A Transmittance-optimized, Point-focus Fresnel Lens Solar Concentrator

The development of a point-focus Fresnel lens solar concentrator for high-temperature solar thermal energy system applications is discussed. The concentrator utilizes a transmittance-optimized, short-focal-length, dome-shaped refractive Fresnel lens as the optical element. This concentrator combines both good optical performance and a large tolerance for manufacturing, deflection, and tracking errors. The conceptual design of an 11-meter diameter concentrator which should provide an overall collector efficiency of about 70% at an 815 C (1500 F) receiver operating temperature and a 1500X geometric concentration ratio (lens aperture area/receiver aperture area) was completed. Results of optical and thermal analyses of the collector, a discussion of manufacturing methods for making the large lens, and an update on the current status and future plans of the development program are included

Peak holding circuit for extremely narrow pulses

An improved pulse stretching circuit comprising: a high speed wide-band amplifier connected in a fast charge integrator configuration; a holding circuit including a capacitor connected in parallel with a discharging network which employs a resistor and an FET; and an output buffer amplifier. Input pulses of very short duration are applied to the integrator charging the capacitor to a value proportional to the input pulse amplitude. After a predetermined period of time, conventional circuitry generates a dump pulse which is applied to the gate of the FET making a low resistance path to ground which discharges the capacitor. When the dump pulse terminates, the circuit is ready to accept another pulse to be stretched. The very short input pulses are thus stretched in width so that they may be analyzed by conventional pulse height analyzers

Monostable multivibrator with complementary NOR gates Patent

Monostable multivibrator for producing output pulse widths with positive feedback NOR gate

Peak-holding circuit for extremely narrow pulses

Circuit was developed which can stretch pulses in 50- to 3200-ns range to make them acceptable for pulse-height analyzers. Circuit uses high-speed wide-band amplifier, does not need excessive frequency compensation, and can handle pulses one-tenth of width normally required by pulse analyzers

One-shot multivibrator with complementary metal-oxide-semiconductor components

Breadboard model is tuned to produce output pulses from one microsecond up to several seconds in width with up to 95 percent duty cycle, and with lower power consumption than previously existing circuits

Software engineering and Ada in design

Modern software engineering promises significant reductions in software costs and improvements in software quality. The Ada language is the focus for these software methodology and tool improvements. The IBM FSD approach, including the software engineering practices that guide the systematic design and development of software products and the management of the software process are examined. The revised Ada design language adaptation is revealed. This four level design methodology is detailed including the purpose of each level, the management strategy that integrates the software design activity with the program milestones, and the technical strategy that maps the Ada constructs to each level of design. A complete description of each design level is provided along with specific design language recording guidelines for each level. Finally, some testimony is offered on education, tools, architecture, and metrics resulting from project use of the four level Ada design language adaptation

Recent work on use of lunar materials for SPS construction

The feasibility of mounting a small operation on the Moon to productively use lunar materials in support of programs such as the solar power satellite is addressed. A cost effective scenario of a small chemical process plant on the surface of the Moon and a small machine shop located in orbit is presented. The mass of the space installation is compared to the projected outputs in 90 days. It is indicated that the system would have the capability of replicating about 90% of its own components and would provide the metals, glasses, and silicon needed for the contruction of 90% to 96% of the mass of one solar power satellite per year

Variable boundary II heat conduction

Computer program for solving both transient and steady-state heat transfer problems is presented. Specific applications of computer program are described. Formulation for individual nodes of solid medium for heat balance is presented. Diffusion equation is solved for all nodes simultaneously at finite increments of time

Purification of Gemini fuel cell water by ion exchange chromatography Final report, 13 Apr. - 12 Nov. 1965

Purification of Gemini fuel cell water by ion- exchange chromatograph

Comparison of satellite derived dynamical quantities in the stratosphere of the Southern Hemisphere

The proceedings are summarized from a pre-MASH planning workshop on the intercomparison of Southern Hemisphere observations, analyses and derived dynamical quantities held in Williamsburg, Virginia during April 1986. The aims of this workshop were primarily twofold: (1) comparison of Southern Hemisphere dynamical quantities derived from various satellite data archives (e.g., from limb scanners and nadir sounders); and (2) assessing the impact of different base-level height information on such derived quantities. These tasks are viewed as especially important in the Southern Hemisphere because of the paucity of conventional measurements. A further strong impetus for the MASH program comes from the recent discovery of the springtime ozone hold over Antarctica. Insight gained from validation studies such as the one reported here will contribute to an improved understanding of the role of meteorology in the development and evolution of the hold, in its interannual variability, and in its interhemispheric differences. The dynamical quantities examined in this workshop included geopotential height, zonal wind, potential vorticity, eddy heat and momentum fluxes, and Eliassen-Palm fluxes. The time periods and data sources constituting the MASH comparisons are summarized