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Online since: January 2014
Authors: Sławomir Rowiński, Wojciech Lorenc, Maciej Kożuch
In the observation channel, built 500 mm from the support, the first fatigue crack was observed at the number of 320 thousand cycles.
Fig. 4 Experimental studies: a) beam scheme with numbered steel dowels, b) steel beam (dowels 1’ to 9’) after cutting, c) steel beam (dowels 1 to 9).
I (Figs. 8a, b) is fine-grained, which could be affected by the cutting technology (oxygen-acetylene cutting).
The product of the remaining number of cycles to the maximum crack length – from 37 to 238 mm (destruction of steel beam) and average speed shows clear decrease of crack propagation speed.
Fig. 4 Experimental studies: a) beam scheme with numbered steel dowels, b) steel beam (dowels 1’ to 9’) after cutting, c) steel beam (dowels 1 to 9).
I (Figs. 8a, b) is fine-grained, which could be affected by the cutting technology (oxygen-acetylene cutting).
The product of the remaining number of cycles to the maximum crack length – from 37 to 238 mm (destruction of steel beam) and average speed shows clear decrease of crack propagation speed.
Online since: February 2019
Authors: V.V. Luchkina
The gaseous allocations from the system of furnaces released into the atmosphere are a problem number one in pollution abatement of the environment by production of cement today.
The detailed composition and structure of clinker for HBC production are not given, but it is clear that in order to ensure activity, the belite must be present in the clinker composition in its hight-temperature polymorphic modifications, and the cement’s grain composition must be carefullyselected.
Over the past 10-15 years, the number of publications devoted to the use of biomineralization phenomenon for obtaining various types of building materials is rapidly increasing.
Therefore for receiving qualitative cement it is necessary to work properly at all these stages, to observe a number of requirements.
The detailed composition and structure of clinker for HBC production are not given, but it is clear that in order to ensure activity, the belite must be present in the clinker composition in its hight-temperature polymorphic modifications, and the cement’s grain composition must be carefullyselected.
Over the past 10-15 years, the number of publications devoted to the use of biomineralization phenomenon for obtaining various types of building materials is rapidly increasing.
Therefore for receiving qualitative cement it is necessary to work properly at all these stages, to observe a number of requirements.
Online since: July 2015
Authors: Zijah Burzić, Ivica Čamagić, Nemanja Vasić, Predrag Živković, Aleksandar Radović, Tamara Sedmak, Meri Burzić
It should be taken into consideration that damage in form of crack appears after large number of load changes with stress level lower than yield stress (high-cycle fatigue) [2].
Strengthening was done in combination of a classic improvement (quenching and tempering), followed by grain refinement due to adequately selected chemical composition, micro alloying and appropriate deposition.
The number of load cycles before fracture and the level of stress under which there is no crack initiation or fracture after a certain number of cycles (usually 106 to 108 cycles) are determined in this testing with constant load range, according to the standard.
Strengthening was done in combination of a classic improvement (quenching and tempering), followed by grain refinement due to adequately selected chemical composition, micro alloying and appropriate deposition.
The number of load cycles before fracture and the level of stress under which there is no crack initiation or fracture after a certain number of cycles (usually 106 to 108 cycles) are determined in this testing with constant load range, according to the standard.
Online since: February 2016
Authors: De Jun Yin, Zhong Min Zhao, Long Zhang
A number of studies were found in literature regarding the performance, deformation characteristics, and processing techniques of the two-component armor systems, which generally referred to ceramic/metal or ceramic/composite armors.
Meanwhile, linear scanning images of EDS determined that a large quantity of Fe, Cr atoms entered the intermediate nearby Ti-6-Al-4V alloy while a number of Ti atoms also passed through the mid-ceramic to come into the intermediate nearby 42CrMo steel, as shown in Fig. 5.
Fig.5 EDS linear scanning images from 42CrMo steel to the mid-ceramic and further to Ti-6Al-4V alloy Fig.6 FESEM image of the microstructure of the mid-ceramic Fig. 7 The hardness distribution curve of the FG multilayer composite In addition, FESEM images showed that the mid-ceramic was composed of a number of very fine ceramic phases such as TiC1-x, TiB and TiB2, of which the majority were smaller than 1 μm in size, and some ones even resided in the range of 100~200 nm in size, as shown in Fig. 6.
Furthermore, because of the loss of a large quantity of the mid-ceramic liquid, there was only low atomic concentration of C and B in the remained mid-ceramic liquid, so TiB2, TiB and TiC solids hardly grew even if they nucleated in the mid-ceramic liquid, finally, ultrafine grained microstructure was achieved in the mid-ceramic after rapid solidification of the mid-ceramic, as shown in Fig. 6.
Meanwhile, linear scanning images of EDS determined that a large quantity of Fe, Cr atoms entered the intermediate nearby Ti-6-Al-4V alloy while a number of Ti atoms also passed through the mid-ceramic to come into the intermediate nearby 42CrMo steel, as shown in Fig. 5.
Fig.5 EDS linear scanning images from 42CrMo steel to the mid-ceramic and further to Ti-6Al-4V alloy Fig.6 FESEM image of the microstructure of the mid-ceramic Fig. 7 The hardness distribution curve of the FG multilayer composite In addition, FESEM images showed that the mid-ceramic was composed of a number of very fine ceramic phases such as TiC1-x, TiB and TiB2, of which the majority were smaller than 1 μm in size, and some ones even resided in the range of 100~200 nm in size, as shown in Fig. 6.
Furthermore, because of the loss of a large quantity of the mid-ceramic liquid, there was only low atomic concentration of C and B in the remained mid-ceramic liquid, so TiB2, TiB and TiC solids hardly grew even if they nucleated in the mid-ceramic liquid, finally, ultrafine grained microstructure was achieved in the mid-ceramic after rapid solidification of the mid-ceramic, as shown in Fig. 6.
Online since: April 2013
Authors: S. Gutierrez, V. Calderón, A. Rodríguez, J. Garabito
After a limited number of uses the polyamide powder no longer serves its initial function and is converted into a waste product.
We have carried out the microstructure examination on different hardened mortars, in which is shown as the PAW is distributed around the grains of lime (fig.4).
These analyzes require a detailed characterization of the mixtures tested, varying percentages of inclusion of PAW and the number of physical, chemical and durability tests according to current regulations.
However, it is required a more thorough study to confirm this improvement with respect to traditional lime mortar, with larger number of specimens and different PAW mixtures.
We have carried out the microstructure examination on different hardened mortars, in which is shown as the PAW is distributed around the grains of lime (fig.4).
These analyzes require a detailed characterization of the mixtures tested, varying percentages of inclusion of PAW and the number of physical, chemical and durability tests according to current regulations.
However, it is required a more thorough study to confirm this improvement with respect to traditional lime mortar, with larger number of specimens and different PAW mixtures.
Online since: August 2004
Authors: Claudio Shyinti Kiminami, Walter José Botta Filho, Claudemiro Bolfarini, L.A. Bereta
Spray forming presents features of rapid solidification techniques and thus results
in fine-grained microstructures, increased solid solubility, non-equilibrium phases and small sizes
intermetallics [1].
The difficult to the characterization of the ternary phase in the Al-Fe-Si system has been attributed to the occurrence of a number of phases over a small composition range and their small size in the order of few micrometers [3].
The problem has been compounded because of a large number of metastable phases occurs in this system.
In the past, the investigations have been carried out to establish the compositions, morphologies and crystal structures of a large number of ternary and binary phases that exist in this ternary system [4-6].
The difficult to the characterization of the ternary phase in the Al-Fe-Si system has been attributed to the occurrence of a number of phases over a small composition range and their small size in the order of few micrometers [3].
The problem has been compounded because of a large number of metastable phases occurs in this system.
In the past, the investigations have been carried out to establish the compositions, morphologies and crystal structures of a large number of ternary and binary phases that exist in this ternary system [4-6].
Online since: April 2011
Authors: Yan Fei Ma, Xue Dong Feng
Secondly, a large number of waste lye penetrated into the adjacent land resulting in soil alkalinity, swampiness, pollution of surface and groundwater sources.
A number of studies, particularly in Western Australia, have shown that red mud applied to soils can be very effective in reducing heavy metal effect on plants.
The shortcomings are listed as follows: (ⅰ) the research on the production technology and activation method is inadequate. (ⅱ) when the heavy metal ions coexist, there is competition among heavy metal ions, so it is necessary to explore the advantageous characteristics of various heavy metal ions and adsorption mechanism. (ⅲ) Now most work has been done on the ion shape of heavy metals, but little consideration was taken on the removal mechanism and adsorption model of complex shape heavy metals. (ⅳ) like the other porous medias, in order to improve the adsorption capacity of red mud, the particle size and grain composition of red mud should be studied which plays an important role in industrial application . (ⅴ) most studies are limited to pot experiments at home, but there are a large number of barren soils because of pollution.
A number of studies, particularly in Western Australia, have shown that red mud applied to soils can be very effective in reducing heavy metal effect on plants.
The shortcomings are listed as follows: (ⅰ) the research on the production technology and activation method is inadequate. (ⅱ) when the heavy metal ions coexist, there is competition among heavy metal ions, so it is necessary to explore the advantageous characteristics of various heavy metal ions and adsorption mechanism. (ⅲ) Now most work has been done on the ion shape of heavy metals, but little consideration was taken on the removal mechanism and adsorption model of complex shape heavy metals. (ⅳ) like the other porous medias, in order to improve the adsorption capacity of red mud, the particle size and grain composition of red mud should be studied which plays an important role in industrial application . (ⅴ) most studies are limited to pot experiments at home, but there are a large number of barren soils because of pollution.
Online since: September 2013
Authors: Wu Sheng Luo, Sheng Fei Yu
Fig.1 Synthesis route of SP
Preparation of SP/SAO-ED: 5.0 g SAO-ED (the grain size: 20–25µm, purity: 99.5%) is firstly added into 50.0 ml different solvent and is ultrasonically dispersed for 15 min, then the suspension is put into a three-necked flask. 0.25g SP is added into the suspension, then the suspension is heated at a rate of 1.2 ºC/min.
With the decreasing of the solvent dielectric constant, the solution color in toluene solvent after irradiation appears from colorless to blue, then to slightly blue, discoloration time and the number of cycles increases firstly, then decreases.
SP/SAO-ED prepared in chloroform in toluene solvent shows better photochromic effect: the solution color is blue, discoloration time is 20s, the number of discoloration cycles is 250.
SP/SAO-ED composite phosphor is formed by N atom on the heterocyclic ring of SP coordinating with metal ions on the surface of SAO-ED, and the maximum EX wavelength is 320 nm, the maximum EM wavelength is 512 nm, and the discoloration time of SP/SAO-ED is longer than that of SP, the number of the discoloration cycles of SP/SAO-ED is more than that of SP.
With the decreasing of the solvent dielectric constant, the solution color in toluene solvent after irradiation appears from colorless to blue, then to slightly blue, discoloration time and the number of cycles increases firstly, then decreases.
SP/SAO-ED prepared in chloroform in toluene solvent shows better photochromic effect: the solution color is blue, discoloration time is 20s, the number of discoloration cycles is 250.
SP/SAO-ED composite phosphor is formed by N atom on the heterocyclic ring of SP coordinating with metal ions on the surface of SAO-ED, and the maximum EX wavelength is 320 nm, the maximum EM wavelength is 512 nm, and the discoloration time of SP/SAO-ED is longer than that of SP, the number of the discoloration cycles of SP/SAO-ED is more than that of SP.
Online since: December 2006
Authors: Meng Yin Tu, Wen Hsiung Wang, Yung Fu Hsu
From the TEM bright field image, there is apparently a large number of
dislocations within bainitic ferrites, and the dislocation density is estimated at about 7.41×10
15 m-2
via calculation from the equation: log10{ρ}= 9.2848 + (6880.73 / T) - (1780360 / T
2) [10].
There is a large number of dislocations formed within the upper bainitic ferrite, but the dislocation density in the upper bainite (about 3.77×10 15 m-2) is less than in the lower bainitic ferrite.
Nevertheless, intergranular fracture usually takes place only in the case of grain boundary segregation of impurities.
Due to a large number of cementite / ferrite interfaces within the bainitic ferrite and the high hardeness of cementite with respect to dislocations that might cut through, a cleavage crack on a ferrite facet will be interfered with acutely.
There is a large number of dislocations formed within the upper bainitic ferrite, but the dislocation density in the upper bainite (about 3.77×10 15 m-2) is less than in the lower bainitic ferrite.
Nevertheless, intergranular fracture usually takes place only in the case of grain boundary segregation of impurities.
Due to a large number of cementite / ferrite interfaces within the bainitic ferrite and the high hardeness of cementite with respect to dislocations that might cut through, a cleavage crack on a ferrite facet will be interfered with acutely.
Online since: November 2014
Authors: Ab Saman Kader, Farid Nasir Ani, Muhammad Anshar
Determination of RS available potential can be determined by using the value of Straw-to-Grain Ratio (SGR) of 1.5 [2, 4-5] and the amount of RP every year, using the equation.
Determination of potential energy of RH surplus can be done based on previous study [6-7], by the equation: EPRS= WRS × CVRS (3) where WRS = number of RS, and CVRS = calorific value of RS.
4,823 15 Jogyakarta 946 1,419 568 426 71 355 4,459 16 Bali 866 1,299 520 390 65 325 4,082 17 Central Kalimantan 756 1,134 454 340 57 284 3,567 18 East Nusatenggara 699 1,049 420 315 53 262 3,291 19 Jambi 625 938 375 281 47 235 2,952 20 North Sulawesi 615 923 369 277 46 231 2,901 21 Bengkulu 582 873 349 262 44 218 2,738 22 East Kalimantan 553 830 332 249 42 208 2,613 23 Southeast Sulawesi 516 774 310 232 39 194 2,437 24 Riau 512 768 307 230 38 192 2,412 25 West Sulawesi 413 620 248 186 31 155 1,947 26 Gorontalo 245 368 147 110 18 92 1,156 27 Papua 138 207 83 62 10 52 653 28 Maluku 84 126 50 38 6 32 402 29 North Maluku 66 99 40 30 5 25 314 30 West Papua 30 45 18 14 2 11 138 31 Bangka Belitung 23 35 14 11 2 9 113 32 Jakarta 11 17 7 5 1 4 50 33 Riau Islands 1 2 1 1 0 1 13 Total 69,044 103,566 41,426 31,070 5,178 25,892 325,204 Table 2 shows the potential surplus of RS and the potential energy for each province is vary in number
The potential surplus of RS in each province various in number, where the largest and smallest was East Java and Riau Islands, respectively.
Determination of potential energy of RH surplus can be done based on previous study [6-7], by the equation: EPRS= WRS × CVRS (3) where WRS = number of RS, and CVRS = calorific value of RS.
4,823 15 Jogyakarta 946 1,419 568 426 71 355 4,459 16 Bali 866 1,299 520 390 65 325 4,082 17 Central Kalimantan 756 1,134 454 340 57 284 3,567 18 East Nusatenggara 699 1,049 420 315 53 262 3,291 19 Jambi 625 938 375 281 47 235 2,952 20 North Sulawesi 615 923 369 277 46 231 2,901 21 Bengkulu 582 873 349 262 44 218 2,738 22 East Kalimantan 553 830 332 249 42 208 2,613 23 Southeast Sulawesi 516 774 310 232 39 194 2,437 24 Riau 512 768 307 230 38 192 2,412 25 West Sulawesi 413 620 248 186 31 155 1,947 26 Gorontalo 245 368 147 110 18 92 1,156 27 Papua 138 207 83 62 10 52 653 28 Maluku 84 126 50 38 6 32 402 29 North Maluku 66 99 40 30 5 25 314 30 West Papua 30 45 18 14 2 11 138 31 Bangka Belitung 23 35 14 11 2 9 113 32 Jakarta 11 17 7 5 1 4 50 33 Riau Islands 1 2 1 1 0 1 13 Total 69,044 103,566 41,426 31,070 5,178 25,892 325,204 Table 2 shows the potential surplus of RS and the potential energy for each province is vary in number
The potential surplus of RS in each province various in number, where the largest and smallest was East Java and Riau Islands, respectively.