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Online since: October 2014
Authors: Temofei Tolmachev, Alexander Patselov, Eugeny Chernyshov, V.P. Pilyugin
Original elemental powders of: a – Cu; b – Zn
Mechanical processing can be divided into four steps: (1) compression with increasing of loading rate of 0.1 GPa/s up to 6.0 GPa of pressure; (2) torsion by various rotation from 15 degrees to 30 revolutions at speed of 0.3 revolutions/minute; (3) reduction of compression at the rate of 0.05 GPa/s; (4) extraction of the sample.
The elongation and reduction of thickness of the particles increase with strain and the sample gets an all-in-one shape without cracks and becomes a conglomerate of laminar layers at e £ 4.8 (n £ 1).
On the basis of these data we can conclude that the original metal powder mixture has been suffering the number of structural and phase transformations determined by the strain during severe plastic deformation up to solid solution formation at room temperature.
SEM fractography images of the samples, strained at 293K: a-15o; b-1 revolution; c-5;d-15; strained at 80K: e-15o; f-1 revolution; g-5;h-15 Comparing the fractography data with the above one also showed significant differences in the view of the fracture surfaces.
So, to explain the effect of lowering the temperature on the behavior of metal powder mixtures it is quite correct to expand the data obtained in pure metals [4,5] to results of the present paper.
The elongation and reduction of thickness of the particles increase with strain and the sample gets an all-in-one shape without cracks and becomes a conglomerate of laminar layers at e £ 4.8 (n £ 1).
On the basis of these data we can conclude that the original metal powder mixture has been suffering the number of structural and phase transformations determined by the strain during severe plastic deformation up to solid solution formation at room temperature.
SEM fractography images of the samples, strained at 293K: a-15o; b-1 revolution; c-5;d-15; strained at 80K: e-15o; f-1 revolution; g-5;h-15 Comparing the fractography data with the above one also showed significant differences in the view of the fracture surfaces.
So, to explain the effect of lowering the temperature on the behavior of metal powder mixtures it is quite correct to expand the data obtained in pure metals [4,5] to results of the present paper.
Online since: May 2022
Authors: Agus Prasetya, Muhammad Mufti Azis, Adam Kusuma Rianto
The present study investigates the effect of decoking pretreatment and size reduction in the phase transformation and metals properties of a calcined NiMo/γ-Al2O3 hydrotreating catalyst during rejuvenation using glycerol mono ethylene glycol (MEG) with silicon as the main target.
The data from WD-XRF was then evaluated with the same principle as Ramirez et al. [7] to estimate catalyst mass before and after rejuvenation.
However, Gly and MEG were rarely used as a solvent to leach out metal in catalyst; therefore, the data regarding this experiment was scarce.
The data of the XRD analysis of decoked, rejuvenated, and fresh NiMo catalysts are shown in Fig. 2.
Conclusion Rejuvenation of spent catalyst containing ~2.5% of silicon was studied by extraction of contaminants with different solvents, namely, Gly, MEG, and a combination of Gly + MEG with different pretreatment of decoking and size reduction.
The data from WD-XRF was then evaluated with the same principle as Ramirez et al. [7] to estimate catalyst mass before and after rejuvenation.
However, Gly and MEG were rarely used as a solvent to leach out metal in catalyst; therefore, the data regarding this experiment was scarce.
The data of the XRD analysis of decoked, rejuvenated, and fresh NiMo catalysts are shown in Fig. 2.
Conclusion Rejuvenation of spent catalyst containing ~2.5% of silicon was studied by extraction of contaminants with different solvents, namely, Gly, MEG, and a combination of Gly + MEG with different pretreatment of decoking and size reduction.
Online since: July 2007
Authors: Thierry Baudin, Richard Penelle, Laurent Barrallier, Polina Volovitch, F. Caleyo
In the
present work we have tried to take into account the phenomena of cell coalescence and growth and
to model nucleation on the basis of experimental TEM data about the early stages of annealing
processes by using a critical nuclei size hypothesis.
The data necessary for using the model are based on the kinetics of stored energy evolution and nucleation mechanisms which are still not well described by analytical models.
However, the driving force for recrystallization is the dislocation density reduction expressed as diminution of the stored energy and it can be ten times greater than the driving force for grain growth [17].
Hnucl/Hdeform Recovery time 85%REX time Fraction of nucleus Final grain size (average value) Final grain size (mean value) 0.5 521 MCS 824 MCS 0.83% 75 µm 92 µm 0.8 97 MCS 355 MCS 1.88% 60 µm 82 µm 0.9 12 MCS 255 MCS 2.37% 59 µm 68 µm Experiment 5 min 75 min No data 71 µm 82 µm It should be also marked (fig. 1b) that the absolute value of the maximum stored energy (and hence the ratio Hmax/ HABγ because of the constant value of HABγ in present simulation) does not influence the kinetics.
The simulation is applied to the annealing of 40% cold-rolled IF-Ti steel and 38% (area reduction) cold drawn copper wires.
The data necessary for using the model are based on the kinetics of stored energy evolution and nucleation mechanisms which are still not well described by analytical models.
However, the driving force for recrystallization is the dislocation density reduction expressed as diminution of the stored energy and it can be ten times greater than the driving force for grain growth [17].
Hnucl/Hdeform Recovery time 85%REX time Fraction of nucleus Final grain size (average value) Final grain size (mean value) 0.5 521 MCS 824 MCS 0.83% 75 µm 92 µm 0.8 97 MCS 355 MCS 1.88% 60 µm 82 µm 0.9 12 MCS 255 MCS 2.37% 59 µm 68 µm Experiment 5 min 75 min No data 71 µm 82 µm It should be also marked (fig. 1b) that the absolute value of the maximum stored energy (and hence the ratio Hmax/ HABγ because of the constant value of HABγ in present simulation) does not influence the kinetics.
The simulation is applied to the annealing of 40% cold-rolled IF-Ti steel and 38% (area reduction) cold drawn copper wires.
Online since: July 2007
Authors: Ruslan Valiev, Rinat K. Islamgaliev, A.R. Kilmametov, N.F. Yunusova, M.A. Bardinova
The plates were rolled with a total
reduction up to 93% to the final thickness of ≈2 mm.
Experimental data obtained for incomplete pole figures were processed by the software package «popLA» [17].
The volume fraction of precipitates (10%) is agreed with the data obtained from the earlier studies of the ECAP samples with the diameter of 20 mm [4,5].
Simultaneously, one could observe a noticeable reduction of the volume fraction of precipitates down to 5%, the average size of which did not exceed 0.2 µm.
The comparison of data given in Table 1 and Fig.6 point at the presence of correlation between the values of texture maxima intensity and elongation to failure at testing in superplasticity conditions.
Experimental data obtained for incomplete pole figures were processed by the software package «popLA» [17].
The volume fraction of precipitates (10%) is agreed with the data obtained from the earlier studies of the ECAP samples with the diameter of 20 mm [4,5].
Simultaneously, one could observe a noticeable reduction of the volume fraction of precipitates down to 5%, the average size of which did not exceed 0.2 µm.
The comparison of data given in Table 1 and Fig.6 point at the presence of correlation between the values of texture maxima intensity and elongation to failure at testing in superplasticity conditions.
Online since: October 2010
Authors: Francisco Rolando Valenzuela-Díaz, Jo Dweck, John J. Sansalone, Frank K. Cartledge, Carolina A. Pinto, L.T. Hamassaki, Pedro M. Büchler, N.E.K. Albanez
The cement hydration is observed in all samples by the presence of the peaks Q1and Q2 and the reduction of the peak of silica monosilicate (SiO4), Q0.
When no clays are added, the higher is the waste content, the lower is the compressive strength, as can be seen comparing CT(10% case), CT15 and CT20 sample data.
A higher reduction is observed when 15% is applied.
The samples containing 20% of waste do not present significant changes when compared to the 15% case data.
F.Barth and P.Percin: Stabilization and solidification of hazardous wastes (Park Ridge, Noyes Data, 19).
When no clays are added, the higher is the waste content, the lower is the compressive strength, as can be seen comparing CT(10% case), CT15 and CT20 sample data.
A higher reduction is observed when 15% is applied.
The samples containing 20% of waste do not present significant changes when compared to the 15% case data.
F.Barth and P.Percin: Stabilization and solidification of hazardous wastes (Park Ridge, Noyes Data, 19).
Online since: January 2013
Authors: Bao Gai Zhai, Yuan Ming Huang, Qing Lan Ma
The release of a portion of the reducing atmosphere from the crucible rendered the reduction of Eu3+ into Eu2+ ions incomplete.
Value of hkl d values (JCPDS data in Å) 2θ (JCPDS data) d values (our case in Å) 2θ (our case) (our case) 011 4.447 19.951 4.449 19.942 120 3.907 22.740 3.908 22.735 -211 3.141 28.386 3.141 28.392 220 3.048 29.275 3.047 29.287 211 2.983 29.922 2.984 29.924 -311 2.432 36.924 2.432 36.924 -231 2.156 41.860 2.213 40.735 400 2.106 42.892 2.107 42.890 240 1.954 46.431 1.954 46.432 1.479 62.770 1.478 62.805 Figure 2.
As a result of the incomplete reduction, both Eu2+ and Eu3+ ions could be incorporated into the host matrix.
The data of the typical transitions of Eu3+ in SrAl2O4 host materials are listed in Table 2.
Value of hkl d values (JCPDS data in Å) 2θ (JCPDS data) d values (our case in Å) 2θ (our case) (our case) 011 4.447 19.951 4.449 19.942 120 3.907 22.740 3.908 22.735 -211 3.141 28.386 3.141 28.392 220 3.048 29.275 3.047 29.287 211 2.983 29.922 2.984 29.924 -311 2.432 36.924 2.432 36.924 -231 2.156 41.860 2.213 40.735 400 2.106 42.892 2.107 42.890 240 1.954 46.431 1.954 46.432 1.479 62.770 1.478 62.805 Figure 2.
As a result of the incomplete reduction, both Eu2+ and Eu3+ ions could be incorporated into the host matrix.
The data of the typical transitions of Eu3+ in SrAl2O4 host materials are listed in Table 2.
Online since: November 2025
Authors: Kostiantyn Afanasenko, Natalia Saienko, Oleksandr Hryhorenko, Volodymyr Lipovyi, Volodymyr Oliinyk
The essence of the method is to heat a set of samples in a standard temperature regime with subsequent assessment of the test data using mathematical analysis methods to obtain the characteristics of the fire protection capacity of the coating.
During the tests, metal samples are placed in a fire furnace, and using thermocouples located at specified points, the temperature data of the samples are taken for varying durations of fire exposure without load.
The results of processing the experimental data allow to determine the thermal conductivity of the expanded coke layer of the fire retardant coating after its stabilization.
The use of an optimized method for evaluating the fire protection effectiveness of intumescent fire retardant coatings allows for a significant reduction in sample preparation time when planning and conducting the experiment.
The use of the optimized method allows for a reduction in the time required for sample preparation when planning and conducting the experiment, as well as investigating the effectiveness of intumescent fire retardant coatings under temperature regimes different from the standard fire regime.
During the tests, metal samples are placed in a fire furnace, and using thermocouples located at specified points, the temperature data of the samples are taken for varying durations of fire exposure without load.
The results of processing the experimental data allow to determine the thermal conductivity of the expanded coke layer of the fire retardant coating after its stabilization.
The use of an optimized method for evaluating the fire protection effectiveness of intumescent fire retardant coatings allows for a significant reduction in sample preparation time when planning and conducting the experiment.
The use of the optimized method allows for a reduction in the time required for sample preparation when planning and conducting the experiment, as well as investigating the effectiveness of intumescent fire retardant coatings under temperature regimes different from the standard fire regime.
Online since: August 2014
Authors: Jing Yu Liu, Jing Xue An, Shui Long Wang, Hai Xia Ju, Ming Feng Xu
Fan Stall Analysis and Accident Analysis
Check the historical trend (table 1, 2 and figure 1, 2), and analysis the fan stall based on the data before and after the accident.
Faced with the accident, Operators cannot response quickly yet, which makes fan operation condition worse and induces sustained reduction of wind pressure
There are many errors about the operation after stall: (1). try to open big stall moving blade of the fan to stop wind pressure reducing at11:33:31; turn A and B motor wind leaf by 82.1% and 82.1% respectively up to 89.8% and 82% and then turn B fan up to 86.8%, aggravating stall; the errors make fan A current overran for a long time coupled with sustained wind pressure reduction. (2).
Figure 1: Historical trend curves of the primary fans operation Figure 2: Historical trend curves of boiler operation during the unit trip Table 1: Operation data of primary fans during the unit trip Accident time Electric Current ,[A] Opening of Primary fan ,[%] Outlet Pressure,[kPa] Main-pipeline Pressure of Primary Air,[kPa] Fan B Outlet Temperature,[℃] Fan A Fan B Fan A Fan B Fan A Fan B 11:25:00 180 183 55 49 12.26 12.46 11.15 28 11:31:18 250 246 75.3 69.3 13.8 1l.84 11.94 28 11:31:26 250 244 75.3 69.3 13.8 13.84 12.11 28 11:31:27 250 246 75.3 69.3 13.8 13.84 12.11 28 11:33:25 275 256 82.1 75.2 11.15 13.74 12.52 28 11:33:26 304 246 82.1 75.1 7.18 8.65 9.51 28 11:33:27 308 209 82.1 75.1 6.28 5.73 5.67 28 11:33:28 315 156 83.8 77.2 6.28 5.09 4.55 28 11:33:29 330 154 85.8 78.8 6.28 5.08 4.31 28 11:33:31 350 156 89.8 82.0 5.46 4.60 4.02 28 11:33:34 370 139 89.8 86.8 4.94 3.89 3.40 28.6 11:34:18 375 158 87.6 86.8 5.6 4.54 4.19 33.5 11:34:30 256 141 70.2 85.7 4.55 3.61 3.36 35.5 11:35:00
Tab.2 Operation Data of Boiler During the Unit Trip Time Unit Load, [MW] Main Vapor Pressure, [Mpa] Main Steam Temperature, [℃] Water Supply, [t/h] Total Amount of Fuel, [t] Furnace Pressure, [Pa] Water-coal Ratio, [%] Qvent, [t/h] 11:33:25 370 17.4 565 1250 207 6 7.88 1410 11:33:35 373 17.4 565 1266 207 -2300 7.88 1561 11:34:58 320 14.3 559 1433 199 -471 10.00 1234 11:35:08 313 14.0 556 1430 174 1343 11.02 1001 11:36:06 296 13.7 543 1224 82 98 20.66 1093 11:36:58 303 14.6 536 972 82 91 19.11 1081 11:38:30 337 16.0 526 734 82 189 13.97 1221 11:39:30 332 15.2 492 957 82 136 16.20 1276 11:39:50 327 15.0 477 906 82 -167 16.20 1350 11:40:02 306 15.3 469 869 82 -208 14.97 1369 Fan Stall Reasons and Operation Measures In 2012, trip accident has happened many times caused by B fan stall in the plant.
Faced with the accident, Operators cannot response quickly yet, which makes fan operation condition worse and induces sustained reduction of wind pressure
There are many errors about the operation after stall: (1). try to open big stall moving blade of the fan to stop wind pressure reducing at11:33:31; turn A and B motor wind leaf by 82.1% and 82.1% respectively up to 89.8% and 82% and then turn B fan up to 86.8%, aggravating stall; the errors make fan A current overran for a long time coupled with sustained wind pressure reduction. (2).
Figure 1: Historical trend curves of the primary fans operation Figure 2: Historical trend curves of boiler operation during the unit trip Table 1: Operation data of primary fans during the unit trip Accident time Electric Current ,[A] Opening of Primary fan ,[%] Outlet Pressure,[kPa] Main-pipeline Pressure of Primary Air,[kPa] Fan B Outlet Temperature,[℃] Fan A Fan B Fan A Fan B Fan A Fan B 11:25:00 180 183 55 49 12.26 12.46 11.15 28 11:31:18 250 246 75.3 69.3 13.8 1l.84 11.94 28 11:31:26 250 244 75.3 69.3 13.8 13.84 12.11 28 11:31:27 250 246 75.3 69.3 13.8 13.84 12.11 28 11:33:25 275 256 82.1 75.2 11.15 13.74 12.52 28 11:33:26 304 246 82.1 75.1 7.18 8.65 9.51 28 11:33:27 308 209 82.1 75.1 6.28 5.73 5.67 28 11:33:28 315 156 83.8 77.2 6.28 5.09 4.55 28 11:33:29 330 154 85.8 78.8 6.28 5.08 4.31 28 11:33:31 350 156 89.8 82.0 5.46 4.60 4.02 28 11:33:34 370 139 89.8 86.8 4.94 3.89 3.40 28.6 11:34:18 375 158 87.6 86.8 5.6 4.54 4.19 33.5 11:34:30 256 141 70.2 85.7 4.55 3.61 3.36 35.5 11:35:00
Tab.2 Operation Data of Boiler During the Unit Trip Time Unit Load, [MW] Main Vapor Pressure, [Mpa] Main Steam Temperature, [℃] Water Supply, [t/h] Total Amount of Fuel, [t] Furnace Pressure, [Pa] Water-coal Ratio, [%] Qvent, [t/h] 11:33:25 370 17.4 565 1250 207 6 7.88 1410 11:33:35 373 17.4 565 1266 207 -2300 7.88 1561 11:34:58 320 14.3 559 1433 199 -471 10.00 1234 11:35:08 313 14.0 556 1430 174 1343 11.02 1001 11:36:06 296 13.7 543 1224 82 98 20.66 1093 11:36:58 303 14.6 536 972 82 91 19.11 1081 11:38:30 337 16.0 526 734 82 189 13.97 1221 11:39:30 332 15.2 492 957 82 136 16.20 1276 11:39:50 327 15.0 477 906 82 -167 16.20 1350 11:40:02 306 15.3 469 869 82 -208 14.97 1369 Fan Stall Reasons and Operation Measures In 2012, trip accident has happened many times caused by B fan stall in the plant.
Online since: September 2014
Authors: Wei Xiong, Hao Chen, Shi Yong Yang, Huang Qiang Li
The method of fuzzy reasoning of fault diagnosis, requires effective means to objectively and fuzzily express uncertain factors of the power , makes full use of the knowledge of history and statistical data and experience.However,when the structure of the object changes,updating maintenance of knowledge base that builded by corresponding fuzzy inference becomes a problem.
Method based on rough set theory[4] The strong qualitative analysis ability is the outstanding advantage of Rough set theory.The main idea is under the premise of keeping the ability of classification, through the reduction of knowledge, exporting decision or classification rules,applying rough set theory to power system fault diagnosis.The basic idea is using the action information of protection and circuit breaker as condition attributes for fault classification,considering various possible fault situation and establishing decision table,deleting unimportant and irrelevant attributes of the knowledge base and then extracting diagnosis rules.
Combining expert system and fuzzy inference[6] The method of fuzzy reasoning needs to make full use of the knowledge of history and statistical data and experience, and this point just can be added by expert system.The expert system provides the historical statistical data and experience and the fuzzy inference is better for dealing with the uncertainty of the action of relay protection and the incompleteness of the fault informations in power system fault diagnosis.
As shown in Figure [3],it uses the reduction of rough set theory to filter the knowledge before the knowledge is put into the knowledge base,eliminates knowledge base’s redundant and forms a simple knowledge base,then uses the method of expert system to diagnose fault.
Method based on rough set theory[4] The strong qualitative analysis ability is the outstanding advantage of Rough set theory.The main idea is under the premise of keeping the ability of classification, through the reduction of knowledge, exporting decision or classification rules,applying rough set theory to power system fault diagnosis.The basic idea is using the action information of protection and circuit breaker as condition attributes for fault classification,considering various possible fault situation and establishing decision table,deleting unimportant and irrelevant attributes of the knowledge base and then extracting diagnosis rules.
Combining expert system and fuzzy inference[6] The method of fuzzy reasoning needs to make full use of the knowledge of history and statistical data and experience, and this point just can be added by expert system.The expert system provides the historical statistical data and experience and the fuzzy inference is better for dealing with the uncertainty of the action of relay protection and the incompleteness of the fault informations in power system fault diagnosis.
As shown in Figure [3],it uses the reduction of rough set theory to filter the knowledge before the knowledge is put into the knowledge base,eliminates knowledge base’s redundant and forms a simple knowledge base,then uses the method of expert system to diagnose fault.
Online since: May 2014
Authors: Kim Verbeken, Herman Terryn, Leo A.I. Kestens, Linsey Lapeire, Iris de Graeve, Esther Martinez Lombardia
The corresponding crystallographic orientation data were obtained by Electron Backscatter Diffraction (EBSD).
Two reactions take place simultaneously on the copper surface, namely the reduction of gold and the oxidation of copper: Cu oxidation: 3Cu(s) ® 3Cu2+(aq) + 6e- (E° = +0.337V) Au reduction: 2Au3+(aq) + 6e- ® 2Au(s) (E° = +1.52V) The local anodic/cathodic reactivity differences at the surface of the copper will provoke very local electrochemical effects.
The data presented so far suggest that a pair of adjacent grains of <111> // ND and <001> // ND orientation is a necessary prerequisite for observing a significant height difference.
Consequently, by linking the results of the gold nanoplating of polycrystalline copper with already established literature data on grain boundary energy and the behavior of special boundaries such as some CSL boundaries; the applicability and potential of the gold nanoplating technique is demonstrated and confirmed.
Two reactions take place simultaneously on the copper surface, namely the reduction of gold and the oxidation of copper: Cu oxidation: 3Cu(s) ® 3Cu2+(aq) + 6e- (E° = +0.337V) Au reduction: 2Au3+(aq) + 6e- ® 2Au(s) (E° = +1.52V) The local anodic/cathodic reactivity differences at the surface of the copper will provoke very local electrochemical effects.
The data presented so far suggest that a pair of adjacent grains of <111> // ND and <001> // ND orientation is a necessary prerequisite for observing a significant height difference.
Consequently, by linking the results of the gold nanoplating of polycrystalline copper with already established literature data on grain boundary energy and the behavior of special boundaries such as some CSL boundaries; the applicability and potential of the gold nanoplating technique is demonstrated and confirmed.