Abstract:
An apparatus for measuring potentials with great accuracy using a self-balancing current comparator. The comparator includes a variable primary winding and a secondary winding wound on a magnetic core. The primary is fed a constant current I2 and the secondary is fed with a direct current such that ampere-turns balance is achieved between the windings. A resistor R1, to which the unknown potential Vin is connected, is in turn connected to the secondary winding. An operational amplifier is connected to the junction between the resistor and the secondary winding. The output of the amplifier adjusts the turns in the primary winding and as a result when the potential across the amplifier is zero, the unknown voltage Vin R1.N2/N3. I2 where N2 and N3 are the turns in the primary and secondary windings respectively.
Abstract:
To reduce splitting ahead of a knife a block of wood is cut by compressively stressing the wood to at least 25% of its yield strength, between clamps, then cutting the wood with a knife along a path between the clamps, releasing the clamps to remove the compression, and then separating the wood from the knife. Two or more knives may be used cutting in opposite or the same, parallel directions.
Abstract:
In a mixture of ethylene and acetylene, the ethylene is selectively oxidized to formaldehyde. This oxidation is used in the determination of nitrogenase (nitrogen fixation) activity where ethylene produced by the enzyme from added acetylene, has to be measured. The formaldehyde produced from the ethylene is proportional to the enzyme activity, and can be assayed colorimetrically or otherwise.
Abstract:
Composite metal articles of high density are made from powders of the following metals: about 25 to about 90 wt. % iron, up to about 5 wt. % of tin, copper or mixtures thereof, and the balance substantially all lead. Preferably zinc in amounts up to about 1.5% is also present. Composite bird shot, for instance, is prepared by agglomeration techniques, sintered and partially alloyed at below about 1,200*C and if desired mechanically compacted to further increase the density. A lead-rich outer layer is advantageous.
Abstract:
A liquid level height measuring device that is a transmission line oscillator comprising a parallel conductor transmission line positionable in the liquid whose height is to be measured and a sensor in the form of a switching device whose switching frequency is dependent only on transmission line length and thus on liquid level. The transmission line preferably includes a length of flexible coaxial cable connected in series to a rigid coaxial conductor structure with the center conductor positioned in relation to and electrically insulated from the outer conductor which has perforations over its working length for ready entry of the liquid into the space between conductors. The sensor is a two terminal bistable switching device, preferably a tunnel diode, connected to the transmission line such that a switching signal is generated whose frequency is dependent only on the transmission length.
Abstract:
This invention relates to improvements in the production of veneer. In accordance with the invention a heated fluid, preferably steam, is directed into the cutting region as the veneer is being cut. Improvements that can be obtained are decrease of the cutting force, surface roughness and severity of lathe checks for the resulting veneer. Preferably the heated fluid is channeled in contact with the cutting blade before being released to the cutting region, in order to raise the temperature of the blade.
Abstract:
A magnetic levitation guidance system having a predetermined arrangement and positioning of the magnets or current carrying conductors in the levitated vehicle in relation to the fixed guideway conductors. In one version of the invention the parallel, longitudinal vehicle magnets or current carrying conductors are positioned such that when the vehicle is positioned above a continuous conducting strip guideway positioned on the trackbed, these magnet edges or current carrying conductors are positioned outward in the horizontal sense of the edges of the conducting strip. In another version where the guideway is the form of loops or ladder shaped arrangements, the parallel, longitudal portions of the magnet edges or current loops on the vehicle are positioned when the vehicle is centered over the guideways such that these magnet edges or current carrying conductors are placed outwardly or inwardly of the co-acting conductors in the guideway. It has been found that if the magnet edges or current carrying conductors are positioned in this manner, there will be an inherent lateral restoring force that will tend to center the vehicle in relation to the guideway.
Abstract:
A frozen food egg substance comprising free flowing discrete particles of the substance, with each particle in pop-corn-like form is produced by dropping the egg substance into direct contact with a non-toxic, liquified gas refrigerant. The egg substance, which may be egg white, egg yolk or homogenized egg yolk and egg white is dropped onto a turbulent surface of the refrigerant, and is removed from it as the discrete particles so that liquified gas on the particles is allowed to evaporate and the particles may be stored in a frozen condition.
Abstract:
An amorphous, pulverulent, dry silica is prepared which is particularly useful for reinforcing rubber. It is produced by: A. PREPARING SEED PARTICLES BY ADDING A MINERAL ACID TO A DILUTE ALKALI METAL SILICATE SOLUTION CONTAINING 1 TO 3% BY WEIGHT OF SiO2 to form a sol having a pH of about 4.5 - 6.5 and allowing the sol to set into a firm aquagel, B. DILUTING AND DISPERSING THE AQUAGEL IN WATER TO FORM AN AQUEOUS DISPERSION OF AQUAGEL SEED PARTICLES, C. MIXING WITH SAID DISPERSION AN ALKALI METAL SILICATE SOLUTION, D. ADDING ACID TO SAID SEED DISPERSION-ALKALI METAL SILICATE MIXTURE AT A TEMPERATURE OF ABOUT 75* - 100* C to quickly lower the pH to about 1 to 4 and precipitate silica, E. SEPARATING THE WET PRECIPITATED SILICA FROM THE ASSOCIATED LIQUID AND DRYING THE FRESHLY PRECIPITATED SILICA.
Abstract:
An instrument for the measurement of energy or power with a high degree of precision. The voltage and current components of the power are determined individually. The voltage component is measured using a precise instrument such as an AC/DC comparator. The current component is measured in a current comparator in which it is balanced against current obtained by applying the voltage component to a high quality resistor and a high quality capacitor. The instrument is especially useful in the calibration of wattmeters and watt-hour meters.