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Online since: March 2010
Authors: Shi Ming Ji, Da Peng Tan, Feng Qing Xiao
The mechanism of AFM has numerous influence factors and machining parameters.
In mechanical engineering field, the steady drag force is the key component of force loading on the particle.
The restrained module can limit the dimensions of the passage, and consequently affected the environment parameters of the flow field (Pressure, flow rate, turbulence intensity etc.).
In 1933 Nikuradse derived from the formulas for near-wall laminar sublayer height that the linear loss coefficient is a function of Reynolds number Re and the relative roughness factor [5].
This property is evidently a significant factor in the development of machining efficiency and quality.
In mechanical engineering field, the steady drag force is the key component of force loading on the particle.
The restrained module can limit the dimensions of the passage, and consequently affected the environment parameters of the flow field (Pressure, flow rate, turbulence intensity etc.).
In 1933 Nikuradse derived from the formulas for near-wall laminar sublayer height that the linear loss coefficient is a function of Reynolds number Re and the relative roughness factor [5].
This property is evidently a significant factor in the development of machining efficiency and quality.
Online since: April 2017
Authors: Federico Gutiérrez-Solana, David Andrés, Roberto Lacalle, José Alberto Álvarez
However, one of the main requirements to extend the design life is to ensure the integrity of the vessel itself, for which it is required to know the evolution of material properties of the vessel.
STP notched specimens: Master Curve approach In the last few decades, the development of methodologies such as Master Curve [2] has allowed a direct estimation of fracture properties for vessel steels to be carried out.
In eq. (7) “dn” is a parameter that depends on tensile properties and can be obtained from [10].
The tensile properties required by the analysis have been calculated using eq. (1) to (4)
Harling, “The Development of a Miniaturized Disk Bend Test for the Determination of Postirradiation Mechanical Properties”, Journal of Nuclear Materials 103-104 (1981), pp. 1545-1550
STP notched specimens: Master Curve approach In the last few decades, the development of methodologies such as Master Curve [2] has allowed a direct estimation of fracture properties for vessel steels to be carried out.
In eq. (7) “dn” is a parameter that depends on tensile properties and can be obtained from [10].
The tensile properties required by the analysis have been calculated using eq. (1) to (4)
Harling, “The Development of a Miniaturized Disk Bend Test for the Determination of Postirradiation Mechanical Properties”, Journal of Nuclear Materials 103-104 (1981), pp. 1545-1550
Online since: July 2014
Authors: Cherng Shing Lin, Chih Chung Lai
Firefighting Tactics during a Fire Event at a Nightclub
Cherng-Shing Lin1, a, Chih-Chung Lai2, b
1~2Department of Mechanical Engineering, Yuan Ze University, Taoyuan 32003, Taiwan (R.O.C.)
Therefore, fire hazards often result in severe casualties and property loss.
The results of this analysis can be used to formulate/analyze the firefighting and rescue tactics for similar fires, which would decrease the risk of disaster occurrence and increase rescue efficiency, thereby reducing casualties and property loss.
The material properties were set based on the FDS 5 manual [7].
The spread of the smoke particles and the decline in the smoke layer heights reduced visibility, affecting the ability of the occupants to identify the escape direction.
Therefore, fire hazards often result in severe casualties and property loss.
The results of this analysis can be used to formulate/analyze the firefighting and rescue tactics for similar fires, which would decrease the risk of disaster occurrence and increase rescue efficiency, thereby reducing casualties and property loss.
The material properties were set based on the FDS 5 manual [7].
The spread of the smoke particles and the decline in the smoke layer heights reduced visibility, affecting the ability of the occupants to identify the escape direction.
Online since: April 2011
Authors: Carlos José de Araújo, Antonio Almeida Silva, Bruno Allison Araújo, Gabriel Dias Travassos, Eudésio Oliveira Vilar, Jorge Palma Carrasco
In the industrial sectors affected for the hydrogen degradation, the petrochemical sector is one of the most prejudiced.
The degradation of mechanical properties as a result of hydrogen interaction with metals and metallic alloys is manifested by diverse ways: blisters on the surface of the material or internal cracks due to Hydrogen-Induced Cracking, fisheyes due to Hydrogen Attack, failure in non-ferrous based materials structures for Cracking from Hydride Formation, failure due to residual hydrogen in Cracking from Precipitation of Internal Hydrogen and catastrophic cracking of high strength steels due to Hydrogen Embrittlement.
The charging of hydrogen was performed for 24 h in absence of mechanical stress.
This can be explained by the fact that the location of hydrogen in regions with high levels of stress triaxial state is a factor that increases the process of hydrogen embrittlement [6].
Degree in Mechanical Engineering.
The degradation of mechanical properties as a result of hydrogen interaction with metals and metallic alloys is manifested by diverse ways: blisters on the surface of the material or internal cracks due to Hydrogen-Induced Cracking, fisheyes due to Hydrogen Attack, failure in non-ferrous based materials structures for Cracking from Hydride Formation, failure due to residual hydrogen in Cracking from Precipitation of Internal Hydrogen and catastrophic cracking of high strength steels due to Hydrogen Embrittlement.
The charging of hydrogen was performed for 24 h in absence of mechanical stress.
This can be explained by the fact that the location of hydrogen in regions with high levels of stress triaxial state is a factor that increases the process of hydrogen embrittlement [6].
Degree in Mechanical Engineering.
Online since: November 2011
Authors: Shu Qin He, Zi Cheng Zheng, Ling Wang
It is closely related to soil physical and chemical properties, and it is regard as an important parameter to evaluate soil resistance to erosion capacity.
Soil Aggregate, Physical and Chemical Properties.
Each physical and chemical soil properties in composite samples for each site of different land-use pattern were averaged at soil depths of 0–20cm to perform statistical analysis.
Land use patterns affected on water stability index and soil organic matter content.
LI, “Effect of soil physical properties to soil erosion in dry and hot valley of Jinshajiang River,” Journal of Water Resources and Water Engineering, vol 19,pp. 38-41,2008
Soil Aggregate, Physical and Chemical Properties.
Each physical and chemical soil properties in composite samples for each site of different land-use pattern were averaged at soil depths of 0–20cm to perform statistical analysis.
Land use patterns affected on water stability index and soil organic matter content.
LI, “Effect of soil physical properties to soil erosion in dry and hot valley of Jinshajiang River,” Journal of Water Resources and Water Engineering, vol 19,pp. 38-41,2008
Online since: August 2014
Authors: Qiu Hong Wang, Ling Wang, Yu Qing Chen, Bao Niu Zhou
For a long time, it was unavailable to realize continuous automatic processing, which seriously affected the processing efficiency and quality, etc.
Since the machining efficiency is influenced by those factors, it is possible that the machine cannot keep continuously working, etc.
From inside the machine, we needed to deal with the workpiece position and motion, the weight and the shape of the works, the relative positions between the workpiece and cutting tools, geometry and position accuracy, dynamic and static mechanical properties, thermal deformation of coupling, etc..
From the external factors we needed to consider the overall machine tool model and the man-machine relationship, etc., and with a bottom-up and top-down design method of interlock we finished the overall design with compact structure, reasonable, beautiful shape, control, maintenance and convenient online linking shown in Fig. 3.
The design has been put into production, and can be used as a model for advanced manufacturing systems, showing the distinctive characteristics. 8.1 the general machine, developed according to typical solutions of parts CNC machining technology, the workpiece by the time the fixture, could complete turning, milling, drilling, reaming, tapping and other complex machining processes with high-speed and had high efficiency, high-precision, high-end CNC machine properties.
Since the machining efficiency is influenced by those factors, it is possible that the machine cannot keep continuously working, etc.
From inside the machine, we needed to deal with the workpiece position and motion, the weight and the shape of the works, the relative positions between the workpiece and cutting tools, geometry and position accuracy, dynamic and static mechanical properties, thermal deformation of coupling, etc..
From the external factors we needed to consider the overall machine tool model and the man-machine relationship, etc., and with a bottom-up and top-down design method of interlock we finished the overall design with compact structure, reasonable, beautiful shape, control, maintenance and convenient online linking shown in Fig. 3.
The design has been put into production, and can be used as a model for advanced manufacturing systems, showing the distinctive characteristics. 8.1 the general machine, developed according to typical solutions of parts CNC machining technology, the workpiece by the time the fixture, could complete turning, milling, drilling, reaming, tapping and other complex machining processes with high-speed and had high efficiency, high-precision, high-end CNC machine properties.
Online since: August 2011
Authors: Xun Chen, Arif Mohamed, Janet Folkes
This affects the grinding thermal performance significantly.
The commonly used AE feature parameters for the AE monitoring are the peak of RMS values, crest factors analysis (i.e. the ratio of the peak to the RMS level of a signal), kurtosis analysis and moving average technique.
All aforementioned ANN models used in grinding monitoring were trained directly from the AE signals in grinding processes, which included not only thermal AE signals but also mechanical AE signals from mechanical deformation of materials and machine tools as well as environment noise.
This could be due to the material property changes at high temperature.
Kannateyasibu, International Journal of Mechanical Sciences, 1980. 22(5): p. 285-296
The commonly used AE feature parameters for the AE monitoring are the peak of RMS values, crest factors analysis (i.e. the ratio of the peak to the RMS level of a signal), kurtosis analysis and moving average technique.
All aforementioned ANN models used in grinding monitoring were trained directly from the AE signals in grinding processes, which included not only thermal AE signals but also mechanical AE signals from mechanical deformation of materials and machine tools as well as environment noise.
This could be due to the material property changes at high temperature.
Kannateyasibu, International Journal of Mechanical Sciences, 1980. 22(5): p. 285-296
Online since: June 2014
Authors: Ji Wei Han, Ya Nan Cui, Zhen Li, Chao Li, Zhen Zheng Liu
The performance of asphalt directly affects the mechanical properties and performance of asphalts mixture.
Group 17 is a comparing group that is for the influence factors on the test results.
Also the DSR and BBR test should be done to study the rheological and mechanical properties change after salt freezing cycles.
Group 17 is a comparing group that is for the influence factors on the test results.
Also the DSR and BBR test should be done to study the rheological and mechanical properties change after salt freezing cycles.
Online since: November 2015
Authors: P. Niketh, A.J.D. Nanthakumar, J. Jancirani
NIKETH3, c
1 Professor, Department of Mechanical Engineering, Anna University, Chennai 25, India.
2Asso.
A plethora of factors need to be considered while employing such design methodology.
It is equivalent of changing the viscosity index of the MR fluid, which affects the yield behaviour of the MR fluid.
The properties of these materials are given in Table 2.
Table 2: Properties of materials used MRF-140CG Density 3.54e3 to 3.74e3 (kg/m3) Viscosity 0.280 ±0.070 (Pa-s) Copper Density 8700(kg/m3) Electrical conductivity 5.998e7(S/m) Relative permeability 1 Relative permittivity 1 AISI-1040CD Density 7845 (kg/m3) Electrical conductivity 58479.5 (S/m) Relative permeability 2000 Meshing: A triangular mesh is adopted to the MR design, which is shown in Figure 2.
A plethora of factors need to be considered while employing such design methodology.
It is equivalent of changing the viscosity index of the MR fluid, which affects the yield behaviour of the MR fluid.
The properties of these materials are given in Table 2.
Table 2: Properties of materials used MRF-140CG Density 3.54e3 to 3.74e3 (kg/m3) Viscosity 0.280 ±0.070 (Pa-s) Copper Density 8700(kg/m3) Electrical conductivity 5.998e7(S/m) Relative permeability 1 Relative permittivity 1 AISI-1040CD Density 7845 (kg/m3) Electrical conductivity 58479.5 (S/m) Relative permeability 2000 Meshing: A triangular mesh is adopted to the MR design, which is shown in Figure 2.
Online since: June 2014
Authors: George Dragoi, Luminita Rosu, Marius Sebastian Rosu, Irina Ionita
In mining, as in most other production-related industries, the safety of workers is dependent upon many interrelated factors, one of which is the worker’s ability to recognize hazards in the workplace and, this ability is critical because the work environment is confined, inherently dangerous, and constantly changing due to the mining process [14].
To reduce the risk the necesary preventive measures can be [16]: · fencing the areas of excavations, dumping grounds, mine waste dumps or unstable mining terrains and ensuring suitable height of scarps and slopes during mining work, depending on the geological conditions and the properties of the rock; · applying a benching (terraced) system instead of having a steep pit wall; · determining (by the dispatcher) the way of leaving workplaces in case of a water hazard; · channelling incoming water down the slopes to collection points to protect the slopes of surface mines- where necessary, installing water pumps at such collection points; · choosing and creating safe passages for crew members above conveyors and equipping conveyors with safety devices protecting excavated material from the falling; · introducing a ban on manual transport on carriages in excavations whose inclination is above 4° and introducing communication and signalling for the workers of transportation squads; ·
MacGregor: Risk as Analysis and Risk as Feelings: Some Thoughts about Affect, Reason, Risk, and Rationality.
Strojniški Vestnik – Journal of Mechanical Engineering, Vol. 55, No. 2 (2009), pp. 119-130
To reduce the risk the necesary preventive measures can be [16]: · fencing the areas of excavations, dumping grounds, mine waste dumps or unstable mining terrains and ensuring suitable height of scarps and slopes during mining work, depending on the geological conditions and the properties of the rock; · applying a benching (terraced) system instead of having a steep pit wall; · determining (by the dispatcher) the way of leaving workplaces in case of a water hazard; · channelling incoming water down the slopes to collection points to protect the slopes of surface mines- where necessary, installing water pumps at such collection points; · choosing and creating safe passages for crew members above conveyors and equipping conveyors with safety devices protecting excavated material from the falling; · introducing a ban on manual transport on carriages in excavations whose inclination is above 4° and introducing communication and signalling for the workers of transportation squads; ·
MacGregor: Risk as Analysis and Risk as Feelings: Some Thoughts about Affect, Reason, Risk, and Rationality.
Strojniški Vestnik – Journal of Mechanical Engineering, Vol. 55, No. 2 (2009), pp. 119-130