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Online since: December 2013
Authors: B.C. Bhatt, M.S. Kulkarni
The effective atomic number Zeff (see Table 1) is an indication of the material’s energy response.
The crystalline material was crushed and sieved to select phosphor powder with grain sizes between 100 and 300 µm.
Finally, the polycrystalline phosphor was crushed and sieved in the grain sizes between 75 and 200 mm.
For preparing pellets, phosphor grains in the range 75 and 200 µm, were compacted into pellets of dia. 4 mm.
Applications of RPL glass dosimeters have been highlighted in a number of publications [216, 217].
The crystalline material was crushed and sieved to select phosphor powder with grain sizes between 100 and 300 µm.
Finally, the polycrystalline phosphor was crushed and sieved in the grain sizes between 75 and 200 mm.
For preparing pellets, phosphor grains in the range 75 and 200 µm, were compacted into pellets of dia. 4 mm.
Applications of RPL glass dosimeters have been highlighted in a number of publications [216, 217].
Online since: October 2016
Authors: Mariana Carla Mendes Rodrigues, Guilherme Corrêa Soares, Vicente Tadeu Lopes Buono, Leandro de Arruda Santos
In order to approach a cyclic saturation level, number of cycles was established as 20.
(a) Dissipated energy as a function of number of cycles; (b) Cumulative residual strain as a function of number of cycles.
It can be seen in Fig. 3b that ԑr tends to accumulate in the extent that the number of cycles increases.
However, as the number of cycles increases a dislocation saturation level tends to be reached, so a roughly stable behavior can be seen after some cycles.
Eggeler, The influence of temperature on the evolution of functional properties during pseudoelastic cycling of ultra fine grained NiTi, Mater.
(a) Dissipated energy as a function of number of cycles; (b) Cumulative residual strain as a function of number of cycles.
It can be seen in Fig. 3b that ԑr tends to accumulate in the extent that the number of cycles increases.
However, as the number of cycles increases a dislocation saturation level tends to be reached, so a roughly stable behavior can be seen after some cycles.
Eggeler, The influence of temperature on the evolution of functional properties during pseudoelastic cycling of ultra fine grained NiTi, Mater.
Online since: April 2021
Authors: Kannan Sekar
The metallurgical aspects including porosity, grain refinement and recrystallization, mechanical and tribological properties of the products; the mechanics of the different processes, and finally the advantages, applications, and disadvantages of squeeze casting technique.
According to Hall Petch theory, the strength is inversely proportional to the grain size.
Fig.4 (a) shows that the ductile fracture with transgranular crack propagation and Fig. 4 (b) Also has shown the same type of ductile fracture with less number of dimples and microcracks.
Fig.4 (d) has shown the intergranular fracture phenomenon that means crack propagated through the weak grain boundaries and it is the indication of brittle fracture [4,10-13].
Because of this agglomeration, ductility, and the energy absorption of the hybrid MMC decreased with an increase in the number of ceramic reinforcement particles.
According to Hall Petch theory, the strength is inversely proportional to the grain size.
Fig.4 (a) shows that the ductile fracture with transgranular crack propagation and Fig. 4 (b) Also has shown the same type of ductile fracture with less number of dimples and microcracks.
Fig.4 (d) has shown the intergranular fracture phenomenon that means crack propagated through the weak grain boundaries and it is the indication of brittle fracture [4,10-13].
Because of this agglomeration, ductility, and the energy absorption of the hybrid MMC decreased with an increase in the number of ceramic reinforcement particles.
Online since: March 2021
Authors: Masayoshi Kawai, Susumu Ikeda, Takashi Ino
The remainders were stored into the TMRA container which was constructed with flat iron boxes packed with grains (small ball) of lead for gamma-ray shielding (see Fig. 11).
Work packing lead grains into iron box of the old TMRA container.
Total number of protons during 26 years was 3.83x1021 with high availability of 94.35% during beam on time of 39,082 hours.
Removal of cold moderator from TMRA, Finishing new TMRA container by packing grains (small balls) of Pb.
It was possible to measure in a wide range of energy and momentum space using a number of devices installed in KENS, observation of the dynamics of atoms and magnetism from the static structure of the material having a size of several Å ~ several μm could be performed.
Work packing lead grains into iron box of the old TMRA container.
Total number of protons during 26 years was 3.83x1021 with high availability of 94.35% during beam on time of 39,082 hours.
Removal of cold moderator from TMRA, Finishing new TMRA container by packing grains (small balls) of Pb.
It was possible to measure in a wide range of energy and momentum space using a number of devices installed in KENS, observation of the dynamics of atoms and magnetism from the static structure of the material having a size of several Å ~ several μm could be performed.
Online since: October 2012
Authors: Zone Ching Lin, Ying Chih Hsu
Fig. 1 Crystal structure of α-Al2O3
Table 1: Calculation parameters for simulation nanocutting of sapphire substrate by molecular statics
Configuration
Nanocutting
Sapphire (workpiece material)
(a= 4.759Å ,c= 12.991Å)
a and c are the lattice constant of sapphire
15a×8a×15c
Number of atoms in Sapphire
56,079
Number of atoms of tool (rigid-body diamond)
2,623
Tip radius of tool (nm)
2
Depth of cut (nm)
0.4, 0.5, 0.6
Fig. 2 Simulation model for nanocutting of sapphire substrate: (a) side view, (b) 3D image.
Table 2: Morse potential parameters for cutting of sapphire workpiece by AFM diamond probe tool Al-Al O-O C-C Al-O Al-C O-C D: (eV) 0.27 5.12 2.423 0.912 0.28 3.522 α: (Å-1) 1.165 2.68 2.555 0.717 2.78 2.617 r0 : (Å) 3.253 1.208 2.522 2.231 2.20 1.865 According to the Morse potential used by this paper, the negative value of Morse potential gradient is taken to find the action force of molecules, which is expressed as (3): (3) As inferred from (3), the expression of action force between atoms is shown in (4): (4) where i is the code number of diamond probe’s atom; j is the code number of oxygen atom and aluminum atom in workpiece; n is the number of workpiece atoms; and is the distance between two atoms.
When the action forces in three axial directions produced from n grains of atoms in material being applied on m grains of probe atoms on cutting tool are added up, the total component forces in three axial directions can be obtained.
Of course, after cutting has proceeded for a certain period, the number of workpiece atoms affected by Morse force of diamond cutting tool is not only one atom.
(7) where : number assigned to all the atoms of diamond probe tool atoms that affect the Morse force of a certain workpiece atom j : number assigned to other workpiece atoms inside the cut-off radius after removal of a certain workpiece atom affected by Morse force of probe tool.
Table 2: Morse potential parameters for cutting of sapphire workpiece by AFM diamond probe tool Al-Al O-O C-C Al-O Al-C O-C D: (eV) 0.27 5.12 2.423 0.912 0.28 3.522 α: (Å-1) 1.165 2.68 2.555 0.717 2.78 2.617 r0 : (Å) 3.253 1.208 2.522 2.231 2.20 1.865 According to the Morse potential used by this paper, the negative value of Morse potential gradient is taken to find the action force of molecules, which is expressed as (3): (3) As inferred from (3), the expression of action force between atoms is shown in (4): (4) where i is the code number of diamond probe’s atom; j is the code number of oxygen atom and aluminum atom in workpiece; n is the number of workpiece atoms; and is the distance between two atoms.
When the action forces in three axial directions produced from n grains of atoms in material being applied on m grains of probe atoms on cutting tool are added up, the total component forces in three axial directions can be obtained.
Of course, after cutting has proceeded for a certain period, the number of workpiece atoms affected by Morse force of diamond cutting tool is not only one atom.
(7) where : number assigned to all the atoms of diamond probe tool atoms that affect the Morse force of a certain workpiece atom j : number assigned to other workpiece atoms inside the cut-off radius after removal of a certain workpiece atom affected by Morse force of probe tool.
Online since: July 2021
Authors: Arkady A. Cherepenko, Elena A. Zvyagina, Artem N. Tkachenko, Elena M. Selemeneva, Michael F. Selemenev
It was established that a decrease in the coefficient of friction from 0.9 to 0.6 leads to a decrease in the number of foci and areas of contact stresses, as well as temperature analysis showed that a decrease in the friction forces reduces heat transfer in the cutting zone by about 40 ° C.
The parameters of dividing the workpiece model into finite elements were chosen so as to ensure sufficient mesh accuracy and, therefore, the accuracy of calculations in the deformation zone with a minimum number of elements (to ensure an acceptable calculation speed).
The total number of elements is relatively small, about 80,000.
For this, the program has a choice of several sets of material properties data that can be modeled and analyzed: • Plastic properties of materials • Elastic properties of materials • Thermal processing data • Diffusion data • Grain growth or recrystallization model • Data on the hardness of materials • Material fragility data These parameters make it possible to specify the required output values of the simulation, which increases the accuracy of the obtained data and reduces the time of their calculation.
Radial and axial deformations were determined directly in the sections with the marked numbers in Figure 12, by the controlled nodal points in each section, circumferential deformations were calculated by the change in the radii of the points [6].
The parameters of dividing the workpiece model into finite elements were chosen so as to ensure sufficient mesh accuracy and, therefore, the accuracy of calculations in the deformation zone with a minimum number of elements (to ensure an acceptable calculation speed).
The total number of elements is relatively small, about 80,000.
For this, the program has a choice of several sets of material properties data that can be modeled and analyzed: • Plastic properties of materials • Elastic properties of materials • Thermal processing data • Diffusion data • Grain growth or recrystallization model • Data on the hardness of materials • Material fragility data These parameters make it possible to specify the required output values of the simulation, which increases the accuracy of the obtained data and reduces the time of their calculation.
Radial and axial deformations were determined directly in the sections with the marked numbers in Figure 12, by the controlled nodal points in each section, circumferential deformations were calculated by the change in the radii of the points [6].
Online since: December 2011
Authors: Yong Yu
As the demand of business and technique changing, a large number of “solitary islands” are destined to be legacy systems, which causing a great waste of resources.
As the demand of business and technique changing, a large number of “solitary islands” are destined to be legacy systems, which causing a great waste of resources.
Through standard and coarse-grained encapsulation of system function, SOA can realize a large scale of reuse of atom services [2].
As the demand of business and technique changing, a large number of “solitary islands” are destined to be legacy systems, which causing a great waste of resources.
Through standard and coarse-grained encapsulation of system function, SOA can realize a large scale of reuse of atom services [2].
Online since: October 2009
Authors: Jean Marc Chaix, Celine Pascal, Aurelie Thomazic
Design of experiments is used to reduce the number of experiments and to
analyse the results.
In a previous investigation [1], to ensure chemical compatibility and to limit the number of chemical elements, a WC-based hard material with a Fe-based binder was defined although cobalt is usually employed in cemented carbide [2].
Below 15 µm thickness (Fig. 2a), η-phase is always discontinuous and does not originate cracks; above 50 µm (Fig. 2c), η-phase forms a continuous layer with large pores; between 15 and 50 µm (Fig. 2b), the brittleness of the interface depends on connections between each grain.
Design of experiments (D.O.E) provides a simple and systematic approach to analyse the effect of these parameters on the densification of both layers and η-phase formation with a limited number of experiments.
D.O.E. by factorial designs requires minimal number of experiments and allows knowing effects of each parameter.
In a previous investigation [1], to ensure chemical compatibility and to limit the number of chemical elements, a WC-based hard material with a Fe-based binder was defined although cobalt is usually employed in cemented carbide [2].
Below 15 µm thickness (Fig. 2a), η-phase is always discontinuous and does not originate cracks; above 50 µm (Fig. 2c), η-phase forms a continuous layer with large pores; between 15 and 50 µm (Fig. 2b), the brittleness of the interface depends on connections between each grain.
Design of experiments (D.O.E) provides a simple and systematic approach to analyse the effect of these parameters on the densification of both layers and η-phase formation with a limited number of experiments.
D.O.E. by factorial designs requires minimal number of experiments and allows knowing effects of each parameter.
Online since: January 2022
Authors: Victoria Alexandrovna Sokolova, Sergey Voinash, Irina Vornacheva, Evgeny Remshev, Zainudin Rasulov, Pavel Kolesnikov, Sergey N. Dolmatov
It is shown that it is possible to prevent loss of stability during the first operation of the technological process, as well as to reduce the number of operations by eliminating annealing between subsequent operations of drawing with thinning.
The work investigated the possibility of using an organofluorine coating to reduce the number of rejects in products made of refractory alloys.
Research Methods The main problem of the technology of manufacturing hollow axisymmetric parts from refractory alloys is the laboriousness of the process, due to the large number of drawing operations and the use of annealing (vacuum heat treatment) after them - for cold hardening removal.
The adsorption layer, lowering the surface energy of the material, facilitates plastic flow in the grains located in the surface layer.
However, in a number of cases, when processing fluorine-surfactant crystals with substances on the base, the effect of increasing the microhardness and strength of metals is observed [15-17].
The work investigated the possibility of using an organofluorine coating to reduce the number of rejects in products made of refractory alloys.
Research Methods The main problem of the technology of manufacturing hollow axisymmetric parts from refractory alloys is the laboriousness of the process, due to the large number of drawing operations and the use of annealing (vacuum heat treatment) after them - for cold hardening removal.
The adsorption layer, lowering the surface energy of the material, facilitates plastic flow in the grains located in the surface layer.
However, in a number of cases, when processing fluorine-surfactant crystals with substances on the base, the effect of increasing the microhardness and strength of metals is observed [15-17].
Online since: December 2024
Authors: A.D. Vishwanatha, Bijayani Panda, A.V. Ramesh Kumar, Anup P. Athresh
It results in lowered surface roughness, higher compressive residual stress, better grain refinement, increased surface hardness, and enhanced corrosion resistance.
Shot peening results in hardening of the surface by generating large number of dislocations, induces near-surface residual compressive stress (RCS), introduces severe plastic deformation (SPD) and roughens the surface [12, 16, 17].
It was observed that adding lower shot intensity at the second stage and the third stage for SP4 resulted in improved refinement in grain.
The key factors causing the increase in hardness are residual compressive stress, grain refinement, and micro strain [27].
Shot peening results in hardening of the surface by generating large number of dislocations, induces near-surface residual compressive stress (RCS), introduces severe plastic deformation (SPD) and roughens the surface [12, 16, 17].
It was observed that adding lower shot intensity at the second stage and the third stage for SP4 resulted in improved refinement in grain.
The key factors causing the increase in hardness are residual compressive stress, grain refinement, and micro strain [27].