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This paper presents new results showing the application of polyomino-based subarrays to limited field of view and wideband, wide-angle scanning. This technology can reduce the number of phase controls in arrays used for limited sector coverage or the number of time delay devices for wideband radar or communications, and so can reduce the cost of space-based active arrays. We concentrate on the wideband application. Results are presented by comparing the gain and peak sidelobe results of irregular polyomino subarray-based arrays with those of rectangular subarrays. It is shown that using irregular polyomino subarrays can result in a major decrease in sidelobes while presenting, in most cases, only a few tenths of a dB gain reduction compared to rectangular subarrays. [ABSTRACT FROM AUTHOR]

An open-air fumigation system was used to expose a winter barley crop (Hordeum vulgare L.) to controlled concentrations of SO2 from November 1982 to July 1983. Monitoring data from a rural site were used as a basis for simulating mean concentrations of 0.023, 0.038 and 0.058 μl l-1 SO2 at a location where background concentrations were 0.01 μl l-1 SO2. There was no evidence of a reduction or stimulation of crop growth over the winter period. During the spring, the crop in SO2 fumigated plots had a higher green leaf area arid dry weight than in control plots which may have resulted from a reduction in the occurrence of the fungal pathogen brown rust (Puccinia hordei Otth.). After ear emergence a delay in senescence of leaves was observed in fumigated plots which gave the plants an extended period for assimilation during grain filling. There was no evidence that the yield of barley was reduced within the range of ambient SO2 concentration in the UK (annual mean < 0.03 μl l-1 SO2). However, at 0.058 μl l-1 SO2, reductions in yield were observed. Treatment with 0.023 μl l-1 SO2 produced increased grain yield. [ABSTRACT FROM AUTHOR]

Three-year-old clonal saplings of Picea abies L. Karst. were fumigated for 60 d during the summer of 1985 with four different levels of O[sub3]. Visible injury (in the form of severe, uniform brown necrosis and shedding of affected needles) occurred after a frost in November on the older needles of three of the clones which had received over 200 μg m[sup-3] of O[sub3] during the summer, 47 d previously. No visible injury occurred during the fumigation period or on the current (1985) year needles. It is suggested that the results provide preliminary evidence for an enhancement of frost sensitivity by O[sub3] which may be significant in the current wave of forest decline affecting high-altitude forests in central Europe. [ABSTRACT FROM AUTHOR]

Ventilated Solardomes (hemispherical glasshouses) have been used for 20 yr for studying the effects of gaseous pollutants on plants. This paper describes a computer-operated facility for studying the effects of CO2 × temperature regimes on plants. The eight chambers were set up for factorial design experiments - with two levels of CO2 (ambient and ambient+ 340 ppmv), two levels of temperature (ambient and 3 °C tracked continuously above ambient) and two replicates of each CO2 × temperature treatment. Monitoring of environmental conditions within the chambers over a 2 yr period has shown highly effective control of CO2 and temperature regimes. Even with high-quality and u.v.-B transmitting glass, the irradiance in the PAR region was reduced by 18% within the domes. Variation in temperature across the radii of the domes increased with higher photosynthetic photon flux density (PPFD). Vapour pressure deficits (VPDs) in the ambient temperature domes compared well with outside conditions but were higher in the elevated temperature domes. The watering regime within the domes affected intermittently the relationship between 'dome' and 'outside' VPDs. The Solardome facility has been used extensively for studies of the impacts of climate change within the UK Programme on Terrestrial Initiative on Global Environmental Research (TIGER). [ABSTRACT FROM AUTHOR]