# Portal:Infrastructure

Infrastructure Portal
 Welcome to Wikipedia's infrastructure portal, your gateway to the subject of infrastructure and its monumental importance for everyday society and the economy.

## Introduction

Infrastructure is the fundamental facilities and systems serving a country, city, or other area, including the services and facilities necessary for its economy to function. Infrastructure is composed of public and private physical improvements such as roads, railways, bridges, tunnels, water supply, sewers, electrical grids, and telecommunications (including Internet connectivity and broadband speeds). In general, it has also been defined as "the physical components of interrelated systems providing commodities and services essential to enable, sustain, or enhance societal living conditions". There are two general types of ways to view infrastructure, hard or soft. Hard infrastructure refers to the physical networks necessary for the functioning of a modern industry. This includes roads, bridges, railways, etc. Soft infrastructure refers to all the institutions that maintain the economic, health, social, and cultural standards of a country. This includes educational programs, official statistics, parks and recreational facilities, law enforcement agencies, and emergency services.

The word infrastructure has been used in French since 1875 and in English since 1887, originally meaning "The installations that form the basis for any operation or system". The word was imported from French, where it was already used for establishing a roadbed of substrate material, required before railroad tracks or constructed pavement could be laid on top of it. The word is a combination of the Latin prefix "infra", meaning "below" as many of these constructions are underground, for example, tunnels, water and gas systems, and railways and the French word "structure" (derived from the Latin word "structura"). The army use of the term achieved currency in the United States after the formation of NATO in the 1940s, and by 1970 was adopted by urban planners in its modern civilian sense.

## Selected article

An airport is a location where aircraft such as fixed-wing aircraft, helicopters, and blimps take off and land. Aircraft may be stored or maintained at an airport. An airport consists of at least one surface such as a runway for a plane to take off and land, a helipad, or water for takeoffs and landings, and often includes buildings such as control towers, hangars and terminal buildings.

Larger airports may have fixed base operator services, seaplane docks and ramps, air traffic control, passenger facilities such as restaurants and lounges, and emergency services. A military airport is known as an airbase or air station. The terms aerodrome, airdrome, airfield, and airstrip may also be used to refer to airports, and the terms heliport, seaplane base, and STOLport refer to airports dedicated exclusively to helicopters, seaplanes, or short take-off and landing aircraft.

Smaller or less-developed airports—which represent the vast majority—often have a single runway shorter than 1,000 m (3,300 ft). Larger airports for airline flights generally have paved runways 2,000 m (6,600 ft) or longer. Many small airports have dirt, grass, or gravel runways, rather than asphalt or concrete. Read more...

## Diagrams

 Graphical phases in the life cycle of a facility Public Vs. Private Provision Infrastructure Systems Cash Flow

## Selected biography

Edwin Howard Armstrong (December 18, 1890 – January 31, 1954) was an American electrical engineer and inventor who invented the modern frequency modulation (FM) radio. Born in New York City, New York, in 1890, he later studied at Columbia University and later became a professor there. He invented the regenerative circuit while he was an undergraduate and patented it in 1914, the super-regenerative circuit (patented 1922), and the superheterodyne receiver (patented 1918).

Armstrong was of the opinion that anyone who had actual contact with the development of radio understood that the radio art was the product of experiment and work based on physical reasoning, rather than on the mathematicians' calculations and formulae (known today as part of "mathematical physics"). His work, as important as it was in its own right, was a part of a continuum of progress in communications and electronics that since his time has brought forward color television, the personal computer, the Internet, cable and satellite radio and TV, personal mobile phones, audio, [[video] and computing, digital stereo radio on both the medium wave and VHF-FM bands, and digital high definition television on VHF, UHF, cable and satellite. Armstrong's FM system was used for communications between NASA and the Apollo program astronauts. Read more...

## Economic Analysis

${\displaystyle \scriptstyle ratio={\frac {PV(B_{2})-PV(B_{1})}{PV(C_{2})-PV(C_{1})}}}$
${\displaystyle \scriptstyle EAC={\frac {NPV}{A_{t,r}}}}$
${\displaystyle \scriptstyle FV=PV\cdot (1+i)^{n}}$
${\displaystyle \scriptstyle NPV=\sum _{n=0}^{N}{\frac {C_{n}}{(1+r)^{n}}}=0}$
${\displaystyle \scriptstyle \mathrm {PV} ={\frac {FV}{(1+i)^{n}}}\,}$
${\displaystyle \scriptstyle ROI={\frac {Profit}{Investment}}\ }$

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