Three liquid-based solar heating systems employing different types of solar collectors were tested side by side near Chicago, Illinois for one year. The three different types of collectors were: (1) a flat plate collector with a black-chrome coated absorber plate and one low-iron glass cover; (2) an evacuated-tube compound parabolic concentrator (CPC) with a concentration ratio of 1.1, oriented with tubes and troughs along a north-south axis; and (3) an evacuated-tube CPC collector with a concentration ratio of 1.3 and one low-iron glass cover, with tubes and troughs oriented along an east-west axis. Results indicate that the flat plate collector system was the most efficient during warm weather, but the CPC systems were more efficient during cold weather, but the CPC systems were more efficient during cold weather, and the CPC systems operated under conditions too adverse for the flat plate collector. The computer simulation model ANSIM was validated by means of the side-by-side tests. The model uses analytical solutions to the storage energy balance. ANSIM is compared with the general simulation TRNSYS.

The TOEPLITZ package is a collection of Fortran subroutines for the numerical solution of systems of linear equations with coefficient matrices of Toeplitz or circulant form. This report provides a description of the algorithms and software in the package and includes program listings.

From introduction: The fabrication of various iris-fed millimeterwave rectangular microstrip patch antennas is described. A model is proposed to describe the iris-fed antenna. Irises ranging in size from 15 percent of the area of the patch to the fully open waveguide are used to couple energy into the antenna. Resonance of the antenna is observed to be insensitive to the size of the iris for irises up to 115 percent of the size of the patch. A study is also made of th? relationship of coupling to the antenna as a function of position of the iris with respect to the transverse plane of the waveguide, the iris always being centered with respect to the patch. In general, the antenna has a VSWR in the waveguide feed on the order of 5:1 at resonance, except for the fully open waveguide which gives rise to a VSWR of 2.9:1 at resonance. Far-field antenna power patterns are observed to be quite broad with H-plane beamwidths on the order of 1300. Maximum antenna gain is seen to be 4.5 dBi with 3 dBi typical. An initial study is made of the microstrip patch antenna fed from a longitudinal waveguide wall. Results indicate that …

Introduction: A reference step-like pulse generator is described which has been developed at NBS. This generator can be used for accurately characterizing the step response of various kinds of trap ient recording equipment (oscilloscopes, waveform recorders, transient digitizers, etc.). Basic design principles are given as well as complete circuit diagrams and descriptions. An analysis of the output stage of the generator is presented together with the circuit models for developing a time-domain computer simulation program using extended- SCEPTRE. Preliminary specifications indicate that the NBS Reference Flat Pulse Generator provides a negative-going reference transition duration (90 to 10 percent) of 600 ps, *20 percent with baseline perturbations of less than *2 percent for less than 5 ns.

From preface: STARPAC documentation is being published as a series of Technical Notes. This Note is the first in the series. It gives an overview of the STARPAC library, defines conventions used in the documentation, provides an example using STARPAC subroutines, and presents general background material. This Note includes information which is essential for using the STARPAC library, and users should be familiar with its contents before attempting to use any STARPAC subroutine.

From preface: This Note documents 16 subroutines for nonlinear least squares regression. Twelve of these compute the least squares estimates, performing either weighted or unweighted analysis with either numerically approximated or user-supplied (analytic) derivatives. The other four are user-callable subroutines for two procedures used within the estimation code: the first selects optimum step sizes for approximating the partial derivatives of the model; and the second checks the validity of a user-supplied derivative subroutine.

The report describes and demonstrates the performance of a modification to an earlier solution algorithm for the calculation of multidimensional fluid flow, heat transfer, and combustion processes. The modification significantly reduces the computer storage required by the earlier algorithm without degrading the rate of convergence. The modification called as telescoping subdomain analysis (TSDA) splits the flow domain into overlapping subregions and solves them in a sequence, with known conditions on the boundaries of the subregions. The procedure has been tested in four different two-dimensional recirculating flows and the convergence rates have been equivalent to the rates with full-domain analysis. The modification offers significant savings of computer storage and cost and permits calculations with larger finite-difference grids.

From purpose and scope: The purpose of this part of the Central Valley Aquifer Project is to gather and analyze all available information on the magnitude and distribution of ground-water pumpage in the Central Valley. These data will be used as input to a digital ground-water model, one of the products of the Central Valley Aquifer Project.

From introduction: The purpose of this report is to develop and evaluate a method to automate the constant-rate-injection technique, described by Cobb and Bailey, with sufficient accuracy and reliability to determine discharge in storm sewers under rapidly varying flow conditions.

From purpose and scope: The purpose of this study are to derive base flow estimates for representative parts of the Cretaceous and Tertiary clastic outcrop area as an aid in estimating recharge to the sand aquifers; to use base flow relations to estimate aquifer hydraulic parameters; and to relate the lithology of the aquifer to the streamflow duration curves.

From purposes and approach of study: The primary purposes of this study were to: (1) Define, on a reconnaissance level, current (1980) water-quality conditions in major aquifers (water-yielding rock formations) in the western Snake River basin, Swan Falls to Glenns Ferry; (2) summarize and interpret available geologic and hydrologic data to assist in understanding the natural and man-cause factors that affect present and future understanding the natural and man-caused factors that affect present and future water-quality conditions; and (3) establish a hydrologic data base on which future data can be compared to evaluate changes. A secondary purpose was to evaluate the possible effects percolation of thermal water applied for irrigation may have on the quality of local, less mineralized, nonthermal ground water.

The Geochemical Atlas of Alaska presents regional geochemical data as computer-generated images having concentration values of the elements displayed as colors and color intensities.