properties of selected engineering materials

... MAGNETOCALORIC PROPERTIES OF SELECTED B-SITE SUBSTITUTED MANGANITES SURESH KUMAR VANDRANGI NATIONAL UNIVERSITY OF SINGAPORE 2012 ELECTRICAL, MAGNETIC AND MAGNETOCALORIC PROPERTIES OF SELECTED ... structure of these materials will help to understand the origin of ferromagnetism in these compounds. Another important highlight of this work is the study of ruthenates. Instead of partial doping of ... class of materials. The objective of the present work is to study the influence of impurity doping at Mn-site in charge ordered (CO) manganites, on the destruction of CO state and other physical properties,

Ngày tải lên: 09/09/2015, 17:53

... MAGNETOCALORIC PROPERTIES OF SELECTED A- and B-SITE SUBSTITUTED MANGANITES SUJIT KUMAR BARIK NATIONAL UNIVERSITY OF SINGAPORE 2011 ELECTRICAL, DIELECTRIC AND MAGNETOCALORIC PROPERTIES OF SELECTED ... Discussions of dc electrical and magnetic properties- -------------------77 3.3.6 Magnetocaloric Properties of x ≤ 0.4---------------------------------------81 3.3.7 AC Magnetoimpedance properties of x ... Tech., Indian Institute of Technology, Kharagpur, India) A THESIS SUBMITTED FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN SCIENCE DEPARTMENT OF PHYSICS NATIONAL UNIVERSITY OF SINGAPORE 2011 Dedicated

Ngày tải lên: 10/09/2015, 15:52

... 15 Designer Wavelengths Variation of band-gap energy with composition x of In 1-x Ga x As. © H.L. Tuller, 2001 3.225 16 Band-Gap Colors Mixed crystals of yellow cadmium sulfide CdS and black ... stability … 3.225 24 Sensor Materials Gas Sensor Electrical Signal compatible with Microprocessor System Chemical Environmental Stimulus Requirements of Gas Sensor Materials • High sensitivity ... materials: 1. Sputtered ZnO film (150 nm (Massachusetts Institute of Technology) 2. Sputtered SnO 2 film (60 nm) (Fraunhofer Institute of Physical Measurement Techniques) • Target gases: H 2 ,

Ngày tải lên: 11/08/2014, 14:20

... the value of σ f for the material, and substitute it along with the value of 10,000 lb for P f , and the problem is solved. A number of materials properties are listed in the Materials Properties 2 module, ... a material’s mechanical properties, and all students of Mechanics of Materials will encounter them often However,... especially in the case of ductile materials that can undergo ... measure of the internal forces within the material. Much of Mechanics of Materials is concerned with elaborating this concept to include higher orders of dimensionality, working out methods of determining

Ngày tải lên: 24/03/2014, 05:20

... herefrom. Library of Congress Cataloging-in-Publication Data Valyashko, V. M. (Vladimir Mikhailovich) Hydrothermal properties of materials : experimental data on aqueous phase equilibria and solution properties ... there that Franck, a pupil of Eucken, began his life’s work on the experimental exploration of the properties of high-temperature, high-pressure aqueous solu- tions of air constituents, acids, ... various chapters of the present book, instead, offer a practical and useful overview of modeling approaches, focused on the current needs, methods and understanding of a wide range of hydrothermal

Ngày tải lên: 01/04/2014, 11:22

... '24C'h20')W7e'! g20')W'%CCƠ '2WV C S ă D Q 9 P P)h('t%!28U24577i!I%E%" i %7177i7i'to4W  of  Ă  7 i & 1"&0 e 10  $" 6 $" p & "  0 $" $0 "p 1( c " B %!2)#$ S7V 4Hf CƠ  e ... " "$ V&  e 1 &0 I A 2!R!'%8e g!'%5320'2Hf 4HF    c( 1 $ iV5 i0 45`)WtX  )h(%4" 2of ă  $" $0 "p 1( p 10 B %!2)#$ 22q) CƠ 3 e V0$p &$" " "$ V&  e & 0 I A F 2!RĐ'%8e g!'%5Đt712m... ... eeggegegegegeggeegegg20')#`24o20'%CiV320')h(%!'2@w ED ED B eeggegegegegeggeegeggegeeggU4CtĂ !4!d7177i% of P ED B " V  1 5"& p i"  0 eeggegegegegeggeegeggegeeggege 20')#t%!4!%Đ B ED B 1 &(&

Ngày tải lên: 21/06/2014, 05:42

... size and diameter of the ball. Commonly used values are D = 10 mm and a force of 29.43 kN = 3000 kp. The choice of parameters depends on the tested material and the thickness of the specimen. ... material because of the constant volume. In reality, the volume of the bulge is usually smaller than that of the indentation, showing that the assumption 110 3 Plasticity and failure of a rigid material ... surface is characterised by a large number of dimples formed in this way. The size of the dimples is in the range of a few micrometres. Sometimes, this kind of fracture is called fibrous fracture.

Ngày tải lên: 11/08/2014, 15:20

... measure the strength of single crystals of pure metals, the values found are several orders of magnitudes below this theoretical value and even lie below that of engineering alloys ... iso 12737): We start by drawing a line with a slope of 95% of that of the elastic line from the experiment (figure 5.16). The intersection of this line with the load- displacement curve determines ... of metals III x2 II IV I x1 V VIII VI VII Fig 6.7 Qualitative illustration of. .. face-centred cubic crystal is close-packed (see section 1.2.2) Planes of type {111} and directions of

Ngày tải lên: 11/08/2014, 15:20

... reduction of the life time of a component (see chapter 10) Table 6. 6 summarises the strength of some particle-strengthened aluminium alloys Precipitation hardening Strengthening of materials ... multitude of ways to influence material properties 6. 4 Strengthening mechanisms 211 Fig 6. 43 Calculation of the average spacing of randomly distributed particles within... area (2a)2 of the ... rectangular one with the appropriate height and width. The width d ∗ of the rectangle is then a measure of the width of the obstacle. A stress of τ m has to b e exerted to move the dislocation through the

Ngày tải lên: 11/08/2014, 15:20

... subject of sections 8.2 to 8.4 Methods to improve the mechanical properties of polymers are discussed subsequently The chapter closes with a brief discussion of the sensibility of polymers ... topic of chapter 9 Table 7. 4 summarises the mechanical properties of some technically important ceramics 7. 5 Strengthening ceramics 249 Table 7. 4 Mechanical properties of some ... useful to consider the probability of survival P s instead of the probability of failure, defined as [...]... amorphous regions 262 8 Mechanical behaviour of polymers fluid T viscous rubbery

Ngày tải lên: 11/08/2014, 15:20

... mechanical properties improve accordingly as already discussed 290 8 Mechanical behaviour of polymers Table 8. 2 Typical properties of several polymers (after [44, 98] ) Since the properties ... ¾ (a) Cross sectional view of a craze. The lens-shaped cavity and the fibrils can be observed (b) Scaled partial view of the edge of a craze Fig. 8.13. Microstructure of a craze (after [82, 128]) ... plastically deformed area (a) Local necking ¾ ¾ (b) Formation of cavities ¾ ¾ (c) Extension of cavities Fig. 8.14. Development of a craze by formation of cavities (after [82]) straightening the molecules

Ngày tải lên: 11/08/2014, 15:20

... glass temperature of about 150℃. Composite properties It was already stressed that the properties of fibre and matrix have to be carefully adjusted to obtain optimal properties of the component ... modulus of 80 GPa and l /d = 100, we find in the ideal case of a perfectly straight fibre a buckling strength of only 5 MPa. Without the presence of the matrix, the compressive strength of the material ... density of carbon bonds can never be as high as that in carbon fibres because of the side groups, it is easily understood that the mechanical properties of polyethylene fibres are inferior to that of

Ngày tải lên: 11/08/2014, 15:20

... occur. These materials thus have no true fatigue limit. To ensure safety of the component, a limiting number of cycles of 10 8 is often used, ten times larger than the usual value for materials ... fatigue limit (S-N curve of type II, figure 10.19(b)). At a number of cycles beyond 10 7 , the slope of the S-N curve is rather small and a limiting number of cycles of N E = 10 7 to 10 8 can ... A instead of σ a . The number of cycles can also be specified in the subscript, as in σ AN f , stating, for example, 15 Failure can be defined as fracture of the specimen or occurrence of a crack.

Ngày tải lên: 11/08/2014, 15:20

... in chemical engineering Exercise 23: Design of a fluid tank You are the design engineer of a company working in chemical engineering Your task is to design the bearing plate of a tank ... average) by the quotient of the volume Ω of the vacancy and the cross section of the grain boundary considered. The force equals the stress multiplied with the cross section of the grain 394 11 Creep ... strength of these alloys The dislocations can cut the particles only at rather high stresses Thus, stresses of 100 MPa can be applied at temperatures of 1000℃ and service times of several

Ngày tải lên: 11/08/2014, 15:20

... statement of the first law is nothing but the law of the conservation of energy To understand the second law, we need to think about the meaning of entropy The entropy of a system is a measure of the ... tensor of any order can be transposed by reverting the sequence of the indices: (Cijkl )T = (Clkji ) In a tensor of second order, this means exchanging the rows and columns The trace of a tensor of ... A , These principal invariants are important in the context of yielding of materials and are used in section 3.3.1 A.8 Derivations of tensor fields Physical quantities are frequently not defined

Ngày tải lên: 11/08/2014, 15:20

... related properties of poplar wood 627 Table VI Density (kg/m3 ), modulus of elasticity and modulus of rupture (N/mm2 ) for a 7-layer plywood for each of the selected clones Beaupré Density of the ... knot-free specimens were loaded at the centre at a rate of mm per in order to reach a duration of the test of 300 ± 120 s Of each stem, two logs of 2.6 m were peeled using industrial equipment to ... surface proportion of an individual zone of 6.25% The distribution of ‘Beaupré’ indicates that this clone has a bigger amount of smaller individual tension wood areas (85% of the tension wood...

Ngày tải lên: 07/08/2014, 16:21

... supervisor Prof Ding Jun in Materials Science and Engineering Department (MSE) of National University of Singapore (NUS) for his guidance, inspiration, and encouragement throughout the course of my ... dependent transport properties of magnetic oxide materials with a high degree of spin polarization A research into the unique properties of magnetic oxides is one of the most important issues for ... of peak (311); 80 Figure XRD spectra of the CoFe2O4 films with a thickness of 100nm deposited at different temperature on glass substrates 84 Figure XRD spectra of the CoFe2O4...

Ngày tải lên: 09/09/2015, 10:15

... development of new materials for the improvement of GMI properties [58, 59, 60] 21 Introduction Figure 1.12: (a)The definition of the impedance of a current carrying conductor (b) Schematic diagram of ... figure -of- merit PF Power factor xxiii Introduction Chapter Introduction Transition metal oxides form an amazing class of materials with a wide range of properties They exhibit a variety of phenomena ... between the sets of energy states is called the crystal field energy which is of the order of eV [1] The ratio of dopant atoms Introduction at the site determines the valency of the Mn (Mn3+/Mn4+)...

Ngày tải lên: 10/09/2015, 09:11

... Fermi level is approximately in the middle of the band gap • The law of mass action describes the electron and hole populations, since the total number of electron states is fixed in the system ... oscillator, get: Ψ Ψdx * hω k x2 = E = e hω kT −1 Average energy of harmonic oscillator 3.225 © E Fitzgerald-1999 22 11 Estimate of T dependence of conductivity k x = E = hω hω e kT − hω = kθ kθ E = θ ... the barrier NCNV is the density of the reactants, and n and p are the products N C NV  → e′ + h • Eg − Eg n np =ekT = i N C NV N C NV b • • • Thus, a method of changing the electron or hole...

Ngày tải lên: 11/08/2014, 14:20

... ψψ *dV = probability of finding particle in volume dV Average or expectation value of variable α = ∫ ψ *α op ψ dV v 3.225 © H.L Tuller-2001 19 Time and Spatial Dependence of ψ Assume ψ (x,y,z,t) ... L π h k πh N= g(E)=density of states=number of electron states per energy per length n= • • N 2k F 2mEF nπ = = or k F = π hπ L n, the electron density, the number of electrons per unit length ... velocity of the highest occupied electron state at T=0 3.225 © E Fitzgerald-1999 Representation of E,k for 2-D Material E= h (k x2 + k y ) E(kx,ky) 2m ky kx 3.225 © E Fitzgerald-1999 Representation of...

Ngày tải lên: 11/08/2014, 14:20