Abstract: A system for monitoring an underground propane tank, comprising a controller; a moisture sensor coupled in communication with the controller, wherein the controller is configured to measure a moisture associated with the tank; a voltage probe coupled in communication with the controller, wherein voltage probe is adapted to be disposed at least partially underground, and wherein the controller is configured to measure a potential difference between the tank and soil surrounding the tank, when the moisture associated with the tank is measured to be above a predetermined threshold; and an anode sensor coupled to an anode of the tank and coupled in communication with the controller, wherein the controller is configured to monitor the anode using the anode sensor.

Abstract: A sensor arrangement for measuring liquid height in a tank can include a housing, a transducer, and a couplant. The housing can have an interior and an aperture, the aperture placing the interior of the housing in communication with the environment external to the housing. The transducer can be seated within the aperture. The couplant can be mechanically connected to the transducer and can have a compressible couplant body. The couplant body can extend between the transducer and the external environment for transmitting an acoustic pulse from the transducer to a tank bottom for measuring height of a liquid overlaying the transducer.

Abstract: A sensor arrangement for measuring liquid height in a tank can include a housing, a transducer, and a couplant. The housing can have an interior and an aperture, the aperture placing the interior of the housing in communication with the environment external to the housing. The transducer can be seated within the aperture. The couplant can be mechanically connected to the transducer and can have a compressible couplant body. The couplant body can extend between the transducer and the external environment for transmitting an acoustic pulse from the transducer to a tank bottom for measuring height of a liquid overlaying the transducer.

Abstract: A sensor arrangement for measuring liquid height in a tank can include a housing, a transducer, and a couplant. The housing can have an interior and an aperture, the aperture placing the interior of the housing in communication with the environment external to the housing. The transducer can be seated within the aperture. The couplant can be mechanically connected to the transducer and can have a compressible couplant body. The couplant body can extend between the transducer and the external environment for transmitting an acoustic pulse from the transducer to a tank bottom for measuring height of a liquid overlaying the transducer.

Abstract: A sensor arrangement for measuring liquid height in a tank can include a housing, a transducer, and a couplant. The housing can have an interior and an aperture, the aperture placing the interior of the housing in communication with the environment external to the housing. The transducer can be seated within the aperture. The couplant can be mechanically connected to the transducer and can have a compressible couplant body. The couplant body can extend between the transducer and the external environment for transmitting an acoustic pulse from the transducer to a tank bottom for measuring height of a liquid overlaying the transducer.

Abstract: A system and method performs a moving target blind rendezvous by exchanging data through a distributed hash table. The system allows users to securely send small pieces of information over a network while only requiring an exchange of public keys ahead of time. The system relies on the size and resilience of the BitTorrent Distributed Hash Table and the security properties of cryptographic constructions such as Elliptic Curve Diffie-Hellman key exchange and secure one-way hash functions.

Abstract: A system and method performs a moving target blind rendezvous by exchanging data through a distributed hash table. The system allows users to securely send small pieces of information over a network while only requiring an exchange of public keys ahead of time. The system relies on the size and resilience of the BitTorrent Distributed Hash Table and the security properties of cryptographic constructions such as Elliptic Curve Diffie-Hellman key exchange and secure one-way hash functions.

Abstract: Various features pertain to two-factor authentication. A user seeking access to the secure facility or system generates a time-limited Quick Response (QR) code with his or her smartphone for display on a touchpad screen of the smartphone. The user presents the display of the QR code to a video camera of an authentication system that controls access to the secure facility or system. The video camera captures both the QR code on the smartphone screen and an image of the user. The authentication system then identifies the user based on a biometric analysis of the image of the user and confirms the authentication by verifying that the QR code corresponds to an authorized user. The QR code may be generated based on a secret key stored within the smartphone and the current date/time, with valid authorization limited to a narrow time window following generation of the QR code.

Abstract: A sensor arrangement for measuring liquid height in a tank can include a housing, a transducer, and a couplant. The housing can have an interior and an aperture, the aperture placing the interior of the housing in communication with the environment external to the housing. The transducer can be seated within the aperture. The couplant can be mechanically connected to the transducer and can have a compressible couplant body. The couplant body can extend between the transducer and the external environment for transmitting an acoustic pulse from the transducer to a tank bottom for measuring height of a liquid overlaying the transducer.

Abstract: A pressure regulator comprising a housing having an inlet port and an outlet port, a linearly sliding member for selectively covering a section of a passage between the inlet port and the outlet port, a diaphragm interconnected to the linearly sliding member to slide the linearly sliding member in reaction to pressure levels in the housing, and a valve seat located in the passage between the inlet port and the outlet port. The linearly sliding member includes a sealing disc for preventing fluid flow past the valve seat. The valve seat is located closer to the outlet port than to the inlet port.

Abstract: A fire safety fluid flow device for engagement with a Schrader valve including a sliding valve a housing having a fluid path therethrough and a pressing member. The pressing member presses against the sliding valve of the Schrader valve when engaged therewith to allow fluid flow through the Schrader valve. The pressing member continues to maintain the sliding valve in an open position when the device is below a predetermined temperature and connected to the Schrader valve. The pressing member is configured to no longer press against the sliding valve of the Schrader valve at and above the predetermined temperature to allow the sliding valve of the Schrader valve to thereby stop fluid flow through the Schrader valve.