Abstract: A method of application to provide a workable solution for tracking the hardness of water utilizing an ion selective electrode by tracking the relative hardness of water at the outflow or egress of an ion exchange column. A monovalent cation exchange membrane (ion selective electrode) distinguishes hard water and softened water in a water flow stream. A voltage is applied across the membrane, facilitating the movement of sodium though the membrane (such that anions and divalent ions are excluded), and the current is measured. The change in current (delta current) is used to determine the hard water concentration or level of hardness in an influent stream. A second application estimates or detects the exhaustion of an ion exchanger, and/or determines the regeneration time/cycle of the ion exchanger through the use of an ion selective membrane. Blending of the influent hard water and effluent soft water allows a user to control hardness levels of the effluent.

Abstract: An apparatus for determining total hardness in a fluid stream utilizing an ion exchange column in a monovalent cationic form having an inlet and an outlet, where one or more monovalent ion selective electrodes are positioned either at an inlet, outlet, or at both locations simultaneously. The monovalent cation selective electrodes are in electrical communication with one another, and in fluid communication with one or more valves incorporated within a fluid path in order to introduce feed water/softened water to the monovalent cation selective electrodes. Additionally, one blending valve may be incorporated in the ion exchange column to allow a fraction of the feed (hard) water to mix with a fraction of the softened water. In this manner, the blending valve may be utilized to adjust the hardness of the water at the output.

Abstract: Methods of calibrating a power amplifier system to compensate for envelope amplitude misalignment are provided. In certain configurations, a method of calibrating a power amplifier system includes amplifying a radio frequency signal from a transceiver using a power amplifier and generating a supply voltage of the power amplifier using an envelope tracker, including generating a scaled envelope signal based on a power control level signal and an envelope signal, and shaping the scaled envelope signal using a shaping table generated at a target gain compression. The method further includes changing a scaling of the scaled envelope signal using a calibration module, monitoring an output of the power amplifier to determine an amount of scaling of the scaled envelope signal at which a detected gain compression of the power amplifier corresponds to the target gain compression of the shaping table, and calibrating the power amplifier system based on the determination.

Abstract: A foot assembly includes a block retainer and a non-skid block. The block retainer is configured to be positioned at least proximate to an edge between a bottom surface and a side surface of a structure. The block retainer includes a planar portion, an angled portion, and a front surface. The planar portion has an interior surface configured to contact the bottom surface. The angled portion is diposed at an angle from the planar portion and includes an interior surface configured to contact an angled contact surface of the structure. The front surface includes a first dynamic coefficient of friction (DCOF). The non-skid block is connected to the planar portion and includes an exterior potion extending from the front surface away from the structure and includes a second DCOF greater than the first DCOF.

Abstract: An electrolytic zinc dosing device that regulates the amount of zinc delivered or dosed into a flowing stream of water as a function, in part, of the current applied to an electrolytic cell and the flow rate of the flowing water. A replaceable electrolytic cell having an anode and a cathode connected to a power supply, and at least one bipolar electrode in aqueous solution between the anode and cathode. Flow rate information and/or total current information are used to determine the dosing quantity of zinc delivered.

Abstract: In one example, a watercraft includes a buoyant body in the form of a single piece structure sized and configured to support the weight of one or more users. The watercraft also includes a retractable fin connected to a pin that resides in a fixed location relative to the body, the pin including a side surface that is in contact with the body. The retractable fin is rotatable about the pin between an extended position and a retracted position, and the retractable fin includes an engagement portion that is engageable with a first portion of the body and with a second portion of the body. The retractable fin assumes the extended position when the engagement portion is releasably retained by the first portion of the body, and the retractable fin assumes the retracted position when the engagement portion is releasably retained by the second portion of the body.

Abstract: One example of a flexible structure includes an elongate body having a first end and a second end, and the first end is configured to be releasably connected to the second end. As well, one or more living hinges are positioned in the elongate body between the first end and the second end, and the one or more living hinges are configured and arranged to enable the first end and second end to be moved toward each other. Finally, the flexible structure is configured to alternatively assume at least a flat state and an assembled state, and in the assembled state, the first end of the elongate body is connected to the second end of the elongate body.

Abstract: In one example, a watercraft includes a buoyant body in the form of a single piece structure sized and configured to support the weight of one or more users. The watercraft also includes a retractable fin connected to a pin that resides in a fixed location relative to the body, the pin including a side surface that is in contact with the body. The retractable fin is rotatable about the pin between an extended position and a retracted position, and the retractable fin includes an engagement portion that is engageable with a first portion of the body and with a second portion of the body. The retractable fin assumes the extended position when the engagement portion is releasably retained by the first portion of the body, and the retractable fin assumes the retracted position when the engagement portion is releasably retained by the second portion of the body.

Abstract: In one example, a board includes a body having a single piece structure, the body including an upper surface that defines a deck, and a lower surface. The board also includes first and second retractable fins, where the first retractable fin is rotatably connected directly to the body at a first fixed location on the body such that the first retractable fin is rotatable about the first fixed location between an extended position and a retracted position, and the first retractable fin including an engagement portion that is engageable with a first portion of the body and with a second portion of the body. The first retractable fin assumes the extended position when the engagement portion is releasably retained by the first portion of the body, and the first retractable fin assumes the retracted position when the engagement portion is releasably retained by the second portion of the body.

Abstract: Methods of calibrating a power amplifier system to compensate for envelope amplitude misalignment are provided. In certain configurations, a method of calibrating a power amplifier system includes amplifying a radio frequency signal from a transceiver using a power amplifier and generating a supply voltage of the power amplifier using an envelope tracker, including generating a scaled envelope signal based on a power control level signal and an envelope signal, and shaping the scaled envelope signal using a shaping table generated at a target gain compression. The method further includes changing a scaling of the scaled envelope signal using a calibration module, monitoring an output of the power amplifier to determine an amount of scaling of the scaled envelope signal at which a detected gain compression of the power amplifier corresponds to the target gain compression of the shaping table, and calibrating the power amplifier system based on the determination.

Abstract: Apparatus and methods for calibration of envelope trackers are provided. In one embodiment, a power amplifier system includes a VGA that amplifies an RF input signal to generate an amplified RF input signal, a power amplifier that amplifies the amplified RF input signal to generate an RF output signal, and an envelope tracker that generates a supply voltage for the power amplifier. The envelope tracker includes a scaling module that generates a scaled envelope signal based on a power control level (PCL) signal and an envelope signal that changes in relation to an envelope of the RF input signal. The envelope tracker further includes a calibration module that controls an amount of scaling of the scaled envelope signal based on calibration data to compensate for an envelope amplitude misalignment of the envelope tracker. The envelope tracker controls the voltage level of the supply voltage based on the scaled envelope signal.

Abstract: Apparatus and methods for calibration of envelope trackers are provided. In one embodiment, a power amplifier system includes a VGA that amplifies an RF input signal to generate an amplified RF input signal, a power amplifier that amplifies the amplified RF input signal to generate an RF output signal, and an envelope tracker that generates a supply voltage for the power amplifier. The envelope tracker includes a scaling module that generates a scaled envelope signal based on a power control level (PCL) signal and an envelope signal that changes in relation to an envelope of the RF input signal. The envelope tracker further includes a calibration module that controls an amount of scaling of the scaled envelope signal based on calibration data to compensate for an envelope amplitude misalignment of the envelope tracker. The envelope tracker controls the voltage level of the supply voltage based on the scaled envelope signal.

Abstract: Apparatus and methods for envelope tracking calibration are provided. In one embodiment, a power amplifier system includes a power amplifier, an envelope tracker that generates the power amplifier's supply voltage, a power detector, and a calibration module. The envelope tracker includes an envelope shaping table generated at a desired gain compression and a scaling module that scales an amplitude of an envelope signal. The power detector measures the power amplifier's output power, and the calibration module provides calibration data to the scaling module to change the scaling of the envelope signal's amplitude. The calibration module sets the calibration data to a first value corresponding to a supply voltage level associated with substantially no gain compression, and reduces the supply voltage level by changing the calibration data until the power detector indicates that the gain compression of the power amplifier is about equal to the desired gain compression.

Abstract: In one example, a basketball system includes a basketball goal, a support structure, a connecting structure connected to the basketball goal and the support structure, and a height adjustment mechanism. The height adjustment mechanism includes a biasing mechanism operably connected to the connecting structure and the basketball goal, and also includes a locking member. An adjustment member of the height adjustment mechanism is engaged with the locking member and is movable relative to the locking member. The adjustment member is also connected to the connecting structure so that the adjustment member and connecting structure are operable to move in unison with each other. Finally, a foot actuator of the height adjustment mechanism is connected to the adjustment member and is operable to releasably engage the locking member.

Abstract: In one example, a board includes a body having a single piece structure, the body including an upper surface that defines a deck, and a lower surface. The board also includes first and second retractable fins, where the first retractable fin is rotatably connected directly to the body at a first fixed location on the body such that the first retractable fin is rotatable about the first fixed location between an extended position and a retracted position, and the first retractable fin including an engagement portion that is engageable with a first portion of the body and with a second portion of the body. The first retractable fin assumes the extended position when the engagement portion is releasably retained by the first portion of the body, and the first retractable fin assumes the retracted position when the engagement portion is releasably retained by the second portion of the body.

Abstract: In one example, a board suitable for use in water sports includes a body that includes an upper surface and a lower surface. The board also includes a retractable fin connected to the body and configured to assume extended and retracted positions. In the extended position, a substantial portion of the retractable fin extends below the lower surface of the body, and in the retracted position, a substantial portion of the retractable fin resides within a recess at least partly defined by the body.