Abstract: A three-part epoxy grout composition comprises a liquid epoxy blend, a liquid hardener, and a graded particulate aggregate, wherein the dry aggregate particles are pretreated with an applied adhesion promoter in an amount of 0.01 to 5% by weight. The volume of pretreated aggregate particles, when mixed with the epoxy blend and the hardener, comprises at least 70% by volume of the cured grout. Pretreatment of the aggregate by coating with adhesion promoter allows more efficient use of chemicals along with improved strength. Related methods are also disclosed.

Abstract: Aspects of this disclosure relate to one or more particles that move within a container in response to a magnetic field. A measurement circuit is configured to output an indication of the magnetic field based on position of the one or more particles.

Abstract: The techniques described herein relate to methods and apparatus for firearm safety mechanisms, visual safety indicators, and related techniques. A firearm includes a handle comprising one or more buttons disposed at least partially within a surface of the handle, such that the one or more buttons can be in contact with an operator's hand when the operator grasps the handle; a safety mechanism in mechanical communication with the trigger. The safety mechanism comprises: a first position that blocks actuation of the trigger; and a second position that does not block actuation of the trigger; and at least one processor configured to: upon determining an input code matches a stored code, transmits a signal to the safety mechanism to change the safety mechanism from the first position to the second position so that the firearm can be fired by the operator.

Abstract: Aspects of this disclosure relate to particles that can move in response to a magnetic field. A system can include a container, particles within the container, and a magnetic structure integrated with the container. The magnetic structure can magnetically interact with both an external magnetic field and the particles. Related methods are disclosed including magnetic field detection methods based on detection of particles within a container.

Abstract: The techniques described herein relate to methods and apparatus for firearm safety mechanisms, visual safety indicators, and related techniques. A firearm includes a handle comprising one or more buttons disposed at least partially within a surface of the handle, such that the one or more buttons can be in contact with an operator's hand when the operator grasps the handle; a safety mechanism in mechanical communication with the trigger. The safety mechanism comprises: a first position that blocks actuation of the trigger; and a second position that does not block actuation of the trigger; and at least one processor configured to: upon determining an input code matches a stored code, transmits a signal to the safety mechanism to change the safety mechanism from the first position to the second position so that the firearm can be fired by the operator.

Abstract: A base extending mechanism is provided for a ladder in the form of pivotable lower leg sections which can be independently rotated outwards to provide a wider ladder base. This extension of the ladder base is complementary to and supported by a compatible ladder levelling mechanism.