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Online since: November 2013
Authors: Xiao Jun Xiang, Kui Gong, Yan Shuang
In recent years, with the deep-going prospecting and research work, there have been found a great number of Pb-Zn anomaly zones in western Hubei Province, southeastern Chongqing, western Hunan Province, etc. on the carbonate platform in the south of the Yangtze block, and the quantity of Pb-Zn resources in some ore fields may come up to 220x105 tons[1].
Galena minerals are relatively coarse in grain size, galena crystals are about 0.5~3 mm in grain diameter, the crystals are euhedral and subhedral, usually occur in veined, stripped or massive, and granular forms and coexist with dolomite and calcite.
The strata in the Shidi mining area contain a large number of gypsum salt layers, which thus can provide potential sources of reducible sulfur which is needed by Pb-Zn minerallogenesis. 4.2 Lead source The contents of U and Th in sulfide minerals are relatively low, so they can be ignored as compared with the contents of Pb in minerals.
Galena minerals are relatively coarse in grain size, galena crystals are about 0.5~3 mm in grain diameter, the crystals are euhedral and subhedral, usually occur in veined, stripped or massive, and granular forms and coexist with dolomite and calcite.
The strata in the Shidi mining area contain a large number of gypsum salt layers, which thus can provide potential sources of reducible sulfur which is needed by Pb-Zn minerallogenesis. 4.2 Lead source The contents of U and Th in sulfide minerals are relatively low, so they can be ignored as compared with the contents of Pb in minerals.
Online since: September 2024
Authors: Alex Li, Ashraf Ashour, Choucha Said, Salhi Mohamed, Benyahia Amar, Toufik Boubekeur
Fig. 4 Grain size curve of sand.
The number of total specimens that were made is 54.
The high specific surface area allows the fine grains to create a higher number of contacts between the particles and to increase the shear threshold and the plastic viscosity.
The number of total specimens that were made is 54.
The high specific surface area allows the fine grains to create a higher number of contacts between the particles and to increase the shear threshold and the plastic viscosity.
Online since: November 2023
Authors: C. Siddaraju, S.N. Nagesh, B. Shivukumara, R. Ranganatha, H.S. Balasubramanya
(c) Microstructure at 500x
Figure 3(a) to 3 (c) illustrates a microstructure characterized by the presence of alpha grains embedded in a matrix consisting of transformed eutectoid beta.
Alpha grains denote regions or domains within the microstructure that predominantly consist of the alpha phase. 3.3 Hardness Test The Brinell hardness test was performed using a steel ball indenter.
· Brinell Hardness Number 159.14 AB2 (with nickel) is superior compared to Brinell Hardness Number 145.16 AB1 (without nickel)
Alpha grains denote regions or domains within the microstructure that predominantly consist of the alpha phase. 3.3 Hardness Test The Brinell hardness test was performed using a steel ball indenter.
· Brinell Hardness Number 159.14 AB2 (with nickel) is superior compared to Brinell Hardness Number 145.16 AB1 (without nickel)
Online since: March 2009
Authors: M.T. del Barrio, Luisen E. Herranz
A small fraction of them are volatile and can migrate under the effect of concentration gradients to
the grain boundaries of the fuel pellet.
Before and after the FGR, it is possible to define the mol number and fraction of gases present at each axial node by applying the ideal gas law at the respective rod pressure.
So, the number of gas moles at node j before FGR and Po rod pressure is given by: b o j j P V n R T = (1) Similarly, the amount of gases in each axial node after pressure equalization (P') is decribed by: ' j j P' V n R T = (2) Estimate of the convective mole transport from the FGR node to upward and downward adjacent nodes proceeds in a stepwise fashion.
Before and after the FGR, it is possible to define the mol number and fraction of gases present at each axial node by applying the ideal gas law at the respective rod pressure.
So, the number of gas moles at node j before FGR and Po rod pressure is given by: b o j j P V n R T = (1) Similarly, the amount of gases in each axial node after pressure equalization (P') is decribed by: ' j j P' V n R T = (2) Estimate of the convective mole transport from the FGR node to upward and downward adjacent nodes proceeds in a stepwise fashion.
Online since: April 2019
Authors: Vera Pelantová
Their relationships and the influence of the substantial neighbourhood lead to the development of a number of problems.
However, organisations often face a number of nonconformities.
There were five small and medium sized organisations and six large organisations according to the number of employees.
This way the number of these nonconformities about material and product problems can decline.
Coarse grains and colour stains appear due to inappropriate added ingredients often in an effort to save up the material in the food industry and in the plastic industry.
However, organisations often face a number of nonconformities.
There were five small and medium sized organisations and six large organisations according to the number of employees.
This way the number of these nonconformities about material and product problems can decline.
Coarse grains and colour stains appear due to inappropriate added ingredients often in an effort to save up the material in the food industry and in the plastic industry.
Online since: February 2011
Authors: Hong Qing Zhou, Xiao Dong Shen, Hui Shao
A Fourier transform infrared spectroscope (FTIR, Nicolet Nexus, Thermo Nicolet) was used to analysis of the glass structure and the wave number ranged from 400-4000 cm–1.The crystallized phases were identified by X-ray diffraction (XRD).
Therefore, B2O3 is substituted for SiO2, then the addition of B2O3 into glass increase both the amount of non-bridging oxygen (Si-O-B) in the silicate network and the number of [BO4] units.
The peak values in this location were 1336.63 cm-1 and 1638.79 cm-1 respectively from B1 to B5.This can be explained the fact that the decreasing of [SiO4] and [BO4] caused the weakening of their bonds, so these bands shifted to lower wave numbers [14].
The number of pores appeared to increase with the amount of B2O3 addition.
The dielectric structure is supposed to comprise the well conducting ceramic grains, which are separated by poorly conducting glass phase.
Therefore, B2O3 is substituted for SiO2, then the addition of B2O3 into glass increase both the amount of non-bridging oxygen (Si-O-B) in the silicate network and the number of [BO4] units.
The peak values in this location were 1336.63 cm-1 and 1638.79 cm-1 respectively from B1 to B5.This can be explained the fact that the decreasing of [SiO4] and [BO4] caused the weakening of their bonds, so these bands shifted to lower wave numbers [14].
The number of pores appeared to increase with the amount of B2O3 addition.
The dielectric structure is supposed to comprise the well conducting ceramic grains, which are separated by poorly conducting glass phase.
Online since: December 2010
Authors: Hai Feng Yang, Zhi Heng Deng, Ying Huang
Cement is from 42.5 Mpa Portland one in “Hailuo”brand;the fly ash and slag is directly come from concrete pumping station which is used for high strength concrete;AF-CA polycarboxylate super plasticizer (liquor) of "Nengbo" brand in Nanning City is adopted, its content accounts for 2.5% of the weight of cementitious materials
Table 1 The Basic Properties of Course Aggregate
Item
Grain diameter
(mm)
Apparent Density
(kg/m3)
Stacking
Density(kg/m3)
Water-Intake
Rate (%)
Crushing
Index(%)
RA
5-15
2430
1260
5.96
19.5
NA
2760
1429
1.35
13
Test scheme.In the test, the recycled aggregate’s autologous additional water absorption rate is not considered .recycled aggregate is to use the equal weight replacing natural aggregate.
Table 3 The Average Values of All Groups of Specimens Water-cement ratio Replacement (%) Confining pressure (MPa) Code number Average Peak stress(MPa) Average peak strain() 0.5 0 0 SA1-1~SA1-3 18.10 1917 4 SA1-4~SA1-6 48.48 16542 8 SA1-7~SA1-9 73.53 15747 12 SA1-10~SA1-12 93.84 25134 16 SA1-13~SA1-15 110.77 31280 100 0 SA5-1~SA5-3 16.87 2353 4 SA1-4~SA1-6 45.48 19020 8 SA1-7~SA1-9 65.14 25227 12 SA1-10~SA1-12 80.48 36376 16 SA1-13~SA1-15 98.24 45531 0.28 100 0 HA5-1~HA5-3 47.98 2520 8 HA1-4~HA1-6 90.65 11939 16 HA1-7~HA1-9 122.51 16996 24 HA1-10~HA1-12 148.39 31959 32 HA1-13~HA1-15 180.30 35950 Failure pattern of recycled concrete.
Fig. 2 Failure Pattern Fig. 3 Failure Pattern under Conventional Triaxial Stress for Natural Aggregat for Recycled Aggregate Fig. 1 is the final failure pattern for the recycle aggregate concrete in triaxial stress state,similar to ordinary concrete,under different confining pressures, the overall presentations of different water-cement ratios of recycled aggregate concrete are about 50-60 degree slant shear failure.Lightly breaking the destroyed surface apart and we find that the ordinary aggregate is almost cut into power in failure surface;while for recycle aggregate concrete,either in ordinary strength or high strength,the failure surface occurs in recyceld aggregate interface,or is split along the aggregate congenital cracks,Fig. 2 and 3 in detail.There are mainly that after a series of processes such as mechanical crushing,artificial selection and second crushing of recycled aggregate, aggregate itself has accumulate a large number
(3) In it, , according to experimental results, fitting the equation ,and the parameter values shown in Table 4, Table 4 The Results of Fitting Parameters Code number Parameter Confining pressure(Mpa) 0 4 8 12 16 SA5 1.26 2.68 2.30 3.48 3.11 A 0.38 0.44 -4.81 -13.87 D 0.96 2.0 2.59 7.16 16.59 Code number Parameter Confining pressure(Mpa) 0 <16 24 32 HA5 1.12 1.71 3.29 2.69 A -0.01 -1.70 -2.04 0.3 D 1.03 3.69 4.82 6.27 Compressive Strain Energy and the Brittleness Index.The above analysis shows that either uniaxial or triaxial compression stress - strain curves is composed of ascending and descending segments.
Table 3 The Average Values of All Groups of Specimens Water-cement ratio Replacement (%) Confining pressure (MPa) Code number Average Peak stress(MPa) Average peak strain() 0.5 0 0 SA1-1~SA1-3 18.10 1917 4 SA1-4~SA1-6 48.48 16542 8 SA1-7~SA1-9 73.53 15747 12 SA1-10~SA1-12 93.84 25134 16 SA1-13~SA1-15 110.77 31280 100 0 SA5-1~SA5-3 16.87 2353 4 SA1-4~SA1-6 45.48 19020 8 SA1-7~SA1-9 65.14 25227 12 SA1-10~SA1-12 80.48 36376 16 SA1-13~SA1-15 98.24 45531 0.28 100 0 HA5-1~HA5-3 47.98 2520 8 HA1-4~HA1-6 90.65 11939 16 HA1-7~HA1-9 122.51 16996 24 HA1-10~HA1-12 148.39 31959 32 HA1-13~HA1-15 180.30 35950 Failure pattern of recycled concrete.
Fig. 2 Failure Pattern Fig. 3 Failure Pattern under Conventional Triaxial Stress for Natural Aggregat for Recycled Aggregate Fig. 1 is the final failure pattern for the recycle aggregate concrete in triaxial stress state,similar to ordinary concrete,under different confining pressures, the overall presentations of different water-cement ratios of recycled aggregate concrete are about 50-60 degree slant shear failure.Lightly breaking the destroyed surface apart and we find that the ordinary aggregate is almost cut into power in failure surface;while for recycle aggregate concrete,either in ordinary strength or high strength,the failure surface occurs in recyceld aggregate interface,or is split along the aggregate congenital cracks,Fig. 2 and 3 in detail.There are mainly that after a series of processes such as mechanical crushing,artificial selection and second crushing of recycled aggregate, aggregate itself has accumulate a large number
(3) In it, , according to experimental results, fitting the equation ,and the parameter values shown in Table 4, Table 4 The Results of Fitting Parameters Code number Parameter Confining pressure(Mpa) 0 4 8 12 16 SA5 1.26 2.68 2.30 3.48 3.11 A 0.38 0.44 -4.81 -13.87 D 0.96 2.0 2.59 7.16 16.59 Code number Parameter Confining pressure(Mpa) 0 <16 24 32 HA5 1.12 1.71 3.29 2.69 A -0.01 -1.70 -2.04 0.3 D 1.03 3.69 4.82 6.27 Compressive Strain Energy and the Brittleness Index.The above analysis shows that either uniaxial or triaxial compression stress - strain curves is composed of ascending and descending segments.
Online since: July 2014
Authors: Feng Fan, Lin He, Jian Yuan
It is indicated that pits as a hole on the tracheid can bring biggish stress concentration at around walls, and the fracture line is about 45° that is similar to the phenomenon at macroscopic, which the damaged line is 59.5°[28] when the wood under compression parallel to grain.
While, a large number of cells in the 2# slice, that were severe damaged regions at late and early wood or between each other (refer with Fig 6a), the cells were almost splitting, and the width of crack between at 2µm and 4µm, even to 7.2µm.
Table 2 Width of cell Number of ring D5 Sample D6 Sample D7 Sample WAR* [µm] WL* [µm] WAR [µm] WL [µm] WAR [µm] WL [µm] WAR [µm] WL [µm] 1 938.98 271.32 1674.955 759.927 1332.66 545.3 1093.293 590.574 2 1042.842 199.5 1431.08 681.292 1186.36 582.54 1106.573 449.54 3 1042.825 218.12 888.635 356.44 1457.682 500.08 949.635 452.231 4 986.95 204.82 601.184 204.889 1165.085 399 960.264 468.168 5 1580.096 321.871 1298.148 505.652 984.232 444.22 968.273 508.313 6 1537.565 441.592 1260.91 500.087 489.447 172.9 / / 7 1510.882 394.003 1149.428 457.59 508.06 236.74 / / *WAR stands for width of annual ring, WL stands for width of late wood Fig 7 Late wood percentage of samples The cell wall area is summarized in Table 3 and cell wall percentage is 100% subtracts lumen percentage that showed in Fig 8.
Table 3 Cell wall area Sample Early wood Late wood Number of cell Lumen percentage [%] Whole area [µm2] Lumen area [µm2] Number of cell Lumen percentage [%] Whole area [µm2] Lumen area [µm2] D5 320 74.40173 381980 513402 240 14.89133 33163 222700 219 72.47406 312211 430790 319 12.34613 39247 317889 168 76.68386 375300 489412 613 10.42319 36329 348540 222 73.89927 434173 587520 372 13.73299 50100 364815 173 76.89976 395780 514670 454 15.43781 86737 561848 169 79.32028 430656 542933 / / / / 173 73.85681 425173 575672 / / / / 217 75.79255 454656 599869 / / / / D6 431 67.05457 394187 587860 668 8.258811 46601 564258 274 71.55494 455991 637260 281 9.150807 23513 256950 358 69.95624 395613 565515 380 6.455645 23240 359995 232 72.60505 399518 550262 223 9.152696 20200 220700 181 74.59685 389870 522636 305 13.91483 75053 539374 346 74.69547 446655 597968 / / / / 418 68.38572 367033 536710 / / / / 335 72.17985 336239 465835 / / / / 335 69.65948 364085 522664 / / / / 193 74.26407 456323 614460
While, a large number of cells in the 2# slice, that were severe damaged regions at late and early wood or between each other (refer with Fig 6a), the cells were almost splitting, and the width of crack between at 2µm and 4µm, even to 7.2µm.
Table 2 Width of cell Number of ring D5 Sample D6 Sample D7 Sample WAR* [µm] WL* [µm] WAR [µm] WL [µm] WAR [µm] WL [µm] WAR [µm] WL [µm] 1 938.98 271.32 1674.955 759.927 1332.66 545.3 1093.293 590.574 2 1042.842 199.5 1431.08 681.292 1186.36 582.54 1106.573 449.54 3 1042.825 218.12 888.635 356.44 1457.682 500.08 949.635 452.231 4 986.95 204.82 601.184 204.889 1165.085 399 960.264 468.168 5 1580.096 321.871 1298.148 505.652 984.232 444.22 968.273 508.313 6 1537.565 441.592 1260.91 500.087 489.447 172.9 / / 7 1510.882 394.003 1149.428 457.59 508.06 236.74 / / *WAR stands for width of annual ring, WL stands for width of late wood Fig 7 Late wood percentage of samples The cell wall area is summarized in Table 3 and cell wall percentage is 100% subtracts lumen percentage that showed in Fig 8.
Table 3 Cell wall area Sample Early wood Late wood Number of cell Lumen percentage [%] Whole area [µm2] Lumen area [µm2] Number of cell Lumen percentage [%] Whole area [µm2] Lumen area [µm2] D5 320 74.40173 381980 513402 240 14.89133 33163 222700 219 72.47406 312211 430790 319 12.34613 39247 317889 168 76.68386 375300 489412 613 10.42319 36329 348540 222 73.89927 434173 587520 372 13.73299 50100 364815 173 76.89976 395780 514670 454 15.43781 86737 561848 169 79.32028 430656 542933 / / / / 173 73.85681 425173 575672 / / / / 217 75.79255 454656 599869 / / / / D6 431 67.05457 394187 587860 668 8.258811 46601 564258 274 71.55494 455991 637260 281 9.150807 23513 256950 358 69.95624 395613 565515 380 6.455645 23240 359995 232 72.60505 399518 550262 223 9.152696 20200 220700 181 74.59685 389870 522636 305 13.91483 75053 539374 346 74.69547 446655 597968 / / / / 418 68.38572 367033 536710 / / / / 335 72.17985 336239 465835 / / / / 335 69.65948 364085 522664 / / / / 193 74.26407 456323 614460
Online since: February 2019
Authors: L.A. Suleymanova, I.A. Pogorelova, M.V. Marushko
The condition of a gas pore’s sphericity is predetermined by the prevalence of capillary forces and is as follows: В0 (Bond number) << 1; We (Weber number)<< 1; Nησ (viscous-capillary criterion) << 1.
The stability is determined by the static condition of a spherical gas pore’s nondeformity, quantitatively characterized with the Bond number В0 = 1.
The decrease of the pores size would reduce the Bond number and increase the role of capillary forces in the aerated concrete’s porous structure formation.
The regularities of a highly-organized porous structure formation and the principles of improving the efficiency of cellular concretes are achieved by using composite binders, controlling processes in a three-phase disperse porous system and updating the manufacturing methods of cellular concrete products, which consist in selecting the composition and grain-size of binders, which would correspond to the structure of thin interpore partitions, and in controlling the mixtures’ properties in order to combine the structure formation processes with account of force balance in the disperse system.
The stability is determined by the static condition of a spherical gas pore’s nondeformity, quantitatively characterized with the Bond number В0 = 1.
The decrease of the pores size would reduce the Bond number and increase the role of capillary forces in the aerated concrete’s porous structure formation.
The regularities of a highly-organized porous structure formation and the principles of improving the efficiency of cellular concretes are achieved by using composite binders, controlling processes in a three-phase disperse porous system and updating the manufacturing methods of cellular concrete products, which consist in selecting the composition and grain-size of binders, which would correspond to the structure of thin interpore partitions, and in controlling the mixtures’ properties in order to combine the structure formation processes with account of force balance in the disperse system.
Online since: April 2012
Authors: Hong Jing Zhang
., this large number of factors increase the crude oil emulsion stability study of complexity.
Generally believed that the basic structure of asphaltenes is a fused aromatic ring system as the core, surrounded by a number of connected naphthenic rings, aromatic and naphthenic ring with a number of varying length alkyl side chain is homogeneous or heterogeneous , mixed with a variety of molecules containing S, N, O of the group, sometimes complex has Ni, V, Fe and other metals.
Over the last decade many researchers have proposed a number of other molecular models, reflecting their chemical structure of asphaltenes in different views.
Figure 2 Aggregation models of asphaltene micelles 1 A-grains; B-side chain; C-particles; D-micelles; E-weak keys; F-holes; G-intramolecular stacking; Intermolecular H-heap; I-gum; K-petroleum porphyrin; M-metal Figure 3 Asphaltene micelle aggregation models 2 Sjoblom that the active component in the interface, the aromatic molecules stacked like a sandwich, the formation of fatty acids in the liquid crystal layer interface association, so that droplets have hard protective layer around is not easy to mutual coalescence.
Generally believed that the basic structure of asphaltenes is a fused aromatic ring system as the core, surrounded by a number of connected naphthenic rings, aromatic and naphthenic ring with a number of varying length alkyl side chain is homogeneous or heterogeneous , mixed with a variety of molecules containing S, N, O of the group, sometimes complex has Ni, V, Fe and other metals.
Over the last decade many researchers have proposed a number of other molecular models, reflecting their chemical structure of asphaltenes in different views.
Figure 2 Aggregation models of asphaltene micelles 1 A-grains; B-side chain; C-particles; D-micelles; E-weak keys; F-holes; G-intramolecular stacking; Intermolecular H-heap; I-gum; K-petroleum porphyrin; M-metal Figure 3 Asphaltene micelle aggregation models 2 Sjoblom that the active component in the interface, the aromatic molecules stacked like a sandwich, the formation of fatty acids in the liquid crystal layer interface association, so that droplets have hard protective layer around is not easy to mutual coalescence.