Energy & Green Tech

Major new study charts course to net zero industrial emissions

A major new study by an interdisciplinary team of researchers finds that it is possible—and critical—to bring industrial greenhouse gas emissions to net zero by 2070. Published Sunday in Applied Energy, the study assesses ...

Energy & Green Tech

Uncertain climate future could disrupt energy systems

Extreme weather events—such as severe drought, storms, and heat waves—have been forecast to become more commonplace and are already starting to occur. What has been less studied is the impact on energy systems and how ...

Energy & Green Tech

Scientists tap unused energy source to power smart sensor networks

The electricity that lights our homes and powers our appliances also creates small magnetic fields that are present all around us. Scientists have developed a new mechanism capable of harvesting this wasted magnetic field ...

Energy & Green Tech

Sunny prospects for start-up's clear solar energy windows

A Redwood City, California-based tech startup has developed a glass window packed with transparent photovoltaic cells that it believes will revolutionize the way solar energy is harnessed.

Energy & Green Tech

Researchers develop novel supercritical water oxidation system

A research group from the Shenzhen Institutes of Advanced Technology (SIAT) of the Chinese Academy of Sciences has proposed a novel supercritical water oxidation (SCWO) system with an inverse cool-wall reactor to realize ...

Engineering

New computer program predicts crack initiation in 3-D

Most structures and materials have defects, and if the conditions are right, these defects can lead to the initiation and propagation of cracks. Finding out where and with what orientation a surface crack is most likely to ...

Robotics

Engineers find ankle exoskeleton aids running

Running is great exercise but not everyone feels great doing it. In hopes of boosting physical activity—and possibly creating a new mode of transportation—engineers at Stanford University are studying devices that people ...

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Energy

In physics, energy (from the Greek ἐνέργεια - energeia, "activity, operation", from ἐνεργός - energos, "active, working") is a scalar physical quantity that describes the amount of work that can be performed by a force, an attribute of objects and systems that is subject to a conservation law. Different forms of energy include kinetic, potential, thermal, gravitational, sound, light, elastic, and electromagnetic energy. The forms of energy are often named after a related force.

Any form of energy can be transformed into another form, but the total energy always remains the same. This principle, the conservation of energy, was first postulated in the early 19th century, and applies to any isolated system. According to Noether's theorem, the conservation of energy is a consequence of the fact that the laws of physics do not change over time.

Although the total energy of a system does not change with time, its value may depend on the frame of reference. For example, a seated passenger in a moving airplane has zero kinetic energy relative to the airplane, but non-zero kinetic energy relative to the Earth.

This text uses material from Wikipedia, licensed under CC BY-SA