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Vibrational properties knowledge helps in design, control and reduce undesirable vibration, but direct measurement is difficult and contain significant errors.
The aim of this paper is the presentation of an efficient method using acoustics that can obtain vibrational properties by measuring other quantities, like fluid pressure dynamics somewhere near the structure.
In Inverse Numerical Acoustics properties of vibrating source i.e. surface vibration of source, is reconstructed by measuring sound pressure of some points of fluid field near the vibrating source.
One major parameter, which affects the history identification, is error in data measurements.
Its properties are material density: 7800 kg/m3, Young’s modulus: 200 Gpa, Poisson ratio: 0.3, thickness: 0.01 m, air density: 1 kg/m3, and wave velocity in air: 334 m/sec.

Weakness: The molded products internal stress caused by poor design problem. 3) POM (polyacetal) Properties: as the crystalline hot plasticity plastic, showed high melting point of 165 ~ 175 ℃, nature is the most close to the metal, generally referred to as tech Advantages: with high mechanical strength and rigidity, the highest fatigue strength, environmental resistance, good resistance to organic solvents, strong resistance to repeated impact, widely use temperature range (- 40 ℃ ~ 120 ℃) 6, excellent electrical properties, good resilience and self lubrication and good abrasion resistance, dimension stability Disadvantages: the thermal decomposition process if long time high temperature, no self-extinguishing, poor resistance to acid and forming shrinkage 4) PP (polypropylene) Properties: light plastic, density of 0.9 g/cm3 without preheating dry processing properties.
Demerits: nylon high hygroscopicity, size precision and the property affected for a long time. 6) PMMA (polynomial methacrylate Jacques plexiglass) Properties: amorphous polymer, 92% light transmittance, thermal denaturation temperature between 74 ~ 102 shrinkage rate between 0.4 and 0.7% 1.5 4mm thick.
Water resistance, drug resistance, electrical properties, excellent soft (LDPE).
Beijing: mechanical industry publishing house, 2004.246-296
Factors influencing the plastic electroplating plastic process analysis.

Therefore, by electrospinning, PVA become to be excellent mechanical properties nanofibers which has good spinnability and film-forming. [7]Polyethylene Glycol (PEG) is a thermoplastic polymer with perfect crystalline and good water-soluble.
The fiber diameter is also affected significantly by the change of spinning area.
(Fig.3; Fig.4; Fig.5) Applied voltage and collect distance may be affect some factors such as mass of polymer fed out from a tip of needle, elongation level of a jet by an electrical force, morphology of a jet (a single or multiple jets), etc.
(Fig.6) A balance among these factors may determine a final diameter of electrospun fibers.
Table1 Thermal properties of PVA/PEG composite nanofibers Polymer DSC ( OC ) ΔH (J/g) Tm Tm(on) Tm(end) Tc Tc(on) Tc(end) ΔHm ΔHc PEG/PVA=6:4 PEG2000:PEG4000 (w/w) 10:0 55.99 49.84 60.47 29.25 34.91 21.79 93.21 89.58 9:1 59.29 49.80 65.32 29.88 34.69 22.97 87.83 83.92 8:2 59.62 50.07 63.98 29.96 35.48 24.26 99.65 90.67 7:3 58.80 51.26 63.68 31.82 36.06 23.80 96.47 95.48 6:4 60.71 50.89 67.02 30.31 36.42 23.65 93.90 99.58 5:5 60.33 51.64 65.26 31.66 36.52 27.54 97.29 102.35 0:10 64.55 54.44 70.33 32.60 38.68 25.70 98.00 92.92 Conclusions In this study, effects of processing parameters for the polymer solution properties and processing condition on the morphology were studied.

The open arc welding robots have been used widely nowadays; however, the elastic deformations of every inner link inevitably affect the welding quality.
Generally, the randomness of the engineering structures may be material randomness, dimension randomness, boundary condition randomness, and physical property randomness.
Motion accuracy of the welding gun head is a main factor affecting the welding quality.
Chinese Journal of Mechanical Engineering,2011,Vol.47,No.23,pp 39-41 [2] Chang Li, Xing Han.
Journal of Mechanical Transmission. 2012(3), 64-66 [6] Yi Wang, Liyan Wu, Liu Geng.

The physical properties and microstructures of supporting anodes are crucial for the performances of the entire SOFCs.
These factors decrease with increasing porosity, and hence usually a porosity of around 40 vol.% is regarded as appropriate.
The big pores may be beneficial to the Transport of the gas, but also may decrease the TPBs to hider the contaction between Ni, block the conducting channel in the anode, make the anode loosen, effect the electrical Properties and Mechanical Properties of the cell.
[5] R.M.C.Clemmer, S.F.Corbin, Influence of porous composite microstructure on the processing and properties of solid oxide fuel cell anodes, Solid State Ionics. 166 (2004) 251–259
Oh, Microstructure and anodic properties of Ni/YSZ cermets in solid oxide fuel cells, Solid State Ionics. 98 (1997) 39-41.

The content and distribution of pore defects are related to the type of resin (different types of resins have different constituent materials, wettability, and rheological properties) and process parameters (temperature, pressure) [15].Pore defects have a significant effect on mechanical properties of composite structures [16,17].Li et al [16] investigated the effect of curing pressure on basic mechanical properties (including tensile, compressive, flexural, and shear properties) of CCF800H/AC531 composites, and found that when the curing pressure was lower than the effective pressure, the internal bubbles in the members were difficult to be eliminated by pressurization, and the mechanical properties decreased by at least 40% at room temperature.
The porosity defined in this way cannot distinguish the location of voids distribution, which affects the inter-ply properties of the composite parts [18].
A finite element calculation of stress intensity factors by a modified crack closure integral.
Effects of porosity on the mechanical properties of additively manufactured components: a critical review.
Effects of variation in autoclave pressure, temperature, and vacuum-application time on porosity and mechanical properties of a carbon fiber/epoxy composite.

There are some factors affecting the biodegradability such as molecular structure, chemical properties and environmental conditions [3].
Some other properties of vegetable oil such as high viscosity index, good lubricity, high flash point and low evaporative loss [4] are measurable characteristics to choose the best lubricant.
Rapeseed oils have excellent lubricating properties, load carrying capacity, and corrosion protection properties compared to mineral oil.
However, vegetable oils have poor performances at high temperature and poor oxidation properties.
Summary The tribological properties of RBD palm olein have been investigated using four-ball tribometer at different operating temperatures.

The effect of undissolved ferrite amount on bending fatigue properties and failure mechanism were studied by using 42CrMo steel with subcritical quenching process The amount of undissolved ferrite were 0%, 10% and 15%, respectively.
Introduction Microstructure is one of important factors which affect the bending fatigue properties and life.
Some researchers studied the effect of undissolved ferrite on contact fatigue properties [3,4].
The effects of undissolved ferrite on bending fatigue properties and life were discussed.
In order to understand the effect of undissolved ferrite on the bending fatigue properties and failure mechanism, the bending fatigue tests were carried out on 12-1type bending fatigue tester.

Introduction A large number of studies have shown that thermal error is one of the main factors influencing the machining accuracy of the high-speed machine tools [1].
There are many complex factors contributing to thermal errors of mechanical processing, so in this way thermal errors show evident grey property [4].
The aim is to calculate relational grade of different factors to finds out key influencing factors in the system.
For two different sequences Xi(m) and Xj(m) of factors i and j, their relational grade are r0i and r0j, respectively .
The results are listed as follows: r01= 0.65060, r02= 0.65245, r03= 0.65348, r04= 0.65396 r05=0.65380, r06= 0.65306, r07= 0.65204, r08=0.65132 So the relational grade order can be got as follows: r04＞r05＞r03＞r06＞r02＞r07＞r08＞r01 It can be concluded that factor 4 has the greatest effect on the reference sequence, and the order of significance of the effects of the 8 factors on the reference sequence is described as factor 4＞factor 5＞factor 3＞factor 6＞factor 2＞factor 7＞factor 8＞factor 1.

These years the principle of elastic dynamic is used to determine the various mechanical properties of materials and interior damage of material appearing in previous period.
The unreversed micro-transformation including micro-flaw extending, space-growing will appear when the structure and organize suffer from exterior load or circumstance factors,which will cause the degradation of the material macroscopical mechanical character’s inferiority-damage.
The bearing ability of structure is affected obviously by the damage.
If the damage cause the material character’s difference between the different segments of the structure,it should be dealed with by subarea according to the various material property.
The damage location a’s effect on the (a)wave amplitude affected curve (b)wave propagation time affected curve The damage region location ‘s effect on the wave propagation is complex comparatively.