| Acronym |
Definition |
| AEM
|
Anion Exchange Membrane: An AEM is a semipermeable membrane that allows anions to pass through while rejecting cations and gases like H2 or O2.
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| AEMFC |
Anion Exchange Membrane Fuel Cell: An AEMFC is a type of fuel cell that uses an anion exchange membrane to separate the anode and cathode compartments.
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| HE
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Hydrogen Embrittlement: Hydrogen embrittlement is the loss of ductility that many metals exhibit due to the presence of hydrogen atoms within the metal lattice.
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| HER
|
Hydrogen Evolution Reaction: HER is the the cathodic process in electrochemical water splitting where H2 is adsorbed at the electrode surface, particularly involving over-potentially deposited H2 on noble metals like Pt, Rh, Ru, Ir, and Pd.
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| HHV
|
Higher Heating Value: HHV is the total amount of heat released when a fuel is combusted and the products are cooled back to the fuel's original temperature. HHV includes the heat released from the condensation of water vapor that forms during combustion.
HHV is also known as gross calorific value (GCV), gross energy, or upper heating value.
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| LHV
|
Lower Heating Value: LHV also known as the net calorific value (NCV), is defined as the amount of heat released by fully combusting a specified quantity less the heat of vaporization of the water in the combustion product.
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| LH2
|
Liquid Hydrogen: LH2 is produced by cooling gaseous H2 to a temperature below its boiling point of -252.87°C (-423.17°F). In its liquid state, H2 is much denser than its gaseous form, which makes it easier to store and transport.
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| LOHC
|
Liquid Organic Hydrogen Carrier: LOHC is an organic compound that can absorb and release H2 through chemical reactions. LOHCs store hydrogen in a liquid form by chemically binding it to the carrier molecule through a process called hydrogenation.
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| MCFC
|
Molten Carbonate Fuel Cell: MCFC is a type of high-temperature fuel cell that operates at temperatures around 600°C to 700°C and uses a mixture of molten carbonate salts as the electrolyte, suspended in a porous ceramic matrix.
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| MEA
|
Membrane Electrode Assembly: MEA is an essential sandwich symmetrical-structure in PEMFC, consisting of several layers of materials including a central layer of polymer electrolyte membrane inserted between two catalyst layers and then covered by two porous gas diffusion layers.
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| MH
|
Metal Hydride: MH are compounds formed between metals and hydrogen and used for H2 storage because they can absorb and release H2 gas through a reversible chemical reaction.
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| ORR
|
Oxygen Reduction Reaction: ORR refers to the reduction half reaction whereby O2 is reduced to H20 or H2O2. In fuel cells, the reduction to H2O is preferred because the current is higher.
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| PEM
|
Proton Exchange Membrane: A PEM is a semipermeable membrane that conducts protons while blocking electrons. PEMs are used in fuel cells, where they allow protons to pass between the anode and cathode, while keeping electrons out.
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| SOFC
|
Solid Oxide Fuel Cell: SOFC is a type of high-temperature fuel cell that uses a solid ceramic electrolyte to conduct oxygen ions from the cathode to the anode. Oxygen from the air is reduced at the cathode to form Oxygen ions, which then migrate through the solid ceramic electrolyte to the anode.
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| T&E
|
Test & Evaluation: T&E is a crucial process to assess the performance, reliability, and safety of various systems, products, or technologies. It involves systematically examining and validating these items to ensure they meet specified requirements and perform as intended.
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| UAS
|
Uncrewed Aerial System: UAS also known as a drone, is an aircraft without a human pilot onboard. It is controlled remotely or autonomously and can be used for various applications such as surveillance, delivery, agriculture, and more. When a UAS is powered by a hydrogen fuel cell, it uses hydrogen as its primary energy source.
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