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The main features found in all of them are the concentration of stresses, a higher or lower degree of wearing, and a considerable reduction of life.
The parameter is therefore (24) where ∆γmax is the shear strain increment in the plane where it is maximum, k is a constant that is fitted from the uniaxial and torsion fatigue tests data, σmax is the normal stress perpendicular to the plane where the maximum of ∆γ is produced, and σy is the yield strength.
It is observed that for the same axial stress variation, life reduction due to fretting can reach up to two orders of magnitude.

The efficiency of the heat exchanger depends essentially on the fluid temperature, the conductivity of the material used in the manufacture of the heat exchanger and the reduction of heat loss [17].
In addition to the elimination and reduction of the fouling ratio, the geometry of the heat exchanger itself influences heat transfer.
Therefore, the thermal analysis and the mathematical modeling of the heat transfer through the evaporator-absorber are realized by choosing a typical day: July 25th 2019, whose weather characteristics are as follows [46]: Tab. 1: Representation of the location data for the evaporator-absorber study, as well as the meteorological characteristics of July 25th, 2019 Location: Oujda, Morocco General information on July 25th, 2019 and coordinates of the location Sunrise time (GMT) Sunset time (GMT) Time zone Latitude (°) Longitude (°) Altitude (m) 5:12 19:15 UTC+1 34°681’ -1°909’ 470 Elevation and azimuth of the sun on July 25th, 2019 6:00 (GMT) 12:00 (GMT) 18:00 (GMT) Elevation(°) 8°27’ 74°64’ 13°82’ Azimuth (°) 71°72’ 167°28’ 276°73’ Meteorological conditions on July 25th, 2019 Maximum temperature (°C) Minimum temperature (°C) Heat index Pressure (hPa) Wind speed (km/h) Humidity (%) Cloud cover (%) 34 23 34 1015 23 66 7 2.2 Methodology details 2.2.1 Description of heat exchanges

Beyond this temperature, no Ni hydrosilicate-related peaks were observed, indicating the complete reduction of the Ni compound.
T(ºC) T(°C) WG(%) T(°C) WL1(%) T(°C) WL2(%) WL1+2(%) 500 n.d. n.d. n.d. n.d. n.d. n.d. 9.1 600 251 -1.1 384 6.7 559 6.8 13.5 700 260 -1.3 360 3.2 533 1.3 4.5 800 274 -1.0 390 2.3 518 3.2 5.5 900 256 -0.1 398 0.8 575 6.7 7.5 1000 274 -0.3 416 1.6 649 19.5 21.1 The data in Table 5 reveals that Ni oxidation occurs between 250 and 270 ºC for all samples, and that samples treated at 900 and 1000 ºC present the lowest WG values.
Rousset, Synthesis of carbon nanotubes–Fe–Al2O3 nanocomposite powders by selective reduction of different Al1.8Fe0.2O3 solid solutions, J.

The XPS spectra were recorded immediately after turning the X-ray source on to avoid any induced artifacts by possible reduction of samples by heating from the beam.
Resistance Data.
Upon hydrogenating the sample the Cr 2p3/2 peak shifts to lower energy which could be assigned to reduction of Cr3+ to Cr2+ state owing to Cr (3d)−O (2p) charge transfer.

This leads to a reduction of the magnetic moment of the alloy which is reflected, for example, in a reduction of the Curie temperature and the saturation magnetization.
The data have been extracted from the cooling curves of the magnetization measurements performed on the alloy quenched from 1173K and then heated up to several temperatures (see inset).

In comparison to RC buildings reinforced entirely with steel rebars, a reduction of the residual roof drift reaching 50% was observed for the variant with SMA rebars.
The applied ground motions could be either natural earthquake records or artificially generated data.
The reduction ratio exceeds 88% for the Canadian building and 75% for the Moroccan building.

From the available data on Ti-Nb-based SMA, there is no uniqueness in indexing some martensite peaks.
Fig. 22d presents the data on the widths of the X-ray diffraction lines of the β-phase in the Ti-Nb-Ta alloy taken at RT after cold deformation by rolling with a reduction to e = 0.26 and PDA at a temperature from 450 to 900°C.
Then, the average values of the cross-sectional area and the depth of the track are calculated from the data obtained.
Table 4 presents summarized measurements data including the initial (Е0) and steady-state (Е∞) potentials of alloys and the maximum shift value (ΔЕ = Е∞ – Е0) under the exposure to the solutions.
On the face of it, this contradicts the data of the OCP curve measurement, according to which the alloy tends to self-passivation under exposure.

This observation is confirmed by the data of semi-quantitative analysis, according to which Ti content in samples 1 (Nb/Cu-Sn-0.24Ti), 2 (Nb-1.11Ti/Cu-Sn) and 6 (Nb-1.75Ti/Cu-Sn) is 0.63 at.%, 1.25 at.% and 1.48 at.% respectively.
However, according to the data given in Table 2, the higher Ti content in the superconducting layers has not improved the Jc, but on the contrary, it got lower.
But in this case, at higher temperatures, when the outflow of Sn from the interface is faster, the columnar grains must predominate, which is not the case and contradicts to the data of [78].
None of these arguments seem completely satisfactory and reliable, because according to our data the columnar grains are retained in the last portions of the residual Nb and do not decompose into the equiaxed ones.
But more accurate analysis of the Nb3Sn grain sizes can be done based on the data of TEM studies and is given below.

The receiving data, which are cell current and voltage, were kept for subsequent analysis.
We separated the data into 3 groups.
They are (i) I-V data of QD solar cell, (ii) I-V data of QD solar cell when temperature is varied and (iii) I-V data of reference cell.
The (i) and (ii) are plotted while only data from (ii) were fitted for finding Iph, n, Io, Rs, and Rsh The plotted and fitting data are showed in the next section.
The raw experimental data (scatter) and the fitted graph (line) of QD solar cell are plotted together.

The grey theory, first proposed by Deng [49]), avoids the inherent defects of conventional, statistical methods and only requires a limited amount of data to estimate the behavior of an uncertain system.
They constitute a systematic method concerning the planning of experiments, collection and analysis of data with near-optimum use of available resources.
However, data to be used in Grey analysis must be preprocessed into quantitative indices to normalize raw data for further analysis.
Preprocessing raw data is a process of converting an original sequence into a decimal sequence between 0.00 and 1.00 for comparison.
Mills, Data Selection for Turning Carbon Steel using a Fuzzy Logic Approach, Journal of Materials Processing Technology, Vol.135, pp.44-58. (2003) [47].