Draft:Original research/Shielding

Shielding is needed for a person or vehicle whenever local conditions are outside fair weather and pleasant circumstances.

In cold weather or cold climates this may take the form of a coat, hat, gloves, and boots.

Vehicle shielding may be for the vehicle itself, its components, or its passengers and driver or operator.

At right the electromagnetic shielding cages inside a mobile phone are shown, with one removed to show the components.

Theoretical radiation shielding
"The straightahead approximation, ie, the approximation that the secondary particles from nucleon-nucleus collisions are emitted in the direction of the incident nucleon, is often used in space-vehicle shielding studies. [...] the approximation is sufficiently accurate to justify its use in obtaining estimates of the secondary-particle contribution to the dose behind thin shields."

Def. a broad piece of metal or another suitable material used as a protection against blows or missiles is called shielding.

Def. "any device which renders a person or thing invisible" is called a cloaking device.

Meteors
"The impact shielding presently incorporated into space platform design may not be adequate under Leonid storm conditions."

Acoustics
Under "certain conditions [...] cloaking devices [...] can mask objects’ effects on other types of waves, including sound waves and water waves [...]."

Ways "of directing waves and currents around an object in a fluid, effectively hiding the object’s presence by cloaking its effect on the surrounding water [...] can also reduce drag or the rocking effect of waves on the object within the cloak."

"Whether for light, sound or water, such cloaks work by steering waves so they travel around an object rather than scattering off it, which would disrupt the waves’ paths and reveal the object’s presence. Instead, the cloak forces the waves to take a small detour around the object and return to the same configuration that they’d be if the object weren’t there."

"To cloak a miniature boat from the swells inside a wave tank, [...] a structure [...] can steer waves away from the tank’s center. Along each side of the wave tank’s long, narrow channel, [...] steel beams [were laid] that gradually sloped upward to a flat region, and then back down. That changes the depth of the water at the edges of the tank in a way that adjusts incoming waves’ speed and direction. In experiments, a toy boat in the tank’s center sat mostly motionless as the waves rolled in. A series of such beams could be constructed in a port to stop boats from bobbing wildly while being loaded with cargo."

A "small object in a flowing stream of water [can be shielded] using a complex, specially designed material made up of more than 500 tiny pillars, each 50 micrometers in width, that encircle the object to be hidden. The interaction of the water with the pillars makes the fluid behave as if it is more viscous, and alters its flow. As a result, water downstream flows as if no obstacle had been in its path. At the same time, the material decreases drag forces on the object, simulations suggest."

“The force cannot penetrate into the inner cloaked region. Reducing drag with this type of material could lead to more fuel-efficient vehicles."

Neutrals
Def. "a reduction in the effective nuclear charge on the electron cloud, due to a difference in the attraction forces of the electrons on the nucleus" is called atomic shielding.

Electromagnetics
"Carbon materials for electromagnetic interference (EMI) shielding [...] include composite materials, colloidal graphite and flexible graphite. Carbon filaments of submicron diameter are effective for use in composite materials, especially after electroplating with nickel."

Dark sky peripheral shielding
Local communities and federal authorities collaborate in the designation; the governments will take measures such as shielding street lights to preserve the area's dark sky.

Where possible, the U.S. Forest Service, which manages much of the land in the area, posts informational signs about the dark sky reserve, and will reduce light pollution from its buildings; compliance by individuals on Forest Service land will be voluntary.

Central Idaho Dark Sky Reserve
The Central Idaho Dark Sky Reserve is a 1416 sqmi dark-sky preserve near the Sawtooth National Recreation Area, in the U.S. state of Idaho. It was designated on December 18, 2017 and is the first gold-tier dark sky preserve in the United States. The area was designated by the International Dark-Sky Association (IDA). The area includes the city of Ketchum, Idaho which was separately designated a "Dark Sky Community" in 2017. Idaho State Highway 75 in the Sawtooth Valley between Redfish Lake and Pettit Lake roughly traverses the reserve's "core areas". Several sky quality meters are installed along State Highway 75 in this area.

Ketchum has had a dark sky ordinance since 1999, and Sun Valley, Idaho, also in the reserve, has its own local ordinance.

Bruneau Dunes State Park
Another dark sky certification effort was under way in 2017 about 80 miles away at Bruneau Dunes State Park, which hosts a public astronomical observatory.

Kerry International Dark-Sky Reserve
The Kerry International Dark-Sky Reserve is a dark-sky preserve in County Kerry, Republic of Ireland. It was designated Ireland's first International Dark Sky Reserve by the International Dark-Sky Association (IDA). Kerry International Dark-Sky Reserve was awarded the Gold Tier Award on January 27, 2014, by the IDA. It was the first Gold Tier Reserve in the northern hemisphere, and is one of only four Gold Tier Dark-Sky Reserves in the world.

The Kerry Dark-Sky Group was created in 2013 after several out-reach meetings with local community groups in the Reserve at the request of attendees to the gatherings. The purpose of the Kerry Dark-Sky Group is to promote astro-tourism in the Reserve via community projects, local outreach, and events.

History
The Spartans used the aspis to create the Greek phalanx formation. Their shields offered protection not only for themselves but for their comrades to their left.

Some knights and common soldiers adopted the buckler, giving rise to the term "swashbuckler".

During the 19th century, Zulu warriors carried large lightweight shields called Ishlangu made from a single ox hide supported by a wooden spine.

Hypotheses

 * 1) Sometimes the best shielding is knowledge and the technology to implement it.