Ribbon

A ribbon or riband is a thin band of material, typically cloth but also plastic or sometimes metal, used primarily as decorative binding and tying. Cloth ribbons are made of natural materials such as silk, velvet, cotton, and jute and of synthetic materials, such as polyester, nylon and polyproylene. Ribbon is used for innumerable useful, ornamental and symbolic purposes. Cultures around the world use ribbon in their hair, around the body, and as ornamentation on animals, buildings, and packaging. Some popular fabrics used to make ribbons are satin, organza, sheer, silk, velvet and grosgrain.

Etymology

The word ribbon comes from Middle English ribban or riban from Old French ruban, which is probably of Germanic origin.

Cloth ribbon

Ribbon (mathematics)

In mathematics (differential geometry) by a ribbon (or strip) is meant a smooth space curve given by a three-dimensional vector , depending continuously on the curve arc-length (), together with a smoothly varying unit vector perpendicular to at each point (Blaschke 1950).

The ribbon is called simple and closed if is simple (i.e. without self-intersections) and closed and if and all its derivatives agree at and . For any simple closed ribbon the curves given parametrically by are, for all sufficiently small positive , simple closed curves disjoint from .

The ribbon concept plays an important role in the Cǎlugǎreǎnu-White-Fuller formula (Fuller 1971), that states that

where is the asymptotic (Gauss) linking number (a topological quantity), denotes the total writhing number (or simply writhe) and is the total twist number (or simply twist).

Ribbon theory investigates geometric and topological aspects of a mathematical reference ribbon associated with physical and biological properties, such as those arising in topological fluid dynamics, DNA modeling and in material science.

Ribbon (rhythmic gymnastics)

Ribbon is a component of rhythmic gymnastics composed of a handle (called "stick"), a ribbon and attachment.

Stick

This can be of any colour and made of wood, bamboo or plastic with a maximum diameter of 1 cm (²/₅") at its widest, a cylindrical or conical shape and should have a length of 50–60cm (20–24") (including the fastening ring). The bottom end of the stick may be covered by an adhesive, anti-slip tape or may have a rubber handle for a maximum length of 10 cm (4") at the level of the grip. The top of the stick, where the ribbon will be attached, may consist of:

Ribbon (company)

Ribbon is a San Francisco payments startup that lets users sell online using a shortened URL that can be shared across email, social media and a seller's own website. The service focuses on bring integrated checkouts directly to platforms like Facebook, YouTube, and Twitter letting buyers purchase without leaving those services.

The company graduated from a startup accelerator called AngelPad as "Kout" in October 2011 and subsequently raised $1.6 million from Tim Draper through Draper Associates, Naguib Sawiris, Emil Michael, Gokul Rajaram, and others bringing its total raised amount to $1.75 million.

Twitter shutdown

On April 10, 2013 the company announced support for "in-stream" payments on Twitter, allowing buyers to purchase items without leaving the Twitter.com stream. Twitter shut down Ribbon's API access after approximately an hour and a half, according to Head of Business Development, Daniel Brusilovsky. Ribbon requested permission to show video cards, but after receiving permission then switched the url to show the hacked checkout system. The company wrote a statement announcing they will revert to showcasing only a summary of their product without the ability to do in-stream payments. As of April 11, 2013 Ribbon links inside Twitter no longer work in-stream and buyers are redirected to purchase on the Ribbon website.

Stream

A stream is a body of water with a current, confined within a bed and stream banks. Depending on its location or certain characteristics, a stream may be referred to as a branch, brook, beck, burn, creek, crick, gill (occasionally ghyll), kill, lick, mill race, rill, river, syke, bayou, rivulet, streamage, wash, run, or runnel.

Streams are important as conduits in the water cycle, instruments in groundwater recharge, and corridors for fish and wildlife migration. The biological habitat in the immediate vicinity of a stream is called a riparian zone. Given the status of the ongoing Holocene extinction, streams play an important corridor role in connecting fragmented habitats and thus in conserving biodiversity. The study of streams and waterways in general is known as surface hydrology and is a core element of environmental geography.

Types

Ribbon (award)

A ribbon is an award made from ribbon and presented to mark an achievement. Such ribbons usually have a pin, brooch or bridle clip as a fastener with which the award can be attached to clothing, animals, walls, or other surfaces.

Award ribbons can be simply a flat piece of ribbon, a flat-folded ribbon, or fancier manipulations of the ribbon material, such as rosettes. A rosette consists of ribbon that is pleated or gathered and arranged in a circle so that it resembles a rose, usually with streamer ribbons attached. Some ribbon rosettes will also have loops, petals and star points as part of the design whilst using Satin ribbons, Velvet ribbons, Sheer ribbons, Lamé ribbons, Tartan ribbons and printed ribbons including personalised printed ribbons to promote the sponsor, event or the reason for giving.

Ribbons are usually imprinted with information about the award, such as the name of the event, the sponsoring organization, the placement (such as first place, second place, etc.), and the date. More sophisticated awards also include the name of the recipient, special motifs and logos.