Abstract: Systems and methods implementing a frost sensor comprising a substrate (S); and sub-sensors disposed on the substrate. The sub-sensors comprising: a resistance-based sub-sensor (RSS) formed of a first trace disposed on S in a winding pattern and configured to measure a temperature; a capacitance-based sub-sensor formed of a second trace defining a first electrode and a third trace defining a second electrode (wherein (i) the first and second electrodes comprise interdigitated fingers or other interdigitated structures (including, but not limited to, round, spiral interdigitated electrodes, etc.

Abstract: A phase change material composition for combined electrochemical and thermal energy storage is provided. The composition includes a salt hydrate, a polymeric stabilizer, a nucleating agent, and a thiosulfate salt hydrate. The salt hydrate is present in the composition in an amount of from 0.1 to 99 wt. %. The polymeric stabilizer is present in the composition in an amount of from 0.1 to 20 wt. %. The nucleating agent is present in the composition in an amount of from 0.1 to 20 wt. %. The thiosulfate salt hydrate is present in the composition in an amount of from 0.1 to 25 wt. %. A combined electrochemical and thermal storage system including the phase change material composition is further provided.

Abstract: A method of carbon-capture sorbent regeneration is provided. The method includes obtaining a sorbent that includes adsorbed carbon dioxide. Magnetic nanoparticles are introduced to the sorbent and adsorbed carbon dioxide to form a mixture. A magnetic field is applied to the mixture. The magnetic nanoparticles generate heat which releases carbon dioxide from the sorbent, thereby regenerating the sorbent. The magnetic nanoparticles include iron oxides, doped ferrites, functionalized iron oxides, functionalized ferrites, and composite materials that are combinations of these. The sorbent includes liquid and solid sorbents, and the regenerated sorbent may be utilized for further carbon capture.

Abstract: A method for regenerating a bis(iminoguanidine) (BIG) carbon dioxide sorbent, the method comprising: (i) providing a carbonate or bicarbonate salt of the BIG carbon dioxide sorbent, and (ii) directly contacting the carbonate or bicarbonate salt of the BIG carbon dioxide sorbent with steam heated to a temperature within a range of 80° C.-130° C. to result in regeneration of the BIG carbon dioxide sorbent with simultaneous conversion of the carbonate or bicarbonate anions into carbon dioxide, wherein the regenerated BIG carbon dioxide sorbent is substantially removed of carbonate or bicarbonate and may optionally contain one or more adduct water molecules. In some processes, the regenerated BIG carbon dioxide sorbent is dissolved in water condensing from the steam during the contacting step to form an aqueous solution of the regenerated BIG carbon dioxide sorbent.

Abstract: A method for manufacturing a fiber-reinforced ceramic matrix composite article is provided. The method includes additively manufacturing a carbon fiber-reinforced thermoplastic article via fused filament fabrication (FFF). The article is then thermally annealed to yield an non-meltable article. The method further includes pyrolyzing the non-meltable article to yield a pyrolyzed article. The pyrolyzed article is infiltrated with an infiltration agent to yield a fiber-reinforced infiltrated matrix composite.

Abstract: A method for electrochemically reducing carbon dioxide includes the step of providing a liquid or supercritical carbon dioxide mixture comprising liquid or supercritical carbon dioxide, water, a phase transfer catalyst, and an ion conducting salt. A potential difference is applied across a portion of the liquid or supercritical carbon dioxide mixture to cause the reduction of carbon dioxide with protons from the water. A reactor for electrochemically reducing carbon dioxide is also disclosed.

Abstract: A boiling heat exchange system includes a heat exchanger including a chamber configured to hold a heat exchange fluid including a heat exchange vapor and a pool of heat exchange liquid and an evaporator tube having an outer surface and a thermally conductive open-cell porous material disposed on the outer surface and comprising a plurality of pores. The evaporator tube can be immersed in the heat exchange liquid held in the chamber and the heat exchange liquid will enter the pores. The open-cells of the open-cell porous material will heat the heat exchange liquid to cause the heat exchange liquid to boil to a heat exchange vapor and exchange heat with a source fluid flowing through the evaporator tube or with a component in thermal contact with the evaporator. A method of performing heat exchange is also disclosed.

Abstract: A server system that includes a host device initiates an encrypted decision tree model executing on an accelerator coupled with the host device. The encrypted decision tree model encrypted uses an agreed upon encryption schema between the host device and a user device accessing the encrypted decision tree model. The host device receives an input, from the user device, to be evaluated using the encrypted decision tree model. The input is encrypted using the agreed upon encryption schema. The host device using the encrypted decision tree model evaluates the input from the user device without decrypting the input. The accelerator using the encrypted decision tree model generates an encrypted output based on the evaluating. The accelerator device provides the encrypted output to the user device.

Abstract: A method of state permutation logic locking (SPeLL) for sequential circuits. The method includes encrypting original states of a sequential circuit to produce encrypted states, by transitioning an initial order of the original states into a secret permutation of the encrypted states, where the secret permutation is different than the initial order. The method also includes determining a cryptographic key that corresponds to the transition from the initial order of the original states to the secret permutation of the encrypted states, and decrypting the encrypted states, by using the cryptographic key to transition from the secret permutation of the encrypted states back to the initial order of the original states.

Abstract: Improved heat exchangers according to several embodiments are provided. The heat exchangers provide improved heat transfer for air flow in wet and dry operating conditions, while minimizing pressure drop across the heat exchanger in some applications. According to one embodiment, an improved heat exchanger includes a plurality of metal foam fins between adjacent heat exchange conduits, the heat exchange conduits being arranged parallel to each other to define parallel flow paths between an inlet header and an outlet header. The metal foam fins occupy a cross-flow region between adjacent conduits, the fins having a fixed angular orientation or being rotatable in unison to vary the thermal capacitance of the heat exchanger.

Abstract: An improved method and system for treating flue gases from a natural gas furnace are provided. The method and system include an acidic gas trap (AGT) adsorber which enables the continuous adsorption and storage of SOx, NOx redox, and formic acid/CO/HC/CH4 oxidation, with a negligible pressure drop. The AGT adsorber includes a catalyst coating having a nanotube structure (e.g., a uniform nanostructure forest coating) or a uniform porous nanostructure of various low-cost oxides through scalable low temperature solution processes, including oxides of Ti, Cu, Ba, Mn, Zr, Zn, Sr, Ca, Li, K, Na, Al, or Ce.

Abstract: A method of capturing carbon dioxide (CO2) present in air is provided. The method includes adding a carbon-dioxide-capturing device to a heating, ventilation, and air conditioning (HVAC) system of a building. The carbon-dioxide-capturing device is added to one or both of an air handler and air-distribution ductwork of the HVAC system. The method further includes circulating air including carbon dioxide through the carbon-dioxide-capturing device in the HVAC system. A direct decarbonization system for capturing carbon dioxide present in air is also provided. The system includes an HVAC unit, air-distribution ductwork connected to the HVAC unit, and a carbon-dioxide-capturing device disposed in one or both of the HVAC unit and the air-distribution ductwork. Carbon dioxide gas present in air passing through the HVAC unit or the air-distribution ductwork is removable from the air by the carbon-dioxide-capturing device.

Abstract: A process for capturing carbon dioxide (CO2) present in a gas stream is provided. The process includes providing a cooling tower that treats a gas stream. The gas stream including CO2 is introduced into the cooling tower. A liquid carbon-dioxide-capturing media is released into the gas stream in the cooling tower. The carbon-dioxide-capturing media absorbs the CO2 in the gas stream, and the carbon-dioxide-capturing media including the absorbed CO2 is collected. An absorber for capture of CO2 in a gas stream is also provided. The absorber includes a cooling tower for treatment of a gas stream including CO2. The cooling tower includes an input for the gas stream, an outlet for a treated gas stream, and a sprayer that releases liquid carbon-dioxide-capturing media into the cooling tower. The carbon-dioxide-capturing media absorbs the CO2 from the gas stream in the cooling tower. A collector collects the carbon-dioxide-capturing media including absorbed CO2.

Abstract: A method for fabricating heat exchangers using additive manufacturing technologies. Additive manufacturing enables the manufacture of heat exchangers with complex geometries and/or with internal and external integral surface features. Additive manufacture also facilitates the manufacture of heat exchangers with regional variations, such as changes in size, shape and surface features. In one embodiment, the present invention provides a heat exchanger with a helicoidal shape that provides axial elastic compliance. In one embodiment, the internal channel of the heat exchanger varies along its length. The internal channel may have a cross-sectional area that increases progressively from one end to the other. In one embodiment, the external shape of the tubular structure may be non-circular to optimize heat transfer with an external heat transfer fluid. In one embodiment, the present invention provides a heat pipe with an internal wicking structure formed as an integral part of the additive manufacturing process.

Abstract: A medium for energy storage includes a plurality of capsules. Each capsule contains a phase changing material (PCM) configured to undergo a liquid-solid phase transition at a solidification temperature, TS. The PCM undergoes a relative volume change due to the phase transition. A shell is filled with the PCM. The shell contains a first heat-conducting material, and is configured to comply to the relative volume change. The relative volume change is configured to cause a buoyancy force, which acts on the capsule when the capsule is disposed in water at a water temperature, TW, to be larger than the capsule's weight for Tw>Ts, and equal to or smaller than the capsule's weight for Tw<Ts. The Ts can be within ±5° F. of a design water temperature To at the outlet of a water tank. The capsule can be neutrally buoyant in water at To.

Abstract: A heat exchanger apparatus includes a tube having a wall with an inner surface and an outer surface. The tube is configured to receive heat exchange fluid at one end, and output, when heated through the wall, vapor of the heat exchange fluid at the opposing end. A first layer of thermally conductive porous material is disposed on the inner surface of the tube. Heating equipment, a heat exchanger, and a method of heating are also disclosed.

Abstract: An improved method and system for treating flue gases from a natural gas furnace are provided. The method and system include an acidic gas trap (AGT) adsorber which enables the continuous adsorption and storage of SOx, NOx redox, and formic acid/CO/HC/CH4 oxidation, with a negligible pressure drop. The AGT adsorber includes a catalyst coating having a nanotube structure (e.g., a uniform nanostructure forest coating) or a uniform porous nanostructure of various low-cost oxides through scalable low temperature solution processes, including oxides of Ti, Cu, Ba, Mn, Zr, Zn, Sr, Ca, Li, K, Na, Al, or Ce.

Abstract: A method for fabricating heat exchangers using additive manufacturing technologies. Additive manufacturing enables the manufacture of heat exchangers with complex geometries and/or with internal and external integral surface features. Additive manufacture also facilitates the manufacture of heat exchangers with regional variations, such as changes in size, shape and surface features. In one embodiment, the present invention provides a heat exchanger with a helicoidal shape that provides axial elastic compliance. In one embodiment, the internal channel of the heat exchanger varies along its length. The internal channel may have a cross-sectional area that increases progressively from one end to the other. In one embodiment, the external shape of the tubular structure may be non-circular to optimize heat transfer with an external heat transfer fluid. In one embodiment, the present invention provides a heat pipe with an internal wicking structure formed as an integral part of the additive manufacturing process.

Abstract: Improved heat exchangers according to several embodiments are provided. The heat exchangers provide improved heat transfer for air flow in wet and dry operating conditions, while minimizing pressure drop across the heat exchanger in some applications. According to one embodiment, an improved heat exchanger includes a plurality of metal foam fins between adjacent heat exchange conduits, the heat exchange conduits being arranged parallel to each other to define parallel flow paths between an inlet header and an outlet header. The metal foam fins occupy a cross-flow region between adjacent conduits, the fins having a fixed angular orientation or being rotatable in unison to vary the thermal capacitance of the heat exchanger.