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Online since: December 2011
Authors: B. Ravi Kumar
Material Processing and Characterisation
The solution treated at 1060 oC commercial AISI 304L grade austenitic stainless steel was subjected to multi pass unidirectional cold rolling of 90% of reduction in thickness in a two-high rolling mill.
TSL OIM analysis software was used for data analysis.
Interestingly, no significant increase in the grain size and reduction in the fraction of low angle boundaries (LAB) were found by increasing the number of TC.
The high recrystallisation kinetics should promote the reduction of the average grain size.
TSL OIM analysis software was used for data analysis.
Interestingly, no significant increase in the grain size and reduction in the fraction of low angle boundaries (LAB) were found by increasing the number of TC.
The high recrystallisation kinetics should promote the reduction of the average grain size.
Online since: July 2007
Authors: Massimo Tolazzi, Marion Merklein
Introduction
The stronger international competition, together with the increasing demands of the costumers is
leading to a drastic reduction of the product's life time and as a consequence to shorter development
cycles.
In the field of automotive this trend goes together with the introduction of new lightweight concepts for the reduction of the vehicles' weight and consumption, like the use of new materials, new manufacturing technologies and new design solutions [1].
Nevertheless the results obtained by numerical approaches can be only as precise as the input data used for modeling the plastic, friction and failure behavior of the material.
It follows that a complex strain path biaxial stretching - plain strain leads to a drastic reduction of the material formability, while the combination biaxial stretching - uniaxial tension gives an unchanged formability compared to a linear strain path up to the same final strains.
In the field of automotive this trend goes together with the introduction of new lightweight concepts for the reduction of the vehicles' weight and consumption, like the use of new materials, new manufacturing technologies and new design solutions [1].
Nevertheless the results obtained by numerical approaches can be only as precise as the input data used for modeling the plastic, friction and failure behavior of the material.
It follows that a complex strain path biaxial stretching - plain strain leads to a drastic reduction of the material formability, while the combination biaxial stretching - uniaxial tension gives an unchanged formability compared to a linear strain path up to the same final strains.
Online since: March 2014
Authors: Wei Pan, Zhi Xue Qu, Qun Wang, Bin Pang, Xue Cheng Hou
The first is in situ reduction sintering.
This may be attributed to the water vapors produced during the reduction of Ni2O3 by H2.
The remarkable feature of the data is that the real and imaginary parts of the permeability almost increase linearly with the increasing content of Ni.
For the first method in situ reduction sintering, almost homogeneous composites were obtained but with a low density.
This may be attributed to the water vapors produced during the reduction of Ni2O3 by H2.
The remarkable feature of the data is that the real and imaginary parts of the permeability almost increase linearly with the increasing content of Ni.
For the first method in situ reduction sintering, almost homogeneous composites were obtained but with a low density.
Online since: December 2012
Authors: Dan Wang, Zhong Chang Liu, Jing Tian
All these temperatures, pressures were record using the LabVIEW data acquisition system.
The maximum EGR and minimum air flow were applied during the rapid reduction in exhaust flow.
However, there was no obviously reduction in peak temperature compared to DPF regeneration during idle without control, the maximum temperature was still around 870℃at TC4.
A reduction of peak temperature by 130˚C was achieved with the control strategy activated compared to the uncontrolled regeneration during idle without control.
The maximum EGR and minimum air flow were applied during the rapid reduction in exhaust flow.
However, there was no obviously reduction in peak temperature compared to DPF regeneration during idle without control, the maximum temperature was still around 870℃at TC4.
A reduction of peak temperature by 130˚C was achieved with the control strategy activated compared to the uncontrolled regeneration during idle without control.
Spinach Ferredoxin (Fdx) as an Organic Material to Improve Optical Band Gap of Chitosan (Cs) Biofilm
Online since: April 2015
Authors: Tulus Ikhsan Nasution, Mohd Nazree B. Derman, Irwana Nainggolan, Devi Shantini Chandrasakaran
Introduction
In the past few years, research on organic and polymeric materials as media for optoelectronic device such as optical information transmission, optical data storage, and processing has dramatically increased [1].
The reduction in band gap energy value indicates that spinach-ferredoxin has improved the optical properties of the film in which less energy is needed for the electron to flow within the films.
Hence, it creates an extra pathway for the electron flow within the films where it contributes to reduction in band gap energy which is consistent with the results depicted in Fig 2.
The reduction in optical band gap values indicates that Cs and Cs-Fdx films have a good potential to be used in optical applications.
The reduction in band gap energy value indicates that spinach-ferredoxin has improved the optical properties of the film in which less energy is needed for the electron to flow within the films.
Hence, it creates an extra pathway for the electron flow within the films where it contributes to reduction in band gap energy which is consistent with the results depicted in Fig 2.
The reduction in optical band gap values indicates that Cs and Cs-Fdx films have a good potential to be used in optical applications.
Online since: January 2012
Authors: Peng Fei Chen, Chen Peng, Zheng Yi Ti
Comparative analysis in 28# model's rigid body limit equilibrium method and numerical simulation by FLAC3D
Comparative analysis in 28# model's rigid body limit equilibrium method and numerical simulation by FLAC3D is shown in Tab. 4.2:
Tab. 4.2 The contrast of safety coefficient by limit equilibrium method and FLAC3D strength reduction method
calculation method
calculation standards
cafety coefficient
rigid body limit equilibrium method
Mohr-Coulomb standards
1.11
FLAC3D shear strength reduction
Mohr-Coulomb Elastic-plastic constitutive model
1.13
From the figure and the table we can see that the results of two methods is almost the same,the safety coefficients are anastomosed.The two methods are both rationality.
Conclusion (1)Basis for the hydrogeological and engineering geological data in the first mining area in Weijiamao open-pit mine, analysis the slope's physical and mechanical properties.According the experiment get the physical and mechanics index with the weak layer in the coal seam roof and floor,knocking out the main factors of slope failure are the weak layer and the loess upper
Based on FLAC strength reduction of slope stability theory [J].
Conclusion (1)Basis for the hydrogeological and engineering geological data in the first mining area in Weijiamao open-pit mine, analysis the slope's physical and mechanical properties.According the experiment get the physical and mechanics index with the weak layer in the coal seam roof and floor,knocking out the main factors of slope failure are the weak layer and the loess upper
Based on FLAC strength reduction of slope stability theory [J].
Online since: December 2011
Authors: Rui Qi Li, Bo Hong Li, Xiao Min Ren, Shan Tao Yan, Zheng Jin, Chuan Li Qin, Dong Yu Zhao
The curves show that there are different oxidation peak potential and reduction peak potential at various CA ratios.
And the biggest oxidation peak current and reduction peak current are obtained at CA:AN=1:4.
a-1:5;b-1:4;c-1:3;d-1:2;e-1:1 Fig. 2 CV curves of PANI composite at various CA and aniline ratio The specific capacitance of PANI/CA composite electrode materials is calculated from the following equation: , where Cp is the specific capacitance of electrode materials (F•g-1), Ia and Ic are the current of oxidation and reduction peaks respectively (mA), m is the mass of the activated material (g), is the scanning rate of voltage (mv•s-1).
Table2 Charge and discharge data of supercapacitors at various CA and aniline CA:AN Cp(F·g-1) Ep(Wh·kg-1) 1:5 6.67 2.08 1:4 127.53 39.85 1:3 32.66 10.21 1:2 20.44 5.39 1:1 7.00 2.19 Ni(OH)2 and PANI/CA composite electrode materials as positive and negative electrodes respectively, are assembled into a supercapacitor.
And the biggest oxidation peak current and reduction peak current are obtained at CA:AN=1:4.
a-1:5;b-1:4;c-1:3;d-1:2;e-1:1 Fig. 2 CV curves of PANI composite at various CA and aniline ratio The specific capacitance of PANI/CA composite electrode materials is calculated from the following equation: , where Cp is the specific capacitance of electrode materials (F•g-1), Ia and Ic are the current of oxidation and reduction peaks respectively (mA), m is the mass of the activated material (g), is the scanning rate of voltage (mv•s-1).
Table2 Charge and discharge data of supercapacitors at various CA and aniline CA:AN Cp(F·g-1) Ep(Wh·kg-1) 1:5 6.67 2.08 1:4 127.53 39.85 1:3 32.66 10.21 1:2 20.44 5.39 1:1 7.00 2.19 Ni(OH)2 and PANI/CA composite electrode materials as positive and negative electrodes respectively, are assembled into a supercapacitor.
Online since: January 2021
Authors: Nageswara Rao Muktinutalapati, Geetha Manivasagam
Such unfavourable aging treatments may adversely affect not only the static properties such as reduction in area and elongation in a tensile test, but also dynamic properties such as impact toughness.
The authors would present the foregoing analysis, based primarily on the wide-ranging researches they carried out on beta titanium alloy Ti15-3 and to some extent data published by researchers on other grades of beta titanium alloys.
Ivasishin et al. [13] carried out preaging at 300 oC for 8 h followed by aging at 450 oC and 538 oC of the Ti15-3 alloy and obtained an improvement in proof strength (PS) and ultimate tensile strength (UTS) coupled with an improvement in % elongation (% El) and % reduction in area (% RA) values, compared to single step aging. 2.2.2 Effect of rate of heating to aging temperature During the aging treatment of metastable β titanium alloys, heating rate adopted to attain the desired temperature plays an important role in α precipitation [14-17].
But the tensile ductility shows a phenomenal increase with reduction in area increasing from 1 to 21% and elongation increasing from 1 to 8 % with grain size dropping from 400 to 60 μm.
Βeta grain size (μm) 0.2 % Proof stress [MPa] Ultimate tensile strength [MPa] % elongation % Reduction in area 400 1275 1335 1 1 60 1275 1350 8 21 Grain growth is a problem during super solvus solution treatment of metastable β titanium alloys.
The authors would present the foregoing analysis, based primarily on the wide-ranging researches they carried out on beta titanium alloy Ti15-3 and to some extent data published by researchers on other grades of beta titanium alloys.
Ivasishin et al. [13] carried out preaging at 300 oC for 8 h followed by aging at 450 oC and 538 oC of the Ti15-3 alloy and obtained an improvement in proof strength (PS) and ultimate tensile strength (UTS) coupled with an improvement in % elongation (% El) and % reduction in area (% RA) values, compared to single step aging. 2.2.2 Effect of rate of heating to aging temperature During the aging treatment of metastable β titanium alloys, heating rate adopted to attain the desired temperature plays an important role in α precipitation [14-17].
But the tensile ductility shows a phenomenal increase with reduction in area increasing from 1 to 21% and elongation increasing from 1 to 8 % with grain size dropping from 400 to 60 μm.
Βeta grain size (μm) 0.2 % Proof stress [MPa] Ultimate tensile strength [MPa] % elongation % Reduction in area 400 1275 1335 1 1 60 1275 1350 8 21 Grain growth is a problem during super solvus solution treatment of metastable β titanium alloys.
Online since: November 2015
Authors: Gunther Reinhart, Stephan Wagner, Max Lutter-Günther, Christian Seidel
Compared to powder bed based additive processes, which are currently in a prevailing positon regarding AM adaption, hybrid additive technologies enable increased build rates, enhanced build volumes and a reduction of machine changes.
Table 1: Input parameters and assumptions for the case study Company data Machine utilization 80 % [22] Working hours per day 16 h/day Working days per year 250 days Programming cost (labour and workstation) 60 EUR/h [5] Rent cost per year 130 €/m2 [22] Labour cost 60 €/h [5] Depreciation time 8 years Interest rate 5 % Market prices Material cost 89 EUR/kg [22] Process gas cost 0,49 Ct/l [23] Energy cost 10,2 Ct/kWh [24] Machine purchase price 1,3 Mio.
EUR Machine & process characteristics Power consumption machining 10 kW [25] Powder utilization 80 % Powder recycling rate 0 % Laser efficiency 25 % [21] Machine setup time 1,1 h Operator attendance 25 % Consumable consumption cost share of machining hour rate 16 % [26] Yearly maintenance cost share of machine purchase price 25 % [1] Power consumption passive 5 kW [21] Machine footprint area 35 m2 Process gas consumption 560 l/h [21] Data preparation time (feature based programming) 5 h Estimation based on [5] EDM process time 0,5 h EDM cost 40 €/h [5] Allowance for machining process 1 mm Tool change time 1 min Average time for tool positioning 20 sec The input data required for the cost model calculation can be obtained from three sources: company database, market prices as well as machine and process characteristics.
The second most influential parameter for cost reduction lies in the build rate, which depends on weld line width and thickness as well as scanning speed.
However, the sensitivity analysis shows cost reduction potentials that can significantly improve the economics of LMD-hybrid manufacturing.
Table 1: Input parameters and assumptions for the case study Company data Machine utilization 80 % [22] Working hours per day 16 h/day Working days per year 250 days Programming cost (labour and workstation) 60 EUR/h [5] Rent cost per year 130 €/m2 [22] Labour cost 60 €/h [5] Depreciation time 8 years Interest rate 5 % Market prices Material cost 89 EUR/kg [22] Process gas cost 0,49 Ct/l [23] Energy cost 10,2 Ct/kWh [24] Machine purchase price 1,3 Mio.
EUR Machine & process characteristics Power consumption machining 10 kW [25] Powder utilization 80 % Powder recycling rate 0 % Laser efficiency 25 % [21] Machine setup time 1,1 h Operator attendance 25 % Consumable consumption cost share of machining hour rate 16 % [26] Yearly maintenance cost share of machine purchase price 25 % [1] Power consumption passive 5 kW [21] Machine footprint area 35 m2 Process gas consumption 560 l/h [21] Data preparation time (feature based programming) 5 h Estimation based on [5] EDM process time 0,5 h EDM cost 40 €/h [5] Allowance for machining process 1 mm Tool change time 1 min Average time for tool positioning 20 sec The input data required for the cost model calculation can be obtained from three sources: company database, market prices as well as machine and process characteristics.
The second most influential parameter for cost reduction lies in the build rate, which depends on weld line width and thickness as well as scanning speed.
However, the sensitivity analysis shows cost reduction potentials that can significantly improve the economics of LMD-hybrid manufacturing.
Online since: July 2013
Authors: Pavel Sherstnev, Evgeniya Kabliman
The model was validated by comparison with experimental data of compression tests of the 6xxx series aluminium alloys and a reasonable agreement of the simulated and measured flow stress curves was found.
The material softening is described by reduction of dislocation density through spontaneous annihilation of dislocations and thermally activated dislocation climb [3]: dρdt=2BdannbρMφ+2CDGb3kBTρ2-ρeq2, (2) where B and C are calibration parameters, kB is the Boltzmann constant and ρeq is the equilibrium dislocation density (1011 m-2).
The obtained results were verified by the experimental data measured for AA6061 and AA6082 using transmission electron microscopy (TEM).
One can note a reasonable agreement of the simulated data and measured flow stress curves.
The material softening is described by reduction of dislocation density through spontaneous annihilation of dislocations and thermally activated dislocation climb [3]: dρdt=2BdannbρMφ+2CDGb3kBTρ2-ρeq2, (2) where B and C are calibration parameters, kB is the Boltzmann constant and ρeq is the equilibrium dislocation density (1011 m-2).
The obtained results were verified by the experimental data measured for AA6061 and AA6082 using transmission electron microscopy (TEM).
One can note a reasonable agreement of the simulated data and measured flow stress curves.