Search results

Thermal analysis and cooling optimization of the built-in micro projector Wei Wei1,a, PingYang1,b, Qianhong He1,c and Quayle Chen2,d 1School of Mechatronics Engineering, University of Electronic Science and Technology of China, Chengdu, Sichuan, 611731, China 2Nokia Research Center Beijing, Beijing,100176,China aweiwei2508402031@163.com, bping@uestc.edu.cn, crobin_hqh@126.com, dquayle.chen@nokia.com Keywords: micro projector; thermal analysis; LED; cooling optimization Abstract.
The material parameters of LED package are shown in Table.1.
FPCB substrate Copper metal Thermal grease Ceramic layer Copper heat sink Thermal conductivity [W/(m·k)] 0.36 385 6 10.31 385 Radiation coefficient 0.92 0.04 - - 0.04 Table.1 The Material parameters of LED package DMD chip.
Make simplifications and assumptions as follows: LED and DMD chip are the thermal sources of the micro projector, so ignore the heat generated by the current through the passive components and attachments; Ignore the thermal properties of optical components, such as lens and optical integrators, and they can be defined as modules which have no heat and no thermal conduction; Assume that every material of the micro projector is isotropic and has uniform thermal conductivity, and the density value of every material takes an average; Boundary conditions: the ambient temperature is 25℃, 1 atm, ρ=1.185kg/m3, CP=1005J/(kg·K), ν=15.53×10-6m2/s, Pr=0.702kg/m3.
[5] Zhou Jing-xian, Wu Rong-zhi, in: Digital Micromirror Device (DMD), edited by Chinese Journal of Liquid Crystals and Displays (2003)

The SIC/CAS of CMCs was simulated from the material parameter from table 1.
Table 1 SiC/CAS material parameter Young’s modulus of the fiber (GPa) 200 Young’s modulus of the matrix (GPa) 97 Fiber radius 7.5 Volume fraction of the fiber 0.37 Fiber possion ratio 0.2 Matrix possion ratio 0.2 The thermal stress(MPa) 8913 Interfacial shear stress (MPa) 10 Interfacial debonding energy （） 1.4 The final stress of the matrix satutated crack (MPa) 250-260 From the above material parameter, the stress/strain curve can be simulated, and the effect of the debonding stress to the curve can be analysed.
The improved Monte Carlo simulation has been made according to the material parameter from table1, which was compared to the Beyerle’s experiment.
B. , Hutchinson, J.W. and Evans, A.G., 1986, "Matrix Fracture in Fiber-Reinforced Ceramics," Journal of-Mechanics and Physics of Solids, Vol. 34,NO. 2, pp. 167-189
Solti, “Modeling of Progressive Damage in Fiber-Reinforced Ceramic Matrix Composites,” AD 96-2 [6] Miaoyan matrix failure model of the ceramic matrix composites Nanjing University of Aeronautics and Astronautics，master's paper . (2007) [7] Aveston, J., Cooper, G.A., and Kelly, A., Single and Multiple Fracture, The Properties of Fibre Composites, IPC Science and Technology Press, Surrey,England, 1971, 15-26

Since raw materials used for energy generation such as oil, coal and natural gas will be used up in the near future.
For example, the materials used in constructions are cheap and the technologies involved are conventional.
Solar Chimneys, Encyclopedia of Physical Science and Technology. 3rd ed.
International Journal of Renewable Energy Engineering, Vol. 3, No. 2, (2001) [6] Koonsrisuk, A. and Chitsomboon,T.

The Effect of Hybrid Surface Modification; Combination of Fine Particle Bombardment Treatment and Nitriding, on Fatigue Properties of Steel Shoichi Kikuchi1, a, Jun Komotori2, b, Yutaka Kameyama 1, c and Kengo Fukazawa3, d 1 Graduate school of Science and Technology, Keio University, 3-14-1, Hiyoshi, Kouhoku-ku, Yokohama-shi, Kanagawa, 223-8522, Japan 2 Department of Mechanical Engineering, Keio University, 3-14-1, Hiyoshi, Kouhoku-ku, Yokohama-shi, Kanagawa, 223-8522, Japan 3 Neturen Co., Ltd.
Introduction Since a fatigue crack is initiated at the surface of material, surface of mechanical parts are commonly strengthened by surface modification process to improve fatigue strength.
However, when a surface is strengthened by some surface modification process, fatigue cracks can be initiated from non-metallic inclusions located within the material (internal fracture mode).
Experimental procedure Material used in this study was AISI 4135 chromium molybdenum steel.
As a result, in the NF series, internal fracture occurred at the non-metallic inclusion inside the material, though they possessed a notch.

Numerical Simulation and Experiment of a New Drive Device of High-temperature Magnetic Pump Danqing Yuan1,a, Youquan He1,b, Jianping Li1,c , He Zhang1,d , Chunfang Chang2,e 1 School of Energy and Power Engineering, Jiangsu University, Zhenjiang 212013,China 2 Institute of Process Equipment, East China University of Science and Technology, Shanghai 2000237, China a ydq@ujs.edu.cn,b heyouquan66@126.com,c freestyle0228@163.com, d he168198737@126.com,e changchunfang1985@163.com Key words: Magnetic coupling; Magnetic pump; Finite element analysis; Electromagnetic field analysis; Induced current Abstract.
With the development of magnetic materials and over half a century of technological innovation, magnetic pump has been widely used in petroleum, chemical, pharmaceutical, food and nuclear power industries, etc.
Sung: Journal of Magnetism and Magnetic Materrials. vol. 239(2002), p.614-616 [11] Nan-Chyuan Tsai, Jiun-Sheng Liou, Chih-Che Lin, etal: Sensors and Actuators A: Physical, vol. 157(2010), p.68-76 [12] Pan Zheng, Yousef Haik, Mohammad Kilani, etal: Jouarnal of Magnetism and Magnetic Materials,vol.241(2002), p.292-302

This approach appears to be behind the concept of "urban environment" of the EU (assumed as the foundation of the methodology described below) as the result of the impact of settlements in terms of damage (withdrawal and pollution) of the finite natural resources (energy, air, water, natural soil, raw materials, emissions, solid waste, etc..) and the related effects on the ecosystems and the quality of human life.
The commitment on this line could allow to resume and deploy the predictive assumptions of Giovanni Astengo towards urbanism as a science, at least in terms of partial but especially in progressive and evolutionary way.
Fig.1 – Methodological route The urban comfort is evaluated according to three main parameters related to: - Permeability of soils, as a potential evapo-transpiration capacity of the soil; substantially corresponds to a index coverage / natural soils; - Albedo, as reflected fraction of solar radiation due to the color and nature of the surface materials and the parts of the settlement (refer with: Fig. 2); - Urban heat island, representing the result of the preceding factors plus others (thermal trap, entropic heat, pollution, particulate matter, etc.). useful in locating the main urban conditions of discomfort in our latitudes in terms of microclimate, the evaluation is done by parametric simulations (refer with: Fig. 3).
In: Journal of climatology 1 (1981) [3] Peter Droege: The Renewable City, John Wiley & Sons Ltd, England (2006) [4] P.

Citation & Copyright (to be inserted by the publisher ) Thermal Stresses in SiC-Si3N4 Cubic-Cell-Divided Multi-Particle-Matrix System L.Ceniga 1 Institute of Materials Research, Watsonova 47, 043 53 Košice, Slovak Republic, ceniga@imrnov.saske.sk, ceniga@saske.sk Keywords: Thermal stress, Si-ceramics.
After the matrix crack formation, the infinitesimal elastic energy of the thermal stresses, 11 dxdxWdW c ϕ= is in the equilibrium state with the infinitesimal matrix crack surface energy, ϕγ ddsdx dWs 1= , and then sdWdW = , where pICp EK /2=γ is the particle crack surface energy per unit area, KICp is the particle fracture toughness, Journal Title and Volume Number (to be inserted by the publisher) 3 ( )21 1 /1 xfdxds ∂∂+= is infinitesimal length of a curve, f, representing a function of pRx ,01∈ , describing the crack shape in the plane x1x3 in the spherical particle, and then ( ) 422 2 1 /1/ ICp pc ICp KEWKxf − −=∂∂ .
An ideal-brittle material is characterized by 0/ 1 =∂∂ xf at a crack tip, as fulfilled for the condition, ( ) 0/ 2 = − pICp c EKW , from which the critical particle radius, Rpc,. as a reason of the particle crack formation, is derived in the form ( )  − = pb ICp pc p KR µ21 2 111 2 2 ( ) ( )( ) ( )( ) ( ) ( ) ( )                                         + −−++         − − − + 5 3/2 23/2 3/1 2 2 3/1 2 2 34 4 32 1 1 3 4 6215 620 pp p cbm p cbpm pm p vR v pp v ppv vE E π µπ π π µ π
The dependences in Figs.3,4 (see Eqs.(2)-(4), (10)) are generated for material constants of the Si3N4 matrix and the SiC particle of the average radius Rp=250 nm, Em=310 GPa, µm=0.235, αm=2.35/3.75×10-6 °C -1 for 20/1100°C and Ep=360 GPa, µp=0.19, αp=4.14/5.05×10-6°C -1 for 20/1100°C, KICp=3.25MPam 1/2 , respectively, and for the initial temperature, Ti=1700°C, and the final temperature, Tf=20°C, of a cooling process of the SiC-Si3N4 multi-particle-matrix system [13][16].
Acknowledgements Supported by the Slovak Grant Agency VEGA (2/4173/04, 2/4175/04, 2/4062/04, 1/111/04), by NANOSMART, Centre of Excellence SAS, by Science and Technology Assistance Agency (APVT-51-049702), by RTN2-2001-00488 SICMAC; by 2003 SO 51/03R8 06 00/03R 06 03-2003, and by EU 5th FP project No.GRD1-2000-25352 `SmartWeld'.

Experimental Section Materials.
That is probably due to the specific structure of the material.
Lee, Stabilization/Solidification of Radioactive Salt Waste by Using xSiO2-yAl2O3-zP2O5 (SAP) Material at Molten Salt State, Environ.
Ciecinska, Preparation, Structure and Properties of Silicate-Phosphate Glasses Obtained by Means of Sol-Gel Method, Journal of Sol-Gel Science and Technology, 3 (1994) 219-227 [7] I.N.

To meet the requirements of the high-speed machine, one can minimize the weight and inertia of structural components in the condition of not affecting the rigidity, such as manufacturing carriage and table with new lightweight materials, optimizing geometry and dimensions of the machine structure components by using the finite element method.
With the increase of processing speed, the possibility of generating vibration increases, so one must improve the structure of basic parts or use materials with good physical properties in order to improve the machine's dynamic and static stiffness and vibration resistance.
Journal of Tsinghua University (Natural Science), 2004,4 (2) :180-189

But in fact, the dispersion performance of pipe materials, the uneven production quality, actual operation pressure fluctuation, and deviation of casing wear depth, these influence factors were variable, thus the traditional method analysis will carry some risks.
Set work pressure for ‘S’, the residual strength of casing for ‘R’, ‘S’ and ‘R’ are independent, so wear casing stress-strength interference model is: (1) The reliability of wear casing is: (2) Casing are generally high toughness materials that failure mode is mainly plasticity invalidation.
Acknowledgements This work is supported by National Natural Science Foundation of China, 51075043/E050403.
Dawson: SPE Drilling Engineering Vol. 2(1) (1987) [2] Yonquan Yin, Zhaowei Chen and Ping’en Li: Chinese Journal of Theoretical and Applied Mechanics Vol. 38(6) (2006) (In Chinese) [3] A.J.