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Online since: May 2013
Authors: Bing Jie Li
The test result demonstrates that the test method could simulate the dangerous conditions during the real construction and check the stress effectively which can provide technical support for the construction of similar bridges.
1.Introduction
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Arch-girder combination bridge becomes more and more important in bridge construction because of its outstanding mechanical property and good adaptability for construction [1].
This test took the contour size and thickness as fundamental dimensional analysis factors.
Because construction period of many bridges is long, the bridge may be affected by the wind load in construction process.
(4) Rigidity, weight, length and other factors should be taken into account, so that large stress and deflection of launching nose does not appear in the biggest cantilever state.
This test took the contour size and thickness as fundamental dimensional analysis factors.
Because construction period of many bridges is long, the bridge may be affected by the wind load in construction process.
(4) Rigidity, weight, length and other factors should be taken into account, so that large stress and deflection of launching nose does not appear in the biggest cantilever state.
Online since: July 2013
Authors: Andreas Kyprianou, Andreas Tjirkallis, George Vessiaris
Tjirkallis A1,b, Kyprianou A2,b, Vessiaris G3,c
1,2,3 School of Engineering Department of Mechanical and
Manufacturing Engineering, University of Cyprus.
However, in reality, structures are subjected to changing environmental and operational factors, such as temperature and moisture, which cause significant changes in its properties.
Wavelet Transform allows a very precise analysis of the regularity properties of a signal, determining the points on a signal or on its derivatives that display abrupt changes.
[3] Cornwell P., Farrar C.R., Doebling S.W., Sohn H., Environmental variability of modal properties, Experimental Techniques, 1999, 45–48
Mechanical Systems and Signal Processing 21 (2007), p. 780-794
However, in reality, structures are subjected to changing environmental and operational factors, such as temperature and moisture, which cause significant changes in its properties.
Wavelet Transform allows a very precise analysis of the regularity properties of a signal, determining the points on a signal or on its derivatives that display abrupt changes.
[3] Cornwell P., Farrar C.R., Doebling S.W., Sohn H., Environmental variability of modal properties, Experimental Techniques, 1999, 45–48
Mechanical Systems and Signal Processing 21 (2007), p. 780-794
Online since: November 2017
Authors: Olena Svietkina, Svitlana Lysytska, Vsevolod Franchuk
The quality of fuel pellets is affected by the moisture content, size and material of the semi-finished product.
Despite of the broad prospects for the processing of wood waste and energy use, there are a lot of factors having a certain impact on the efficiency of the using of woody biomass.
In addition, the physicochemical and thermal properties of different species of woody biomass have some differences therefore, knowledge of the specific features of woody biomass allows us to provide qualified development and implementation of measures for economical and ecological efficient operation of boilers.
Discussion of Results of Research The quality of pellets depends on several factors: humidity, size and material of the semi-finished product.
The intensity of supply of mechanical power was 2 W / g.
Despite of the broad prospects for the processing of wood waste and energy use, there are a lot of factors having a certain impact on the efficiency of the using of woody biomass.
In addition, the physicochemical and thermal properties of different species of woody biomass have some differences therefore, knowledge of the specific features of woody biomass allows us to provide qualified development and implementation of measures for economical and ecological efficient operation of boilers.
Discussion of Results of Research The quality of pellets depends on several factors: humidity, size and material of the semi-finished product.
The intensity of supply of mechanical power was 2 W / g.
Online since: March 2012
Authors: Zhi Ming Zhang, Bin Sun, Hong Di Zhang, Jie Zheng, Zhi Hua Zhang, Wei Hua Han, Feng Shao, Jia Yin Huang, Yun-Ze Long
Introduction
One-dimensional (1D) nanotubes, nanowires and nanofibers have been extensively explored due to their unique physical and chemical properties and potential applications in nanoscale devices [1,2].
Humidity is another factor to influence the surface morphology of electrospun fibers.
However, the fiber morphology is less affected by the spinning distance, beaded fibers mixed with uniform fibers are obtained in all the cases.
In the present case, the repeated bends in Fig.4 that have characteristic repeat distance of several (or a few tens of) microns are typical of the mechanical buckling features.
The formation mechanism of helical and wavelike fibers can be ascribed to mechanical jet buckling and/or electrical driven bending instability.
Humidity is another factor to influence the surface morphology of electrospun fibers.
However, the fiber morphology is less affected by the spinning distance, beaded fibers mixed with uniform fibers are obtained in all the cases.
In the present case, the repeated bends in Fig.4 that have characteristic repeat distance of several (or a few tens of) microns are typical of the mechanical buckling features.
The formation mechanism of helical and wavelike fibers can be ascribed to mechanical jet buckling and/or electrical driven bending instability.
Online since: March 2014
Authors: Doina Elena Gavrilă, Horia Catalin Gavrilă
The realization of HAMR involved some challenges from both optical design and media properties [3, 4].
It is based on the fact that the drastic decrease of the intrinsic magnetic properties of the medium (saturation magnetization Ms, anisotropy field, and coercive field Hc) when the temperature T of the media is increased.
Nevertheless, the lattice structure and the magnetic properties of the FePt-based alloys, correlated by the spin-orbital interaction, are affected by thermal agitation and, therefore, the heating and cooling issues are very important factors for HAMR media in both static and dynamic aspects [1].
Nevertheless, the technology based on lithography and nanoprinting involves the process of etching to form the magnetic bit, which damages the bit, thus affecting the magnetic anisotropy (and therefore the thermal stability) and increasing the switching field distribution.
A good choice of the layers separating the recording layer from the substrate (interlayer, seed layer and heat sink layer) is crucial from the viewpoint of the thermal design of HARM media so more as this design must take into consideration the magnetic, structural and even mechanical properties of the media configuration.
It is based on the fact that the drastic decrease of the intrinsic magnetic properties of the medium (saturation magnetization Ms, anisotropy field, and coercive field Hc) when the temperature T of the media is increased.
Nevertheless, the lattice structure and the magnetic properties of the FePt-based alloys, correlated by the spin-orbital interaction, are affected by thermal agitation and, therefore, the heating and cooling issues are very important factors for HAMR media in both static and dynamic aspects [1].
Nevertheless, the technology based on lithography and nanoprinting involves the process of etching to form the magnetic bit, which damages the bit, thus affecting the magnetic anisotropy (and therefore the thermal stability) and increasing the switching field distribution.
A good choice of the layers separating the recording layer from the substrate (interlayer, seed layer and heat sink layer) is crucial from the viewpoint of the thermal design of HARM media so more as this design must take into consideration the magnetic, structural and even mechanical properties of the media configuration.
Online since: March 2024
Authors: V.R. Muruganantham, M. Thirumalaimuthukumaran
A current state map is developed with available information gathered from the production unit, to identify the time-consuming factors like waiting time, improper inspection, and the lack of material and resources for manufacturing.
If the product is waiting for a long time, it tends to change the property of the material due to rust formation and also increases the lead time of the product.
In Future State Map, time-consuming factors in the current state map were identified.
It concludes that lack of material handling devices and defective part manufacturing is the major factors for an excess cycle time of the product.
[4] Anupam Sinha, Vinod Kumar, Umed Khod, “Application of value stream mapping in small scale industry”, International Journal of Mechanical Engineering and Robotics Research, vol. 3, no. 3, pp. 738-746, 2014
If the product is waiting for a long time, it tends to change the property of the material due to rust formation and also increases the lead time of the product.
In Future State Map, time-consuming factors in the current state map were identified.
It concludes that lack of material handling devices and defective part manufacturing is the major factors for an excess cycle time of the product.
[4] Anupam Sinha, Vinod Kumar, Umed Khod, “Application of value stream mapping in small scale industry”, International Journal of Mechanical Engineering and Robotics Research, vol. 3, no. 3, pp. 738-746, 2014
Online since: September 2011
Authors: Jian Jun Xi, Guo Jun Niu, Jun Zhao
Micro-arc oxidation ceramic coating is produced by micro plasma oxidation which improves the corrosion resistance property of titanium alloy.
The property of MAO coating is related with the compact layer.
So in order to impove the property of coating, it is emphasized that the reasearch on the electrical and solution parameters which are helpful to improve the the rate of compact layer is important.
Fig.6 Friction coefficient of MAO coating of the three types of electrolyte Ablation affected by the concentration of NaF The ablation phenomenon is common during the MAO, which reduces the film's mechanical and corrosion resistance.
It can be inferred that the concentration of NaF is a factor leading ablation.
The property of MAO coating is related with the compact layer.
So in order to impove the property of coating, it is emphasized that the reasearch on the electrical and solution parameters which are helpful to improve the the rate of compact layer is important.
Fig.6 Friction coefficient of MAO coating of the three types of electrolyte Ablation affected by the concentration of NaF The ablation phenomenon is common during the MAO, which reduces the film's mechanical and corrosion resistance.
It can be inferred that the concentration of NaF is a factor leading ablation.
Online since: April 2004
Authors: Jae Do Kwon, Sang Jin Cho, Yong Tak Bae
Changes to the mechanical properties such as hardness, tensile strength and fatigue
limit are as a result of micro structural changes that are induced by the thermal degradation of
materials.
Fretting is a kind of surface degradation mechanism observed in mechanical components and structures.
Thus, the evaluation of fatigue limits that factor thermal degradation and fretting damage are essential to ensure reliability of equipment.
Table 1 Chemical compositions of degraded 1Cr-0.5Mo steel Composition, wt. % C Si Mn P S Ni Cr Mo Cu Al 0.18 0.27 0.68 0.016 0.014 0.095 0.94 0.44 0.12 0.008 Table 2 Mechanical properties of 1Cr-0.5Mo steel Material 0.2% yield strength (MPa) Tensile strength (MPa) Elongation (%) Youngs modulus (GPa) Degraded 313 487 26 188 Reheat-treated 329 481 32 199 a) Degraded material b) Reheat-treated material Fig. 1 Optical micrographs for degraded and reheat-treated materials Test temperture ( o C ) -200 -100 0 100 200 300 Impact absorbed energy ( J ) 0 50 100 150 200 250 300 Degraded material Reheat-treated material Fig. 2 Results of impact test Constant normal load was measured by strain gauges bonded to the side of proving ring.
In the degraded materials, it is considered that internal micro-cracks, occurring in regions below the contact surface, of highly populated coarse carbides, affect crack growth.
Fretting is a kind of surface degradation mechanism observed in mechanical components and structures.
Thus, the evaluation of fatigue limits that factor thermal degradation and fretting damage are essential to ensure reliability of equipment.
Table 1 Chemical compositions of degraded 1Cr-0.5Mo steel Composition, wt. % C Si Mn P S Ni Cr Mo Cu Al 0.18 0.27 0.68 0.016 0.014 0.095 0.94 0.44 0.12 0.008 Table 2 Mechanical properties of 1Cr-0.5Mo steel Material 0.2% yield strength (MPa) Tensile strength (MPa) Elongation (%) Youngs modulus (GPa) Degraded 313 487 26 188 Reheat-treated 329 481 32 199 a) Degraded material b) Reheat-treated material Fig. 1 Optical micrographs for degraded and reheat-treated materials Test temperture ( o C ) -200 -100 0 100 200 300 Impact absorbed energy ( J ) 0 50 100 150 200 250 300 Degraded material Reheat-treated material Fig. 2 Results of impact test Constant normal load was measured by strain gauges bonded to the side of proving ring.
In the degraded materials, it is considered that internal micro-cracks, occurring in regions below the contact surface, of highly populated coarse carbides, affect crack growth.
Online since: January 2022
Authors: Zi Ting Tian
It should be advantageous because simplicity and convenience are important factors in industrial production.
By adjusting the used polymers, the electric field, and other conditions of electrospinning, researchers can control the fiber diameters and the pore size that are related to the mechanical properties of nanomaterials.
The final film has relatively steady properties of resistance and transmittance with outstanding mechanical flexibility [14].
Since different polymers have various physical properties, it is possible to find a suitable material that both has appropriate properties and could be used in electrospinning.
For example, temperature affects surface tension, adhesion, and viscosity, allowing scaffolds made of certain materials to change mechanical properties such as shape or the rate of degradation.
By adjusting the used polymers, the electric field, and other conditions of electrospinning, researchers can control the fiber diameters and the pore size that are related to the mechanical properties of nanomaterials.
The final film has relatively steady properties of resistance and transmittance with outstanding mechanical flexibility [14].
Since different polymers have various physical properties, it is possible to find a suitable material that both has appropriate properties and could be used in electrospinning.
For example, temperature affects surface tension, adhesion, and viscosity, allowing scaffolds made of certain materials to change mechanical properties such as shape or the rate of degradation.
Online since: September 2018
Authors: I.V. Lukiyanchuk, Vladimir S. Rudnev, Alexander Yu. Ustinov, Ksenia A. Sergeeva, A.V. Nepomnyaschiy, E.S. Zykova, Galina I. Marinina, Marina S. Vasilyeva
At the same time, one should emphasize that indicator properties of metal–oxide electrodes are substantially affected by the composition, structure, and properties of the surface in immediate contact with solution.
With respect to the modified electrode, in addition to the above factors, one should know the type of modifying agent (in this case gold) present on the surface.
The absence of indicator properties in these electrodes must be caused by their low electronic conductivity. 4.
In comparison with the glass electrode, they have high mechanical stability.
Rudnev, Electroanalytical properties of metal–oxide electrodes formed by plasma electrolytic oxidation, J.
With respect to the modified electrode, in addition to the above factors, one should know the type of modifying agent (in this case gold) present on the surface.
The absence of indicator properties in these electrodes must be caused by their low electronic conductivity. 4.
In comparison with the glass electrode, they have high mechanical stability.
Rudnev, Electroanalytical properties of metal–oxide electrodes formed by plasma electrolytic oxidation, J.