Intensive Property

3 Key excerpts on "Intensive Property"

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  Fundamentals of Modern Manufacturing

  Materials, Processes, and Systems

  • Mikell P. Groover(Author)
  • 2019(Publication Date)
  • Wiley

    (Publisher)

  For example, thermal properties of the work material in machining determine the cutting temperature, which affects how long the tool can be used before it fails. In microelectronics, electrical properties of silicon and the way in which these properties can be altered by various chemical and physical processes comprise the basis of semiconductor manufacturing. This chapter covers the physical properties that are most important in manufacturing—properties that are encountered in subsequent chapters of the book. They are divided into major categories such as volumetric, thermal, electrical, and so on. Also, as in the previous chapter on mechanical proper- ties, the importance of these properties in manufacturing is discussed. 4.1 Volumetric and Melting Properties These properties are related to the volume of solids and how they are affected by temperature. The properties include density, thermal expansion, and melting point. They are explained in the follow- ing, and typical values for selected engineering materials are presented in Table 4.1. 4.1.1 | DENSITY In engineering, the density of a material is its mass per unit volume. Its symbol is ρ, and typical units are g/cm 3 (lbm/in 3 ). The density of an element is determined by its atomic number and other factors such as atomic radius and atomic packing. The term specific gravity expresses the density of a mate- rial relative to the density of water and is therefore a ratio with no units. Density is an important consideration in the selection of a material for a given application, but it is generally not the only property of interest. Strength is also important, and the two properties are often related in a strength-to-weight ratio, which is the tensile strength of the material divided by its density. The ratio is useful in comparing materials for structural applications in aircraft, automo- biles, and other products in which weight and energy are of concern.

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  eBook - PDF

  Fundamentals of Chemical Engineering Thermodynamics, SI Edition

  • Kevin Dahm, Donald Visco(Authors)
  • 2014(Publication Date)
  • Cengage Learning EMEA

    (Publisher)

  Conversely, the mass and volume of water are examples of extensive properties; they are directly proportional to the number of moles of water present. Examples 4-2 and 4-3 will give an illustration of two very different paths from the same initial state to the same final state. Specific internal energy is an example of an Intensive Property, which is discussed further in the next section. The word “extensive” shares a root with the word “extend.” You might say that as the amount of a material extends (gets larger) the extensive proper-ties change, but the intensive properties do not. Copyright 2015 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 55 C H A P T E R 2 The Physical Properties of Pure Compounds The distinction between intensive and extensive properties is important, because intensive properties are fundamental and repeatable properties of a mate-rial, while extensive properties only can be used to describe a particular sample of a material. For example, if told “the mass of the water is 1 kg,” the value of 1 kg is an extensive property that is applicable only to that particular sample of water. But “the density of water at T 5 323.15 K and P 5 0.1 MPa is 988 kg/m 3 ” is an Intensive Property and is valid for any system or process involving water at that T and P . The relationship among the temperature, pressure, and density of pure liquid water is illustrated in Table 2-2. Notice that, if any two of these properties are known, there is only one value the third can have, and it can be determined from the table.

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  Manufacturing Technology

  Materials, Processes, and Equipment

  • Helmi A. Youssef, Hassan A. El-Hofy, Mahmoud H. Ahmed(Authors)
  • 2011(Publication Date)
  • CRC Press

    (Publisher)

  15 2 Properties of Engineering Materials 2.1 INTRODUCTION Every.engineer.should.be.vitally.concerned.with.the.materials.available.to.him . .Whether.the.prod-uct.under.consideration.is.a.bridge,.a.computer,.a.machine.tool,.or.an.automobile.exhaust.system,. he. must. have. an. intimate. knowledge. of. the. properties. and. characteristics. of. the. material. from. which.the.product.is.to.be.designed.to.function.satisfactorily . .In.making.his.choices,.the.designer. must.take.into.account.such.properties.as.strength,.rigidity,.hardness,.toughness,.electrical.and/or. thermal.conductivity,.density,.and.others . .Furthermore,.he.must.consider.the.material.behavior.dur-ing.processing,.such.as.formability,.machinability,.electrical.and.thermal.stability,.as.well.as.cost. and.availability . .Finally,.the.engineer.must.know.which.of.the.properties.are.significant,.how.these. properties.are.determined,.and.what.restrictions.should.be.placed.on.their.use . The.following.discussion.of.the.properties.of.engineering.materials.will.be.introductory.only . . Its.purpose.will.be.to.identify.the.more.common.properties.in.order.to.compare.between.different. materials.or.different.structures.of.the.same.material . .Three.general.types.of.properties.are.physi-cal,.mechanical,.and.manufacturing.(fabricating) . 2.2 PHYSICAL PROPERTIES A.common.means.of.distinguishing.one.material.from.another.is.by.evaluating.physical.properties . . Physical.properties.of.particular.interest.are.density,.thermal.properties,.electrical.and.magnetic. properties,.optical.properties,.chemical.properties,.and.resistance.to.oxidation.and.corrosion . .For. some.engineering.applications,.the.physical.properties.of.an.engineering.material.may.be.even.more. important.than.mechanical.properties . . For. this. reason,. it. is. essential. to. discuss. some. important. physical.properties.briefly . 2.2.1 D ENSITY The.density.of.a.material.is.the.mass.per.unit.volume .

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