Abstract: An apparatus configured to perform non-destructive, electrical measurements on a plant stalk to detect and quantify internal damage is disclosed. This apparatus includes features to minimize misalignments that can negatively affect the precision and/or accuracy of the electrical measurements.

Abstract: An apparatus configured to perform non-destructive, electrical measurements on a plant stalk to detect and quantify internal damage is disclosed. This apparatus includes features to minimize misalignments that can negatively affect the precision and/or accuracy of the electrical measurements.

Abstract: In one general aspect, an apparatus includes at least two conductive elements disposed in a polymeric foam and at least two voltage detectors. Each voltage detector is coupled to a respective conductive element and configured to detect a charge generated by an impact to the polymeric foam within a sensing radius of the respective conductive element. In another general aspect, an apparatus includes a deformation sensor and a voltage detector. The deformation sensor includes a conductive element disposed in a polymeric foam, a portion of the conductive element extending beyond an outer wall of the polymeric foam. The voltage detector is coupled to the portion of the conductive element and detects a charge generated by the deformation sensor responsive to an impact to the polymeric foam.

Abstract: In one general aspect, a computer-readable storage medium can be configured to store instructions that when executed cause a processor to perform a process. The instructions comprising instructions to trigger flow of an alternating current having a waveform defining a range of frequencies from a waveform generator to a reinforcing bar embedded within concrete via a probe coupled to a surface of the concrete, and receive an indicator of a time-resolved current magnitude of the alternating current through a portion of the concrete associated with the surface of the concrete.

Abstract: In one general aspect, a system can include a probe configured to be coupled to a concrete surface of a portion of concrete. The system can include a waveform generator configured to trigger flow of a current to the portion of concrete via the probe and configured to reference a potential of a reinforcing bar embedded within the concrete. The system can also include a current detector configured to detect a magnitude of the current.

Abstract: In one general aspect, an apparatus includes at least two conductive elements disposed in a polymeric foam and at least two voltage detectors. Each voltage detector is coupled to a respective conductive element and configured to detect a charge generated by an impact to the polymeric foam within a sensing radius of the respective conductive element. In another general aspect, an apparatus includes a deformation sensor and a voltage detector. The deformation sensor includes a conductive element disposed in a polymeric foam, a portion of the conductive element extending beyond an outer wall of the polymeric foam. The voltage detector is coupled to the portion of the conductive element and detects a charge generated by the deformation sensor responsive to an impact to the polymeric foam.

Abstract: Accelerometers and capacitive touch sensors fabricated from inexpensive, lightweight, disposable substrate materials, such as paper, are provided. These can be fabricated using simple technologies, such as laser cutting and screen printing. In one embodiment, a touch sensor includes a parallel plate capacitor having a fixed plate formed of a substrate material having a conductive layer and a deflectable plate formed of a paper substrate material having a conductive layer. In a second embodiment, a touch sensor includes a parallel plate capacitor formed of an exterior conductive layer deposited on a paper substrate material and an interior conductive layer deposited on a substrate material. In a third embodiment, a touch sensor includes an active electrode and a grounded electrode patterned on the surface of a paper substrate material. In another embodiment, an accelerometer includes a parallel plate capacitor containing a fixed plate and a free plate containing a paper substrate.

Abstract: A probe is configured for measuring an electrical impedance of a workpiece using external testing equipment. The probe includes a non-conducting base and an array of at least four spaced-apart line conductors. The at least four spaced-apart line conductors are disposed generally in parallel to each other along their lengths on a surface of the non-conducting base and are electrically connected to a corresponding array of at least four terminals on the non-conducting base. The non-conducting base is configured to be placed over a surface of the workpiece so that the at least four spaced-apart line conductors contact the surface of the workpiece and the at least four terminals are configured to be connected the external testing equipment.

Abstract: In one general aspect, an apparatus can include a block defining a temperature control channel therethrough and a defining a sample chamber. The apparatus can also include an electrode disposed inside of the block such that the sample chamber is fluidically isolated from the temperature control channel by the electrode. The electrode can be configured to receive a signal from an impedance analyzer during a dielectric spectroscopy experiment related to a sample included in the sample chamber.

Abstract: In one general aspect, an apparatus can include a block defining a temperature control channel therethrough and a defining a sample chamber. The apparatus can also include an electrode disposed inside of the block such that the sample chamber is fluidically isolated from the temperature control channel by the electrode. The electrode can be configured to receive a signal from an impedance analyzer during a dielectric spectroscopy experiment related to a sample included in the sample chamber.

Abstract: In one general aspect, a system can include a probe configured to be coupled to a concrete surface of a portion of concrete. The system can include a waveform generator configured to trigger flow of a current to the portion of concrete via the probe and configured to reference a potential of a reinforcing bar embedded within the concrete. The system can also include a current detector configured to detect a magnitude of the current.