Building Research Establishment

Daylight is essential for circadian entrainment, yet current daylighting metrics and guidance do not address this aspect. Latest recommendations for light exposure suggest a daytime melanopic equivalent daylight illuminance (EDI) of 250 lx at the eye. This paper investigates the feasibility of these recommendations using daylight data from Watford, England and computer modelling in example offices achieving the minimum and high levels of recommendation in EN17037. In predominantly cloudy climates, it is impractical to require a specific melanopic EDI every day of the year. Instead, it is more feasible to aim for a certain number of daily hours on a given proportion of annual days. This paper evaluates a metric of achieving four hours with 250 lx melanopic EDI on 90% of annual days. Daylight may be sufficient for circadian entrainment in spaces that meet the high level of recommendation in EN17037 and if facing unobstructed windows. However, facing large windows can cause glare. It is easier to achieve 250 lx melanopic EDI over any four hours throughout the day than just in the morning, although this may not guarantee adequate circadian entrainment. Balancing daylight provision targets and daylight levels for circadian stimulation while limiting glare from daylight is challenging.

Commercial software packages that utilise published CPTU correlations are frequently used for quick presentation of soil parameters such as soil unit weight, over consolidation ratio, undrained shear strength, lateral stress ratio, and peak friction angle. It is a well-known fact that such correlations are not globally valid, but many practitioners use the parameters obtained this way even in foundation design. At the Norwegian soft clay, quick clay, silt, and sand sites, high quality sampling and laboratory testing have resulted in a consistent representative database of reliable soil parameters. Moreover, high quality results of CPTU, seismic cones, self-boring pressuremeter and a novel flow cone tool are also available at the sites. Using these high-quality benchmark parameters gives an excellent opportunity to evaluate the validity of the soil parameters derived from 18 published CPTU correlations used in commercial software packages. For transparency, the correlations are described in some detail with full reference to the source. A comparison of correlation derived parameters and reliable laboratory-based benchmark soil parameters showed that the use of global correlations can be too conservative and, in some cases, dangerous. Local correlations are not only recommended but are essential for design. In this study, we did not cover highly overconsolidated clays and very dense sands, though similar conclusions on those soils may be expected.

Current generation sonar signal processors need to operate with throughputs of several hundred million arithmetic operations per second to achieve acceptable operational performance.The digital processing load imposed by this processing requirement is beyond the capability of currently available individual "off-the-shelf" DSP components.Distributed networks of processing engines, based on a signal flow architecture [1], have been employed in some applications and are capable of supporting throughputs in excess of 500 million arithmetic operations per second.Future generation systems require a major increase in throughput [2], three orders of magnitude, if they are to keep pace with the perceived improvements in threat performance.This processing power is required to handle the data from larger aperture arrays, to perform more complex adaptive processing at the front end of the systems and to reduce operator/analyst load at the back end of the system and, although the throughput of standard DSP parts has increased significantly over the past few years, the improvements have nowhere near matched those needed to maintain a leading edge in system design.System throughputs can obviously be increased by using extended multi-processor distributed networks, but not without some problems in the

Approved Doctuuent l5.1 speci es that-the leaves of cavity masonry separating walls (Wall Type 2) should be connected where necessary by butterfly ties. This generic ype of wall tie is speci ed because of its ability to satisfy the structural requirements of 555628 without compromising the

How can domestic housing be adapted to support people living with dementia staying in their own homes for as long as they choose? This paper describes the innovative practice of using evidence-based design personas in a building refurbishment project (Chris and Sally's House) with a multidisciplinary team of architects, ergonomists, psychologists and experts. A 100 sqm Victorian two bedroom house was adapted to help educate house builders, carers and relatives on how to better support those living with dementia to live in their own home for longer. The design principles include clear sight lines, mobility support and provision for overnight carers.

Although the oxidation of pyrite in geological materials has been linked to various problems in civil engineering works for many years, the risk of further problems has not been eliminated. Pyrite occurs widely as a minor constituent of geo-materials and many construction processes result in the exposure of pyrite-bearing materials to air and water, which then result in oxidation. The paper presents an historical review of construction scenarios in which pyrite has had significant adverse impact. The cases considered include rapid deterioration of rock materials, chemical attack on concrete and metallic structures in the ground, and the expansion of fills and stabilized soils. These cases have been important turning points in understanding deleterious pyrite processes and the development of guidance for their avoidance. By following the guidance presented in the relevant standards and technical documentation, destructive processes due to pyrite should be avoided. However, as many of the problems are influenced by variables, such as site location factors and construction processes, adhering to published guidance may not eliminate the possibility of adverse impacts. It is important that expert technical advice is provided at all stages of projects and that any deviations from the expected performance should be properly evaluated.