Materials Cycle and Environmental Impacts
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Questions and Answers

What is the first stage of the materials cycle?

  • Recycling and reuse
  • Raw materials extraction (correct)
  • Product design and manufacture
  • Consumer usage

    • Which of the following is NOT considered an engineered material?

  • Cement (correct)
  • Metal alloys
  • Ceramic powders
  • Plastics

    • What happens to products after they become obsolete according to the materials cycle?

  • They are reused indefinitely
  • They are always recycled
  • They may be recycled or disposed of as waste (correct)
  • They are permanently destroyed

    • How much energy consumed by manufacturing industries in the United States goes to produce and fabricate materials?

    <p>About one-half</p> Signup and view all the answers

    Which of the following accurately describes the earth's resource situation?

    <p>Resources are virtually a closed system and finite</p> Signup and view all the answers

    What role do raw materials play in the materials cycle?

    <p>They are extracted and transformed into various forms</p> Signup and view all the answers

    Approximately how many tons of raw materials are extracted worldwide each year?

    <p>15 billion tons</p> Signup and view all the answers

    What is a consequence of increasing population relative to resource availability?

    <p>Resources grow scarcer, demanding better utilization</p> Signup and view all the answers

    What is a significant consequence of the extraction of raw materials?

    <p>Ecological damage and landscape spoilage</p> Signup and view all the answers

    Why is recycling considered a desirable approach in the materials cycle?

    <p>It reduces the extraction of raw materials</p> Signup and view all the answers

    What impact does manufacturing a 'green' product have on costs?

    <p>It often raises manufacturing costs</p> Signup and view all the answers

    How does the energy requirement for recycling aluminum compare to refining natural aluminum ores?

    <p>Recycling requires significantly less energy</p> Signup and view all the answers

    What role do governmental regulatory agencies play in environmental issues?

    <p>They establish environmental standards</p> Signup and view all the answers

    What is a critical consideration when designing end-of-life products?

    <p>Ensuring minimal impact on the environment</p> Signup and view all the answers

    What happens during the synthesis and processing stage of materials cycle?

    <p>Pollutants may be expelled into the environment</p> Signup and view all the answers

    What happens to the quality of alloys with each recycling cycle?

    <p>It diminishes.</p> Signup and view all the answers

    Which of the following is NOT directly associated with recycling?

    <p>Increasing the need for raw material extraction</p> Signup and view all the answers

    Which joining method is preferred when joining two similar alloys?

    <p>Welding</p> Signup and view all the answers

    What is a significant barrier to recycling glass?

    <p>The requirement for sorting salvaged glass.</p> Signup and view all the answers

    What characteristic of aluminum alloys contributes to their recyclability?

    <p>They are nonbiodegradable.</p> Signup and view all the answers

    What is the primary reason for the low market value of scrap glass?

    <p>The cost of production of new glass is low.</p> Signup and view all the answers

    What is one application of recycled rubber tires?

    <p>Automotive bumper guards</p> Signup and view all the answers

    What are aluminum alloys primarily derived from?

    <p>Used beverage cans.</p> Signup and view all the answers

    Which type of contamination can hinder the recycling of alloys?

    <p>Coatings such as paints.</p> Signup and view all the answers

    What complicates the recycling of composite materials?

    <p>Their multiphase composition</p> Signup and view all the answers

    Which process is the first step in recycling thermoset- and thermoplastic-matrix composites?

    <p>Shredding/grinding</p> Signup and view all the answers

    Which of the following is NOT an advantage of using recycled glass?

    <p>Lower costs of raw materials.</p> Signup and view all the answers

    What happens to the fibers during the recycling of composites?

    <p>They shorten and lose mechanical strength</p> Signup and view all the answers

    In recycling composites, what is sometimes recovered from the matrix material?

    <p>Monomers</p> Signup and view all the answers

    What is one of the uses of ground rubber particles?

    <p>Filler materials for polymers</p> Signup and view all the answers

    What is the primary challenge in recycling polymer-matrix composites?

    <p>Intermixing of materials on a fine scale</p> Signup and view all the answers

    What advantage does recycled rubber provide compared to its disposal as waste?

    <p>Reduced raw material usage</p> Signup and view all the answers

    What does life cycle analysis/assessment primarily focus on?

    <p>Assessing environmental impact from material extraction to disposal</p> Signup and view all the answers

    Which characteristic is associated with an ideal material from an environmental perspective?

    <p>It should be either recyclable or biodegradable.</p> Signup and view all the answers

    What role does materials science and engineering play in recycling?

    <p>It influences the recyclability and disposability of materials during design.</p> Signup and view all the answers

    What is a characteristic of recyclable materials?

    <p>They can be reused indefinitely after proper reprocessing.</p> Signup and view all the answers

    Why are some metals considered hazardous when land-filled?

    <p>They can leach toxic elements into the soil and water.</p> Signup and view all the answers

    What does the term

    <p>It covers the entire life of a product, including disposal.</p> Signup and view all the answers

    Which of the following best describes biodegradable materials?

    <p>They can break down naturally and return to their original state.</p> Signup and view all the answers

    During materials selection, which criterion is significant for environmental impact?

    <p>The recyclability and disposability of the materials.</p> Signup and view all the answers

    What is the primary reason synthetic polymers are popular as engineering materials?

    <p>They exhibit chemical and biological inertness.</p> Signup and view all the answers

    Why are biodegradable polymers not widely used?

    <p>They are relatively expensive to produce.</p> Signup and view all the answers

    What is a common application for recycled plastics?

    <p>Shoe soles and tool handles.</p> Signup and view all the answers

    What complicates plastics recycling?

    <p>The degradation of properties with each recycle.</p> Signup and view all the answers

    Which type of polymer is most amenable to recycling?

    <p>Thermoplastic polymers.</p> Signup and view all the answers

    What is a major source of nonbiodegradable rubber waste in the United States?

    <p>Discarded automobile tires.</p> Signup and view all the answers

    How are some thermoset resins recycled?

    <p>By grinding up and adding to virgin material.</p> Signup and view all the answers

    What is a negative aspect of burning rubber waste for disposal?

    <p>It results in dirty emissions.</p> Signup and view all the answers

    Study Notes

    Materials Cycle

    • Materials pass through various stages in a technology-economy-environment scheme
    • The "materials cycle" or "cradle-to-grave" life cycle of a material is depicted in Figure 23.1
    • Raw materials are extracted from the Earth (mining, drilling, harvesting)
    • Raw materials are purified, refined and converted into bulk forms
    • "Engineered materials" (metal alloys, ceramics, plastics, etc) are created from the transformed bulk raw materials
    • Materials are shaped, treated and assembled into products
    • Consumers use products, and they are discarded
    • Discarded materials can be recycled/reused, incinerated or disposed of as waste in landfills

    Environmental Impacts

    • Extraction of materials can damage the environment and landscapes
    • Synthesis and processing stages can cause air and water pollution
    • Materials should be designed for minimal environmental impacts during their lifetime
    • Recycling materials conserves resources and reduces environmental impact
    • Recycling energy needs are normally less than for their natural counterparts
    • There is no need to dispose of recycled materials, so it is a closed system involving interactions of materials, energy and the environment
    • Environmental problems are addressed through standards and solutions for existing problems.

    Recycling

    • Recycling means a material can be reprocessed, re-used and re-introduced into the materials cycle
    • Biodegradability means a material deteriorates, returning to a starting state (via environmental interactions)
    • Metals (ex: Fe, Cu) experience corrosion and are biodegradable (though some are toxic)
    • Recycling techniques may diminish alloy quality
    • Separation techniques help recycle various alloy types
    • Recycling thermoset resins is difficult due to their crosslinked structure

    Composite Materials

    • Composites are multiphase materials, making recycling complicated
    • These materials can be ground into particles, which can be used as fillers
    • Recycling polymer-matrix materials can involve shredding or grinding then separating fibres
    • Polymers can be volatilized or recovered as a monomer
    • Recovery results in shorter fibres with reduced strength, depending on the recovery techniques

    Questions about Material Science and Engineering

    • The questions about material science and engineering are not related to the text provided and concern aspects of the material cycle and its environmental impact and implications.

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    Environmental and Societal Considerations PDF

    Description

    This quiz explores the stages of the materials cycle within a technology-economy-environment framework. Participants will learn about the extraction, processing, usage, and disposal of materials, as well as their environmental impacts. Understand the importance of recycling and designing materials with minimal environmental effects.

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