Abstract: A mobile volumetric concrete mixing system includes a suction system that vacuums up trench spoils while a trench is being cut. These trench spoils are then screened on-site for particle size to be reused and mixed with water, cement, and/or other admixtures at an auger mixer to form a backfill mixture. This backfill mixture may then be loaded into a hopper that continuously agitates the mixture so that the mixture does not harden before pouring. The agitating hopper is coupled to a discharge chute of the auger mixer and includes one or more augers disposed at various orientations that the backfill mixture is channeled through. From the agitating hopper, the backfill mixture is channeled to an applicator that moves along the trench and that enables the mixture to be quickly poured into the trench with little clean-up required.

Abstract: A capacitive amplifier device and technique for mitigating the perturbation within the switchable terminals of a feedback capacitor which is produced by the switching activity performed as part of the device's operation. The capacitive amplifier contains feedback components which can be switched without producing significant kickback or poorly behaved transitions due to the inclusion of at least one dedicated circuit. The dedicated circuit is a kickback limiter circuitry which is connected to a switchable node and is designed to reduce the kickback. The technique for reducing the kickback produced can be achieved by connecting and activating the kickback limiter circuitry.

Abstract: A continuous process for forming a coated proppant, said process comprising the steps of: (a) washing particles, (b) drying the particles at a first predetermined temperature, (c) cooling the particles, (d) feeding the cooled particles with a second predetermined temperature lower than the first predetermined temperature to an inlet of a combined continuous mixer and conveyor unit, (e) feeding a coating composition into the combined continuous mixer and conveyor unit, (f) mixing and simultaneously conveying the particles and the coating composition for a predetermined time, (g) curing the coating composition by transfer of heat from the particles, (h) discharging the coated particles from an outlet of the combined continuous mixer and conveyor unit, wherein said process does not comprise a step of heating the particles after the drying.

Abstract: Techniques for interpolating two voltages without loading them and without requiring significant power or additional area are described. The techniques include specific topologies for the buffering amplifiers that offer accuracy by cancelling systematic error sources without relying on high gain, thus simplifying the frequency compensation, and reducing power consumption. This can be achieved by biasing the amplifiers from the load current by an innovative feedback structure, which can remove the need for high impedance nodes inside the amplifiers.

Abstract: A circuit may include or may be coupled to a precharge structure to reduce or minimize a net perturbation, caused by switching, in the input source. Apparatus and techniques shown herein may enable low input current operation in a signal chain of an analog circuit by such reduction or minimization of such perturbation.

Abstract: Techniques for interpolating two voltages without loading them and without requiring significant power or additional area are described. The techniques include specific topologies for the buffering amplifiers that offer accuracy by cancelling systematic error sources without relying on high gain, thus simplifying the frequency compensation, and reducing power consumption. This can be achieved by biasing the amplifiers from the load current by an innovative feedback structure, which can remove the need for high impedance nodes inside the amplifiers.

Abstract: A circuit may include or may be coupled to a precharge structure to reduce or minimize a net perturbation, caused by switching, in the input source. Apparatus and techniques shown herein may enable low input current operation in a signal chain of an analog circuit by such reduction or minimization of such perturbation.

Abstract: Coated proppant particles are prepared by coating the particles with at least one polyisocyanate, and at least one urethane catalyst, and starch is present during at least part of the curing step. The starch becomes incorporated into in at least a portion of the cured coating. The coating cures rapidly at moderate temperatures, and bonds to itself well under conditions of heat and pressure as are experienced by the particles in subterranean formations.

Abstract: Temperature adjusting device couplable with a valve body of a thermostatic mixing valve, including: a hollow housing provided with a wall having at least one portion shaped for coupling firmly with an opening end provided on the valve body; an adjusting element received inside the housing and movable along an operating direction with respect to the housing between a first calibrating position and a second calibrating position to adjust, in use, a mixing temperature of a flow of water exiting the valve body; on the wall at least one opening being obtained that is shaped for receiving a locking element, the adjusting element including an abutting portion shaped for abutting on the locking element so as to arrest a movement of the adjusting element and limit a stroke thereof between the first and second calibrating position.

Abstract: Thermostatic mixing valve including a valve body provided with an inner cavity, a first inlet for a first flow of water into the cavity, a second inlet for a second flow) of water into the cavity, and an outlet for a third flow of mixed water exiting the cavity, a mixing device shaped to be placed in fluid connection with the first inlet, the second inlet and the outlet, and to define a mixing chamber for the first and second flow, the mixing device being internally provided with a thermostatic actuating element that is movable along an operating direction, and a temperature adjusting device provided with a housing and with a positioning element that is slidable with respect to the housing, and configured for adopting, by adjustment, a set position with respect to the housing, and for imposing on the thermostatic actuating element a calibration position along the operating direction corresponding to a desired mixing temperature.

Abstract: A continuous process for forming a coated proppant, said process comprising the steps of: (a) washing particles, (b) drying the particles at a first predetermined temperature, (c) cooling the particles, (d) feeding the cooled particles with a second predetermined temperature lower than the first predetermined temperature to an inlet of a combined continuous mixer and conveyor unit, (e) feeding a coating composition into the combined continuous mixer and conveyor unit, (f) mixing and simultaneously conveying the particles and the coating composition for a predetermined time, (g) curing the coating composition by transfer of heat from the particles, (h) discharging the coated particles from an outlet of the combined continuous mixer and conveyor unit, wherein said process does not comprise a step of heating the particles after the drying.

Abstract: Coated proppant particles are prepared from a coating composition that includes at least one polyisocyanate and an isocyanate trimerization catalyst. The coating composition preferably is devoid of an effective amount of a urethane, urea and carbodiimide catalyst. The coating composition cures rapidly at moderate temperatures, and bonds to itself well under conditions of heat and pressure as are experienced by the particles in subterranean formations.

Abstract: A method of preparing a polymer concrete composition includes preparing one or more adhesion promoter pre-coated aggregates, each having a base substrate and an adhesion promoter coating and the adhesion promoter coating being an outermost layer on the base substrate, providing a base composition including an isocyanate component and an isocyanate-reactive component, and mixing the one or more adhesion promoter pre-coated aggregates, the isocyanate component, and the isocyanate-reactive component to form the polymer concrete composition.

Abstract: A mobile volumetric concrete mixing system includes a suction system that vacuums up trench spoils while a trench is being cut. These trench spoils are then screened on-site for particle size to be reused and mixed with water, cement, and/or other admixtures at an auger mixer to form a backfill mixture. This backfill mixture may then be loaded into a hopper that continuously agitates the mixture so that the mixture does not harden before pouring. The agitating hopper is coupled to a discharge chute of the auger mixer and includes one or more augers disposed at various orientations that the backfill mixture is channeled through. From the agitating hopper, the backfill mixture is channeled to an applicator that moves along the trench and that enables the mixture to be quickly poured into the trench with little clean-up required.

Abstract: A machine for backfilling pavement material into a trench defined within a pavement surface includes a frame defining a longitudinal axis and having at least one wheel. The frame being configured to move along the pavement surface. A hopper supported on the frame and including an inlet opening configured to receive pavement material and an outlet opening configured to discharge pavement material into the trench. The machine also includes a compactor supported on the frame and aligned with the hopper along the longitudinal axis. The compactor is configured to compact the discharged pavement material within the trench.

Abstract: A polymer concrete composition has a base composition including a first isocyanate component and a first isocyanate reactive component, and one or more pre-coated aggregates that each has a base substrate and a two-component reaction product polymeric coating on an outer surface of the base substrate. The polymeric coating is the reaction product of a second isocyanate component and a second isocyanate-reactive component.

Abstract: Provided are proppants for use in hydraulic fracturing operations. The proppants comprise particles having coatings disposed on them as described herein. The proppants exhibit reduced dust generation, for instance during transloading, conveying and/or offloading of the proppant at a wellsite and/or at intermediate shipping transload points.

Abstract: A coated article, such as a proppant, includes a base substrate and one or more polyurethane based coatings on an outer surface of the base substrate. The one or more polyurethane based coatings including the reaction product of an isocyanate component that has at least one isocyanate and an isocyanate-reactive component that has one or more simple polyols and one or more polyether monols at a ratio from 1:18 to 18:1. An isocyanate index is greater than 0.2 and less than 1.0.

Abstract: A coated proppant includes a solid core proppant particle and a heavy metal recovery coating, including heavy metal recovery crystals embedded within a polymer resin matrix. A process for the manufacture of a coated proppant includes providing a solid core proppant particle, and forming on the solid core proppant particle, a heavy metal recovery coating including heavy metal recovery crystals embedded within a polymer resin matrix.

Abstract: A switched-capacitor integrator is described having the contribution to offset from the charge injection mismatch of switches connected to the summing nodes mitigated by using a switching scheme that conveys basically all the charge injection to the output, thus preventing net offset from being integrated.