Abstract: Alcohol-insoluble polyamide (nylon) microporous separation membranes are prepared from alcohol-soluble polyamide (nylon) polymers. The membranes are hydrophilic and contain crosslinked amide groups of the structure: ##STR1## wherein d is an integer of about 1 to 3.

Abstract: Microporous nylon materials which retain near constant time to hydrosaturation during and after heating to temperatures necessary for sealing together a plurality of surfaces, and the synthesis thereof. Nylon 46 dissolved into a mixture of liquid nylon 46 solvents and nonsolvents is dispersed on a fabric substrate, then precipitated to form a laminate, from which a wash removes the nonsolvents and forms the microporous material.

Abstract: A continuous process for producing a microporous cellulosic membranes supported with an integral non-woven polymer web by preparing a casting lacquer comprising at least one cellulosic polymer, at least one solvent and at least one non-solvent wherein the casting lacquer is at the point of incipient gelation.

Abstract: An aircraft heading correction system utilizing the horizontal field strength of the earth's magnetic field to determine the tangent of the dip angle generally associated with a given field strength. The tangent of the dip angle is then used to generate a signal which corrects the flux valve heading during accelerated flight.

Abstract: The present invention is directed to a sacrificial or competitive adsorbate for surfactants contained in chemical flooding emulsions for enhanced oil recovery operations. The adsorbate to be utilized in the method of the present invention is a caustic effluent from the bleach stage or the weak black liquor from the digesters and pulp washers of the kraft pulping process. This effluent or weak black liquor is injected into an oil-bearing subterranean earth formation prior to or concurrent with the chemical flood emulsion and is adsorbed on the active mineral surfaces of the formation matrix so as to effectively reduce adsorption of surfactant in the chemical flood. Alternatively, the effluent or liquor can be injected into the subterranean earth formation subsequent to a chemical flood to displace the surfactant from the mineral surfaces for the recovery thereof.

Abstract: An automatic rate range switching and control system adapts the full range of an analog output signal of a gyroscopic rate sensor to a range consistent with the precision conversion thereof into a digitally compatible signal. In a digital strapped down inertial reference system, for example, a plurality of strapped down, force-rebalanced rate sensors is used to sense aircraft body rates, wherein each gyro pick off signal is fed back to the gyro torquer in a manner to maintain the pick off signal essentially null, the torquer current signal thus being proportional to the sensed aricraft rate. The full range of the gyro's rate sensing capability may extend from zero to several hundred degrees per second. However, with the present invention, the switching and conversion of the analog rate signal into a digitally compatible signal is necessary only over a limited range.

Abstract: An improved second order gyroscopic attitude and heading reference system including separate variable time constant accelerometer integrators for independently controlling the velocity error signals associated with respective east and north acceleration signals to provide velocity damped output signals so that a high acceleration input signal of dubious accuracy will have minimal precessional authority while a lower acceleration input signal of greater accuracy will retain nominal control.