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Introduction Continuous technology development generates demand for materials with unique properties.
The use of spinels as dielectrics at low temperatures or semiconductors at high temperature depends on their electrical properties [8].
As the process for preparing the spinel depends on many factors (e.g. time, temperature, starting substrates used in process) it is not still fully described.
Tavangarian, Sintering behavior, microstructure and mechanical properties of vacuum sintered SiC/spinel nanocomposite, J.
Kennedy, Synthesis, characterization of nickel aluminate nanoparticles by microwave combustion method and their catalytic properties, Mat.

Whilst they work in terms of being more lossy than the alumina and so, when added in sufficient quantities, improve the ability to heat the ceramic from cold and hence be heated and densified, in terms of the final properties achieved, they range from potentially property-enhancing, e.g.
However, whilst composites based on Al2O3 with SiC are known to offer potentially superior mechanical properties, unfortunately they are also significantly more expensive than the monolithic version of alumina, restricting the uses for the end product to high value applications. 2.
For example, research on the firing of zinc oxide varistors yielded results that showed that hybrid sintered devices exhibited more homogeneous and finer microstructures that exhibited superior electrical properties [15].
Taking aluminium nitride, AlN, a ceramic that has many attractive properties for electronics and refractory applications [23], as an example, it is synthesised using two main industrial processes.
Both multimode [29] and single mode [30] approaches have been used; the former suffer from the problem that the whole ceramic part heats up so potentially affecting the microstructure and/or component deformation.

It is concluded that the variations of the bathing saline concentration significantly affect the sound speed in artC and should be well documented in the ultrasonic studies of artC.
ArtC has a important mechanical task to transmit load across joints and provides almost frictionless surfaces to allow unhampered locomotions [1-2].
Significant differences in sound speed were observed in the saline as well as the artC specimens with the change of the saline-concentration (Single-factor ANOVA, p <0.001).
Previously, our group conducted experiments to investigate the swelling properties of artC with changes in the saline solution concentration [19].
Further research is being conducted in our laboratory to find out the dynamic diffusion of saline and various enzymes in artC in order to investigate its swelling properties.

Most researches of ultra-precision machining would focus on a particular aspects of the technology, and seldom link up the different length scales which all affect the quality of machined surface at the micro and nano levels.
Microplasticity Model Microplasticity Model Dynamic Model Dynamic Model Surface Topography Model Surface Topography Model Input Layer Model Layer Output Layer Surface topography and surface roughness Patterns of variation of the shear angle Relative displacement between tool and workpiece Periodicity of the variation of the cutting forces Predicted patterns and power spectrum of micro-cutting force variation Predicted friction angle for the cutting force model Materials properties (e.g. shear strain and stress, etc.)
Based on the crystal plasticity, the shear angle can be inferred from the value of the Taylor factor for a given crystallographic orientation.
It also helps to explain quantitatively the additional roughness caused by the variation of the crystallographic properties of the workpiece, and leads us to a better understanding of the further improvement of the performance of ultra-precision machines.
"A Dynamic Surface Topography Model for the Prediction of Nano-surface Generation in Ultra-precision Machining," International Journal of Mechanical Sciences, Vol. 43, No. 4, p.961 (2001)

Study on Characteristics of Damage Mechanics of Ductile Iron Zhiqiang Jiang1, a, Xilan Feng2,b and Jinfa Shi1,c 1 Department of Industrial Engineering, Zhengzhou Institute of Aeronautics, Zhengzhou 450015, China 2 Department of Mechanical Engineering, Zhengzhou Institute of Aeronautics, Zhengzhou 450015, China a newroom@zzia.edu.cn, b jwen912@zzia.edu.cn, c cad@zzia.edu.cn Keywords: Ductile cast-iron; Damage mechanics; Damage threshold; Critical damage value Abstract.
Introduction Damage mechanics [1-2] studies the material characters that containing mass holes from uniform idea of metal physics, material intensity, continuous medium mechanics etc, and describing the hole size, distributing, shape, forming, growing up and aggregation to affecting the property of material mechanics.
For the plastic strain brought the plastic damnification, one of simple model is that the damaging speed D& is only lied on the effective stress, and σ* is as multiply, fp is as factor.
So, it is very important reference for the design and select material of mechanical structure and configuration.
The critical damage variable can forecast the residual lifecycle of mechanical structure and prevent the paroxysmal accident.

We have investigated the role of the Si excess on the photoluminescence properties of Er doped substoichiometric SiOx layers.
In this paper, we will report our study on the luminescence properties of Er doped SiOx layers having different Si contents.
Films having a good morphology, high stability, and very promising optical properties were obtained through a careful optimization of the annealing conditions.
The optical properties of the as-deposited and annealed Er-Si-O films were studied by photoluminescence measurements.
The PL properties of the Er-Si-O/Si multilayer were explored within a wide range of annealing processes.

,Ltd, Tianjing, 300400, China 2School of Environment & Chemical Engineering, NanChang University, Nanchang, Jiangxi, 330031, China 3School of Mechanical Engineering, Hebei University of Technology, Tianjing, 300130, China atjxiaobing@163.com Keywords: digital test, virtual prototype, product design, bag filter, LabVIEW.
Achieve parallel designing and testing, which is full with the zero-cost, zero-lag, zero error of large and complex mechanical equipment design testing.
In recent years, the digital testing methods was widely applying in aerospace field, it simulation analysed the mechanical properties of various honeycomb structure in different loading conditions by FEM software in the literature [2], then analysed of the structure on the overall mechanical properties of the spacecraft.
Many factors affect the dust gas uniformity, our testing project research the effect to dust gas uniformity by filter wind speed and bag-filter permeability, get the best filter wind speed and bag-filter permeability of the bag filter.
Manufacturing and the future of China-The Chinese 2002 Mechanical Engineering Society Annual Meeting Proceedings [M], 2002, In Chinese

Therefore, stress required to move the dislocations through a lattice having both short- and long-range obstacles is comprised of two components and can be represented as, (1) Here is the athermal stress as it is produced from long-range barriers that are not affected by thermal fluctuation and strain rate.
The isothermal uni-axial compression tests were carried out in a Gleeble thermo-mechanical simulator.
(4) Here, is the Taylor factor and the value of for the steel is 3.06 [7].
Dieter, Mechanical Metallurgy, SI Metric ed.
Raj (Eds.), High Nitrogen Steels and Stainless Steels, Manufacturing, properties and application, Narosa Publishing House, New Delhi, 2004

If motors of out of step have large number, their dynamic process will affect the stability of system.
Dynamic characteristics of motor under disturbance Rotor motion equation of induction motor: (1) Where: is mechanical torque which , is electromagnetic torque,.The slip corresponding the maximum electromagnetic torque is .
Therefore, according to the slip coherent properties, it is need to divide into motors in normal operation and motors of out of step for load modeling.
The paper set the static load and motor mechanical load factor as typical parameters,only identifying the parameters as follows:,The limit of the parameters are,,,,,,,; Load parameter identification is a optimization process, which hope to find a set of optimal parameters to make the model’s response be possible consistent with the actual measurement process.

NUMERICAL ANALYSIS OF NATURAL CONVECTIVE HEAT TRANSFER OVER A VERTICAL CYLINDER USING EXTERNAL FINS Anwesha Panigrahi1,a*, D.P.Mishra2,b, Deepak Kumar3,c 1,2,3 Department of Mechanical Engineering Birla Institute of Technology, Mesra, Ranchi-835215, Jharkhand, India aanwesha199021@gmail.com, bdpmishra@bitmesra.ac.in, cdeepak.bit2013@gmail.com, Keywords: Natural convection, Fins, Cylinder, Nusselt number Abstract The present numerical study deals with the natural convection heat transfer on the surface of a vertical cylinder with external longitudinal fins.
The addition of fins increases the surface area and also rate of heat transfer but the increment is up to a certain limit beyond which they will resist the air flow and cause boundary layer interference that will e\affect the heat transfer adversely.
Water at supercritical pressure has a distinct feature of creating the natural convection in it due to buoyancy forces because of the difference in densities at different points of its flow cross section and this factor exerts an influence of the process of heat transfer in the core of the nuclear reactor.
The fluid properties are constant except density which is a function of temperature. 4.
[5] Leung C.W., et al., “Heat Exchanger Design: Thermal Performances of Rectangular Fins Protruding from Vertical or Horizontal Rectangular Bases”, Applied Energy, 123-140, (1985) [6] Yüncü H. and Güvenc A., “An Experimental Investigation on Performance of Rectangular Fins on a Vertical Base in Free Convection Heat Transfer”, Heat and Mass Transfer, 409-416, (2001) [7] Yüncü H. and Mobedi M., “A Three Dimensional Numerical Study on Natural Convection Heat Transfer from Short Horizontal Rectangular Fin Array”, Heat and Mass Transfer, (2003) [8]Jeong et al., “Natural convection heat transfer estimation from a longitudinally finned vertical pipe using CFD”, Mechanical Science and Technology, 1517-1527, (2009) [9] A.