Millions of people worldwide ride bicycles for fun, exercise, transportation and to get from one place to another. The bicycle is considered the most efficient human-powered means of transport because it allows people to travel farther for a given amount of energy. However, riding a bicycle is more complex than it appears and requires a significant amount of technical knowledge and skill. The engineering behind the working of a bicycle is more science than art, and it involves both the cyclist and bicycle.

The Bicycle: History and Development

The first bicycles were invented in the 1800s and were called velocipedes or cyclones. They were made of wood or metal, and had a front wheel that turned the cranks, which powered the rear wheel. The earliest bicycles were quite heavy, weighing upwards of 100 pounds.

Over time, engineers improved the design of the bicycle, making it lighter and more durable. The modern bike has a frame of steel, aluminium, carbon fibre or titanium, with suspension forks and wheel brakes. Most modern bikes have a drive system with a chain and cassette of sprockets that allow the cyclist to change gears to increase or decrease the amount of power they are using. The cassette is usually held in a derailleur, a mechanism that moves the chain between sprockets when the shifters are activated. Most riders use electronic derailleurs instead of mechanical ones.

Many modern bicycles have drop handlebars, which can be positioned in a number of ways depending on the rider’s preference and the type of cycling being done. Some riders like to ride in the drops, placing their hands on either side of the stem for a more aerodynamic position, while others prefer to ride in the hoods, with their fingers pointed back towards the saddle. Whether in the drops or on the hoods, most riders will also use the bars to control the brake levers and turn the front wheels of their bicycles for steering and stability.

Most modern bikes also have a front and rear derailleur, with the chain being moved between the cassette sprockets by the derailleurs when the shifters are activated. This is used to allow the cyclist to use a range of gears that best suit the terrain and their fitness level.

Some bicycles are designed for specific purposes, such as racing, touring, commuting or carrying cargo. Some are equipped with suspension, which makes the ride more comfortable for long distances or steep climbs. Other bikes are designed with disc brakes, which have more stopping power than traditional rim brakes. Some are built with a short-wheelbase, allowing the rider to generate enough force at the front wheel during braking to flip the bicycle longitudinally, an act known as a stoppie, endo or front wheelie.

Most important, the bicycle is a safe mode of transportation when operated properly. Bicyclists must obey traffic laws, and wear helmets, lights and reflective clothing. They should always use the shoulder of the road, and not ride against traffic. Motorists often do not see bicycles, and it is important for bicyclists to be as visible as possible to other road users.

A Go board, the flat, oblong gameboard on which Go is played. The word is an abbreviation of the Japanese words for “board” and “go,” which also mean ‘to move’. Go is a game of strategy and planning, as well as chance and luck. It is one of the world’s oldest board games, and it has a rich and varied history.

In go, the objective is to gain control of the opponent’s territory by surrounding and enclosing their stones. The first player to reach this state wins the game. There are many ways to do this, including the use of ‘komi’, or fixed points that determine how much territory each player can win. Go has a large number of moves, far more than chess (over five times as many in fact). For this reason, an exhaustive computer program for the game would be extremely expensive to develop. Most computer programs only calculate the best move on each turn, rather than every possible move.

The GOES satellite series is designed to monitor the Earth’s weather from geostationary orbit 22,300 miles above the ground. Each spacecraft is equipped with a variety of sensors and is operated by NOAA’s SOCC (Satellite Operations Control Center) at NOAA/NESDIS in Suitland, Maryland. The GOES system is designed to provide improved operational services, enhance atmospheric science research and support NOAA’s numerical weather prediction models.

The satellites in the GOES series fly the SEM instrument package, provided by NOAA/SEC (Space Environment Center). This includes the Solar X-ray Imager (SXI) and the Space Environment Monitoring Sounder (SEM). The SXI instrument provides near real-time imaging of the Sun’s explosive atmosphere, allowing NOAA forecasters to provide timely warnings when the sun’s activity could harm astronauts and satellites in space as well as on Earth.

GOES Sounder provides a full disk scanning capability over the Earth’s surface at 10 minutes intervals. This is a key feature for detecting areas of turbulence and for monitoring the movement of clouds and other phenomena such as volcanic eruptions.

The GOES system also includes self-timed and random reporting Data Collection Platforms (DCPs). These simple platforms are configured to report their sensor measurements on a regular schedule or at the signal strength threshold of the GOES satellite. This allows the DCP to provide a more consistent data stream to the satellite, reducing the frequency of its communication to the GOES. The GOES system also includes EPS and HEPAD, which detect high energy protons and alpha particles using the phenomenon of Cerenkov radiation. This enables the GOES to detect very high energy events such as solar flares and to continuously monitor galactic cosmic rays.