Previously reported work resulted in a transputer tree network using thirty transputers to perform the Radon transform. The Radon transform was used to enhance linear features in noisy synthetic aperture radar images. The work presented here describes modification of the transputer network by the addition of INMOS B004 link switches, and controlling T222 transputer. The tree configuration is replaced such that link switches now dynamically switch between the image data source transputer (farmer) and the transputers which perform the calculations (workers). It is shown that this arrangement is more cost-effective since the worker transputers are all relieved of their data-routing role. The paper includes a comparison of the previous tree network with the new switched network, and presents results for both techniques.

The formulation and solution of the large elastic axisymmetric deformation problem corresponding to a membrane shell from an initially flat laminated composite material is provided. The numerical solution method developed is found to be very stable and accurate and is easily implemented on a personal computer. The results which consider initial pretension in the membrane are compared with the finite element results and with results obtained by assuming an approximate deflected shape in conjunction with the energy methods. The deformed profile, surface slope, and in-plane tensions are presented as a function of radial distance. Their variation with initial tension and normal pressure parameters is also shown. This problem is of importance in the design of large-diameter membrane concentrators for solar applications.

The authors briefly describe the Radon transform and the computational considerations necessary to enhance linear features in noisy images. The implementation of the transform a multitransputer network is discussed, and results are presented to demonstrate the performance of the network topology. Feature identification in synthetic aperture radar (SAR) images is considered as an example. The multitransputer network described performs Radon transforms within a few seconds, and linear features in noisy images can be rapidly enhanced. The transputer network architecture can easily be reconfigured to suit various processing algorithms, and the system therefore provides versatile high-speed image processing facilities for a number of computationally intensive applications.< >

The paper describes the Radon transform and the computational considerations necessary to enhance linear features in noisy images. The implementation of the transform via a multitransputer network is discussed, and results are presented to demonstrate the performance of the network topology.

A new fast discrete Radon transform method for enhancement of lines in noisy images is described. It is based on the Fourier slice theorem, with variable length slices to utilise all of the frequency domain data. It is shown that this new method achieves a significant increase in computational speed compared with an existing technique.

Postischemic limb swelling following reperfusion may be related to microvascular changes associated with ischemia. We used lymph-to-plasma total protein concentration ratios (LP) and lymph flow (QL) as an index of transvascular exchange in the intact dog hindlimb during steady state (C) (1 hr), ischemia (I) (6 hr), and reperfusion (R) (3 hr). Central pressures, femoral arterial and venous pressures (PA, PV), and QL were recorded every 15 min. Lymph was collected from a femoral lymphatic in the passively flexed leg (50 cycles/min). Three groups of animals were studied: GI, sham-operated (N = 5); GII, moderate ischemia (N = 7, PA = 30–45% C); and GIII, severe ischemia (N = 7, PA = 5–20% C). In GI, QL gradually increased over 10 hr without change in LP. Moderate ischemia produced a decrease in QL, 3.55 ± 2.02 mg/hr to 0.92 ± 0.53 mg/hr (P < 0.0001), and QL remained below baseline during R with no change in LP over the 10 hr. Severe ischemia produced a similar decrease in QL, 1.91 ± 2.05 mg/hr to 0.15 ± 0.1 mg/hr (P < 0.01); however, an increase to 2.56 ± 2.14 mg/hr occurred during R. Severe ischemia increased LP 0.42 ± 0.08 to 0.64 ± 0.23 (P < 0.001) and remained elevated during R at 0.63 ± 0.18 (P < 0.001). An increase in the wet-to-dry weight ratio of ischemic to nonischemic muscle after reperfusion was noted only in GIII, 3.82 ± 1.17 vs 2.60 ± 0.45 (P < 0.04). Severe ischemia produces changes in vascular integrity which augment protein flow. Prevention of these vascular changes may help to minimize the muscle swelling of reperfusion.

Energy conservation and economic potential of large capacity (∼MWth) solar-assisted water-to-water heat pumps (SAHP) is evaluated for year round low temperature (<100° C) industrial process heating applications at four locations in the United States. The long-term thermal performance of the SAHP system is determined by a recently proposed utilizability method that accounts for the variable coefficient of performance of the SAHP system. The large SAHP system appears to be an attractive energy conservation alternative to fuel oil and electricity for locations with high solar resources and low electricity costs. In all but one location, the SAHP system was clearly superior to the solar only systems, such as flat plate and concentrating collectors, from the point of view of the annualized delivered energy cost. For the ranges of collector area and load temperatures considered in this study, the large SAHP system has clearly superior energy conservation potential at all four locations compared to other alternatives such as fuel oil or electricity. However, the practial suitability of SAHP cycle, as determined by the levelized cost of delivered energy, is unfavorable at all four locations when compared with fuel oil.

The performance benefits of the direct (in situ) generation of steam in the receiver tube of a line-focus solar collector are assessed. Compared to existing technology using steam-flash or unfired boiler systems, the in situ technique could produce 25% more steam at a reduced delivery cost. The analysis indicates that two-phase flow instabilities, if present, can be readily controlled, and that the possibility of freezing is not an impediment to using water in cold climates.

The performance benefits of the direct (in situ) generation of steam in the receiver tube of a line-focus solar collector are assessed in this paper. Compared to existing technology using steam-flash or unfired boiler systems, the in situ technique could reduce the delivered cost of steam in excess of 25 percent. The analysis indicates that two-phase flow instabilities, if present, can be readily controlled, and that the possibility of freezing is not an impediment to the use of water in cold climates.

Improved parabolic trough concentrating collectors will result from better design, improved fabrication techniques, and the development and use of improved materials. This paper presents and implements an easily applied methodology that quantifies the performance potential of selected parabolic through component improvements from a systems viewpoint and uses performance data to determine the economic value of each improvement. Specifically considered are evacuated receivers, silvered glass reflectors, improved receiver selective coatings, higher optical accuracy concentrators, and higher transmittance receiver glazings. Upper-bound costs for each improvement are provided as are estimates of the increased solar energy system rates of return made possible by these improvements. The performance and economic potentials of some of these improvements are substantial, especially at higher collector operating temperatures.