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Online Test TwoQ:Photovoltaic Semi conducting ceramics such as Indium Galium SelinideA:Produce energy as part of a p-n junction CORRECTQ:How would the strength of a ceramic component be enhanced during manufacture?A:Hot isostatic pressing CORRECTQ:Solidified steel crystal structure isA:body centred cubic or face centred cubic. CORRECTQ:Which is theincorrectstatement from the following listA:Ceramics have poor high temperature properties. CORRECTQ:Which is the correct statement from the following list:Engineers favour the use of composites in aerospace applications becauseA:They have excellent strength to density properties CORRECTQ:creep can be defined as;A:Increasing strain on a part with constant stress at high Temperatures. CORRECTQ:A ceramic material has a fracture toughness value of 4.5MPa m-1/2and is under a tensile stress of1000MPa, where Y=1 what is the critical crack dimension before brittle fracture.A:20um CORRECTQ:Select the correct answer form the following statements; Increasing the initial stress during a creeptestA:Lowers the temperature during the testing process WRONGQ:Which is the correct statement from the following listTo produce a ceramic the ceramic powder isA:mixed with binder and dispersantCORRECTQ:From the following list identify theincorrectstatementCeramic acetabular components used in replacement hip joints must have the following properties
A:High friction coefficient CORRECTQ:The tensile strength of ceramics is approximately related to the porosity by the expression UTS=UTS0e-nPwhere P is the volume fraction of pores in the solid, UTS0is the tensile strength at zero porosity andthe exponent n=4, UTS0=150Mpa and the porosity is 20%What is the calculated value of the UTS.A:673MPa CORRECTQ:From the following statements, select the correct answer;Side groups on polymer mer unitsA:decreases polymer chain flexibility CORRECTQ:Polyethylene thermoplastic polymers is;A:always very flexible WRONGQ:From the following statements, select the correct answer;Thermoplastic polymers;A:soften when heated CORRECTQ:Elastomeric polymers are...A:melt when heated WRONGQ:Which is the correct statement from the following listIn producing a fully dense ceramic, the sintering process is driven by;a:diffusion within powder particles CORRECTQ:Select the correct answer from the listPolymeric materials are;A:can be both amorphous and crystalline CORRECTQ:Which is theincorrectstatement from the following listA laminar composite isA:composed of alternating layers of fibre materialsWRONGQ:Cermet composites have a better shock resistance when they are used as cutting tools whenA:the % of matrix decreases WRONG
Q:Which is the correct statement from the following listUnder tensile loading the bond strength of fibres in a matrix mustA:be greater than the tensile strength of fibre CORRECTQ:Which is the correct statement from the following listEngineers favour the use of composites in aerospace applications becauseA:They have excellent strength to density properties CORRECTQ:Choose the correct answer from the following list.Dispersion strengthened compositesA:Have enhanced creep properties CORRECTQ:Building Integrated Flexible Photo Voltaic cells areA:10-15% efficient at conversion of solar energy into electrical energy CORRECTQ:Which factor DOES NOT reduce the fatigue life of a componentA:carburising the surface CORRECTQ:Which statement in the following list isincorrectThe main service requirements of the matrix material in a composite areA:should not be strongly bonded to the matrix to allow cracks to propagate CORRECTQ:Colours in polymers fillers in polymers are produced byA:the addition of pigments and dyes CORRECTQ:Tape casting of Al2O3tiles is used for producing;A:IC chips CORRECTQ:The largest use of polymers in industryA:consumer products WRONGQ:Addition reaction used in the polymerisation processA:need initiation catalysts CORRECTQ: A steel component has a hardness of 225HB (Brinell hardness) calculate its approximate ultimatetensile strengthA:775MPa CORRECTEXAM OVER
Q:The modulus of elasticity of a ceramic is approximately related to the porosity by the expressionE=E0(1 - 1.9P + 0.9P2) where E0is the modulus at zero porosity. If a fully dense ceramic has theproperties of and E0=300Gpa what is the resulting modulus at 40% porosity.A:115Gpa CORRECTQ:A brittle fracture of a test specimen in an impact test is usually characterised by;A:A bright sparkling surface CORRECTQ:Select the correct answer from the listPolymeric materials are;A: Can be both amorphous and crystalline CORRECTQ:Which statement in the following list isincorrectThe main service requirements of the matrix material in a composite areA:should not be strongly bonded to the matrix to allow cracks to propagate. CORRECTQ:Select the correct answer from the listPolymer crystallinityA:does not change the polymer density WRONGQ:Which of the following statements is NOT correctGlass transition temperature is increased by;A:Polymer chain cross links CORRECTQ:Which is the correct statement from the following listIn producing a fully dense ceramic, the sintering process is driven by;A:diffusion within powder particles WRONG
Q:Which is theincorrectstatement from the following listSintering can be aided by;A:larger powder particles CORRECTQ:Tape casting of Al2O3tiles is used for producing;A:IC chips CORRECTQ:From the following statements, select the correct answer;Side groups on polymer mer unitsA:decrease polymer chain flexibility CORRECTQ:Elastomeric polymers are;-A:are highly flexile thermoplastic polymers WRONGQ:Choose the correct answer from the following list.Dispersion strengthened compositesA:have enhanced creep properties CORRECTQ:Which is the correct statement from the following listTo produce a ceramic the ceramic powder isA:mixed with binder and dispersant CORRECTQ:Which is the correct statement from the following listUnder tensile loading the bond strength of fibres in a matrix mustA:be greater than the tensile strength of the fibre CORRECTQ:A ceramic material has a fracture toughness value of 4.5MPa m-1/2and is under a tensile stress of1000MPa, where Y=1 what is the critical crack dimension before brittle fracture.A:20um CORRECTQ:From the following statements, select the correct answer;
Thermoplastic polymers;A:soften when heated CORRECTQ:From the following list identify theincorrectstatementCeramic acetabular components used in replacement hip joints must have the following propertiesA:high friction coefficient CORRECTQ:A thermoplastic material filled with 20% glass fibre wouldA:increase the materials ductility WRONGQ:Which of the following statements concerning thermoplastics is incorrectA:increasing the temperature increases the ductility CORRECTQ:Which statement from the following list isincorrectA:Ceramics have excellent thermal conduction properties CORRECTQ:Which of the following statements is incorrectA:Thermosetting polymers are used in recycling CORRECTQ:When measuring fatigue strength of a material the results are represented on a graph whereA:Stress is plotted against number of stress cycles CORRECTQ:The tensile strength of ceramics is approximately related to the porosity by the expression UTS=UTS0e-nPwhere P is the volume fraction of pores in the solid, UTS0is the tensile strength at zero porosity andthe exponent n=4, UTS0=150Mpa and the porosity is 20%What is the calculated value of the UTS.A:673Mpa CORRECTQ:Interstitial solid solution hardening isA:not normally employed for hardening metals WRONG
Q:Select the correct answer form the following statements; Increasing the initial stress during a creeptestA:increases the rate of creep WRONGQ:Which is theincorrectstatement from the following listA:ceramics have poor high temperature properties CORRECTQ:Which is theincorrectstatement from the following listA laminar composite isA:composed of particle reinforced elements CORRECTQ:For a specimen under a tensile stress of 100N/m2and having a “notch” type flaw whose length is3mm with a tip radius of 50μm, calculate the stress at the tip of the notch.A:1649 Nm2 CORRECTQ:From the following list identify theincorrectstatementCeramic acetabular components used in replacement hip joints must have the following propertiesA:high friction coefficient CORRECTQ:The largest use of polymers in industryA:packaging CORRECTEXAM OVER:
Q:The largest use of polymers in industryA:Packaging CORRECTQ:From the following statements, select the correct answer;Thermoplastic polymers;A:soften when heated CORRECTQ:From the following list identify theincorrectstatementCeramic acetabular components used in replacement hip joints must have the following propertiesA:HFC CORRECTQ:Which is the correct statement from the following listEngineers favour the use of composites in aerospace applications becauseA:excellent strength to density properties CORRECTQ:Elastomeric polymers are;-A:thermoplastic polymers with no cross links between chains WRONGQ:Select the correct answer from the list:Vulcanisation is;A:making synthetic rubber for road tyres WRONGQ:Addition reaction used in the polymerisation processA:need initiation catalysts CORRECTQ:Which is theincorrectstatement from the following listIn terms of electrical properties ceramics can
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