Encyclopedia of 20th century technology

Peter Morris, Science Museum, LondonProfessor John Pickstone, Centre for the History ofScience, Technology and Medicine, University of ManchesterKeith Thrower, former Technical Director

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RT3865_half title 9/21/04 3:53 PM Page 1

ENCYCLOPEDIA OF 20TH-CENTURY

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Routledge is an imprint of the Taylor & Francis Group.

All rights reserved No part of this book may be reprinted or reproduced or

utilized in any form or by any electronic, mechanical, or other means, now

known or hereafter invented, including photocopying and recording, or in

any information storage and retrieval system, without permission in writing

from the publisher.

Library of Congress Cataloging-in-Publication Data

Encyclopedia of 20th-century technology / Colin A Hempstead, editor; William E Worthington, associate editor.

p cm.

Includes bibliographical references and index.

ISBN 1-57958-386-5 (set : alk paper)—ISBN 1-57958-463-2 (vol 1 : alk paper)—

ISBN 1-57958-464-0 (vol 2 alk paper)

1 Technology—Encyclopedias I Hempstead, Colin II Worthington, William E., 1948–

T9.E462 2005

603—dc22

This edition published in the Taylor & Francis e-Library, 2005.

“To purchase your own copy of this or any of Taylor & Francis or Routledge’s

collection of thousands of eBooks please go to www.eBookstore.tandf.co.uk.”

ISBN 0-203-99699-2 Master e-book ISBN

Dr Jon Agar, Department of History and

Philosophy of Science, University of

Cambridge

Professor Janet Bainbridge, Chief Executive,

EPICC (European Process Industries

Competitiveness Centre), Teesside

Dr Hans Joachim Braun, Universita¨ t der

Bundeswehr Hamburg

Dr Robert Bud, Principal Curator of Science,

Science Museum, London

Dr Michael Duffy, formerly Department of

Engineering, University of Sunderland

Dr Slava Gerovitch, Dibner Institute for the

History of Science and Technology, MIT

Dr Ernst Homburg, Department of History,University of Maastricht

Dr Sally Horrocks, Department of Economic andSocial History, University of Leicester

R Douglas Hurt, Professor and Director, GraduateProgram in Agricultural History and RuralStudies, Department of History, Iowa StateUniversity

Dr Peter Morris, Science Museum, LondonProfessor John Pickstone, Centre for the History ofScience, Technology and Medicine, University

of ManchesterKeith Thrower, former Technical Director at RacalElectronics, UK

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List of Entries ixThematic List of Entries xvEditor’s Preface xxiAssociate Editor’s Preface xxiiiAcknowledgments xxvContributors xxviiEntries A through Z 1

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Antibiotics, Developments through 1945

Antibiotics, Use after 1945

Artificial Insemination and in Vitro Fertilization

Artificial Intelligence

Audio Recording, Compact Disc

Audio Recording, Electronic Methods

Audio Recording, Mechanical

Audio Recording, Stereophonic and Surround

Sound

Audio Recording, Tape

Audio Recording, Wire

Audio Systems

Audiology, Hearing Aids

Audiology, Implants and Surgery

Audiology, Testing

Automobiles

Automobiles, Electric

Automobiles, Hybrid

Automobiles, Internal Combustion

Batteries, Primary and Secondary

Battleships

Biomass Power Generation

BiopolymersBiotechnologyBlood Transfusion and Blood ProductsBoranes

Breeding, Animal: Genetic MethodsBreeding, Plant: Genetic MethodsBridges, Concrete

Bridges, Long Span and SuspensionBridges, Steel

Building AcousticsBuildings, Designs for Energy ConservationBuildings, Prefabricated

Calculators, ElectronicCalculators, Mechanical and ElectromechanicalCameras, 35 mm

Cameras, AutomaticCameras, DigitalCameras, DisposableCameras, Lens Designs: Wide Angle and ZoomCameras, Polaroid

Cameras, Single Lens Reflex (SLR)Cancer, Chemotherapy

Cancer, Radiation TherapyCancer, Surgical TechniquesCardiovascular Disease, Pharmaceutical TreatmentCardiovascular Surgery, Pacemakers and HeartValves

CatamaransCeramic MaterialsChanging Nature of WorkChemical Process EngineeringChemicals

ChromatographyCivil Aircraft, Jet DrivenCivil Aircraft, Propeller DrivenCivil Aircraft, SupersonicCleaning: Chemicals and Vacuum CleanersClocks and Watches, Quartz

Clocks, AtomicCloning, Testing and Treatment MethodsCoatings, Pigments, and Paints

Color Photography

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Computer Memory, Early

Computer Memory, Personal Computers

Contraception: Hormonal Methods and Surgery

Contraception: Physical and Chemical Methods

Control Technology, Computer-Aided

Control Technology, Electronic Signals

Electrical Power Distribution

Electricity Generation and the Environment

Engineering: Cultural, Methodological andDefinitional Issues

Engineering: Production and Economic GrowthEntertainment in the Home

Environmental MonitoringError Checking and CorrectionExperimental Stress AnalysisExplosives, CommercialFarming, Agricultural MethodsFarming, Growth PromotionFarming, MechanizationFax Machine

FeedstocksFertility, HumanFertilizersFibers, Synthetic and Semi-SyntheticFilm and Cinema: Early Sound FilmsFilm and Cinema: High Fidelity to SurroundSound

Film and Cinema: Sets and TechniquesFilm and Cinema: Wide Screen SystemsFire Engineering

Fish FarmingFission and Fusion BombsFly-by-Wire SystemsFood Additives and SubstitutesFood Preparation and CookingFood Preservation: Cooling and FreezingFood Preservation: Freeze Drying, Irradiation,and Vacuum Packing

Food, Processed and FastFossil Fuel Power StationsFuel Cells

Gender and TechnologyGene Therapy

Genetic Engineering, ApplicationsGenetic Engineering, MethodsGenetic Screening and TestingGlobal Positioning System (GPS)Globalization

Green ChemistryGyrocompass and Inertial GuidanceHall Effect Devices

HealthHearts, ArtificialHelicoptersHematologyHighwaysHistologyLIST OF ENTRIES

Hormone Therapy

Hovercraft, Hydrofoils, and Hydroplanes

Hydroelectric Power Generation

Integrated Circuits, Design and Use

Integrated Circuits, Fabrication

Intensive Care and Life Support

Internal Combustion Piston Engine

Lasers, Theory and Operation

Laundry Machines and Chemicals

Light Emitting Diodes

Lighting, Public and Private

Methods in the History of Technology

Microscopy, Electron Scanning

Microscopy, Electron Transmission

Microscopy, Optical

Microwave Ovens

Military versus Civil Technologies

Missiles, Air to Air

Missiles, Air to Surface

Missiles, Defensive

Missiles, Long Range and Ballistic

Missiles, Long Range and Cruise

Missiles, Short Range and Guided

Missiles, Surface-to-Air and Anti-Ballistic

Mobile (Cell) Telephones

Motorcycles

Nanotechnology, Materials and Applications

Neurology

Nitrogen FixationNuclear FuelsNuclear Magnetic Resonance (NMR) andMagnetic Resonance Imaging (MRI)Nuclear Reactor Materials

Nuclear Reactors: Fast BreedersNuclear Reactors: Fusion, Early DesignsNuclear Reactors: Fusion, Later DesignsNuclear Reactors: Thermal, Graphite ModeratedNuclear Reactors: Thermal, Water ModeratedNuclear Reactors: Weapons Material

Nuclear Waste Processing and Storage

Oil from Coal ProcessOil Rigs

OphthalmologyOptical AmplifiersOptical MaterialsOptoelectronics, Dense Wavelength DivisionMultiplexing

Optoelectronics, Frequency ChangingOptometry

Organ TransplantationOrganization of Technology and Science

Packet SwitchingParticle Accelerators: Cyclotrons, Synchrotrons,and Colliders

Particle Accelerators, LinearPersonal Stereo

Pest Control, BiologicalPesticides

PhotocopiersPhotosensitive DetectorsPlastics, ThermoplasticsPlastics, ThermosettingPositron Emission Tomography (PET)Power Generation, Recycling

Power Tools and Hand-Held ToolsPresentation of Technology

PrintersProcessors for ComputersProspecting, MineralsPsychiatry, Diagnosis and Non-Drug TreatmentsPsychiatry, Pharmaceutical Treatment

Quantum Electronic Devices

Radar aboard AircraftRadar, Defensive Systems in World War IIRadar, Displays

Radar, High Frequency and High PowerRadar, Long Range Early Warning SystemsRadar, Origins to 1939

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Radio: AM, FM, Analog, and Digital

Radio, Early Transmissions

Radio Receivers, Coherers and Magnetic Methods

Radio Receivers, Crystal Detectors and Receivers

Radio Receivers, Early

Radio Receivers, Valve and Transistor Circuits

Radio Transmitters, Continuous Wave

Radio Transmitters, Early

Radioactive Dating

Radio-Frequency Electronics

Radionavigation

Rail, Diesel and Diesel Electric Locomotives

Rail, Electric Locomotives

Rail, High Speed

Rail, Steam Locomotives

Rocket Propulsion, Liquid Propellant

Rocket Propulsion, Solid Propellant

Semiconductors, Postband Theory

Semiconductors, Preband Theory

Ships: Bulk Carriers and Tankers

Skyscrapers

Smart and Biomimetic Materials

Social and Political Determinants of Technological

Space Exploration, Fly Past

Space Exploration, Manned Orbiters

Space Exploration, Moon, Manned

Space Exploration, Moon, Unmanned

Space Exploration, Planetary Landers

Space Exploration, Unmanned

Space Launch Vehicles

Space Shuttle

Space Stations, International Space Station

Space Stations, Mir

Space Stations, Skylab

Spectroscopy and Spectrochemistry, Visible andUltraviolet

Spectroscopy, InfraredSpectroscopy, RamanSpectroscopy, X-ray FluorescenceSports Science and TechnologySputniks

Strobe FlashesSubmarines, MilitarySubmersibles

Superconductivity, ApplicationsSuperconductivity, DiscoverySurgery, Plastic and ReconstructiveSynthetic Foods, Mycoprotein and HydrogenatedFats

Synthetic ResinsSynthetic RubberSystems ProgramsTanks

Technology and EthicsTechnology and LeisureTechnology, Arts and EntertainmentTechnology, Society and the EnvironmentTelecommunications

Telephony, Automatic SystemsTelephony, Digital

Telephony, Long DistanceTelescopes, Computer-controlled MirrorsTelescopes, Ground

Telescopes, RadioTelescopes, SpaceTelevision, Beginning Ideas (Late 19th and Early20th Century)

Television, Cable and SatelliteTelevision, Color, ElectromechanicalTelevision: Color, Electronic

Television, Digital and High Definition SystemsTelevision, Electromechanical Systems

Television Recording, DiscTelevision Recording, TapeThin Film Materials and TechnologyTimber Engineering

Tissue CulturingTomography in MedicineTransistors

TransportTransport, FoodstuffsTransport, Human PowerTravelling Wave TubesTunnels and TunnelingTurbines, Gas

Turbines: Gas, in AircraftTurbines: Gas, in Land VehiclesTurbines, Steam

LIST OF ENTRIES

Warplanes, Fighters and Fighter BombersWarplanes, Reconnaissance

Wind Power GenerationWorld Wide WebWright FlyersX-ray CrystallographyX-rays in Diagnostic Medicine

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Thematic List of Entries

Breeding, Animal: Genetic Methods

Breeding, Plant: Genetic Methods

Cloning, Testing and Treatment Methods

Gene Therapy

Genetic Engineering, Methods

Genetic Engineering, Applications

Genetic Screening and Testing

Mobile (Cell) TelephonesRadio-Frequency ElectronicsSatellites, CommunicationsTelecommunicationsTelephony, Automatic SystemsTelephony, Digital

Telephony, Long DistanceComputers

Artificial IntelligenceComputer and Video GamesComputer Displays

Computer Memory, EarlyComputer Memory, Personal ComputersComputer Modeling

Computer NetworksComputer ScienceComputer-Aided Design and ManufactureComputers, Analog

Computers, Early DigitalComputers, HybridComputers, MainframeComputers, PersonalComputers, SupercomputersComputers, Uses and ConsequencesComputer–User Interface

Control Technology, Computer-AidedControl Technology, Electronic SignalsError Checking and Correction

Encryption and Code BreakingGlobal Positioning System (GPS)Gyrocompass and Inertial GuidanceInformation Theory

InternetPacket Switching

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Calculators, Mechanical and Electromechanical

Clocks and Watches, Quartz

Control Technology, Electronic Signals

Integrated Circuits, Design and Use

Integrated Circuits, Fabrication

Josephson Junction Devices

Lasers, Theory and Operation

Lasers, Applications

Lasers in Optoelectronics

Light Emitting Diodes

Lighting, Public and Private

Vacuum Tubes/ValvesTravelling Wave TubesSee also Television, Radio, Audio RecordingEnergy and Power

Batteries, Primary and SecondaryBiomass Power GenerationElectrical Energy Generation and Supply, LargeScale

Electrical Power DistributionElectricity Generation and the EnvironmentFossil Fuel Power Stations

Fuel CellsHydroelectric Power GenerationNuclear Reactors: Fast BreedersNuclear Reactors: Fusion, Early DesignsNuclear Reactors: Fusion, Later DesignsNuclear Reactors: Thermal, Graphite ModeratedNuclear Reactors: Thermal, Water ModeratedPower Generation, Recycling

Solar Power GenerationTurbines, Gas

Turbines, SteamTurbines: Gas, in Land VehiclesWind Power Generation

EnvironmentEnvironmental MonitoringGreen Chemistry

Satellites, Environmental SensingTechnology, Society and the EnvironmentSee also Energy and Power

Film, Cinema, PhotographyCameras, 35 mm

Cameras, AutomaticCameras, DigitalCameras, DisposableCameras, PolaroidCameras, Single Lens Reflex (SLR)Cameras: Lens Designs, Wide Angle, ZoomFilm, Color Photography

Film and Cinema: Early Sound FilmsFilm and Cinema: High Fidelity to SurroundSound

Film and Cinema: Sets and TechniquesFilm and Cinema: Wide Screen SystemsFood and Agriculture

Activated CarbonTHEMATIC LIST OF ENTRIES

Agriculture and Food

Crop Protection, Spraying

Dairy Farming

Farming, Agricultural Methods

Farming, Growth Promotion

Farming, Mechanization

Fertilizers

Fish Farming

Food Additives and Substitutes

Food Preparation and Cooking

Food Preservation: Cooling and Freezing

Food Preservation: Freeze Drying, Irradiation,

and Vacuum Packing

Food, Processed and Fast

Irrigation Systems

Nitrogen Fixation

Pesticides

Pest Control, Biological

Synthetic Foods, Mycoprotein and Hydrogenated

Antibiotics, Developments through 1945

Antibiotics, Use after 1945

Audiology, Hearing Aids

Audiology, Implants and Surgery

Audiology, Testing

Blood Transfusion and Blood Products

Cancer, Chemotherapy

Cancer, Radiation Therapy

Cancer, Surgical Techniques

Cardiovascular Disease, Pharmaceutical

Treatment

Cardiovascular Surgery, Pacemakers and Heart

Valves

Contraception, Hormonal Methods and Surgery

Contraception, Physical and Chemical Methods

NeurologyOphthalmologyOptometryOrgan TransplantationPositron Emission Tomography (PET)Psychiatry, Diagnosis and Non-Drug TreatmentsPsychiatry, Pharmaceutical Treatment

Surgery, Plastic and ReconstructiveTomography in Medicine

Ultrasonography in MedicineVitamins, Isolation and SynthesisX-rays in Diagnostic MedicineHomes

Air ConditioningBuildings, Designs for Energy ConservationBuildings, Prefabricated

Cleaning: Chemicals and Vacuum CleanersDishwashers

Domestic HeatingEntertainment in the HomeLaundry Machines and ChemicalsLighting, Public and PrivateMicrowave Ovens

Leisure and EntertainmentAudio Recording

Audio SystemsComputer and Video GamesLoudspeakers and EarphonesPersonal Stereo

Radio, Early TransmissionsSports Science and TechnologyTechnology, Arts and EntertainmentTechnology and Leisure

Television, Various EntriesSee also Film, Cinema, Photography; TV, Radio,Audio Recording

MaterialsAbsorbent MaterialsAdhesives

Alloys, Light and FerrousAlloys, Magnetic

Ceramic MaterialsComposite MaterialsCrystals, SyntheticFibers, Synthetic and Semi-SyntheticIron and Steel Manufacture

Liquid CrystalsMaterials and Industrial ProcessesNanotechnology, Materials and Applications

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Nuclear Fuels

Nuclear Reactor Materials

Nuclear Waste Processing and Storage

Semiconductors, Postband Theory

Semiconductors, Preband Theory

Semiconductors: Crystal Growing, Purification

Superconductivity, Discovery

Smart and Biomimetic Materials

Synthetic Resins

Synthetic Rubbers

Thin Film Materials and Technology

See also Chemistry

Microscopy, Electron (Scanning)

Microscopy, Electron (Transmission)

Microscopy, Optical

Nuclear Magnetic Resonance (NMR) and

Magnetic Resonance Imaging (MRI)

Particle Accelerators: Cyclotrons, Synchrotrons,

Research and Development in the 20th Century

Spectroscopy and Spectrochemistry, Visible and

Rocket Propulsion, Liquid Propellant

Rocket Propulsion, Solid Propellant

Satellites, Communications

Satellites, Environmental Sensing

Space

Space Exploration, Fly Past

Space Exploration, Manned Orbiters

Space Exploration: Moon, MannedSpace Exploration: Moon, UnmannedSpace Exploration, Planetary LandersSpace Exploration, UnmannedSpace Launch Vehicles

Space ShuttleSpace Stations, International Space StationSpace Stations, Mir

Space Stations, SkylabSputniks

Telescopes, Computer-Controlled MirrorsTelescopes, Ground

Telescopes, RadioTelescopes, SpaceThematic OverviewsAgriculture and FoodBiotechnology

Changing Nature of WorkChemicals

CommunicationsComputers, Uses and ConsequencesConstructed World

ElectronicsEnergy and PowerEngineering: Cultural, Methodological andDefinitional Issues

Engineering: Production and Economic GrowthGender and Technology

GlobalizationHealthMaterials and Industrial ProcessesMedicine

Methods in the History of TechnologyMilitary Versus Civil TechnologiesOrganization of Technology and SciencePresentation of Technology

Research and Development in the 20th CenturySocial and Political Determinants of TechnologicalChange

SpaceTechnology, Arts and EntertainmentTechnology and Ethics

Technology and LeisureTechnology, Society and the EnvironmentTelecommunications

TransportWarfareTransportationAir Traffic Control SystemsAircraft Design

Aircraft InstrumentationAutomobiles

Automobiles, ElectricTHEMATIC LIST OF ENTRIES

Automobiles, Hybrid

Automobiles, Internal Combustion

Catamarans

Civil Aircraft, Jet Driven

Civil Aircraft, Propeller Driven

Civil Aircraft, Supersonic

Dirigibles

Fly-by-Wire Systems

Helicopters

Highways

Hovercraft, Hydrofoils, and Hydroplanes

Internal Combustion Piston Engine

Motorcycles

Rail, Diesel and Diesel Electric Locomotives

Rail, Electric Locomotives

Rail, High Speed

Rail, Steam Locomotives

Transport, Human Power

Turbines: Gas, in Aircraft

Urban Transportation

Wright Flyers

Television, Radio, Audio Recording

Audio Recording, Compact Disc

Audio Recording, Electronic Methods

Audio Recording, Mechanical

Audio Recording, Stereophonic and Surround

Sound

Audio Recording, Tape

Audio Recording, Wire

Audio Systems

Iconoscope

Loudspeakers and Earphones

Personal Stereo

Radio Receivers, Coherers and Magnetic Methods

Radio Receivers, Crystal Detectors and Receivers

Radio Receivers, Early

Radio Receivers, Valve and Transistor Circuits

Radio Transmitters, Continuous Wave

Radio Transmitters, Early

Radio, Early TransmissionsRadio: AM, FM, Analog, and DigitalTelevision Recording, Disc

Television Recording, TapeTelevision, Cable and SatelliteTelevision, Digital and High Definition SystemsTelevision, Electro-Mechanical Systems

Television, Beginning Ideas (Late 19th and Early20th Century)

Television, Color, ElectromechanicalTelevision: Color, Electronic

See also Film and Cinema; Leisure andEntertainment

WarfareAircraft CarriersBattleshipsExplosives, CommercialFission and Fusion BombsMilitary Versus Civil TechnologiesMissiles, Air-to-Air

Missiles, Air-to-SurfaceMissiles, DefensiveMissiles, Long Range and BallisticMissiles, Long Range and CruiseMissiles, Short Range and GuidedMissiles, Surface-to-Air and Anti-BallisticNuclear Reactors: Weapons MaterialRadar Aboard Aircraft

Radar, Defensive Systems in World War IIRadar, Displays

Radar, High-Frequency and High-PowerRadar, Long Range and Early Warning SystemsRadar, Origins to 1939

SonarSubmarines, MilitaryTanks

WarfareWarfare, BiologicalWarfare, ChemicalWarfare, High Explosive Shells and BombsWarfare, Mines and Antipersonnel DevicesWarplanes, Bombers

Warplanes, Fighters and Fighter BombersWarplanes, Reconnaissance

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Editor’s Preface

All editors of encyclopedias are faced with the

problem of what to include Even if the title is

agreed and the numbers of volumes and pages have

been decided, the sum of possible entries could be

very large In the case of the Encyclopedia of

20th-Century Technology, the editor decided that in

order to construct a logical and consistent set of

entries it was necessary to adopt what could be

described as an analytic framework During the

20th century a plethora of manufactured articles

have appeared for which the real costs have

continuously fallen The products in industrialized

societies have become universal, and many of the

good ones are within the reach of a large

propor-tion of humanity In keeping with this democratic

trend of the century it was decided that people and

their experiences with technology should be central

to the encyclopedia Readers are urged to read the

entries in the light of the humanistic core

An examination of people and their lives led to

six broad, related areas of society from which the

four hundred entries that comprise these volumes

could be derived The type of analysis carried out is

indicated in the diagrams on the next page The

first shows the six basic areas; the second diagram

is an outline of the detailed application for the

category FOOD Five or six levels of analysis

allowed the definition of headers that provided the

individual entries Of course, entries could be

found in two or more basic areas or could be

related to others: entries in refrigerating in the

domestic situation as found in food preservation

would lead to entries in the technology of

refrig-eration per se Thus the contents were defined

The encyclopedia contains two types of entries

The greatest number of entries are of 1000 words,

and as far as possible these standard entries are

devoid of interpretation Nevertheless, it is

recog-nized that all history is redolent of the era in which it

is constructed, and this encyclopedia is of its own

particular society, that of Western industrial The

factual nature of the standard entries is leavened bylonger essays in which historical and interpretativethemes are explored Among other things, theseessays describe and analyze the relationshipbetween society and technology, touch on themodern debates on the nature of the history oftechnology of history, and relate what peopleexpect of the products of modern industrialcivilisation

The encyclopedia is concerned with century technology but not with 20th-centuryinventions The technologies included are thosethat had an impact on the mass of the population

20th-in 20th-industrial societies So many technologiesinvented in the 19th century did not begin toimpinge markedly on many lives until the middle ofthe 20th century, so they are considered to be ofthe 20th century Similarly, many products in theconstructed world are old conceptions, trans-formed by modern materials or production meth-ods They have found a place in the encyclopedia.The inclusion of pre-20th-century products com-pares with the exclusion of recently developedtechnologies that have yet to have any effect on themass of the public However, the encyclopedia isnot intended to be futuristic In the 20th century,scientific engineering came to majority, and many

if not all the products of modern technology can beseen to be the results of science However, there are

no entries that discuss science itself Within theessays, however, science as science related to eachsubject is described

Even with four hundred entries, the pedia is not canonical, and gaps will be noted.However, the standard entries, the interpretativeessays, and the lists of references and furtherreading suggestions allow readers to appreciatethe breadth and depth of the technology of the20th century

encyclo-Colin Hempstead

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Associate Editor’s Preface

Technology is a vital subject It grows

continu-ously New technologies are introduced, existing

technologies evolve, and the outmoded are

aban-doned Looking dispassionately at technology, it is

always exciting, for it is the product of human

ingenuity For the purposes of this encyclopedia,

we felt it could not and should not be discussed

devoid of its human element It is breathtaking to

consider the panoply of developments which

occurred during the last century, but it is necessary

to recall that these developments did not take place

in isolation It was our desire to see that events,

where possible, were described in context Thus,

you will find names, places, dates, and events

critical to the development of a particular

technol-ogy The reader will note that some entries contain

a surprising amount of information on

19th-century events This was appropriate, for some

20th-century technologies were firmly rooted in

that earlier time and can be best understood in

light of the past To avoid a deadly dull recitation

of formulae and regurgitation of dry facts, we

sought to give the reader the broadest possible

picture

The encyclopedia was created for the lay reader

and students as well as for historians of science and

technology In light of this, we attempted to

minimize the use of the jargon that tends to grow

around some technologies Although many of thesubjects are highly technical, our belief was thateven complicated subjects could be rendered insuch a way as to make them comprehensible to awide audience In the same way that an electricalengineer might need explanations when encounter-ing genetic terminology, students and non-special-ists will also appreciate the clarification Because ofthe pervasiveness of the subjects in all facets of ourlives, the encyclopedia should be a handy referencetool for a broad range of readers Our aim was tomake the subjects, which many of us deal withdaily and do not necessarily grasp completely,readily understood with a minimum need foradditional reference However, should the readerwish to delve further into any particular subject,our expert authors have provided a selection offurther bibliographic readings with which to begin.The scope of the encyclopedia is intended to beinternational Discussions were to be as inclusive aspossible and avoid focus solely on the events of anyone country Nonetheless, some skewing wasunavoidable due simply to the prodigious number

of developments that have taken place in somecountries

William E Worthington, Jr

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A host of workers and authors contributed to this

encyclopedia, and I wish to extend my thanks to

every person without whom these volumes would

be stillborn My particular thanks are offered to

Gillian Lindsey of Routledge Gillian conceived

the idea of an encyclopedia of 20th-century

technology, and appointed me the editor of the

work in 2000 Her energy and ideas were legion,

although she glossed over the amount of work for

me! However, the editorship was rewarding,

offer-ing the possibility of producoffer-ing a worthwhile

publication with academic colleagues from around

the globe The selection of technologies and of

particular subjects suggested by Gillian and me

were critiqued and extended by our advisers Their

contributions, drawn from their specialist

knowl-edge and scholarship, were invaluable When

circumstances forced my withdrawal from the

active editorship, William Worthington, then with

the National Museum of American History in

Washington, stepped into the hot seat To William

I give my heartfelt thanks

Finally I acknowledge the publishers and the20th century which presented all of us with theopportunity to examine and extol some of thecontent and effects of modern technology.Nevertheless, the encyclopedia is partial, and anyomissions and shortcomings are mine

Colin Hempstead

My thanks go to Gillian Lindsey for presenting mewith the challenge of filling the void left by Colin’sdeparture However, the prospect of assuming arole in a project already well under way andnatural differences in approach and style wereconcerns Nonetheless, the final third of theencyclopedia was crafted in such a way that itblends seamlessly with the sections completedunder Colin’s careful guidance This was due in

no small part to the untiring efforts of SallyBarhydt, and to her I extend sincere thanks

William E Worthington, Jr

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W.A Addis, Buro Happold, Middlesex, United

Kingdom

Aaron Alcorn, Cleveland Heights, Ohio, USA

K.W Allen, Joining Technology Research Center,

Oxford Brookes University, United Kingdom

Paul Anastas, White House Office of Science and

Technology, National Security and International

Activities Division, USA

Joe Anderson, Agricultural History and Rural

Studies Program, Iowa State University, USA

Stuart Anderson, Department of Public Health and

Policy, London School of Hygiene and Tropical

Medicine, United Kingdom

Rachel A Ankeny, Unit for History and

Philosophy of Science, University of Sydney,

Australia

Peter Asaro, Departments of Computer Science

and Philosophy, University of Illinois at

Champaign, USA

Glen Asner, Department of History, Carnegie

Mellon University, Pittsburgh, Pennsylvania,

USA

Janet Bainbridge, School of Science and

Technology, University of Teesside, and Chief

Executive of EPICC (European Process

Industries Competitiveness Centre), United

Kingdom

Guy D Ball, Product Information, Unisys, Tustin,

California, USA

Susan B Barnes, Department of Communication

and Media Studies, Fordham University, New

York, USA

Keith Bartle, Department of Chemistry, University

of Leeds, United Kingdom

Donald R Baucom, Department of Defense,

Ballistic Missile Defense Organization, USA

Reinhold Bauer, Universita¨ t der Bundeswehr

Hamburg, Germany

Joyce E Bedi, National Museum of American

History, Lemelson Center for the Study of

Invention and Innovation, USA

Randal Beeman, Archives Director, Bakersfield

College, California, USA

Hal Berghel, Department of Computer Science,University of Nevada at Las Vegas, USA.Beverly Biderman, Adaptive Technology ResourceCentre, University of Toronto, Canada

David I Bleiwas, U.S Geological Survey, Reston,Virginia, USA

F.K Boersma, Department of Culture,Organization and Management, VrijeUniversiteit Amsterdam, Netherlands

James Bohning, Center for Emeritus Scientists

in Academic Research (CESAR), LehighUniversity, Bethlehem, Pennsylvania,USA

Brian Bowers, Engineering Historian and Writer,Retired Senior Curator, Science Museum,London, United Kingdom

Hans-Joachim Braun, Universita¨ t der BundeswehrHamburg, Germany

Catherine Brosnan, United Kingdom

David J Brown, Ove Arup & Partners, London,United Kingdom

Louis Brown, Department of TerrestrialMagnetism, Carnegie Institution of Washington,USA

Nik Brown, Science and Technology Studies Unit,University of York, United Kingdom

Timothy S Brown, Department of History,Pomona College, California, USA

Robert Bud, Head of Research (Collections),Science Museum, London, United Kingdom.William L Budde, Office of Research andDevelopment, U.S Environmental ProtectionAgency

Ian Burdon, Head of Sustainable EnergyDevelopments, Energy and Utility Consulting,

PB Power Ltd., Newcastle, United Kingdom.Larry Burke, Carnegie Mellon University,Pittsburgh, Pennsylvania, USA

Russell W Burns, Retired Professor, Nottingham,United Kingdom

Michael Bussell, London, United Kingdom

J Stewart Cameron, St Thomas’ and Guy’sHospital, London, United Kingdom

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Rodney P Carlisle, History Associates

Incorporated, Rockville, Maryland, USA

Ste´phane Castonguay, De´partement des sciences

humaines, Universite´ du Que´bec a´

Trois-Rivie`res, Canada

Carol A Cheek, Rensselaer Polytechnic Institute,

Troy, New York, USA

Dennis W Cheek, John Templeton Foundation,

Radnor, Pennsylvania, USA

Mark Clark, General Studies Department, Oregon

Institute of Technology, USA

Noel G Coley, Department of the History of

Science, Technology and Medicine, Open

University, Milton Keynes, United Kingdom

Paul Collins, Ironbridge Institute, University of

Birmingham, United Kingdom

Yonina Cooper, University of Nevada at Las

Vegas, USA

Peter Copeland, National Sound Archives, British

Library, United Kingdom

Anthony Coulls, Formerly of the Museum of

Science and Industry in Manchester, United

Kingdom

Jennifer Cousineau, Charlottesville, Virginia, USA

Trevor Cox, Acoustics Research Center, University

of Salford, Greater Manchester, United

Kingdom

Jennifer Croissant, Program on Culture, Science,

Technology, and Society, University of Arizona,

USA

Donard de Cogan, School of Information Systems,

University of East Anglia, Norwich, United

Kingdom

Guillaume de Syon, Department of History,

Albright College, USA

Marc J de Vries, Philosophy and Social Sciences,

Eindhoven University of Technology,

Netherlands

Andrew Dequasie, Pownal, Vermont, USA

Maggie Dennis, National Museum of American

History, Smithsonian Institution, Washington,

D.C., USA

Panos Diamantopoulos, School of Engineering,

University of Sussex, United Kingdom

John Dolan, Retired, Nobel Division ICI, United

Kingdom

Michael Duffy, Lancashire, United Kingdom;

formerly of the Department of Engineering,

University of Sunderland

Charles Duvall, Bandwidth 9, Duluth, Georgia,

USA

Matthew Eisler, Department of History and

Classics, University of Alberta, Edmonton,

Jim Farmer, Chief Technical Officer, Wave 7Optics, Alpharetta, Georgia, USA

David L Ferro, Computer Science Department,Weber State University, Ogden, Utah, USA.Mark Finlay, Department of History, ArmstrongAtlantic State University, Savannah, Georgia,USA

Gerard J Fitzgerald, Department of History,Carnegie Mellon University, Pittsburgh,Pennsylvania, USA

Amy Foster, Ph.D Candidate, Auburn University,Alabama, USA

Philip L Frana, Charles Babbage Institute,University of Minnesota, USA

Philip J Gibbon, Temple University, Philadelphia,Pennsylvania, USA

Bruce Gillespie, Braamfontein, South Africa.Julia Chenot GoodFox, University of Kansas,USA

David Grier, Department of History, Center forHistory of Recent Science, George WashingtonUniversity, Washington, D.C., USA

Reese Griffin, 2 Stroke International Engine Co.,Beaufort, South Carolina, USA

Eric Grove, Center for Security Studies, University

of Hull, United Kingdom

David Haberstich, National Museum of AmericanHistory, Smithsonian Institution, Washington,D.C., USA

John Hamblin, Medical Doctor, Essex, UnitedKingdom

Jennifer Harrison, Department of InformationTechnology, College of William & Mary,Williamsburg, Virginia, USA

Ulf Hashagen, Deutsches Museum, Germany.Peter Hawkes, CEMES-CNRS, Toulouse, France.Stephen Healy, School of Science and TechnologyStudies, University of New South Wales,Sydney, Australia

David Healy, North Wales Department ofPsychological Medicine, University of WalesCollege of Medicine, Bangor, United Kingdom.Colin Hempstead, Darlington, United Kingdom;formerly Reader in History of Science andTechnology, University of Teesside

Martin Hempstead, Corning PhotonicsTechnology, Corning Inc., New York, USA.CONTRIBUTORS

Klaus Hentschel, Institut fu¨ r Philosophie,

University of Berne, Switzerland

Arne Hessenbruch, Dibner Institute, Massachusetts

Institute of Technology, USA

Robert D Hicks, Chemical Heritage Foundation,

Philadelphia, Pennsylvania, USA

Roger Howkins, Ove Arup & Partners, London,

United Kingdom

Peter J Hugill, Department of Geography, Texas

A&M University, USA

Merritt Ierley, Sussex, New Jersey, USA

Mary Ingram, Department of Sociology,

University of California, Santa Barbara, USA

Muzaffar Iqbal, Center for Islam and Science,

Canada

Ann Johnson, Department of History, Fordham

University, New York, USA

Sean Johnston, Science Studies, University of

Glasgow, United Kingdom

Suzanne W Junod, History Office, U.S Food and

Drug Administration

David Kaplan, Biomedical Engineering, Tufts

University, Boston, Massachusetts, USA

Christine Keiner, Science, Technology, and Society

Department, Rochester Institute of Technology,

New York, USA

Karen D Kelley, U.S Geological Survey, Reston,

Virginia, USA

David Kirsch, Smith School of Business, University

of Maryland, USA

Timothy Kneeland, Department of History and

Political Science, Nazareth College, Rochester,

New York, USA

Ramunas A Kondratas, Division of Science,

Medicine, and Society, National Museum of

American History, Smithsonian Institution,

Washington, D.C., USA

Helge Kragh, History of Science Department,

University of Aarhus, Denmark

John Krige, School of History, Technology, and

Society, Georgia Institute of Technology, USA

Alex Law, Department of Sociology, University of

Abertay, Dundee, United Kingdom

Michal Lebl, Illumina, Inc & Spyder Instruments,

Inc., San Diego, California, USA

Tim LeCain, Department of History, Montana

State University, USA

Trudy Levine, Computer Science Department,

Fairleigh Dickinson University, Teaneck, New

Juan Lucena, Liberal Arts and InternationalStudies, Colorado School of Mines, USA.Harro Maat, Technology & Agrarian Development(TAO), Wageningen University, Netherlands.Alex Magoun, Executive Director, David SarnoffLibrary, Princeton, New Jersey, USA

A.M Mannion, Department of Geography,University of Reading, United Kingdom

J Rosser Matthews, History Office, NationalInstitutes of Health, Bethesda, Maryland, USA

W Patrick McCray, Center for History of Physics,American Institute of Physics, College Park,Maryland, USA

Ian C McKay, Department of Immunology andBacteriology, University of Glasgow, UnitedKingdom

Shelley McKellar, Department of History,University of Western Ontario, London,Canada

Dennis McMullan, London, United Kingdom.Kenneth Mernitz, History and Social StudiesDepartment, Buffalo State College, New York,USA

Lolly Merrell, Paonia, Colorado, USA

Andre Millard, Department of History, University

of Alabama at Birmingham, USA

Carl Mitcham, Liberal Arts and InternationalStudies, Colorado School of Mines, USA.Susan Molyneux-Hodgson, Department ofSociological Studies, University of Sheffield,United Kingdom

Gijs Mom, Foundation for the History ofTechnology, Technical University of Eindhoven,Netherlands

John Morello, Department of General Education,DeVry Institute of Technology, Addison,Illinois, USA

Peter Morris, Science Museum, London, UnitedKingdom

Robin Morris, Retired Lecturer, West Malvern,United Kingdom

David L Morton, Tucker, Georgia, USA

Susan Mossman, Senior Curator, Science Museum,London, United Kingdom

Karel Mulder, Technology Assessment Group,Delft University of Technology, Netherlands.Peter Myers, Department of Chemistry, University

of Leeds, United Kingdom

Francis Neary, Centre for the History of Science,Technology and Medicine, University ofManchester, United Kingdom

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Caryn E Neumann, Department of History, The

Ohio State University, USA

William O’Neil, CNA Corporation, Alexandria,

Virginia, USA

Andrew Panay, Department of Sociology,

University of Abertay, Dundee, United

Kingdom

Kayhan Parsi, Neiswanger Institute for Bioethics

and Health Policy, Stritch School of Medicine,

Loyola University of Chicago, USA

Mike Pavelec, Department of History, The Ohio

State University, USA

Niocola Perrin, Nuffield Council on Bioethics,

London, United Kingdom

James Perry, Formerly Strategic Assessment

Center, SAIC, USA

John Pfotenhauer, Applied Superconductivity

Center, University of Wisconsin-Madison, USA

Robert Raikes, Meko Ltd., United Kingdom

Thomas W Redpath, Department of Biomedical

Physics and Bioengineering, University of

Aberdeen, United Kingdom

Antoni Rogalski, Institute of Applied Physics,

Military University of Technology, Warsaw,

Poland

David Rose, Retired Otorhinolaryngology

Consultancy, Stockport NHS Trust,

Manchester, United Kingdom

Paul Rosen, Department of Sociology, University

of York, United Kingdom

Robin Roy, Department of Design and Innovation,

Open University, United Kingdom

Pedro Ruiz-Castell, St Cross College, University of

Oxford, Valencia, Spain

Robert W Rydell, Department of History,

Montana State University, USA

Nicholas Saunders, London, United Kingdom

Roger Scantlebury, Integra SP, London, United

Kingdom

Jessica R Schaap, Policy and Communications,

NewMediaBC, Canada

Elizabeth Schafer, Loachapoka, Alabama, USA

Thomas Schlich, Institut fuer Geschichte der

Medizin, Albert-Ludwigs-Universitaet,

Freiburg, Germany

Jeff Schramm, History Department, University of

Missouri-Rolla, USA

Stuart Shapiro, Senior Information Security

Scientist, The MITRE Corporation, Bedford,

Massachusetts, USA

G Terry Sharrer, National Museum of American

History, Smithsonian Institution, Washington,

D.C., USA

Duncan Shepherd, School of Engineering,University of Birmingham, United Kingdom.John K Smith, Department of History, LehighUniversity, Bethlehem, Pennsylvania, USA.John S Sobolewski, Computer & InformationResearch and Technology, University of NewMexico, USA

Lawrence Souder, Department of Culture andCommunication, Drexel University,

Philadelphia, Pennsylvania, USA

James Steele, National Physical Laboratory,United Kingdom

Carlene Stephens, National Museum of AmericanHistory, Smithsonian Institution, Washington,D.C., USA

Christopher Sterling, George WashingtonUniversity, Washington, D.C., USA

Jack Stilgoe, University College London, UnitedKingdom

Anthony Stranges, Department of History, Texas A

& M University, USA

James Streckfuss, College of Evening andContinuing Education, University of Cincinnati,USA

Rick Sturdevant, HQ AFSPC/HO, Peterson,Colorado, USA

Eric G Swedin, Computer Science Department,Weber State University, Ogden, Utah, USA.Derek Taylor, Altechnica, Milton Keynes, UnitedKingdom

Ernie Teagarden, Professor Emeritus, DakotaState University, Madison, South Dakota,USA

Jessica Teisch, Department of Geography,University of California, Berkeley, USA.Thom Thomas, Halmstad University, Sweden.Lana Thompson, Florida Atlantic University, BocaRaton, USA

James E Tomayko, School of Computer Science,Carnegie Mellon University, Pittsburgh,Pennsylvania, USA

Anthony S Travis, Sidney M Edelstein Center forHistory and Philosophy, Hebrew University,Jerusalem, Israel

Simone Turchetti, Centre for History of Science,Technology and Medicine, University ofManchester, United Kingdom

Steven Turner, National Museum of AmericanHistory, Smithsonian Institution, Washington,D.C., USA

Aristotle Tympas, Department of Philosophy andHistory of Science, University of Athens,Panepistimioupolis, Greece

CONTRIBUTORS

Eric v.d Luft, Historical Collections, Health

Sciences Library, State University of New York

Upstate Medical University, Syracuse, USA

Helen Valier, Centre for History of Science,

Technology and Medicine, University of

Manchester, United Kingdom

Peter Van Olinda, Power Systems Engineer, New

York, USA

Colin Walsh, Medical Physics and Bioengineering

Department, St James’s Hospital, Dublin,

Ireland

John Ward, Senior Research Fellow, Science

Museum, London, United Kingdom

Frank Watson, Reynolds Metals Company,

Richmond, Virginia, USA

David R Wilburn, U.S Geological Survey, Reston,

Virginia, USA

Mark Williamson, Kirkby Thore, The Glebe

House, United Kingdom

Duncan Wilson, Centre for History of Science,

Technology and Medicine, University of

Manchester, United Kingdom

Frank Winter, Curator, Rocketry, National Airand Space Museum, Smithsonian Institution,Washington D.C., USA

Bob Wintermute, Scholar in Residence, ArmyHeritage Center Foundation; DoctoralCandidate, Department of History, TempleUniversity, Philadelphia, Pennsylvania, USA.Stewart Wolpin, New York, New York, USA.William E Worthington, Jr., National Museum ofAmerican History, Smithsonian Institution,Washington, D.C., USA

Jeffrey C Wynn, U.S Geological Survey, Reston,Virginia, USA

Yeang, Chen Pang, Program in Science,Technology and Society, Massachusetts Institute

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Absorbent Materials

For thousands of years, plant-derived materials

have served as the primary ingredient of absorbent

materials Jute, flax, silk, hemp, potatoes, and

primarily cotton, have been employed since

pre-Roman times These simple plant-based fibers

demonstrated molecular properties such as surface

tension and colloid attraction, but it wasn’t until

the development of the ultramicroscope in 1903

that the size and structure of molecules was better

understood and the actual chemical process of

absorption grasped The late nineteenth century

inspired a new wave of design for the specialized

applications of absorbent material—as sanitary

napkins and diapers—and eventually helped drive

innovative applications for the burgeoning fields of

organic and polymer science in the twentieth

century

The need for sterile bandages in medicineprecipitated the design of mass-producible, absor-

bent materials In 1886, the medical supply

com-pany Johnson & Johnson developed surgical

wound dressings made of heated, sterilized

absor-bent cotton with a gauze overlay to prevent fibers

sticking to wounds This design for sterile wound

dressing became a fixed part of medical treatment,

although it was still unavailable to the general

public However, as women changed their clothing

styles and became more independent, demand

increased for transportable absorbent menstrual

napkins, as well as disposable diapers In 1887 an

American, Maria Allen, created a cotton textile

diaper covered with a perforated layer of paper, to

draw blood away from the skin, with a gauze layer

stitched around it It was an improvement over the

usual washable cotton ‘‘rag’’ that was extremely

leaky (as both a sanitary napkin and a diaper)

However, it was too expensive for mass tion

produc-Johnson & produc-Johnson continued to improve onthe absorption capacity of their original bandage

They discovered that heating and compressingseveral layers of cotton together provided higherabsorption, less leakage, and less bulk in theirdressings When the Lister Towel, as it was named,became widespread in 1896, menstrual productssuch as the German-manufactured Hartman’s Padsand bolts of ‘‘sanitary’’ cotton cloth appeared incatalogs for women However, the Johnson &

Johnson product was expensive Cotton, whilereadily available, still had to be hand picked,processed and sterilized So, in 1915, anAmerican paper supply company calledKimberly–Clark developed Cellucotton, a bandagematerial that combined sterile cotton with woodpulp-derived cellulose During World War I,nurses working in Europe began to use both theLister Towel and Cellucotton as menstrual pads

By 1921, propelled by this innovative application,Kimberly–Clark manufactured Cellucotton-baseddisposable pads called Kotex Thick, with a gauzeoverlay, they employed several different securingdevices Used in diapers, Cellucotton was some-times covered by a thick rubber pant, whichinhibited evaporation and could exacerbate diaperrash and urinary tract infections in babies

‘‘Breathability’’ would become one of the lenges in the decades to come

chal-After the turn of the twentieth century, themolecular properties of most fibers were thor-oughly understood Protein fiber-based materials,such as wool, are made up of long, parallel,molecular chains connected by cross-linkages

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While able to absorb 30 percent of its weight, it

would also expel liquid readily when squeezed,

making it an unattractive menstrual or diaper

material Plant-based material such as cotton was

made up of long chains of cellulose molecules

arranged in a collapsed tube-like fiber Cotton

could easily absorb water by holding the water

molecules within the tubes and between the fibers

In addition, the shape of the fibers meant that

cotton could be easily manipulated by surfactants

and additives The rate of absorption depended

largely on the surface tension between the

absor-bent material, and the fluid it was absorbing

Manipulating surface tension would become an

element of future products

For the first half of the twentieth century,

absorbent materials varied little, but design

chan-ged dramatically Tampons, available for

millen-nia, now incorporated the new cotton-hybrid

materials and by 1930 appeared widely on the

market In 1936, Dr Earle C Haas, an American

physician, created and earned a patent for a

cardboard tampon applicator Soon thereafter,

his product became the first Tampax brand

tampon and was sold by Tambrands

By 1938, American chemist Wallace Hume

Carothers of the DuPont Company had helped

create nylon, the first polymer textile, and it was

soon included as a barrier to prevent leakage In

1950, American housewife Marion Donovan

created a plastic envelope from a nylon shower

curtain that was perforated on one side and filled

with absorbent cotton gauze By 1973, scientists

working at the Illinois-based National Center for

Agricultural Utilization Research invented

H-Span They combined synthetic chemicals with

cornstarch to create a uniquely absorbent polymer

of hydrolyzed starch called polyacrylonitrile The

‘‘Super Slurper,’’ as it became known, was capable

of absorbing up to 5,000 times its weight in water

In a dry powdered state, the polymer chains are

coiled and then treated with carboxylate to initiate

a faster colloid transfer of water molecules to the

starch

Soon afterwards, ‘‘superthirsty’’ fibers appeared

in absorbent products around the world By the

late 1970s, disposable diapers included a layer of

some sort of highly absorbent fibers, covered with

a lightweight plastic or nylon shell that allowed for

more evaporation without leakage The

American-based company Procter & Gamble introduced a

‘‘superthirsty’’ synthetic material, made up of

carboxymethylcellulose and polyester, into their

tampons The product, named Rely, far surpassed

the absorbency of other competing tampons

Under competitive pressure, Tambrands andPlaytex both produced versions of superthirstytampons using derivatives of polyacrylate fibers

Diaper designs began to include conveniencefeatures such as refastenable tapes, elastic legs,barrier leg cuffs, elasticized waistbands, and ‘‘fit’’

guides to guarantee less leakage The popularcreped cotton tissue interior was replaced withdenser cellulose-fiber mats, utilizing a highlyabsorbent cotton treated with a surfactant toencourage rapid absorption by increasing the sur-face tension between water molecules and cotton

Research continued and resulted in a new wave

of polymer-manipulated superabsorbers, namelyhydrophilic cross-linked polymers Incorporating athree-dimensional polymeric structure, this mate-rial did not dissolve in water and could absorb inthree dimensions By 1980, Japanese scientistscreated the first disposable diaper incorporating asuperabsorbent polymer Procter & Gamble soondeveloped ‘‘ultra thin’’ pads using a crystallinepolymer layer that would gel when it absorbedwater This design also included a ‘‘Dri-Weave’’

top sheet, separating the wearer from the ent layer and using a capillary-like, nonwovenmaterial to inhibit a reverse flow

absorb-In the late 1970s, a dramatic increase in cases oftoxic shock syndrome appeared among users ofsuperabsorbent tampons Eventually, the ‘‘super-thirsty’’ absorbent was found to encourage growth

of the bacteria Staphyloccocus aureus In the early1980s more health problems seemed to be linked toimprovements in absorption, and by 1986Tambrands and Playtex had removed their poly-acrylate tampons from the market Six years laterthe U.S Food and Drug Administration reportedthat trace amounts of dioxin used to bleach andsterilize cotton components of pads, tampons, anddiapers could cause birth defects and possiblycancer

At the beginning of the twenty-first century,pads were comprised of anything from an absor-bent, compressed cotton and cellulose-pulp core, aplastic moisture-proof liner, a soft nonwoventextile for drawing moisture away from the skin(like viscose rayon and cotton blend), and chemi-cals such as polyacrylates to prevent leakage andkeep the product from falling apart Scientistsworking for the U.S Department of Agriculturehad discovered that the cellulose properties ofground chicken feathers could be manipulated andused as an absorbent material, utilizing billions oftons of discarded poultry-plant waste The fibersare straight polymer chains—like cotton—makingthem highly absorbent Internationally, the use ofABSORBENT MATERIALS

tampons, disposable diapers, and sanitary napkins

is still largely reserved for developed countries

However, as more innovative techniques reduce the

reliance on expensive imported products (e.g., bird

feathers), the convenience of absorbent technology

may stretch beyond current economic, cultural,

and geographic borders

See also Fibers; Synthetic; Semi-Synthetic

LOLLYMERRELL

Further Reading

Asimov, I New Guide to Science New York, 1994,

533–550.

Gutcho, M Tampons and Other Catamenial Receptors.

Noyes Data Corporation, Park Ridge, NJ, 1979.

Hall, A Cotton-Cellulose: Its Chemistry and Technology E.

Benn, London, 1924.

Park, S The Modern and Postmodern Marketing of

Menstrual Products J Pop Cult., 30, 149, 1996.

Swasy, A Soap Opera Times Books, New York, 1993.

Activated carbon is made from any substance with

a high carbon content, and activation refers to the

development of the property of adsorption

Activated carbon is important in purification

processes, in which molecules of various

contami-nants are concentrated on and adhere to the solid

surface of the carbon Through physical

adsorp-tion, activated carbon removes taste and

odor-causing organic compounds, volatile organic

com-pounds, and many organic compounds that do not

undergo biological degradation from the

atmo-sphere and from water, including potable supplies,

process streams, and waste streams The action can

be compared to precipitation Activated carbon is

generally nonpolar, and because of this it adsorbs

other nonpolar, mainly organic, substances

Extensive porosity (pore volume) and large

avail-able internal surface area of the pores are

respon-sible for adsorption

Processes used to produce activated carbonswith defined properties became available only after

1900 Steam activation was patented by R von

Ostreijko in Britain, France, Germany, and the

U.S from 1900 to 1903 When made from wood,

the activated carbon product was called Eponite

(1909); when made from peat, it was called Norit

(1911) Activated carbon processes began inHolland, Germany, and the U.S., and the productswere in all cases a powdered form of activatedcarbon mainly used for decolorizing sugar solu-tions This remained an important use, requiringsome 1800 tons each year, into the twenty-firstcentury

In the U.S., coconut char activated by steamwas developed for use in gas masks during WorldWar I The advantage of using coconut shell wasthat it was a waste product that could be converted

to charcoal in primitive kilns at little cost By 1923,activated carbon was available from black ash,paper pulp waste residue, and lignite In 1919, theU.S Public Health Service conducted experiments

on filtration of surface water contaminated withindustrial waste through activated carbon At first,cost considerations militated against the wide-spread use of activated carbon for water treatment

It was employed at some British works before

1930, and at Hackensack in New Jersey From thattime there was an interest in the application ofgranular activated carbon in water treatment, andits subsequent use for this purpose grew rapidly Asimproved forms became available, activated car-bon often replaced sand in water treatment wherepotable supplies were required

Coal-based processes for high-grade adsorbentrequired for use in gas masks originally involvedprior pulverization and briquetting under pressure,followed by carbonization, and activation Theprocess was simplified after 1933 when the BritishFuel Research Station in East Greenwich, at therequest of the Chemical Research DefenceEstablishment, began experiments on direct pro-duction from coke activated by steam at elevatedtemperatures In 1940, Pittsburgh Coke & IronCompany, developed a process for producinggranular activated carbon from bituminous coalfor use in military gas masks During World War

II, this replaced the coconut char previouslyobtained from India and the Philippines Thelarge surface area created by the pores and itsmechanical hardness made this new materialparticularly useful in continuous decolorizationprocesses The Pittsburgh processes developed bythe Pittsburgh Activated Carbon Company wereacquired in 1965 by the Calgon Company In latetwentieth century processes, carbon was crushed,mixed with binder, sized and processed in low-temperature bakers, and subjected to high tem-peratures in furnaces where the pore structure ofthe carbon is developed The activation process can

be adjusted to create pores of the required size for aparticular application Activation normally takes

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place at 800–900
C with steam or carbon dioxide

Powdered activated carbon is suitable for liquid

and flue gas applications—the granulated form for

the liquid and gas phases, and pelleted activated

carbon for the gas phase Granulated activated

carbon is used as a filter medium for contaminated

water or air, while the powdered form is mixed into

wastewater where it adsorbs the contaminants and

is later filtered or settled from the mixture

Activated carbon has also been used in chemical

analysis for prior removal and concentration of

contaminants in water Trade names for activated

carbon used in these processes are Nuchar and

Darco

Activated carbon has been used in the

large-scale treatment of liquid waste, of which the

effluent from the synthetic dye industry is a good

example Synthetic dye manufacture involves

reac-tions of aromatic chemicals, and the reactants and

products are sometimes toxic In addition to an

unpleasant taste and odor imparted to water, this

waste is also highly colored, complex, and

invari-ably very difficult to degrade Fortunately, many of

the refractory aromatic compounds are nonpolar,

the property that permits adsorption onto

acti-vated carbon In the 1970s, three large dye-making

works in New Jersey used activated carbon to

remove aromatics and even trace metals such as

toxic lead and cadmium from liquid waste In two

cases, powdered activated carbon was added to the

activated sludge treatment process to enhance

removal of contaminants In a third case, following

biological treatment, the liquid effluent was

adsorbed during upward passage in towers packed

with granular activated carbon The spent carbon

from this continuous process was regenerated in a

furnace, and at the same time the adsorbed waste

solute was destroyed

In 1962, Calgon utilized activated granular

carbon for treating drinking water, and at the

end of the twentieth century, municipal water

purification had become the largest market for

activated carbon The older methods that involved

disposal of spent carbon after use were replaced by

the continuous processes using granulated

acti-vated carbon By continuous reuse of the

regener-ated activregener-ated carbon, the process is ecologically

more desirable Apart from the inability to remove

soluble contaminants (since they are polar) and the

need for low concentrations of both organic and

inorganic contaminants, the cost of the carbon is

the greatest limitation in the continuous process

Activated carbon also found wide application in

the pharmaceutical, alcoholic beverage, and

elec-troplating industries; in the removal of pesticides

and waste of pesticide manufacture; for treatment

of wastewater from petroleum refineries and textilefactories; and for remediation of polluted ground-water Although activated carbons are manufac-tured for specific uses, it is difficult to characterizethem quantitatively As a result, laboratory trialsand pilot plant experiments on a specific waste typenormally precede installation of activated carbonfacilities

See also Green Chemistry; Technology, Society, andthe Environment

A Brief History of Activated Carbon and a Summary

of its Uses: http://www.cee.vt.edu/program_areas/

environmental/teach/gwprimer/group23/achistory.html Calgon Carbon, Company History: http://www.calgoncarbon.

com/calgon/calgonhistory.html Chemviron Carbon: http://www.chemvironcarbon.com/

activity/what/history/menu.htm

Adhesives

Adhesives have been used for about six millennia,but it was only from the first decade of thetwentieth century that any significant developmenttook place, with the introduction of syntheticmaterials to augment earlier natural materials

The driving force for development has been theneeds of particular industries rather than techno-logical advances themselves The introduction ofsynthetic resins began in about 1909, but althoughthe growth in plywood manufacture was acceler-ated by World War I, little innovation wasinvolved Significant advances began with WorldWar II and the development of epoxy and urea/

formaldehyde adhesives for the construction ofwooden aircraft, followed by the phenol/formalde-hyde/polyvinyl formal adhesives for bonding alu-minum, which cannot generally be welded Later,adhesive bonding in conjunction with riveting wasapplied to automobile construction, initially tohigh-performance models but increasingly to mass-produced vehicles The fastening of compositematerials is, with few exceptions, accomplished

by use of adhesives

ADHESIVES

If the forces of adhesion are to be effective,intimate contact must be established between two

components, one of them a liquid that will wet and

flow across the other before solidifying so that the

bond can resist and transmit any applied force

This change of phase from liquid to solid is

achieved in a variety of ways

Solution-Based Adhesives

The earliest adhesives were all natural products

such as starch and animal protein solutions in

water These are still in use for applications where

only low strength is required (e.g., woodworking or

attaching paper and similar materials).In these

cases, the cost has to be low because the uses are

high volume Until about 1930 these were the main

adhesives used in all carpentry and furniture

Polyvinyl acetate adhesives are now probably the

most important range of water-based adhesives

The base polymer is dispersed in water to give an

emulsion that has to be stabilized, usually with

approximately 5 percent polyvinyl alcohol

Solutions in organic solvents were first duced in 1928, and they are now perhaps the most

intro-widely used adhesives both for manufacturing and

for do-it-yourself purposes Based on solutions of

polychloroprene as base polymer dissolved in

organic solvents, they provide a fairly strong

‘‘quick-stick’’ bond Particular grades are

exten-sively used in the footwear industry Because of the

toxic, environmentally unfavorable properties of

the solvents, considerable efforts are being devoted

to replacing these with water-based products, but

these have not yet been entirely satisfactory

Hot-Melt Adhesives

One of the oldest types of adhesive is sealing wax

Since about 1960, these hot-melt adhesives have

been introduced initially for large-scale industrial

use and more recently for small-scale and

do-it-yourself uses Polyethylene is extensively used as

the base for hot-melt adhesives since it is widely

available in a range of grades and at low cost

Ethylene vinyl acetate is similarly a useful base,

and the two are commonly used in combination to

give effective adhesives with application

tempera-tures in the range of 160–190
C This means that

the adhesives have an upper limit of service use of

perhaps 140
C, and the materials being joined

must be able to withstand the higher temperature

These adhesives are quite widely used in large-scale

manufacturing However there are a considerable

number of applications where the temperature

involved for normal hot-melt adhesives is

exces-sive Consequently, in the 1990s a group of specialformulations evolved that have an applicationtemperature in the range of 90 to 120
C withoutany loss of adhesive strength The most recentdevelopments are adhesives that are applied as hot-melts and are then ‘‘cured’’ by various means Theyhave all the advantages of ease of application andquick achievement of useful strength supplemented

by a much higher service temperature Curing may

be achieved either by heating to a higher ture than that of application or by irradiation with

tempera-an electron beam

Reactive AdhesivesReactive adhesives include epoxides, urethanes,phenolics, silicones, and acrylates

Epoxides Introduced in the early 1940s, thesedepend on three-membered epoxy or oxirane rings

at the end of carbon chains with pendant hydroxylgroups, all of which react with various secondcomponents to produce thermoset polymers Thesecond components are principally amines or acidanhydrides Generally the epoxides give bonds ofconsiderable strength and durability, but untilrecently they tended to be too brittle for manypurposes Developments beginning in the 1970shave enhanced the toughness of these and otherstructural adhesives

Urethanes These involve the reaction of anisocyanate with an organic compound containing

a hydroxyl group Like the epoxides, variation ofthe properties of the final polymer can readily becontrolled with two ingredients to give a productthat may be an elastomer, a foam, or one that isstiff and bristle-like Urethanes are increasinglyused in a wide variety of situations

Phenolics The phenolics group of adhesivesincludes two that are somewhat different in theiruses The first, urea/formaldehyde formulations,were developed in the 1920s and 1930s and aremainly significant in the manufacture of plywoodand similar products The second group is phenol/

polyvinyl formal formulations mainly used inaircraft construction for bonding aluminum anddeveloped during World War II Phenolics allinvolve curing under considerable pressure at anelevated temperature, typically 1500
C for 30minutes at a pressure of 10 atmospheres for anaircraft adhesive The bonds are of considerablestrength and durability, suitable for primary air-craft structures

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Silicones Silicones, generally silicone (or

silox-ane) rubbers, are largely used as sealants that

combine adhesion with their gap-filling

character-istics Commonly used for sealing around baths

and similar fittings, they cure by reaction with

moisture from the environment Industrially,

par-ticularly in automobile construction, there are

many situations where providing a bond of

moderate strength together with filling a gap

between parts, which may amount to several

in thread locking in machinery and in thesecuring of coaxial joints

2 Cyanoacrylates, or ‘‘super glues,’’ weredeveloped in 1957 They are colorless, verymobile liquids derived from cyanoacrylicacid They readily polymerize, particularly

in conjunction with the imperceptible film ofmoisture that is invariably present on sur-faces The bonds are very susceptible toattack by water and are only stable belowabout 80
C Nevertheless, they are exten-sively used in product assembly in theelectronics industry where they are likely to

be exposed to only benign conditions

3 Reactive acrylics (sometimes called ‘‘secondgeneration’’ acrylates, developed in 1975)depend upon a polymerization reaction thatfollows a free radical path This means thatthe ratio of the two components is relativelyunimportant, so careful control of quanti-ties is unnecessary In parallel with thedevelopment of this system, a techniquewas perfected for increasing the toughness

of the cured adhesive by incorporatingminute particles of rubber The adhesive is

in two parts: a viscous gel and a mobileliquid These two are spread one on eachside of the joint When the two are broughttogether, they react quickly to give a strongbond, which is handleable in 2 to 3minutes, with full working strength in 1hour and ultimate strength in 24 hours

These adhesives not only give a strongbond of high toughness very quickly, they

are also able to contend with oily surfaces

They provide an exceedingly satisfactoryproduct that meets a number of require-ments in advanced assembly, especiallywithin the automobile industry

4 A series of acrylic adhesives has beenproduced which are cured by irradiationwith ultraviolet light Clearly they can only

be used where the radiation can reach theadhesive; for example, where one component

is transparent to the UV wavelength While

a considerable range of these products hasbeen developed, very little information hasbeen released about their composition

High-Temperature AdhesivesAll the adhesives considered so far can onlyprovide useful bonds up to very limited tempera-tures, commonly 100
C or perhaps 150
C Thereare demands, mainly military, for bonds that canwithstand up to 300
C To meet these needs, someadhesive base polymers have been developed thatare based on carbon and nitrogen ring systemswith a limited service life at these high tempera-tures

Pressure-Sensitive AdhesivesPressure-sensitive adhesives (e.g., Scotch Tape, firstsold in 1940) are totally different from any others

These adhesives depend on an exceedingly viscosity liquid that retains this state throughout itslife and never cross-links or cures The strength ofthe bond is dependent on the pressure applied to it

high-as the bond is made The useful life of sensitive adhesives is generally limited to perhapsone or two years

Agriculture and Food

In late-twentieth century Western societies, food

was available in abundance Shops and

super-markets offered a wide choice in products and

brands The fast-food industry had outlets in every

neighborhood and village For those in search of

something more exclusive, there were smart

restau-rants and classy catering services People chose

what they ate and drank with little awareness of

the sources or processes involved as long as the

food was tasty, nutritious, safe, and sufficient for

everyone These conditions have not always been

met over the last century when food shortages

caused by economic crises, drought, or armed

conflicts and war, occurred in various places

During the second half of the twentieth century,

food deficiency was a feature of countries outside

the Western world, especially in Africa The

twentieth century also witnessed a different sort

of food crisis in the form of a widespread concern

over the quality and safety of food that mainly

resulted from major changes in production

pro-cesses, products, composition, or preferences

Technology plays a key role in both types of crises,

as both cause and cure, and it is the character of

technological development in food and agriculture

that will be discussed The first section examines

the roots of technological developments of modern

times The second is an overview of three patterns

of agricultural technology The final two sections

cover developments according to geographical

differences

Before we can assess technological ments in agriculture and food, we must define the

develop-terms and concepts A very broad description of

agriculture is the manipulation of plants and

animals in a way that is functional to a wide

range of societal needs Manipulation hints at

technology in a broad sense; covering knowledge,

skills, and tools applied for production and

consumption of (parts or extractions of) plants

and animals Societal needs include the basic

human need for food Many agricultural products

are food products or end up as such However,

crops such as rubber or flax and animals raised

for their skin are only a few examples of

agricultural products that do not end up in the

food chain Conversely, not all food stems from

agricultural production Some food is collected

directly from natural sources, like fish, and there

are borderline cases such as beekeeping Some

food products and many food ingredients are

artificially made through complicated biochemical

processes This relates to a narrow segment

of technology, namely science-based food nology

tech-Both broad and narrow descriptions of ture are relevant to consider In sugar productionfor example, from the cultivation of cane or beets

agricul-to the extraction of sugar crystals, both traditionaland science-based technologies are applied

Moreover, chemical research and developmentresulted in sugar replacements such as saccharinand aspartame Consequently, a randomly chosensoft drink might consist of only water, artificialsweeteners, artificial colorings and flavorings, andalthough no agriculture is needed to produce suchproducts, there is still a relationship to it One canimagine that a structural replacement of sugar byartificial sweeteners will affect world sugar pricesand therewith the income of cane and beet sugarproducers Such global food chains exemplify thecomplex nature of technological development infood and agriculture

The Roots of Technological DevelopmentScience-based technologies were exceptional inagriculture until the mid-nineteenth century

Innovations in agriculture were developed andapplied by the people cultivating the land, andthe innovations related to the interaction betweencrops, soils, and cattle Such innovation is exem-plified by farmers in Northern Europe who con-fronted particular difficulties caused by the climate

Low temperatures meant slow decomposition oforganic material, and the short growing seasonmeant a limited production of organic material to

be decomposed Both factors resulted in slowrecuperation of the soil’s natural fertility afterexploitation The short growing season also meantthat farmers had to produce enough for the entireyear in less than a year Farmers therefore devel-oped systems in which cattle and other livestockplayed a pivotal role as manure producers forfertilizer Changes in the feed crop could allow anincrease in livestock, which produced more manure

to be used for fertilizing the arable land, resulting

in higher yields Through the ages, farmers inNorthern Europe intensified this cycle From aboutthe 1820s the purchase of external suppliesincreased the productivity of farming in thetemperate zones Technological improvementsmade increases in productivity not only possiblebut also attractive, as nearby markets grew anddistant markets came within reach as a result of thenineteenth century transportation revolution

An important development at mid-nineteenthcentury was the growing interest in applying

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science to agricultural development The two

disciplines with the largest impact were chemistry

and biology The name attached to agricultural

chemistry is Justus von Liebig, a German chemist

who in the 1840s formulated a theory on the

processes underlying soil fertility and plant growth

He propagated his organic chemistry as the key to

the application of the right type and amount of

fertilizer Liebig launched his ideas at a time when

farmers were organizing themselves based on a

common interest in cheap supplies The synergy of

these developments resulted in the creation of

many laboratories for experimentation with these

products, primarily fertilizers During the second

half of the nineteenth century, agricultural

experi-ment stations were opened all over Europe and

North America

Sometime later, experimental biology became

entangled with agriculture Inspired by the ideas

of the British naturalist Charles Darwin,

biolo-gists became interested in the reproduction and

growth of agricultural crops and animals Botany

and, to a lesser extent, zoology became important

disciplines at the experimental stations or

pro-vided reasons to create new research laboratories

Research into the reproductive systems of

differ-ent species, investigating patterns of inheritance

and growth of plant and animal species, and

experimentation in cross-breeding and selection

by farmers and scientists together lay the

founda-tions of genetic modification techniques in the

twentieth century

By the turn of the century, about 600

agricul-tural experiment stations were spread around the

Western world, often operating in conjunction with

universities or agricultural schools Moreover,

technologies that were not specifically developed

for agriculture and food had a clear impact on the

sector Large ocean-going steamships, telegraphy,

railways, and refrigeration, reduced time and

increased loads between farms and markets Key

trade routes brought supplies of grain and other

products to Europe from North America and the

British dominions, resulting in a severe economic

crisis in the 1880s for European agriculture Heat

and power from steam engines industrialized food

production by taking over farm activities like

cheese making or by expanding and intensifying

existing industrial production such as sugar

extrac-tion The development of synthetic dyes made

crop-based colorants redundant, strongly reducing

or even eliminating cultivation of the herb madder

or indigo plants These developments formed the

basis of major technological changes in agriculture

and food through the twentieth century

Patterns of Technology DevelopmentThe twentieth century brought an enormousamount of technology developed for and applied

to agriculture These developments may be ined by highlighting the patterns of technology inthree areas—infrastructure, public sector, andcommercial factory—as if they were seen in crosssection The patterns are based on combinedmaterial and institutional forces that shapedtechnology

exam-A major development related to infrastructureconcerns mechanization and transport The com-bustion engine had a significant effect on agricul-ture and food Not only did tractors replace animaland manual labor, but trucks and buses alsoconnected farmers, traders, and markets Thedevelopment of cooling technology increased sto-rage life and the distribution range for freshproducts Developments in packaging in generalwere very important It was said that World War Iwould have been impossible without canned food

Storage and packaging is closely related to hygiene

Knowledge about sources and causes of decay andcontamination initiated new methods of safehandling of food, affecting products and trade aswell as initiating other innovations In the dairysector, for example, expanding markets led to thegrowth and mergers of dairy factories Thatchanged the logistics of milk collection, resulting

in the development of on-farm storage tanks

These were mostly introduced together with pression and tube systems for machine milking,which increased milking capacity and improvedhygiene conditions A different area of infrastruc-ture development is related to water management

com-Over the twentieth century, technologies for tion and drainage had implications for improved

irriga-‘‘carrying capacity’’ of the land, allowing the use ofheavy machinery Improved drainage also meantgreater water discharge, which in turn requiredwider ditches and canals Water control also hadimplications for shipping and for supplies ofdrinking water that required contractual arrange-ments between farmers, governing bodies, andother agencies

During the twentieth century, most governmentssupported their agricultural and food sectors Theoverall interest in food security and food safetymoved governments to invest in technologies thatincreased productivity and maintained or im-proved quality Public education and extensionservices informed farmers about the latest methodsand techniques Governments also became directlyinvolved in technological development, most nota-bly crop improvement Seed is a difficult product toAGRICULTURE AND FOOD