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Online since: January 2016
Authors: Lukáš Bednář, Martin Miczán, Michal Hoznedl, Ladislav Tajč
It results in certain complication when comparing the experimental and predicted data.
The original valve is designed for the pressure reduction from 14 to 0.9 bar.
If the steam reduction occurs as early as in the tested valve, the specific volume of steam before the regulating valve will increase.
For recording and processing the data the measuring unit OROS and also the control unit AGILENT were used.
It was necessary to calculate all the forces from the measured data for designed parameters.
The original valve is designed for the pressure reduction from 14 to 0.9 bar.
If the steam reduction occurs as early as in the tested valve, the specific volume of steam before the regulating valve will increase.
For recording and processing the data the measuring unit OROS and also the control unit AGILENT were used.
It was necessary to calculate all the forces from the measured data for designed parameters.
Online since: October 2007
Authors: L.G. Guo, He Yang
(6) A uniform mesh with 8-noded first-order reduction integration continuum elements is used.
According to the experimental conditions in Ref. [8], simulations for six ring blank samples have been performed and the obtained roll force results were compared with the experimental data.
Table 2 Calculation Conditions and Parameter Values Sizes of ring blank Outer radius R0 (mm) 61.915 Inner radius r0 (mm) 39.685 Height B0 (mm) 25.4 Thickness H0 (mm) 22.23 Sizes of forming rolls Radius of driver roll R1 (mm) 104.8{34.9,52.35,69.8,139.6,174.5,209.4,244.3,279.2, 314.1} Radius of idle roll R2 (mm) 34.9 {10,14,18,22,26,30,38} Radius of guide roll R3 (mm) 34.9 Reduction in thickness △ H 28% Forming parameters Rotational speed of driver roll n1 (r/min) 160 {60,90,120,160,200,250,300,350,450,600} Feed rate of idle roll v (mm/s) 1.22 {0.3,0.5,0.7,0.9,1.22,2.0,2.5,3.0,3.5,4.0} Influence of forming rolls on force and power parameters.
Time (s) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 0 20 40 60 80 100 120 ( KN) )(9.341 mm R = )(8.1041 mm R = )(5.1741 mm R = )(3.2441 mm R = )(1.3141 mm R = t RF Time (s) 0 . 0 0 . 5 1 . 0 1 . 5 2 . 0 2 . 5 3 . 0 3 . 5 4 . 0 4 . 5 5 . 0 5 . 5 - 1 0 0 0 - 5 0 0 0 5 0 0 1 0 0 0 1 5 0 0 2 0 0 0 2 5 0 0 Datum line )(9.341 mm R = )(8.1041 mm R = )(5.1741 mm R = )(3.2441 mm R = )(1.3141 mm R = t )( mN ⋅RM (a) (b) Fig.4 Influence laws of the radius of driver roll (R1) on roll force (RF) and roll moment (RM) Figure 5 illustrates the influence laws of the radius of idle roll (R2) on roll force (RF) and roll moment (RM).
Vol. 69 (1997), p. 273 Time (s) -2 0 2 4 6 8 10 12 14 16 18 20 22 0 10 20 30 40 50 60 70 80 90 100 110 120 ( KN) )(30 mm/s .v = )(70 mm/s .v = )(22.1 mm/s v = )(0.3 mm/s v = )(0.4 mm/s v = t RF Time (s) -2 0 2 4 6 8 10 12 14 16 18 20 22 -400 -200 0 200 400 600 800 1000 1200 1400 1600 1800 2000 Datum line )(30 mm/s .v = )(70 mm/s .v = )(22.1 mm/s v = )(0.3 mm/s v = )(0.4 mm/s v = t )( mN ⋅RM (a) (b)
According to the experimental conditions in Ref. [8], simulations for six ring blank samples have been performed and the obtained roll force results were compared with the experimental data.
Table 2 Calculation Conditions and Parameter Values Sizes of ring blank Outer radius R0 (mm) 61.915 Inner radius r0 (mm) 39.685 Height B0 (mm) 25.4 Thickness H0 (mm) 22.23 Sizes of forming rolls Radius of driver roll R1 (mm) 104.8{34.9,52.35,69.8,139.6,174.5,209.4,244.3,279.2, 314.1} Radius of idle roll R2 (mm) 34.9 {10,14,18,22,26,30,38} Radius of guide roll R3 (mm) 34.9 Reduction in thickness △ H 28% Forming parameters Rotational speed of driver roll n1 (r/min) 160 {60,90,120,160,200,250,300,350,450,600} Feed rate of idle roll v (mm/s) 1.22 {0.3,0.5,0.7,0.9,1.22,2.0,2.5,3.0,3.5,4.0} Influence of forming rolls on force and power parameters.
Time (s) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 0 20 40 60 80 100 120 ( KN) )(9.341 mm R = )(8.1041 mm R = )(5.1741 mm R = )(3.2441 mm R = )(1.3141 mm R = t RF Time (s) 0 . 0 0 . 5 1 . 0 1 . 5 2 . 0 2 . 5 3 . 0 3 . 5 4 . 0 4 . 5 5 . 0 5 . 5 - 1 0 0 0 - 5 0 0 0 5 0 0 1 0 0 0 1 5 0 0 2 0 0 0 2 5 0 0 Datum line )(9.341 mm R = )(8.1041 mm R = )(5.1741 mm R = )(3.2441 mm R = )(1.3141 mm R = t )( mN ⋅RM (a) (b) Fig.4 Influence laws of the radius of driver roll (R1) on roll force (RF) and roll moment (RM) Figure 5 illustrates the influence laws of the radius of idle roll (R2) on roll force (RF) and roll moment (RM).
Vol. 69 (1997), p. 273 Time (s) -2 0 2 4 6 8 10 12 14 16 18 20 22 0 10 20 30 40 50 60 70 80 90 100 110 120 ( KN) )(30 mm/s .v = )(70 mm/s .v = )(22.1 mm/s v = )(0.3 mm/s v = )(0.4 mm/s v = t RF Time (s) -2 0 2 4 6 8 10 12 14 16 18 20 22 -400 -200 0 200 400 600 800 1000 1200 1400 1600 1800 2000 Datum line )(30 mm/s .v = )(70 mm/s .v = )(22.1 mm/s v = )(0.3 mm/s v = )(0.4 mm/s v = t )( mN ⋅RM (a) (b)
Online since: August 2008
Authors: Ricardo Arthur Sanguinetti Ferreira, Yogendra Prasad Yadava
)
(642)
(620)
(440)
(422)
(420) (400)
(220)
(200)
(111)
2θ
Fig. 1: X-ray diffraction spectrum of Ba2AlWO5,5
Tabela 1: XRD data of Ba2AlWO5,5
2θ d(Å) I/I0 hkl
19,908 4,456 33,22 1 1 1
26,885 3,3134 16,94 2 0 0
30,990 2,8833 100 2 2 0
34,614 2,5892 28,66 3 1 1
40,422 2,2296 22,31 2 2 2
44,252 2,0450 34,36 4 0 0
46,772 1,9406 5,7 4 2 0
54,835 1,6728 39,25 4 2 2
64,169 1,4502 14,82 4 4 0
72,847 1,2973 14,01 6 2 0
81,042 1,1855 6,35 5 3 3
89,116 1,0978 13,84 6 4 2
For double cubic perovskite of the formula A2BB'O6 the intensity, in particular of the (111)
and/or (311) superstructure reflection, is proportional to the difference in scattering power of the B
and B' atoms, when all the atoms are situated in the ideal position [8].
XRD data of Ba2AlWO5.5 obtained from the XRD spectrum are tabulated in Table 1.
The lattice parameter of Ba2AlWO5.5, calculated from the experimental XRD data is aexp = 8.3504Å.
The liquid at high temperature facilitates mass transport by liquid phase mechanism and results with the reduction of solid - liquid dihedral angle, which increases the wettability and thus the liquid drags the grain towards each other.
The driving force in the sintering process is obtained by the reduction of the total surface energy, which increases the contact and growth between the grains.
XRD data of Ba2AlWO5.5 obtained from the XRD spectrum are tabulated in Table 1.
The lattice parameter of Ba2AlWO5.5, calculated from the experimental XRD data is aexp = 8.3504Å.
The liquid at high temperature facilitates mass transport by liquid phase mechanism and results with the reduction of solid - liquid dihedral angle, which increases the wettability and thus the liquid drags the grain towards each other.
The driving force in the sintering process is obtained by the reduction of the total surface energy, which increases the contact and growth between the grains.
Online since: July 2005
Authors: E.C. Oliver, Philip J. Withers, Mark R. Daymond
In
contrast, during compressive straining, a very intense 0002 reflection emerges, coincident with a
reduction in intensity of the 0110 reflection.
Datapoints show average strains recorded over each data acquisition interval.
These are due to creep during each data acquisition period.
For comparison to the tensile data, compressive strains have been multiplied by a factor of -1.
The intensity variations in the third and fourth cycles follow those in the second cycle very closely, with no evidence of a reduction in twinning or untwinning activity.
Datapoints show average strains recorded over each data acquisition interval.
These are due to creep during each data acquisition period.
For comparison to the tensile data, compressive strains have been multiplied by a factor of -1.
The intensity variations in the third and fourth cycles follow those in the second cycle very closely, with no evidence of a reduction in twinning or untwinning activity.
Online since: July 2003
Authors: R.P.C. Sampaio, N.M.M. Maia, J.M.M. Silva
This can happen when one deals
with real data.
The damage is simulated with a reduction in the second moment of area of the element 12.
• 3 cases of the undamaged beam data simulating 3 different measurements of the beam without damage - damage cases 2, 3 and 4
• 6 cases of the damaged beam (90, 80, 70, 60, 40 and 20% reduction of the second moment of area of the element 12) - damage cases 5 to 10.
The signals were fed into the Multi-channel Data Acquisition Unit Bruel&Kjaer 2816 (PULSE) and analyzed directly with the Labshop 6.1 Pulse software from the attached laptop (Dell series 400).
The damage is simulated with a reduction in the second moment of area of the element 12.
• 3 cases of the undamaged beam data simulating 3 different measurements of the beam without damage - damage cases 2, 3 and 4
• 6 cases of the damaged beam (90, 80, 70, 60, 40 and 20% reduction of the second moment of area of the element 12) - damage cases 5 to 10.
The signals were fed into the Multi-channel Data Acquisition Unit Bruel&Kjaer 2816 (PULSE) and analyzed directly with the Labshop 6.1 Pulse software from the attached laptop (Dell series 400).
Online since: July 2006
Authors: Igor V. Alexandrov, Vil D. Sitdikov, Roza G. Chembarisova
An algorithm was developed and asoftware was written in
FORTRAN 77 to make calculations for the above variable parameters, which were chosen to
account with experimental data and physical sense.
The Modeling results and Discussion As a result of fitting of the abovementioned modeling parameters ( *α , *β , ko, К) very good correspondence between experimental and modeling data was obtained (Fig. 1).
This increase may be connected with a reduction of the length of dislocation segments, resulting from an increase of the dislocation density, which leads to growth of the shearing stresses necessary for operation of Frank-Reed sources.
The coefficient * β related to dislocation density increment in the cell interiors increases 3.5 times as a result of dislocation sinking into the cell walls, which apparently is conditioned by a reduction of the dislocation free path length in connection with a decrease of grain-cell sizes as a result of the pressure rise.
From the modeling it can be concuded that: 1) the Estrin-Tóth model adequately describes the stress-strain state of Cu under HPT; 2) the predicted average dislocation densities, as well as the correlation between the dislocation densities in the cell walls and lattice dislocations, conforms quite reasonably with experimental data; 3) the size of grain-cells decreases, with increasing strain and reaches a state of saturation which continues to decrease when the applied pressure encreases; 4) the dislocation interaction parameter α changes dramatically from 0.24 to 0.41 as a result of severe plastic deformation. 0 2 4 6 8 10 12 14 16 18 0 200 400 600 800 1000 1200 1400 γ r d, nm 0,8 GPa 2 GPa 8 GPa5 GPa a) 0 2 4 6 8 10 12 14 16 18 0 2 4 6 8 10 12 θ, deg γr 8 GPa 0.8 GPa 2 GPa 5 GPa b)References [1].
The Modeling results and Discussion As a result of fitting of the abovementioned modeling parameters ( *α , *β , ko, К) very good correspondence between experimental and modeling data was obtained (Fig. 1).
This increase may be connected with a reduction of the length of dislocation segments, resulting from an increase of the dislocation density, which leads to growth of the shearing stresses necessary for operation of Frank-Reed sources.
The coefficient * β related to dislocation density increment in the cell interiors increases 3.5 times as a result of dislocation sinking into the cell walls, which apparently is conditioned by a reduction of the dislocation free path length in connection with a decrease of grain-cell sizes as a result of the pressure rise.
From the modeling it can be concuded that: 1) the Estrin-Tóth model adequately describes the stress-strain state of Cu under HPT; 2) the predicted average dislocation densities, as well as the correlation between the dislocation densities in the cell walls and lattice dislocations, conforms quite reasonably with experimental data; 3) the size of grain-cells decreases, with increasing strain and reaches a state of saturation which continues to decrease when the applied pressure encreases; 4) the dislocation interaction parameter α changes dramatically from 0.24 to 0.41 as a result of severe plastic deformation. 0 2 4 6 8 10 12 14 16 18 0 200 400 600 800 1000 1200 1400 γ r d, nm 0,8 GPa 2 GPa 8 GPa5 GPa a) 0 2 4 6 8 10 12 14 16 18 0 2 4 6 8 10 12 θ, deg γr 8 GPa 0.8 GPa 2 GPa 5 GPa b)References [1].
Online since: November 2016
Authors: Maria Teresa di Giovanni, Emanuela Cerri, Lars Arnberg, Mattia Merlin, Daniele Casari, Gian Luca Garagnani
A specifically designed clip-on stainless steel axial extensometer connected to an optical position measuring system was used to collect the stress-strain data.
A general reduction of UTS is noted for the samples tested at 235°C.
After a 6 h aging, an average reduction of 56 and 60 HV (approximately 50% lower than the peak hardness) can be observed for the sand cast and permanent mould cast alloys, respectively.
In conclusion, an empirical correlation between Vickers hardness, yield stress and tensile stress (Fig 3c) was analysed by combining data from six independent samples: A356, N, V, A356 T6, N T6,V T6 sand cast.
While the strength in the T6 condition, for both the casting process, shows a small decrease at HT as compared to the RT. (3) Ageing curves show a significant loss of hardness in the T6 alloys between 30 min and 1 h exposure time at 235°C After 6 h ageing, no evidence of heat treatment is observed in the investigated alloys. (4)A linear correlation between the hardness values obtained after the HT tensile test with those obtained after heat treatment, confirmed that static time exposures of 5 min and 10 min finely approximates ageing occurring during the HT tensile test.(5) Empirical correlations between Vickers hardness, yield stress and tensile stress were obtained by combining data from six independent samples.
A general reduction of UTS is noted for the samples tested at 235°C.
After a 6 h aging, an average reduction of 56 and 60 HV (approximately 50% lower than the peak hardness) can be observed for the sand cast and permanent mould cast alloys, respectively.
In conclusion, an empirical correlation between Vickers hardness, yield stress and tensile stress (Fig 3c) was analysed by combining data from six independent samples: A356, N, V, A356 T6, N T6,V T6 sand cast.
While the strength in the T6 condition, for both the casting process, shows a small decrease at HT as compared to the RT. (3) Ageing curves show a significant loss of hardness in the T6 alloys between 30 min and 1 h exposure time at 235°C After 6 h ageing, no evidence of heat treatment is observed in the investigated alloys. (4)A linear correlation between the hardness values obtained after the HT tensile test with those obtained after heat treatment, confirmed that static time exposures of 5 min and 10 min finely approximates ageing occurring during the HT tensile test.(5) Empirical correlations between Vickers hardness, yield stress and tensile stress were obtained by combining data from six independent samples.
Online since: October 2015
Authors: Jing Xia Guo, Xiao Yang Wang, Xiao Bin Cui
Hard milling, which can even be an alternative for the grinding process in some cases, owns advantages such as reduction of machining costs and elimination of part distortion caused by heat treatment et al..
The sampling frequency of data was set to be 7000 Hz.
The increase of cutting temperature also leads to the reduction of the friction between the tool rake face and the chip, and the shear angle will increases with increasing cutting speed.
For the purpose of converting the trial result data into a value for the evaluation characteristics in the optimum setting analysis, the S/N ratio is used instead of the average value.
Based on the S/N ratio data, the results of Analysis of variance (ANOVA) for the resultant cuting force can be obtained as shown in Tables 4 and 5.
The sampling frequency of data was set to be 7000 Hz.
The increase of cutting temperature also leads to the reduction of the friction between the tool rake face and the chip, and the shear angle will increases with increasing cutting speed.
For the purpose of converting the trial result data into a value for the evaluation characteristics in the optimum setting analysis, the S/N ratio is used instead of the average value.
Based on the S/N ratio data, the results of Analysis of variance (ANOVA) for the resultant cuting force can be obtained as shown in Tables 4 and 5.
Research on Techniques and Experiments of Electrostatic Radon Elimination in Underground Engineering
Online since: May 2012
Authors: Shi Bin Geng, Wei Qi, Te Hui Ouyang, Qiu Lin Liu
EPA promulgated the "residential air purifiers" which notes that it has not been confirmed that the air purification methods is effective in reduction of radon-induced risk, yet the use of air purifier can not be interrupted according to available data.
We measure the concentration of radon daughters continuously using professional radon daughters measuring instrument BWL with recording hourly data and averaging them.
Record hourly data.
Exploration of radon affected work and living places and methods for the reduction of the radon exposure [3] Daniel J.
We measure the concentration of radon daughters continuously using professional radon daughters measuring instrument BWL with recording hourly data and averaging them.
Record hourly data.
Exploration of radon affected work and living places and methods for the reduction of the radon exposure [3] Daniel J.
Online since: August 2004
Authors: Xiao Ming Wang, Greg Foliente, Minh Nguyen
The application of more efficient and accurate tools to predict and assess the service life or reliability of poles will certainly contribute to cost reductions in both the maintenance and management of utility poles.
A reduction in maintenance costs of 20% for power companies alone would save approximately $8~10 million every year.
The NDE systems collected data on the project test population over a 5-month period.
Half of this data were provided to practitioners for calibrating their systems.
· Need for collaborative R&D programs with industry to implement reliability analysis for asset management, obtaining ‘feedback’ and management data for calibrating the asset management procedure, including decay modelling
A reduction in maintenance costs of 20% for power companies alone would save approximately $8~10 million every year.
The NDE systems collected data on the project test population over a 5-month period.
Half of this data were provided to practitioners for calibrating their systems.
· Need for collaborative R&D programs with industry to implement reliability analysis for asset management, obtaining ‘feedback’ and management data for calibrating the asset management procedure, including decay modelling