Abstract: Use of shallow pools of liquid to collect low-temperature solar generated thermal energy on a large scale for commercial use becomes economically feasible when use is made of efficient means to keep the liquid in the pond clean, prevent evaporation, prevent air convection and prevent convective circulation of the liquid. Narrow elongated trenches, grouped together over a wide area, can be formed by bulldozer type equipment. Each trench is lined with a heat-absorbing black liner. The liquid in the bottom of each trench, used to absorb the solar energy, may be a brine solution or plain water, depending on the means used to remove the thermal energy from the pond. The heat-absorbing liquid is kept separate from the thermal energy removing fluid by means such as clear polyethylene material. The covering for the pond may be a fluid or solid. If the covering is a fluid, fire fighting foam, continuously generated, or siloons are used to keep the surface covering clean and insulated.

Abstract: A fixed, linear, ground-based primary reflector having an extended curved-sawtooth contoured surface covered with a metallized polymeric reflecting material, reflects solar energy to a movably supported collector that is kept at the concentrated line focus of the reflector primary. The primary reflector may be constructed by a process utilizing well-known freeway paving machinery. The solar energy absorber is preferably a fluid-transporting pipe. Efficient utilization leading to high temperatures from the reflected solar energy is obtained by cylindrical shaped secondary reflectors that direct off-angle energy to the absorber pipe. To obtain higher temperature levels, refocusing secondary reflectors, that cause a series of discrete spots of highly concentrated solar energy to fall on the fluid-transporting pipe, are utilized. A seriatim arrangement of cylindrical secondary reflector stages and spot-forming reflector stages produces a high temperature solar energy collection system of greater efficiency.

Abstract: A closure for a drain port in a receptacle such as a bath tub or sink. The closure includes a base member for attachment to the receptacle. It includes a fulcrum which engages one side of a bi-stable disc spring. A pair of actuators are situated on the opposite side of the spring, and contact it respectively radially inwardly and outwardly from the fulcrum. The spring can be moved by the actuators to assume a respective one of its two stable configurations. The spring, when in one configuration, permits a seal to bear against a peripheral surface around the drain port to close it. When in the other configuration, it causes the seal to move away from the peripheral surface and open the drain port.

Abstract: A cryostat system for cooling a device to a temperature on the order of 2.degree.K or less includes a dewar, in which helium, in other than the superfluid state, is stored. Helium flows from the dewar through a heat exchanger tube and a restrictor tube, which controls the helium flow rate, into the cavity of a heat exchanger, to whose outer wall the device to be cooled is attached. A pressure regulator valve controls the pressure in the cavity to be very low, e.g., on the order of 30 Torr. As the helium exits the restrictor tube into the cavity, due to low pressure cavity, it becomes an aerosol mixture of helium gas and superfluid helium droplets at the desired temperature. The latter form a thin layer or film of superfluid helium on the inner side of the heat exchanger wall and thereby cool the device, which is attached to the wall to the desired temperature.

Abstract: A liquid measuring device for use in dispensing a measured quantity of a liquid each time the pressure of liquid conveyed to such a device is reduced can be constructed utilizing associated inlet and outlet valves and an accumulator. The valves are constructed so that the inlet valve will be opened to the accumulator while the outlet valve is closed in response to an increase in the pressure of the liquid conveyed to the device. When the pressure of such supplied liquid is reduced as, for example, by the supply of liquid being cut off, the inlet valve is closed and the outlet valve is opened so as to discharge the liquid in the accumulator. Such devices are primarily intended for agricultural watering.

Abstract: Apparatus for sensing the temperature, velocity, and direction of the wind, including four temperature-dependent crystal oscillators spaced about an axis, a heater centered on the axis, and a screen through which the wind blows to pass over the crystals. In one method of operation, the frequency of the oscillators is taken when the heater is not energized, to obtain the temperature of the wind, and the frequencies of the oscillators are taken after the heater is energized to determine the direction and velocity of the wind. When the heater is energized, the wind causes the downwind crystals to achieve a higher temperature than the upwind crystals, and with the magnitude of the difference indicating the velocity of the wind.

Abstract: It is known to construct fluid dispensing structures which utilize tubes or conduits which expand or contract in cross-section in accordance with the internal pressure of a fluid within such a tube or conduit in combination with one or more flow control members mounted on such a tube or conduit. These devices are constructed so that there is relative motion between such a tube or conduit and such a flow control member as the tube or conduit changes in cross-sectional configuration. Structures of this type may be modified so that they are usable in providing a relatively constant discharge of a fluid regardless of changes in the fluid pressure within such a tube or conduit by utilizing a pressure compensating spring in combination with each flow control member used.

Abstract: An atmosphere sampler includes a very thin filter element with straight-through holes on the order of 1.mu.. A sample of air with particles to be examined is driven by means of a pressurized low molecular weight gas, e.g., He to the filter element front side. A partial vacuum may be present at the back side of the filter element. The pressure differential across the filter element is just below the rupture point of the filter element. By admixing a low molecular weight gas as the carrier gas with the air sampler the velocity with which the air sample is driven to the filter element is maximized for the particular pressure differential across the filter element, so that at least some particles with diameters less than the hole diameter do not follow changes in the air stream line direction as it passes through the filter element holes and therefore the smaller diameter particles are deposited on the filter element. When using a filter element of plastic material of a thickness on the order of 10.mu.