A static approach to investigate the impact of predictive maintenance in the reliability level and the failure cost of industrial installations

Digital IoT(Internet of Things)solutions for equipment condition monitoring andnew advanced algorithms to process big data, enablethe application of predictive maintenance.Consequently, actual implementations of such a system in industrial installations triggers theverification of its potentialbenefits. Thus, this project attempts to quantify the impact of a predictive maintenance system in the failure rate and the maintenance costof industrial installations.The lack oftime depended data lead to a static approach that utilizes average failure rate and mean time to repair values coming from IEEE standards and other sources. Next, a methodology that links the equipment causes of failure with a predictive maintenance system functions, is proposed. Consequently, new reduced failure rates for theassets under monitoring are defined.To perform the reliability calculations the spreadsheet methodology is presented and utilized. Additionally, the revenue requirement methodology is described and is used for the cost benefit analysis.Finally, the approach is applied in two theoretical and two actual industrial installations. Sensitivity analyses regarding different parameters of a predictive maintenance system are conducted in the first two cases,to evaluate the impact on different reliability indices. Moreover, cost benefit analysis is performed in the actual industrial networks and according to the resultspredictive maintenance should be preferred. Lastly, regarding the failure rate, a small or high reduction is observed depending on the type of failures, the utility sources,the system configuration,the number of monitored equipment and other paramet

Optimized Spintronic Terahertz Emitters Based on Epitaxial Grown Fe/Pt Layer Structures

We report on generation of pulsed broadband terahertz radiation utilizing the inverse spin Hall effect in Fe/Pt bilayers on MgO and sapphire substrates. The emitter was optimized with respect to layer thickness, growth parameters, substrates and geometrical arrangement. The experimentally determined optimum layer thicknesses were in qualitative agreement with simulations of the spin current induced in the ferromagnetic layer. Our model takes into account generation of spin polarization, spin diffusion and accumulation in Fe and Pt and electrical as well as optical properties of the bilayer samples. Using the device in a counterintuitive orientation a Si lens was attached to increase the collection efficiency of the emitter. The optimized emitter provided a bandwidth of up to 8 THz which was mainly limited by the low-temperature-grown GaAs (LT-GaAS) photoconductive antenna used as detector and the pulse length of the pump laser. The THz pulse length was as short as 220 fs for a sub 100 fs pulse length of the 800 nm pump laser. Average pump powers as low as 25 mW (at a repetition rate of 75 MHz) have been used for terahertz generation. This and the general performance make the spintronic terahertz emitter compatible with established emitters based on nonlinear generation methods.Comment: 10 pages, 7 figure

Studies of the functional tyrosyl residues of insulin

Acetylimidazole was used to acetylate the tyrosyl residues of insulin. The kinetics of acetylation were studied by termination of the reaction at several time intervals, isolation of acetylated insulin and determination of 0-acetyltyrosyl groups by deacetylation with hydroxylamine. The deacetylation was also studied kinetically by means of the absorbancy change during the reaction. The degree of availability of the tyrosyl groups in native insulin, and of the 0-acetyltyrosyl groups in the acetylated insulin was studied by the above kinetic studies. Two tyrosyl residues were acetylated at a rate sufficiently more fast than the remaining two so that a diacetyl derivative could be isolated. This preparation was fully active. The completely acetylated insulin was only thirty percent as active as native insulin in the mouse convulsion test. Native and acetylated insulin were inactivated by seventy percent on treatment with hydroxylamine. These and other findings lead to the conclusion that one or both of the slowly acetylated tyrosyl residues of insulin are involved in the mechanism of action of the hormone. In order to determine the location of the two acetylated tyrosyl residues, the diacetyl derivative of insulin was oxidized and the A and B chains isolated were assayed for acetyl groups. The diacetyl derivative was also digested separately with trypsin and chymotrypsin, and each core was also assayed for acetyl groups. From the results of these assays it was concluded that the diacetyl derivative of insulin was acetylated to the A19 and B16 tyrosyl residues, which are characterized as reactive, while the other two tyrosyl residues, A14 and B26 are non-reactive or bound. The fact that both tyrosyl B26, and asparaginyl A21 are bound and essential for hormone activity suggests a specific tyrosyl B26-carboxylate A21 interaction essential for maintaining the native conformation and the activity of insulin. The usefulness of the kinetic and structural studies employed here for evaluation of the degree of exposure of tyrosyl residues, selective blocking of tyrosyl groups, and determination of the location of reactive and non-reactive tyrosyl residues of insulin, for the purpose of structure-and-function studies on other problems, is discussed

Broadband enhancement of the magneto-optical activity of hybrid Au loaded Bi:YIG

We unravel the underlying near-field mechanism of the enhancement of the magneto-optical activity of bismuth-substituted yttrium iron garnet films (Bi:YIG) loaded with gold nanoparticles. The experimental results show that the embedded gold nanoparticles lead to a broadband enhancement of the magneto-optical activity with respect to the activity of the bare Bi:YIG films. Full vectorial near- and far-field simulations demonstrate that this broadband enhancement is the result of a magneto-optically enabled cross-talking of orthogonal localized plasmon resonances. Our results pave the way to the on-demand design of the magneto-optical properties of hybrid magneto-plasmonic circuitry.Comment: 6 Pages, 3 Figure

Shaping THz emission spectra by using sub-wavelength nanopatterned spintronic THz emitters

We show in theory and experiment that in periodically patterned spintronic THz emitters (STE), charge dynamics can modify the emission spectrum in a well-controlled way. Characterization of sub-wavelength patterned STE at frequencies up to 30 THz shows that the STE's emission spectrum systematically changes with emitter size. The spectral intensity exhibits significant reductions at frequencies below 4 THz, accompanied by pronounced dips at around 15 THz and 24 THz. While reducing the STE size enhances the modulation of all features, it does not alter the dip frequencies. The effect originates from the charging of the structure's edges by THz currents, causing a backflow that interferes with the primary current pulse. An analytical model quantitatively reproduces these results and agrees well with control experiments. Our findings enable a detailed investigation of the charge dynamics in STE and provide additional means for controlled shaping of STE emission spectra by nano patterning.Comment: 7 pages, 4 figure