Experiments have been performed by LLL which indicate a definite density profile steepening. One possible mechanism for this effect is the ponderomotive force. LASNEX has been modified to include the light momentum deposition in the form rho dv/dt = -nabla P - nabla(radical epsilon + radical 1/epsilon) I/2c. Results will be presented from numerical simulations on spherical glass targets at laser intensities from 10/sup 14/ to 10/sup 16/ watts/cm/sup 2/. Emphasis is placed on the nature of the density profile near the critical region as a function of laser intensity and plasma conditions. The existence of this sharp step, whose scale length is of the order of a micrometer may imply a local reduction in the thermal conductivity.

The Folksam office building in Farsta, near Stockholm, has operated since December 1977 with an energy use for direct space heating of only 60 kWh/m/sup 2/ (19,000 Btu/ft/sup 2/), which is only half the Stockholm average for new buildings. To this 60 kWh/m/sup 2/ must be added the typical electric use of another 60 kWh/m/sup 2/ for lights, equipment, fans, etc. Even though Stockholm has 3580 deg-day (C), new Swedish buildings are so well insulated that their temperature floats upwards during most winter working days. In the Folksam building, this surplus heat from 40 full-occupied hours per week is stored in hollow-core concrete slabs, and then is used to compensate for the heat losses during the remaining 128 unoccupied hours. The energy transport/storage system necessary to keep the indoor temperature comfortable, summer and winter, is called Thermodeck, and is described in detail.

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A procedure based on chemicsl separation techniques and activation anslysis was developed for the sequential analysis of low levels of /sup 131/I, / Sup 129/I, and natural iodine in environmental samples. The iodine is first separated from the samples by oxidation. The separated iodine is then counted by low-level, beta-gated gamma spectrometry for the measurement of /sup 131/I. The chemical yield for the separation is measured by means of /sup 125/I tracer. Activation analysis is used for measurement of the separated natural iodine (/sup 127/I) and /sup 129/I. The natural iodine is estimated from either the /sup 126/ I or /sup 128/I activity produced in the sample; the induced /sup 130/I is used to estimate the /sup 129/I concentration. The measurement of /sup 130/I at low levels requires specialized counting methods. Interfering activities that may be present in the irradiated sample include /sup 125/I, /sup 126/I, short-lived fission-product iodine activities produced by activation of uranium impurities, and /sup 82/Br from bromine impurities. Since /sup 130/I decays with several coincident gamma rays, multiple gamma coincidence counting techniques can be used to reduce background and discriminate against interfering activities. Severail three- and four-segmented NaI(Tl) detectors were used for these measurements and compared …