1A barrier that allows passage of defined agents while preventing or impeding others, in particular.
- ‘Furthermore, such active barriers are expensive and add equipment and design cost to the system.’
- ‘This was done to best assess the positioning of the future bank of permanent, active barriers.’
- ‘The following diagrams showing crash performance data for a variety of passive and active barriers.’
- ‘If you're not sure, then use an active barrier.’
- ‘In the past, there were active barriers that filtered out people of a certain race or gender.’
- 1.1A security barrier that responds to attempted entries with sensors or personnel.
- ‘The active barrier will be placed as a protection of the terrace of the experimental house to demonstrate the possibility to control an outdoor space.’
- ‘The combined structure is designed as a single active barrier system which is simple and cheap to install.’
- ‘This technology takes active barrier structures into the 21st century of perimeter detection systems’
- ‘Security improvements to perimeter fencing and gates include sentry booths, pass office, truck inspection station, inspection canopy, passive barriers, active barriers, emergency generators, and site lighting.’
- 1.2A physical or chemical barrier that intercepts contaminants, debris, or other unwanted substances.
- ‘And what it does is it's an active barrier in the sense that it swells when moisture migrates into it and seals.’
- ‘Whereas the salivary gland and hindgut were active barriers in the parent Sg-SC and most of the hybrids tested, other hybrids were identified with single barriers.’
- ‘This layer behaves as an active barrier that prevents the interfacial reactions between the aluminium and the silicon carbide and that have a detrimental effect on the material properties.’
- ‘The passive barriers which have been tested include water trough barriers, stone dust barriers, and dispersed barriers and the active barriers include gas and a mixture of gas and water.’
- ‘There is a need for an active barrier system that will provide localized immunosuppression in the surrounding environment, thus, enhancing tolerance of the grafted tissue.’
- ‘The biologically active barrier is set up vertical to the groundwater flow direction according to the flow characteristics and main contaminant concentration of the groundwater.’