Abstract: The present disclosure relates to aqueous compositions containing water and the ammonium salt of a polyamide-amic acid. Processes for producing such aqueous compositions and uses thereof are described.

Abstract: An apparatus to treat an influent solution comprising ions to obtain a selectable ion concentration in an effluent solution. The apparatus comprises an electrochemical cell comprising a housing comprising first and second electrodes. A water-splitting ion exchange membrane is between the first and second electrodes, the membrane comprising ananion exchange surface facing the first electrode, and an cation exchange surface facing the second electrode, or vice versa. The housing also has an influent solution inlet and an effluent solution outlet with a solution channel that allows influent solution to flow past both the anion and cation exchange surfaces of the water-splitting ion exchange membrane to form the effluent solution. A variable voltage supply is capable of maintaining the first and second electrodes at a plurality of different voltages during an ion exchange stage.

Abstract: An apparatus and method to treat a solution comprising ions in an ion removal step and an ion rejection step are provided. The apparatus comprises an electrochemical cell comprising a housing comprising first and second electrodes and a solution channel. A variable voltage supply is capable of maintaining the first and second electrodes at a plurality of different voltages during an ion exchange stage and a flow control device is capable of controlling the flow of solution through the channel of the cell. A controller is provided to control the voltage supply and flow control device. The ion removal step can comprise, for example, a deionization step and the ion rejection step can comprise, for example, a cell regeneration step.

Abstract: An electrode power supply for an electrochemical ion exchange cell having an ion exchange membrane between a pair of electrodes, has a voltage selector to receive an AC voltage and selectively couple the AC voltage to a voltage supply. The voltage supply produces an output voltage from the AC voltage. A zero crossing detector detects zero-crossing events in the AC voltage and produce an indication related to the zero-crossing events. The selective coupling of the voltage selector is enabled based on the indication of the zero-crossing events.

Abstract: An electrode power supply for an electrochemical ion exchange cell has an output terminal and is capable of receiving an AC voltage and generating a DC voltage at the output terminal for electrodes of the electrochemical ion exchange cell. The electrode power supply comprises a DC voltage supply capable of producing the DC voltage having selectable voltage levels from the AC voltage, a current detector to detect the current level of the DC voltage at the output terminal, a voltage selector to select the voltage level of the DC voltage in relation to the detected current level, and a polarity selector to select the polarity of the DC voltage relative to the output terminal. In one version, a controlled power supply for the ion exchange cell has the electrode power supply and a microcontroller.

Abstract: An apparatus to treat an influent solution comprising ions to obtain a selectable ion concentration in an effluent solution. The apparatus comprises an electrochemical cell comprising a housing comprising first and second electrodes. A water-splitting ion exchange membrane is between the first and second electrodes, the membrane comprising ananion exchange surface facing the first electrode, and an cation exchange surface facing the second electrode, or vice versa. The housing also has an influent solution inlet and an effluent solution outlet with a solution channel that allows influent solution to flow past both the anion and cation exchange surfaces of the water-splitting ion exchange membrane to form the effluent solution. A variable voltage supply is capable of maintaining the first and second electrodes at a plurality of different voltages during an ion exchange stage.

Abstract: A concealed gun holster, primarily to be worn by off duty law enforcement personnel, is modeled after the popular sports fanny packs. The modified pack, held in place with an integral belt, is designed to conceal a hand gun holster for either left or right hand use. A snap release secures the weapon snugly in the holster, yet releases with the same feel and pressure as commonly used police holster releases. A hidden pocket, interior to the pack, may be used to hold a clip of ammunition. The integral belt used to wear the pack comprises zippered pockets which are suitable for storing ammunition, hand cuffs, or other equipment.