physical and mechanical properties of structural materials

... compares the strength and conductivity of copper and several types of copper alloys.31 4.20.4 Mechanical Properties of Copper and Copper Alloys Physical properties of pure copper and copper alloys ... presented, followed by a summary of their physical and mechanical properties The radiation effects on the physical and mechanical properties of copper and copper alloys as well as their irradiated ... Testing and Materials: Philadelphia, 1992; p 813 682 Physical and Mechanical Properties of Copper and Copper Alloys The size of SFTs is small, $2–3 nm As doses increased, the density of SFTs...

Ngày tải lên: 03/01/2018, 17:11

... decided to select 10 trees presenting clear sectors of reaction wood, with the widest possible diversity and to measure the physical and mechanical properties in the tension wood sector as compared ... Aubl for example has a rather high resin content in all parts of the trunk) Figure Size of samples used for mechanical and physical properties CSCP: Crushing strength in compression parallel to ... gymnosperms and physical- mechanical models of wood behaviour, a low value for MFA should result in (i) a high value of specific modulus of elasticity, (ii) a higher value of tangential and radial shrinkage,...

Ngày tải lên: 07/08/2014, 16:21

... increasing height, following the trend of increasing density 3.4 Veneer quality – Density and mechanical properties of plywood Figure gives an overview of the efficiency of the veneer processing as well ... clone Table VI gives an overview of the density, modulus of elasticity and modulus of rupture for each clone Both mechanical properties were tested perpendicular and parallel to the grain as described ... 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...

Ngày tải lên: 07/08/2014, 16:21

... uniform The results of physical and mechanical characterisation of Atlas cedar wood from Southern Italy are summarised on table IV Table V refers about physical and mechanical properties found on ... principles of testing and classification of the natural durability of wood [10] ISO 3131, Wood – Determination of density for physical and mechanical tests [11] ISO 3133, Wood – Determination of ultimate ... age of duramification The physical and mechanical features have shown a wood characterised by rather good values, highlighting that the wood is very stable and that the structural efficiency of...

Ngày tải lên: 08/08/2014, 14:20

... and utilization The physical and mechanical properties of bamboo vary with the age of the bamboo and the height of the culm [Chauhan 2000] In general, SG and the properties of bamboo drop from ... on the physical properties of pulp [Tamolong 1967; Zamuco et al 1969] Aging of a bamboo culm influences physical, chemical, and mechanical properties, and consequently its processing and utilization ... on the utilization of bamboo fibers to MDF This chapter investigated the effects of age of bamboo fibers and the resin content level on the physical and mechanical properties of the manufactured...

Ngày tải lên: 22/02/2014, 09:20

... Conductivity of Metals? • Drude model: Sea of electrons – all electrons are bound to ion atom cores except valence electrons – ignore cores – electron gas Schematic model of a crystal of sodium ... R=V/I; σ=E/j=neµ) Ohms/square ⇒ Note, if L=W, then R= ρ /t independent of magnitude of L and W Useful for working with films of thickness, t R R R 3.225 © H.L Tuller-2001 17 How to Make Resistance ... from electric force on electron! 3.225 © E.A Fitzgerald-1999 Equation of Motion - Impact of Collisions Assume: • probability of collision in time dt = dt/τ • time varying field F(t) v(t+dt) = (1-...

Ngày tải lên: 11/08/2014, 14:20

... 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 ... E F =  m*   * + kbT ln h   me  Eg Since me* and mh* are close and in the ln term, the Fermi level sits about in the center of the band gap ( ) − Eg  k T 2 * * p or n = ni = 2 b  me ... 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

... capable of sensing a change in environment and responding without need for a microprocessor A device has both gas sensing and actuating function by integration of semiconducting oxide and piezoelectric ... Electrode ∆f Resonator Electrode 3.225 © H.L Tuller-2001 23 Choice of Piezoelectric Materials • Temperature limitations of piezoelectric materials Material Max Operating Limitations o Temperature ( ... control down to 0.1 mm through the use of highly selective p-n junction etch-stops • fabrication of structures with negligible internal stresses • fabrication of structures not constrained by specific...

Ngày tải lên: 11/08/2014, 14:20

... (Najafi and Hetke, IEEE Trans Biomed Eng 37, 474 (1990).) 3.225 28 14 Measurement of Gas Sensor Performance • Gas sensing materials: Sputtered ZnO film (150 nm (Massachusetts Institute of Technology) ... stability … 3.225 23 Sensor Materials Chemical Environmental Stimulus Gas Sensor Electrical Signal compatible with Microprocessor System Requirements of Gas Sensor Materials • • • • • • • • 3.225 ... Traditionally admired for their stability • Mechanical • Chemical • Thermal • Exhibit other key functional properties • Electrical, Electrochemical, Electromechanical • Optical • Magnetic 3.225 20...

Ngày tải lên: 11/08/2014, 14:20

... , z )ψ = − i ∂t 2m ψ and ∆ ψ must be finite, continuous and single valued ψψ * real with 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) separable into ψ(x,y,z) and φ(t) Applying separation of variables: − h ∇ 2ψ h ∂φ +V = − =ε 2m ψ i φ ... determined by the crystal structure and valence n determines the energy and 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...

Ngày tải lên: 11/08/2014, 14:20

... achieved where diffusive flux of the carriers is balanced by the drift flux 3.225 © E Fitzgerald-1999 12 Joining p and n p n Ec EF Ev Carriers flow under driving force of diffusion until EF is flat ... Qualitative Effect of Bias • • • Applying a potential to the ends of a diode does NOT increase current through drift The applied voltage upsets the steady-state balance between drift and diffusion, ... Means to Create Internal Potentials: Heterojunctions • Different semiconductor materials have different band gaps and electron affinity/work functions Internal fields from doping p-n must be superimposed...

Ngày tải lên: 11/08/2014, 14:20

... of a chromium atom (A) and a trivalent chromium ion (B) 3.225 © H.L Tuller, 2001 10 Octahedral Environment of Transition Metal Ion Interaction of the d orbitals of a central ion with six ligands ... Fitzgerald-1999 Characteristics of Optical Fiber 3.225 Colors Produced by Chromium Above: alexandrite, emerald, and ruby Center: carbonate, chloride, oxide Below: potassium chromate and ammonium dichromate ... of positive and negative ions 3.225 © E Fitzgerald-1999 © H.L Tuller, 2001 Ferroelectrics Applications • Capacitors • Non-volatile memories • Photorefractive materials 3.225 Characteristics of...

Ngày tải lên: 11/08/2014, 14:20

... the valence band to the conduction band E Ec near band gap E=hν k Creates a ‘hole’ in the valence band Ev near band gap 3.225 © E Fitzgerald-1999 Holes and Electrons • • Instead of tracking electrons ... 1,000,000 Remember that: 3.225 µ= eτ m* and 1 ∂2E = m * h ∂k 2 Metals and Insulators • EF in mid-band area: free e-, metallic • EF near band edge – EF in or near kT of band edge: semimetal – EF in gap: ... Real Band Structures • GaAs: Very close to what we have derived in the nearly free electron model • Conduction band minimum at k=0: Direct Band Gap 3.225 © E Fitzgerald-1999 15 Review of H atom...

Ngày tải lên: 11/08/2014, 14:20

... since energy ~ LI and for loop L = ΦB I Φ B = ∫ ∫ H ⋅ dS ~ HA ∴ µH = Φ B I = HAI and ∴ µ = IA e ω A = πr c 2π e µ = − ωr 2c I =− 3.225 © E Fitzgerald-1999 Microscopic Source of Magnetization • ... induction, “softer” Magentic anisotropy hardness of loop dependent on crystal direction comes from spin interacting with bonding 3.225 © E Fitzgerald-1999 Domains in Ferromagnetic Materials B ... Fe, Ni, Co -> J positive! Other elements J is negative Rule of Thumb: interatomic distance r ≡ > 2ra 2(atomic radius) J is a function of distance! 3.225 © E Fitzgerald-1999 Ferromagnetism M M (T...

Ngày tải lên: 11/08/2014, 14:20

... metals look like free-electron Drude metals • Valence=2 and 3, magnitude and sign suggest problems 3.225 © E.A Fitzgerald-1999 25 13 Response of Free e- to AC Electric Fields • Microscopic picture ... 3.225 © E.A Fitzgerald-1999 Complex Representation of Waves sin(kx-ωt), cos(kx-ωt), and e-i(kx-ωt) are all waves e -i(kx-ωt) is the complex one and is the most general imaginary A θ Acosθ iAsinθ ... Response of e- to AC Electric Fields • Momentum represented in the complex plane imaginary p (ω>>1/τ) p p (ω

Ngày tải lên: 11/08/2014, 14:20

... susceptibility All detail of material response is in εr and therefore P 3.225 © E Fitzgerald-1999 Origin of Polarization • • • We are interested in the true dipoles creating polarization in materials (not ... So polarization slows down the velocity of the wave in the material © E Fitzgerald-1999 Compare Optical (index of refraction) and Electrical Measurements of ε Material Optical, n2 Electrical, ε ... E-M waves travel in insulating materials: What is the response of the material (εr) to these waves? 3.225 © E Fitzgerald-1999 Wave Eqn with Insulating Material and Polarization r r ∂B ∇xE = −...

Ngày tải lên: 11/08/2014, 14:20

... appearance of second absorbance at 700 nm can be assigned to the transition of electron from t2g bands to eg bands of Fe3+ ions [34, 35] The slight decrease of optical band gap in doped and co-doped ... 2.03, 2.00, 1.97, and 1.85 eV, respectively (in Fig 4b) The valence band of BFO material are well known forming by 3d-Fe and 2pO states The conduction band is composed of 3d-Fe and 6p-Bi states ... (BNFNO and BNFCO) exhibit the shift of three Raman modes A1-1, A1-2 and A1-3 to higher frequency The changes of both intensity and position of these peaks indirectly indicates the substitution of...

Ngày tải lên: 16/12/2017, 16:10

... thought of as the absence of a plane of atoms (intrinsic stacking faults) or the insertion of rows of atoms that disturb the arrangement of atoms (extrinsic stacking faults) Intrinsic and extrinsic ... Nucleation and Growth The random motion of atoms and vacancies in solids, liquids, and gases are associated with atomic collisions that may give rise to the formation of small embryos or clusters of ... will be followed by a simple description of phase nucleation and grain growth The kinetics of phase nucleation and growth and growth in selected systems of engineering significance will be illustrated...

Ngày tải lên: 23/12/2013, 00:15

... macroscopic level of understanding of structure [Figs 16(a)–(d)] They are often unaware of the atomic and microstructural constituents that can affect the mechanical behavior of materials and of the role ... Inc 1 Overview of Crystal/Defect Structure and Mechanical Properties and Behavior 1.1 INTRODUCTION The mechanical behavior of materials describes the response of materials to mechanical loads ... the development of a basic understanding of the mechanical properties of materials It is not intended to be a comprehensive review of all the different aspects of mechanical properties; such...

Ngày tải lên: 23/12/2013, 00:15

... macroscopic level of understanding of structure [Figs 16(a)–(d)] They are often unaware of the atomic and microstructural constituents that can affect the mechanical behavior of materials and of the role ... Inc 1 Overview of Crystal/Defect Structure and Mechanical Properties and Behavior 1.1 INTRODUCTION The mechanical behavior of materials describes the response of materials to mechanical loads ... the development of a basic understanding of the mechanical properties of materials It is not intended to be a comprehensive review of all the different aspects of mechanical properties; such...

Ngày tải lên: 14/03/2014, 17:44