and materials exposed to the space environment on the NASA LDEF mission

With continually increasing demands for improvements to atmospheric and planetary remote-sensing instrumentation, for both high optical system performance and extended operational lifetimes, an investigation to access the effects of prolonged exposure of the space environment to a series of infrared interference filters and optical materials was promoted on the NASA LDEF mission. The NASA Long Duration Exposure Facility (LDEF) was launchd by the Space Shuttle to transport various science and technology experiments both to and from space, providing investigators with the opportunity to study the effects of the space environment on materials and systems used in space-flight applications. Preliminary results to be discussed consist of transmission measurements obtained and processed from an infrared spectrophotometer both before (1983) and after (1990) exposure compared with unexposed control specimens, together with results of detailed microscopic and general visual examinations performed on the experiment. The principle lead telluride (PbTe) and Zinc Sulphide (ZnS) based multilayer filters selected for this preliminary investigation consist of : an 8-12µm low pass edge filter, a 10.6µm 2.5% half bandwidth (HBW) double half-wave narrow bandpass filter, and a 10% HBW triple half-wave wide bandpass filter at 15µm. Optical substrates of MgF2 and KRS-5 (T1BrI) will also be discussed.

Generating virtual environments to allow increased access to the built environment

The problems encountered by individuals with disabilities when accessing large public buildings is described and a solution based on the generation of virtual models of the built environment is proposed. These models are superimposed on a control network infrastructure, currently utilised in intelligent building applications such as lighting, heating and access control. The use of control network architectures facilitates the creation of distributed models that closely mirror both the physical and control properties of the environment. The model of the environment is kept local to the installation which allows the virtual representation of a large building to be decomposed into an interconnecting series of smaller models. This paper describes two methods of interacting with the virtual model, firstly a two dimensional aural representation that can be used as the basis of a portable navigational device. Secondly an augmented reality called DAMOCLES that overlays additional information on a user’s normal field of view. The provision of virtual environments offers new possibilities in the man-machine interface so that intuitive access to network based services and control functions can be given to a user.

Virtual reality as a visualisation tool: benefits and constraints

The benefits and applications of virtual reality (VR) in the construction industry have been investigated for almost a decade. However, the practical implementation of VR in the construction industry has yet to reach maturity owing to technical constraints. The need for effective information management presents challenges: both transfer of building data to, and organisation of building information within, the virtual environment require consideration. This paper reviews the applications and benefits of VR in the built environment field and reports on a collaboration between Loughborough University and South Bank University to overcome constraints on the use of the overall VR model for whole lifecycle visualisation. The work at each research centre is concerned with an aspect of information management within VR applications for the built environment, and both data transfer and internal data organisation have been investigated. In this paper, similarities and differences between computer-aided design (CAD) and VR packages are first discussed. Three different approaches to the creation of VR models during the design stage are identified and described, with a view to providing sharing understanding across the interdiscipliary groups involved. The suitable organisation of building information within the virtual environment is then further investigated. This work focused on the visualisation of the degradation of a building, through its lifespan, with the view to provide a visual aid for developing an effective and economic project maintenance programme. Finally consideration is given to the potential of emerging standards to facilitate an integrated use of VR. The convergence towards similar data structures in VR and other construction packages may enable visualisation to be better utilised in the overall lifecycle model.

Konjac glucomannan hydrolysate beneficially modulates bacterial composition and activity within the faecal microbiota

The prebiotic potential of a konjac glucomannan hydrolysate (GMH) was investigated in vitro using batch cultures inoculated with human faeces. Bacterial enumeration was carried out using the culture independent technique, fluorescent in situ hybridisation (FISH), and short chain fatty acid (SCFA) production was monitored by gas chromatography. The populations of Bifidobacterium genus, Lactobacillus–Enterococcus group and the Atopobium group all significantly increased after GMH and inulin fermentation. The Bacteroides–Prevotella group had a lower end population after GMH fermentation while inulin gave an increase, although these differences were not significant. No significant differences in SCFA concentrations were observed between inulin and GMH. As with inulin, GMH produced selective stimulation of beneficial gut microbiota and a favourable SCFA profile. In order to confirm a beneficial effect of GMH further in vivo studies involving healthy human volunteers should be considered.