Abstract: An electrochemical H2S sensor comprises a housing, an electrolyte disposed within the housing, and a plurality of electrodes in contact with the electrolyte within the housing. The plurality of electrodes comprise a porous working electrode that comprises a first surface that is hydrophobic and a second surface that is treated with a surfactant. The first surface is exposed to an ambient gas, and the second surface treated with the surfactant is in contact with the electrolyte.

Abstract: A gas separation cartridge including a housing comprising an inlet port for an air sample to enter; a top cover attached to the housing; an upper cavity comprising individual chambers comprised of a chemical or an absorbent or a mixture thereof attached to the top cover wherein each end of each chamber has an opening; a bottom cover attached to the upper cavity, wherein the bottom cover comprises a lower cavity, a separate opening for an air sample traveling from an individual chamber to pass through, and a separate opening for an air sample that does not pass through an individual chamber; and a base upon which the bottom cover of the cartridge is seated, wherein the base has an exit port.

Abstract: A hydroponic system includes a first sensor system that measures one or more characteristics of a nutrient solution, a second sensor system that measures one or more characteristics of an environment of a plant; and a network device including a communication interface to the first sensor system and a communication interface to the second sensor system. The network device may be configured to transmit measurements from the sensor systems through a wireless network to a remote device or database. The network device and the sensor systems may be implemented in a housing that fits within a collar of the hydroponic system. The collar can allow easy replacement of the sensor systems and can electrically isolate the sensor systems.

Abstract: A hydroponic system includes a first sensor system that measures one or more characteristics of a nutrient solution, a second sensor system that measures one or more characteristics of an environment of a plant; and a network device including a communication interface to the first sensor system and a communication interface to the second sensor system. The network device may be configured to transmit measurements from the sensor systems through a wireless network to a remote device or database. The network device and the sensor systems may be implemented in a housing that fits within a collar of the hydroponic system. The collar can allow easy replacement of the sensor systems and can electrically isolate the sensor systems.

Abstract: A hydroponic system provides photosynthetic light intensities from below a plant, e.g., underneath the leaves of the plant, to accelerate the photosynthesis process in plants. The hydroponic system may further include gas supply tubes underneath the leaves and the gas supply tubes may be integrated with an under-lighting system. The under-leaf lighting system can be used with lighting from above the plant, e.g., direct sunlight or through artificial lighting, to increase the total plant area exposed to light suitable for photosynthesis.

Abstract: A gas separation cartridge including a housing comprising an inlet port for an air sample to enter; a top cover attached to the housing; an upper cavity comprising individual chambers comprised of a chemical or an absorbent or a mixture thereof attached to the top cover wherein each end of each chamber has an opening; a bottom cover attached to the upper cavity, wherein the bottom cover comprises a lower cavity, a separate opening for an air sample traveling from an individual chamber to pass through, and a separate opening for an air sample that does not pass through an individual chamber; and a base upon which the bottom cover of the cartridge is seated, wherein the base has an exit port.

Abstract: An oxygen sensor includes a solid polymer electrolyte, e.g., on an acid treated Nafion membrane and uses a diffusion-limited fuel cell type reactions. The sensor avoids electrolyte leakage and avoids consumption of electrodes. In different configurations, a counter or reference electrode can be on the same or the opposite side of the electrolyte as a sensing electrode. An insert limits and controls oxygen diffusion into a sensing chamber containing the sensing electrode that catalyzes reduction of oxygen. Applying appropriate bias voltages to the reference and sensing electrodes causes an output current of the sensing electrode to be proportional to the rate of oxygen consumption based on Frick's law under a diffusion-limited mode. The output current can be measured, e.g., using a resistor to convert the current to a voltage signal.

Abstract: An oxygen sensor includes a solid polymer electrolyte, e.g., on an acid treated Nafion membrane and uses a diffusion-limited fuel cell type reactions. The sensor avoids electrolyte leakage and avoids consumption of electrodes. In different configurations, a counter or reference electrode can be on the same or the opposite side of the electrolyte as a sensing electrode. An insert limits and controls oxygen diffusion into a sensing chamber containing the sensing electrode that catalyzes reduction of oxygen. Applying appropriate bias voltages to the reference and sensing electrodes causes an output current of the sensing electrode to be proportional to the rate of oxygen consumption based on Frick's law under a diffusion-limited mode. The output current can be measured, e.g., using a resistor to convert the current to a voltage signal.