Glossary
Half-Life
**Half-Life** is a scientific term that refers to the amount of time it takes for half of a given quantity of a substance to undergo a process of decay or transformation. This concept is most commonly associated with radioactive decay in physics, where it measures the time required for half of...
Heat Island Effect
**Heat Island Effect** refers to the phenomenon where urban or metropolitan areas become significantly warmer than their surrounding rural areas. This temperature difference results from human activities, extensive modification of land surfaces, and the high concentration of buildings, roads, and...
Heavy Water Reactor (HWR)
A **Heavy Water Reactor (HWR)** is a type of nuclear reactor that employs heavy water (deuterium oxide, D2O) as both its coolant and neutron moderator. Unlike light water reactors which use regular water, the heavy water in HWRs is highly efficient at slowing down neutrons, allowing the reactor...
Heliostat
A **Heliostat** is a sophisticated device used to harness solar energy by tracking the movement of the sun. It consists of a mirror or an array of mirrors that pivot throughout the day to continually reflect sunlight toward a fixed target, such as a solar power tower, a specific location needing...
High-Level Waste (HLW)
**High-Level Waste (HLW)** is a type of radioactive waste that arises from the reprocessing of spent nuclear fuel. This waste contains a mix of radioactive isotopes, including both short-lived and long-lived radionuclides. Due to its high level of radioactivity, HLW generates significant amounts...
High-Resolution Climate Modeling
**High-Resolution Climate Modeling** refers to the use of advanced computational techniques to simulate the Earth's climate at a finer spatial and temporal scale. Unlike traditional climate models that may generalize vast regions of the planet into large grid cells, high-resolution models break...
Horizontal Axis Wind Turbine (HAWT)
A **Horizontal Axis Wind Turbine (HAWT)** is a type of wind turbine where the main rotor shaft and electrical generator are mounted at the top of a tower, and must be pointed into the wind. This design contrasts with vertical axis wind turbines (VAWT), where the main rotor shaft is set...
Hybrid Wind-Solar System
A **Hybrid Wind-Solar System** is an innovative approach to renewable energy that combines both wind and solar power, optimizing efficiency and energy production. These systems integrate wind turbines and photovoltaic (PV) panels to harness energy from two of the most abundant natural resources:...
Hydrofluorocarbons (HFCs)
**Hydrofluorocarbons (HFCs)** are a class of synthetic compounds primarily used as refrigerants, solvents, and in foam blowing applications. As part of the broader group of fluorinated gases, HFCs were initially introduced to replace ozone-depleting substances such as chlorofluorocarbons (CFCs)...
Hydrological Cycle Changes
**Hydrological Cycle Changes** refer to the alterations in the movement, distribution, and quality of water throughout the Earth due to natural and anthropogenic factors. This cycle, known as the water cycle, traditionally involves the evaporation of water, its condensation into clouds,...
Hydrological Modeling
**Hydrological Modeling** is a crucial scientific process used to simulate the distribution, movement, and properties of water within natural and built environments. This advanced technique employs mathematical models and computational tools to analyze various hydrological phenomena, such as...
Hydropower
**Hydropower**, also known as hydroelectric power, is a form of renewable energy that captures the energy from moving water to generate electricity. This process typically involves the construction of dams on large rivers, where the stored water in a reservoir is released through turbines. The...
Hydropower Lifecycle Analysis
**Hydropower Lifecycle Analysis** is a comprehensive assessment method used to evaluate the environmental impacts of hydroelectric power generation across its entire lifespan. This analytical approach encompasses the evaluation of every stage from the construction of the hydroelectric facility,...