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Online since: November 2011
Authors: Shou Jun Peng, Wei Wang, Wei Guo Liu
The total pressure force affected the dynamics of the moving plate, is known as squeeze-film damping.
As an important factor of sliping micro-mechanical system performance, squeeze-film damping has always been used to modulate Q value of the micro-resonator[1].
It can be used to model squeeze thin-film damping of MEMS unperforated plate structure in three different flow regimes: continuum theory, high Knudsen number, and high Knudsen number with accommodation factors.
If we make use of appropriate substitution of material properties such that: , , , the degree of freedom TEMP will be analogous to pressure.
Make appropriate substitution of material properties and the elements of FEM must be replaced as requirement in Section.Ⅲ, the equation of squeeze thin-film theory and heat transfer analogy theory can be equivalent when we do FEM simulation analyze.
As an important factor of sliping micro-mechanical system performance, squeeze-film damping has always been used to modulate Q value of the micro-resonator[1].
It can be used to model squeeze thin-film damping of MEMS unperforated plate structure in three different flow regimes: continuum theory, high Knudsen number, and high Knudsen number with accommodation factors.
If we make use of appropriate substitution of material properties such that: , , , the degree of freedom TEMP will be analogous to pressure.
Make appropriate substitution of material properties and the elements of FEM must be replaced as requirement in Section.Ⅲ, the equation of squeeze thin-film theory and heat transfer analogy theory can be equivalent when we do FEM simulation analyze.
Online since: June 2017
Authors: Martin Krejsa, Jiri Protivinsky, Monika Kubzova
The dynamic properties of the boilers were tested experimentally in the last year [1] and recently, numerically as well [1, 10, 11, 12, 13, 14, 15, 16].
Reference [12] analyses possibilities of mathematical simulations of the mechanical behaviour of membrane walls.
It is obvious that it is a system with significantly anisotropic properties.
The geometric scale was chosen; scales respecting material properties will be used for the model.
If this scale refers to the quantity that affects the specific activity only marginally, the relevant model law can be declared to be weak.
Reference [12] analyses possibilities of mathematical simulations of the mechanical behaviour of membrane walls.
It is obvious that it is a system with significantly anisotropic properties.
The geometric scale was chosen; scales respecting material properties will be used for the model.
If this scale refers to the quantity that affects the specific activity only marginally, the relevant model law can be declared to be weak.
Online since: August 2013
Authors: Jun Fu Lu, Xue Min Liu, Zhou Hang Li, Yu Xin Wu
The different flow patterns not only affect the mechanical relationship between the two phases, but also affect the heat and mass transfer characteristics [1,2].
To nuclear power, for example, a core of the reactor safety is the heat transfer control, and an important factor of the heat transfer control is the flow pattern judgment.
Many factors have influence on the flow pattern, such as the flow direction, pipe diameter, void fraction and fluid properties [3].
To nuclear power, for example, a core of the reactor safety is the heat transfer control, and an important factor of the heat transfer control is the flow pattern judgment.
Many factors have influence on the flow pattern, such as the flow direction, pipe diameter, void fraction and fluid properties [3].
Online since: October 2007
Authors: H.H. Radamson, Nikolay V. Abrosimov, H. Riemann, N.A Bekin, A.N. Yablonsky, R.Kh. Zhukavin, Y.N. Drozdov, V.N. Shastin, Sergeij G. Pavlov, Heinz Wilhelm Hübers
SiGe crystals [3] and Si/SiGe heterostructures [4] open a broad
field for engineering of electronic and phononic spectra, lifetimes of localized electronic states,
mechanical properties of these media.
This factor minimized impurity broadening, so that the effect of the germanium content on the donor emission efficiency could be studied.
Thus, in the case of superlattices, phosphor donor centers were not affected by strain, but may undergo stronger interaction with neighboring donors, because of the large doping concentration (NP ≈ 10 17 cm-3).
The intensity of the THz photoluminescence on Ge:Ga detector was a factor 5-7 less than the spontaneous emission observed from similar Si:P single crystals, which hade the same size and doping level.
This may affect the depletion rate of the lower level, 1s(T), in the emitter scheme.
This factor minimized impurity broadening, so that the effect of the germanium content on the donor emission efficiency could be studied.
Thus, in the case of superlattices, phosphor donor centers were not affected by strain, but may undergo stronger interaction with neighboring donors, because of the large doping concentration (NP ≈ 10 17 cm-3).
The intensity of the THz photoluminescence on Ge:Ga detector was a factor 5-7 less than the spontaneous emission observed from similar Si:P single crystals, which hade the same size and doping level.
This may affect the depletion rate of the lower level, 1s(T), in the emitter scheme.
Online since: November 2011
Authors: Jun Xiao, Yong Gan, Qun Wang
According to mechanical knowledge of σ=F/S, a force above 4262KN acting on the axel-end can cause the axle-end upsetting.
In order to show the actual results, the material properties in ANSYS are set the same value as that of the actual parameter.
Provided that the analysis results are not affected, it is unwise to choose lower grid-precision grades.
Summary In this paper, reasons of upsetting on axle-end are analyzed with the knowledge of mechanical on the wheelset disassembly and assembly, and the new axle-end protection equipment is designed to solve these problems, which has been analyzed with the finite element software ANSYS.
The application of convex spherical indenter pressing head can eliminate partial load factors cause by mechanical errors and insure the fully fitting of the pressing head and the axle-end surface.
In order to show the actual results, the material properties in ANSYS are set the same value as that of the actual parameter.
Provided that the analysis results are not affected, it is unwise to choose lower grid-precision grades.
Summary In this paper, reasons of upsetting on axle-end are analyzed with the knowledge of mechanical on the wheelset disassembly and assembly, and the new axle-end protection equipment is designed to solve these problems, which has been analyzed with the finite element software ANSYS.
The application of convex spherical indenter pressing head can eliminate partial load factors cause by mechanical errors and insure the fully fitting of the pressing head and the axle-end surface.
Online since: March 2021
Authors: Mary Donnabelle L. Balela, Sellina M. Sy, Wayne Christian P. Datiles
These slicks can affect marine, terrestrial, and human lives if not mitigated properly.
However, the spill intensity and location are key factors in determining the proper treatment with minimum environmental impact and lowest operation cost [1,2].
Cellulose and hemicellulose are responsible for the hydrophilic properties, partial insolubility in organic solvents, and sparingly insolubility in water while the lignin is associated with hydrophobic properties [3].
The effects of pyrolysis temperature and time on the wettability and oil sorption property of the carbonized kapok were also determined.
After each cycle, the solvent was removed from the fibers through mechanical squeezing.
However, the spill intensity and location are key factors in determining the proper treatment with minimum environmental impact and lowest operation cost [1,2].
Cellulose and hemicellulose are responsible for the hydrophilic properties, partial insolubility in organic solvents, and sparingly insolubility in water while the lignin is associated with hydrophobic properties [3].
The effects of pyrolysis temperature and time on the wettability and oil sorption property of the carbonized kapok were also determined.
After each cycle, the solvent was removed from the fibers through mechanical squeezing.
Online since: August 2011
Authors: Po Jung Lai, Wen Ren Jong
The diversified market demand and shorter production cycle, as well as other factors, have increasingly complicate the problems of mold during design and manufacturing.
Considering both design and manufacturing to facilitate the production progress, the effective collaborative development becomes an important issue for mold factor.
In case of selection of mechanical processing machines, cutting tools and different processes in the planned template, the special type mold components and its executive program were optimized via genetic algorithm.
The comparison of optimized properties was based on annealing simulation algorithm and genetic algorithm.
The report can affect the cost of manufacturing the mold, and also provide a reference to the follow-up mold design stage.
Considering both design and manufacturing to facilitate the production progress, the effective collaborative development becomes an important issue for mold factor.
In case of selection of mechanical processing machines, cutting tools and different processes in the planned template, the special type mold components and its executive program were optimized via genetic algorithm.
The comparison of optimized properties was based on annealing simulation algorithm and genetic algorithm.
The report can affect the cost of manufacturing the mold, and also provide a reference to the follow-up mold design stage.
Online since: December 2023
Authors: Franco Zanardi, Giuliano Angella
Introduction
In materials defects and metallurgical discontinuities affect significantly the magnitude and the variability of mechanical properties, which can be very significant in castings because of section sensitivity.
High Silicon Strengthened Ductile Irons (HSiSDIs) present excellent tensile properties, when they are compared to conventional pearlitic-ferritic Ductile Irons (DIs) with similar strengths for Si contents lower than 4.2%wt [1-3].
Indeed, tensile mechanical properties are usually the basic properties required from the international standards for materials classification.
The rationalization of Equation 3 is the following: · kr takes into account the presence and the stress raising power of the defects that make the cracks to nucleate and grow at defects and metallurgical discontinuities; · v should be related to the metallic matrix properties (e.g. ductility), strength and geometry of the metallic matrix-defects interfaces (e.g. nodular, CHG, vermicular or lamellar graphite, shrinkage porosity etc.).
As cast high silicon ductile irons with optimized mechanical properties and remarkable fatigue properties.
High Silicon Strengthened Ductile Irons (HSiSDIs) present excellent tensile properties, when they are compared to conventional pearlitic-ferritic Ductile Irons (DIs) with similar strengths for Si contents lower than 4.2%wt [1-3].
Indeed, tensile mechanical properties are usually the basic properties required from the international standards for materials classification.
The rationalization of Equation 3 is the following: · kr takes into account the presence and the stress raising power of the defects that make the cracks to nucleate and grow at defects and metallurgical discontinuities; · v should be related to the metallic matrix properties (e.g. ductility), strength and geometry of the metallic matrix-defects interfaces (e.g. nodular, CHG, vermicular or lamellar graphite, shrinkage porosity etc.).
As cast high silicon ductile irons with optimized mechanical properties and remarkable fatigue properties.
Online since: March 2007
Authors: Jean Louis Soubeyroux, Stéphane Gorsse, G. Orveillon
The ODF model, synthesized alloys by mould casting,
characterization by X-ray diffraction and DSC techniques are presented.
1.Introduction
Bulk metallic glasses (BMG) exhibit particularly attractive mechanical properties like high stresses
to fracture and large elastic strains.
It is also important to produce alloys with a high critical diameter (or thickness) in order to produce thick pieces with the vitrous characteristics responsible of the good mechanical properties.
There is a lack of data on the surface energies; however, the driving forces are the main factor that affects nucleation kinetics [10,11] and can be calculated if the Gibbs free energies of the crystalline phases are known.
Concerning the particular alloys obtained in this study, the best compositions studied are for a rare earth content of 11 or 12%, they present a high crystallization temperature (≈ 396 K for Y, ≈ 385 K for Gd), a high melting temperature (≈ 730 K for Y, ≈ 708 K for Gd), a large ΔT (75-70 K) and a high γ value (> 0.41), samples with 10 millimeter diameter are almost fully amorphous with the presence of a minor crystallized fraction that could have a good influence on mechanical properties.
Mechanical properties under compression at room temperature and in the ΔT range are under investigations.
It is also important to produce alloys with a high critical diameter (or thickness) in order to produce thick pieces with the vitrous characteristics responsible of the good mechanical properties.
There is a lack of data on the surface energies; however, the driving forces are the main factor that affects nucleation kinetics [10,11] and can be calculated if the Gibbs free energies of the crystalline phases are known.
Concerning the particular alloys obtained in this study, the best compositions studied are for a rare earth content of 11 or 12%, they present a high crystallization temperature (≈ 396 K for Y, ≈ 385 K for Gd), a high melting temperature (≈ 730 K for Y, ≈ 708 K for Gd), a large ΔT (75-70 K) and a high γ value (> 0.41), samples with 10 millimeter diameter are almost fully amorphous with the presence of a minor crystallized fraction that could have a good influence on mechanical properties.
Mechanical properties under compression at room temperature and in the ΔT range are under investigations.
Online since: August 2018
Authors: Ya Ran Niu, Xue Bin Zheng, Jin Liang Sun, Xin Zhong, Tao Zhu, Hong Li
Some investigations have been focused on the mechanical and thermal properties of bulk Yb2SiO5 and Yb2Si2O7.
However, the microstructure and properties of Yb2SiO5 and Yb2Si2O7 coatings are quite different from those of bulk materials.
The aging stress (σa) is a stress due to changes in physical, mechanical and chemical properties of a coating that are induced by thermal exposures.
Zhou, Mechanical and thermal properties of Yb2SiO5: a promising material for T/EBCs applications, J.
Sun, Microstructure and thermal properties of atmospheric plasma sprayed Yb2Si2O7 coating, J.
However, the microstructure and properties of Yb2SiO5 and Yb2Si2O7 coatings are quite different from those of bulk materials.
The aging stress (σa) is a stress due to changes in physical, mechanical and chemical properties of a coating that are induced by thermal exposures.
Zhou, Mechanical and thermal properties of Yb2SiO5: a promising material for T/EBCs applications, J.
Sun, Microstructure and thermal properties of atmospheric plasma sprayed Yb2Si2O7 coating, J.