The soles of many modern shoes and boots are made of crepe rubber, which is composed of coagulated latex that is pressed into sheets, creating a layered material that is durable yet flexible. Crepe-soled shoes are known for being quiet, as opposed to harder rubber or wooden soles that create clicking sounds when walking.
In airports, there are security machines that use x-ray technology to scan both passengers and luggage in order to make sure no weapons or drugs are going to be taken on board. After the tragedy of September 11, 2011, air traffic security tightened significantly. Now, Transportation Security Administration (TSA) security officers use x-ray stations to scan for items that used to be considered innocuous but which are now considered potentially lethal, such as flammable items, items with sharp edges, and even liquids in excess of 3 ounces.
A cylindrical device that attaches to the end of a barrel of a gun and muffles the loud noise of a fired shot. A silencer works by adding volume to the short, narrow barrel, thereby reducing the pressure created by the hot gas that is released when the gunpowder is activated.
A main component of a larger system of long-distance transportation, such as a railroad or a highway. The term also commonly refers to a long pipeline used to transport oil or natural gas. Spurlines branch off the trunkline, connecting smaller depots, towns, or sites of natural resource extraction to the main trunkline, similar to tributaries running into a river.
Pressured to cooperate with the U.S. federal government in order retain at least some vestige of recognition as a sovereign nation, the Navajo Nation transitioned from traditional governance to a representative system in 1922. Under the paternalistic guidance of the U.S. Secretary of the Interior, the Navajo Business Council was created to negotiate mineral releases on tribal lands. In 1934 they disbanded after refusing to adopt the Indian Reorganization Act, only to reform under a new name, Navajo Nation Council, in 1937. The Navajo Tribal Council is presided over by a council-elected speaker and includes 24 elected members from 110 tribal chapters. The Navajo Tribal Council meets at Window Rock, Arizona at least four times a year, when they discuss new legislation for and issues on the Navajo Nation Reservation.
An alloy is a metal that is made by combining at least two other metals or a metal and a nonmetal element. The characteristics of an alloy are different than the characteristics of the separate elements. Aluminum alloy includes mainly aluminum. By combining aluminum and copper, in the right amounts, results in a lightweight metal that is stronger and lighter than either aluminum or copper were before they were combined. Because they are relatively light, aluminum alloys are commonly found in transportation technologies including aerospace equipment, automobiles, and cycling frames.
A rifle is a firearm with an extended barrel that is generally raised up to the shoulder for firing. The interior surface of the long barrel is carved with spiral grooves down its length. The length of the barrel, in combination with its interior grooves, improves the accuracy of the shot fired by increasing the stability of the projectile as it spins out of the barrel. The rifle, as opposed to another long-barreled firearm, the shotgun, fires a single projectile at a time.
A U.S.-based company that makes shotguns, rifles, handguns, and ammunition. The total company name is Remington Arms Company, LLC, and it is the oldest rifle-making company in the U.S., having been in the arms and ammunition business since 1816.
Radar, an acronym for "radio detection and ranging," was developed and in use by several nations as early as World War II. Radar is a system that detects objects and their movements through time and space by emitting pulses of radio waves. When these waves encounter an object, the waves' movement is disrupted, and readings of this disruption bounce back in the direction from which they were emitted, where their energy is read and analyzed to determine size and direction and speed of movement of the object encountered.
