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Online since: October 2022
Authors: Jindřich Melichar, Ámos Dufka, Tomáš Melichar, Jiří Bydžovský
A number of renovated scientific teams have dealt with the issue of matrix formation on the basis of these substances, while in the case of alkali-activated metakaolin the term geopolymer, resp. geopolymerization [1], resp. the term geosynthesis is generally used.
One of the key factors influencing the formation of the AAM matrix structure is the presence of an alkali metal, the temperature during the maturation of the material and a number of other circumstances also play an important role [4].
Table 6: Technical characteristics of used filler Fraction Bulk density Grain density Absorbency W60 Crushing resistance 0-4 mm 500 kg.m-3 925 kg.m-3 5% 3 MPa Mixtures were prepared from the mixtures, the composition of which is given in Table 1, on which the determination of fresh mortar consistency (EN 1015-3), Subsequently, the mixtures were placed in molds, and thus test specimens in the form of beams with dimensions of 40x40x160 mm were produced.
The relatively compact structure and the as yet unreacted ash grain are evident.
One of the key factors influencing the formation of the AAM matrix structure is the presence of an alkali metal, the temperature during the maturation of the material and a number of other circumstances also play an important role [4].
Table 6: Technical characteristics of used filler Fraction Bulk density Grain density Absorbency W60 Crushing resistance 0-4 mm 500 kg.m-3 925 kg.m-3 5% 3 MPa Mixtures were prepared from the mixtures, the composition of which is given in Table 1, on which the determination of fresh mortar consistency (EN 1015-3), Subsequently, the mixtures were placed in molds, and thus test specimens in the form of beams with dimensions of 40x40x160 mm were produced.
The relatively compact structure and the as yet unreacted ash grain are evident.
Online since: March 2015
Authors: Alan G. Leacock, Gregor Volk, Desmond Brown, Mark Cosby, Graham Cowan, David McCracken
(a) (b)
(c) (d)
(e)
Figure 1: (a) raster build scheme (b) tensile specimen dimensions, (c) 3D layout of specimen build on printer (d) plan view of specimen build on printer and specimen numbers and (e) friction plate geometry
Specimens with an edge build direction (specimens 4, 5 and 6) while in general show similar yield strengths do however show higher elongation (Fig. 2(b)) than that observed for the flat specimens.
In the plane of the build table, two orientations of the friction plates were produced: (a) with the plate long edge at 45° to the Y axis and (b) with the plate long edge parallel to the table Y axis resulting in the surface grain of the laydowns as shown in Figure 5 (a) and (b) respectively.
The displacement is the total displacement of the strip in relation to a given friction plate (i.e. the number of passes times 50 mm) including all speeds and pressures.
(a) (b) Figure 5: Surface grain with edge of friction plate (a) at 45° to FDM machine Y axis, (b) parallel to the Y axis (a) (b) Figure 6: Wear on tools parallel to the build plane orthotropic axes showing (a) incident light to highlight smoothing and (b) build-up of wear materials following complete test programme (a) (b) Figure 7: Static and dynamic coefficient of friction vs total strip displacement for friction plates with the surface filaments oriented to the pull direction (a) at 0° and (b) at 45° .
In the plane of the build table, two orientations of the friction plates were produced: (a) with the plate long edge at 45° to the Y axis and (b) with the plate long edge parallel to the table Y axis resulting in the surface grain of the laydowns as shown in Figure 5 (a) and (b) respectively.
The displacement is the total displacement of the strip in relation to a given friction plate (i.e. the number of passes times 50 mm) including all speeds and pressures.
(a) (b) Figure 5: Surface grain with edge of friction plate (a) at 45° to FDM machine Y axis, (b) parallel to the Y axis (a) (b) Figure 6: Wear on tools parallel to the build plane orthotropic axes showing (a) incident light to highlight smoothing and (b) build-up of wear materials following complete test programme (a) (b) Figure 7: Static and dynamic coefficient of friction vs total strip displacement for friction plates with the surface filaments oriented to the pull direction (a) at 0° and (b) at 45° .
Online since: June 2007
Authors: Nobusuke Hattori, Shinichi Nishida, Tuan Suhaimi Salleh
The shape and dimension of notched specimen in detail (unit:mm)
The materials are heat treated as described in Table 1 in order to provide more malleability and
ductility in Material A, to refine the grain structure and to create more homogeneous austenite (γ)
structure in material Q and to reduce the brittleness imparted by hardening process in materials T1
and T2.
The specimens were produced to the shape and dimensions shown in Fig. 2, the notch R1 (ρ) with a stress concentration, α ≈ 2.762, calculated from the following equation [3]; α = 1 + [2(1 + υ)/(3 + υ)][(d/ρ) 1/2 ] (1) In this case; υ = 0.3, d = 5 and ρ = 1 The etching processes have been employed before a hardness number is measured using a Vickers Hardness tester at 1.96N load.
Fig. 3(a) shows S-N diagram, which is the relationship between stress amplitude, σa and the number of cycles to failure.
In material Q the crack was initiated due to the existence of inclusions and voids within grain structures which caused lack of fatigue strength [8,9].
The specimens were produced to the shape and dimensions shown in Fig. 2, the notch R1 (ρ) with a stress concentration, α ≈ 2.762, calculated from the following equation [3]; α = 1 + [2(1 + υ)/(3 + υ)][(d/ρ) 1/2 ] (1) In this case; υ = 0.3, d = 5 and ρ = 1 The etching processes have been employed before a hardness number is measured using a Vickers Hardness tester at 1.96N load.
Fig. 3(a) shows S-N diagram, which is the relationship between stress amplitude, σa and the number of cycles to failure.
In material Q the crack was initiated due to the existence of inclusions and voids within grain structures which caused lack of fatigue strength [8,9].
Online since: October 2007
Authors: Ulrich Herr, Harald Kaps, M. Zachau, Thomas Gleich, Vahid Raeesi, Heiko Paul
The basic heat transfer equation is:
( ))(
)()(
)()()(
W
2 xTT
xurxc
xNux
dx
xdT
p
−
⋅
=
ρ
κ
, (2)
where Nu represents the Nusselt number, κ the heat conductivity, cp heat capacity, u(x) velocity of
the gas, r reactor tube radius and ρ the density of the gas.
The temperature dependent Nusselt number and heat capacity were calculated for each temperature T(x) using data given in [3].
In comparison with a coarse grained YAG:Ce reference sample (shown in Fig. 5a), which has its maximum emission at 550 nm, a blue-shift of the peak maximum of 20 nm is observed.
This deviation between the nano-powder and the coarse-grained YAG can be attributed to a different crystal-field of the host lattice acting on the Ce.
The temperature dependent Nusselt number and heat capacity were calculated for each temperature T(x) using data given in [3].
In comparison with a coarse grained YAG:Ce reference sample (shown in Fig. 5a), which has its maximum emission at 550 nm, a blue-shift of the peak maximum of 20 nm is observed.
This deviation between the nano-powder and the coarse-grained YAG can be attributed to a different crystal-field of the host lattice acting on the Ce.
Online since: January 2013
Authors: Xiao Feng Wei, Yan Feng, Ri Chu Wang
A large number of lead-free solders research studies [4-7] have been reported which have focused primarily on microstructural analysis and mechanical properties for specified compositions of lead-free solders.
After taking a heat-treatment at 150˚C for 150 h, the microstructure of the solder matrix coarsens significantly, and (Ni,Au)3Sn2 grains centralize at the interface between solder and Ni substrate.
With prolonging the aging time, the (Ni,Au)3Sn2 grains are unchanged in numbers but agglomerate and coarsen gradually.
After taking a heat-treatment at 150˚C for 150 h, the microstructure of the solder matrix coarsens significantly, and (Ni,Au)3Sn2 grains centralize at the interface between solder and Ni substrate.
With prolonging the aging time, the (Ni,Au)3Sn2 grains are unchanged in numbers but agglomerate and coarsen gradually.
Online since: September 2019
Authors: Boubaker Benhaoua, Atmane Benhaoua, Achour Rahal, Abdelkader Hima, Saied Chahnez, Barani Djamel, Segueni Leila, Brahim Gasmi, Allag Nassiba
The increase in the values of band gap energy with different dopant is attributed to the decrease in crystallinity and grain size of ZnO films [14].
Fig. 3 Plot of grain size and band gap versus La- concentration of ZnO thin films.
The texture coefficients TC(hkl) have been based on the following formula [19]: (4) where TC(hkl) is the texture coefficient of the plane (hkl), I(hkl) is the measured intensity, I0(hkl) is the standard intensity, N is the reflection number and n is the number of diffraction peaks.
Fig. 3 Plot of grain size and band gap versus La- concentration of ZnO thin films.
The texture coefficients TC(hkl) have been based on the following formula [19]: (4) where TC(hkl) is the texture coefficient of the plane (hkl), I(hkl) is the measured intensity, I0(hkl) is the standard intensity, N is the reflection number and n is the number of diffraction peaks.
Online since: February 2024
Authors: Oleksandr Umanskyi, Oleksandr Terentyev, Oleksiy Melnyk, Maryna Storozhenko, Oleksandr Koval, Oleksandr Chernyshov, Tatiana Chevychelova, Valera Brazhevsky, Viktor Varchenko
A large number of fine phases are precipitated in these areas due to the partial dissolution of (Ti,Cr)C in the melted binder metal.
Additionally, the high content of the brittle carbide grains and increased porosity in the (Ti,Cr)C-18wt.
%Ni binder is enough to prevent the brittle fatigue and detachment of carbide grains under friction load.
On the other hand, a reduced number of pores and cracks inside the coatings also prevents losses of carbide particles.
Additionally, the high content of the brittle carbide grains and increased porosity in the (Ti,Cr)C-18wt.
%Ni binder is enough to prevent the brittle fatigue and detachment of carbide grains under friction load.
On the other hand, a reduced number of pores and cracks inside the coatings also prevents losses of carbide particles.
Online since: March 2022
Authors: Felisca Melin Dianes, Yanuar Nugraha, Muhammad R. Ryan, Muhammad Rafli Supriadi, Reyza Halim, Alfirano Alfirano
The longer heating time causes the grain size to increase so that it will provide more inter-grain space for the interstitial atoms such as nitrogen.
Table 2 White Layer Thickness and diffusion depth of the sample after nitriding No Sample Code Holding Time Layer Thickness [µm] Diffusion Depth [µm] 1 N2Z2 2 jam 3,1 32,7 2 N4Z2 4 jam 2,9 36,4 3 N6Z2 6 jam 3,616 61 Table 3 White Layer Thickness Data Variation in Number of Media No Sample Code Amount of Urea Layer Thickness [µm] Diffusion Depth [µm] 1 N4Z1 0,3 d.o.a 3,238 34 2 N4Z2 0,4 d.o.a 3,616 61 Fig 1 Cross section SEM images of (a) N2Z2, (b) N4Z2 and (c) N6Z2 nitrided-samples.
From the results of the analysis, the phase formed from the white layer is the a-Fe2N phase based on the number of dissolved nitrogen atoms in the sample, which is more than 12% [12].
Table 2 White Layer Thickness and diffusion depth of the sample after nitriding No Sample Code Holding Time Layer Thickness [µm] Diffusion Depth [µm] 1 N2Z2 2 jam 3,1 32,7 2 N4Z2 4 jam 2,9 36,4 3 N6Z2 6 jam 3,616 61 Table 3 White Layer Thickness Data Variation in Number of Media No Sample Code Amount of Urea Layer Thickness [µm] Diffusion Depth [µm] 1 N4Z1 0,3 d.o.a 3,238 34 2 N4Z2 0,4 d.o.a 3,616 61 Fig 1 Cross section SEM images of (a) N2Z2, (b) N4Z2 and (c) N6Z2 nitrided-samples.
From the results of the analysis, the phase formed from the white layer is the a-Fe2N phase based on the number of dissolved nitrogen atoms in the sample, which is more than 12% [12].
Online since: January 2016
Authors: Anton Puškár, Martin Hépal
Vitková [2] defines the degree of representation of functions in functionally mixed territory as particles, where coarse grains are large shopping centers and small grains are shops in parterres and arcades of buildings.
Parameter of comfort is then expressed as a dimensionless number as follows: [11] Ψ = v+σv0+σ0 (1) Studies aimed at determining the boundaries of discomfort realized by Hunt in 1976, which were based on experiments in a wind tunnel, were completed by Jackson in 1978.
The implementation can be performed in a number of ways.
Parameter of comfort is then expressed as a dimensionless number as follows: [11] Ψ = v+σv0+σ0 (1) Studies aimed at determining the boundaries of discomfort realized by Hunt in 1976, which were based on experiments in a wind tunnel, were completed by Jackson in 1978.
The implementation can be performed in a number of ways.
Online since: January 2022
Authors: Abdeldjalil Slimani, Lakhdar Saihi, Dalila Menacer, Saadoun Boudebous
This behavior signified that the fluid is fully convected for higher Darcy number.
Other areas of applications are in food processing, grain storage, soil heating, storage of radioactive waste, porous radiant burners [5], and uncovered flat plate solar collectors having rows of vertical strips collector [6] etc.
Furthermore, the absolute value of local Nusselt number for MWCNT is more than SWCNT.
Parametric studies of the effect of Darcy number and the mixed convection parameter, Richardson number on the flow behavior and heat transfer have been performed.
· For lower Darcy’s number, the distribution of contour patterns is eventually similar for both values of Richardson’s number considered in this work
Other areas of applications are in food processing, grain storage, soil heating, storage of radioactive waste, porous radiant burners [5], and uncovered flat plate solar collectors having rows of vertical strips collector [6] etc.
Furthermore, the absolute value of local Nusselt number for MWCNT is more than SWCNT.
Parametric studies of the effect of Darcy number and the mixed convection parameter, Richardson number on the flow behavior and heat transfer have been performed.
· For lower Darcy’s number, the distribution of contour patterns is eventually similar for both values of Richardson’s number considered in this work