## 2 Transmissibility of the Acceleration Base
This allowed the researchers to characterize the skin and the behavior of the skin of the hand when disrupted, as well as investigate the effect of different factors on the transmissibility of vibrations. The results showed that vibration transmissibility to the hand varied between individuals, and the key finding was that exposure to vibration had a significant effect on the fingers when changing the temperature even for a short test period. Figure 3: Anatomical dots (**a**,**b**) paired points considered in [32]. The second study presented in [33] (Figures 4-6) focused on the vibrations transmitted to the thumb. It was found that these vibrations were concentrated in the thumb's most-vascularized area. Vibration transmissibility was influenced by temperature (Table 2). Figure 4: Diagram of the three orthogonal directions—x, y, and z—and the frequency weighting curve (\(W_{\text{h}}\)) as outlined in SR EN ISO 5349-1/2003 [33]. Figure 5: A two-dimensional (2D) finite-element model of a fingertip in contact with a flat surface [33]. \begin{table}
\begin{tabular}{l c c c c c c} \hline \hline  & \multicolumn{2}{c}{**Temperature Before Vibration**} & \multicolumn{2}{c}{**Temperature After Vibration**} & \multicolumn{2}{c}{**Temperature Drop [\({}^{\circ}\)C]**} \\  & \multicolumn{2}{c}{**Exposure [\({}^{\circ}\)C]**} & \multicolumn{2}{c}{**Exposure [\({}^{\circ}\)C]**} & \multicolumn{2}{c}{**Temperature Drop [\({}^{\circ}\)C]**} \\ \hline Region & D & P & D & P & D & P \\ Mean & 31.75 & 31.73 & 29.64 & 30.07 & 2.1 & 1.6 \\ SD & 3.69 & 2.98 & 3.16 & 3.01 & - & - \\ Min & 21.60 & 23.60 & 22.48 & 23.92 & - & - \\ Max & 34.92 & 35.22 & 33.96 & 34.40 & - & - \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Mean values of finger temperature at the distal (D) and proximal (P) positions, measured before and after exposure to vibrations [33]. Figure 6: Temperature drop after vibration exposure for all participants [33]. Figure 7 presents the microscopic structure of three products used in the study of glove materials. It appears that structure b belongs to a more appropriate material to study from the point of view of density. The data presented in [11] established a method for measuring biodynamic responses to vibrations in the hand-arm system. For this purpose, the vibration exposure of a worker holding and pressing a usual work piece on a sanding belt was simulated. This method was applied to measure the apparent mass and vibration transmissibility produced by two different feed forces (15 N and 30 N) and six simulated grinding interfaces with different stiffness values. A major resonance was observed in each transmissivity spectrum of the work piece, which correlated with the major impedance resonance of the entire system. In conclusion, these resonant frequencies depended on the mass of the work piece, the stiffness of the grinding interface, and the feed force. Increasing the feed force increased the overall vibration transmissibility to the hand-arm system, and the transmissibility to the work piece was not significantly affected by the interface conditions. A review paper made a short introspective analysis, showing a similarity between hand and foot vibration transmission as a way to biometrically recognize a person [32]. The research in question used the frequency response function (FRF, measured between two points--one of excitation and the other of response--both belonging to a mechanical structure) of the human body, in particular for the fingers, and used this information for personal identification. All these methods were similar to the biometric measurement procedure for the upper limbs (hand-arm). In these studies, the FRF values of the individuals' fingers were measured. A biodynamic system model was simulated for the component elements of a finger, namely the phalanges, the joints, and the skin.