B p. Chemical, In this work, an overview of the published works on the deposition of AlN thin films for harsh condition applications is presented. In these applications, sensors are required for monitoring and controlling pressure, temperature, fluid flow, chemical contents, PH and among others.
As such, the sensor materials should be able to withstand the high and cyclic temperature conditions within the operating systems. AlN is a ceramic material, which finds application in micro-electromechanical systems MEMS such as acoustic sensors, energy harvesters, transducers and resonators. These applications are motivated by its high piezoelectric effect, high surface acoustic wave velocity, excellent dielectric permittivity, high thermal stability, wide band gap, chemical inertness, etc.
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As such, AlN films have been deposited on various non-metallic substrates such as Si, sapphire and polymers and on metallic substrates such as Ti6Al4V, diamond, Al, Cr and L stainless steel for different sensing applications. Literature on magnetron sputtering and future direction of these films will be detailed for improvement of performance and applications the films.
Mieczyslaw Scendo 1 , Katarzyna Staszewska-Samson 2. Corrosion resistance of nickel coatings on the Al substrate in the acidic chloride solution were investigated. The Ni coating was produced by cold spray CS method. For this purpose, nickel powders of various sizes and morphology were used.
The surface and microstructure of the specimens were observed in a scanning electron microscope SEM. The corrosion electrochemical parameters of nickel coatings were determined by electrochemical method. It has been found that the size of Ni powders have a significant effect on the corrosion resistance of nickel coatings. The porosity of nickel coatings on the Al alloy increase with increasing size of nickel powders.
Therefore, the corrosion rate of nickel coatings in the chloride environment decreases as the diameter of the nickel powder decreases.
On the other hand, the most corrosion-resistant of nickel coatings were obtained using of Ni powders with irregular spherical or dendritic structure. Besides, large particles of nickel powder cause large residual stresses compared to the small grains in the depth of nickel coatings. Tofik Nagiev 1. It has been established that a biomimetic sensor, where a semiconductor Si is used as an electrode, exhibits high sensitivity, stability and reproducibility. In the study of this biomimetic electrode on catalase activity, it was found that the detection limit of hydrogen peroxide in aqueous solution was wt.
When using metal Al as an electrode, despite its very high sensitivity to the environment, the threshold of sensitivity also amounted to wt. Harry Ngwangwa 1. A defective bearing can induce impacts and shocks in the rotor system so that the resulting dynamic forces may cause failure. In this paper, the rotor-disk assembly is modelled as an assemblage of component models for the rotor, disk and ball bearings. The defects in the bearing are modelled by introducing more nonlinearities in the elastohydrodynamic contact equation.
The main purpose of this work is to assess the changes in the dynamic forces and monitor the shifts in the stability regions as a result of the defects. The rotor is assumed to account for the rotatory inertia and shear deflection effects while the disk is assumed to be rigid. In the bearing equations the effects of lubrication are neglected.
Shift in stability regions for the rotor system are monitored through changes in critical speeds on a Campbell diagram. Further study will include the design of a control system for the rotor-disk system to avoid catastrophic failure of the system. The amazing and versatile properties of porphyrin-type heterocycles recommend them in several applications, such as: detection of anions and cations, gas, VOCs, pharmaceutically active molecules , catalysis and corrosion inhibition . Porphyrins have intrinsic sensing, catalytic or corrosion inhibiting properties but when they are conjugated, chemically bonded or simply accompanied to a proper partner: noble metal particles PtNPs, AuNPs, AgNPs  or magnetic particles , inorganic silica matrices, polymers, carbon nanotubes, pseudo-binary oxides or semiconductor type materials, their desired optical, electrical or corrosion inhibiting properties are remarkably enhanced.
Several efficient associations that imply especially Pt-porphyrins or porphyrins in hybrids with PtNPs are reviewed. Pt-porphyrins complexed with gold colloids are capable to optically detect trace amounts of triiodide ion ; a methoxy-substituted Pt-porphyrin in PVC membrane is able to potentiometrically detect bromide  or to optically detect hydrocortisone; a water soluble Zn-porphyrin in complex with AgNPs is used for recognition and monitoring of p-aminosalicylicacid drug ; trace oxygen sensing were realized by using a newly porphyrin heterodimeric complex ; a functionalized A3B-type porphyrin with Fe3O4 magnetic NPs has both catalytic and detection properties, proving to be a multifunctional material; sandwich layers of mixed substituted A3B porphyrins and pseudo-binary oxides Zn3Ta2O8 and Zn3Nb2O8 proved high inhibition efficiency in saline environments .
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The capacity of both hydrophilic and hydrophobic porphyrins to form complexes or associations with hexachloroplatinic acid and in this way to recover platinum from leaching solutions of exhausted automotive catalysts is also presented. Literature data  and our preliminary results  indicate that the electrochemical recovery of metals from waste printed circuit boards WPCBs represents an economical and eco-friendly recycling alternative if an appropriate recycling strategy is selected and the operational parameters are well controlled.
The main objective of the present research was to optimize the experimental parameters for the electrodetection of copper, tin, lead and iron from real WPCBs leaching solutions. In order to avoid the overlapping of the specific metal ions signals, the process was studied by cyclic voltammetry, square-wave voltammetry and rotating disc electrode, in a restrained scanning potential window at rigorous controlled experimental parameters, like different scan rates, frequencies or rotation rates.
Also, a mathematical modeling and treatment of the recorded data was proposed and successfully used to diminish the copper signal and enhance the iron electrodetection. Concerning the pH and ORP monitoring, the tests based on several commercial available equipments failed due to a poor accuracy or even a complete blocking as a result of excessive common mode voltage. Consequently, for this type of measurements, optimized galvanic insulated adapters were designed, manufactured and successfully tested, proving excellent accuracy and thermal stability.
References: 1. Diaz, T. Lister, Waste Manag. Dorneanu, A.
Modern Aspects of Electrochemistry | John O'M. Bockris | Springer
Avram, A. Marincas, N. Cotolan, T. Frentiu, P. Dorneanu, G. There has been a growing interest in terahertz technology that can be applied in numerous fields such as security, military, medical, communications, and so on. Utilizing the specific electromagnetic response property of metamaterials, the material having the capability to absorb the incident spectrum in the frequency range from 0.
Therefore, the design for terahertz metamaterial structures and the research on electromagnetic characteristics of the terahertz metamaterial are valuable. In this paper, the unit structure of the amorphous silicon metamaterial in the terahertz band base on microelectronic technology is designed.
The reflectivity and the transmittance of the metamaterial corresponding to the designed unit in the band are calculated by using the simulation software of electro-magnetic field. The mechanical properties of materials can be estimated by measuring the elastic constants of materials. For a homogeneous and isotropic material, the elastic behavior of the material can be defined with just two independent elastic constants.
The elastic constants of a material can be measured using ultrasonic transmission or reflection methods. Ultrasound critical angle reflectometry UCR is a noninvasive and nondestructive reflection technique used to estimate the elastic constants of bone both in vitro and in vivo. In this study, UCR technique is used to measure the elastic constants of a horizontal transversely isotropic HTI phenolite. By analyzing the reflection amplitudes of ultrasounds scanning from different azimuths, the critical angles for the longitudinal wave qP and fast transverse wave qSH are estimated, and then the azimuth-dependent velocities and the elastic constants of the HTI phenolite can be calculated.
The elastic constants of the HTI phenolite were obtained previously by a transmission method, therefore the error of UCR technique can be estimated. That indicates this technique is an effective method to estimate the elastic constants of anisotropic media.
Pavel Degtyarenko 1. One of the most important problem of development AC superconducting transmission lines is the decreasing of AC losses in high temperature superconducting HTS cables. The efficiency of power transmission and costs of cryogenic systems essentially depend on the value of AC losses. Various design versions of HTS cables proposed in  allow decreasing of AC losses in several times, and their level becomes comparable with or even lower than the natural cryostat heat losses.
However, there is an opportunity of the further decreasing of losses in 1. The large copper amount in HTS cables is necessary in the most of instances where a cable operates in fault current modes to protect it from overheating. However, this is valid for short samples of cables as shown in .
Modern Aspects of Electrochemistry 42
And for the most of actual HTS power transmission lines a reversed situation takes place, i. Moreover, a considerable decreasing of the latter enables a self-protection from overheating and operation of the HTS cable itself as a fault current device, i. The realization of this opportunity is no less important than the decreasing of AC losses. In this paper the determination of the minimal thickness of 2G HTS tape copper layer which ensures the critical parameters of the tape allowing its long reliable operation in the AC mode at Hz is considered and discussed. Transistor controlled by two MOS systems, one of them traditionally formed on the channel surface and another represented as buried oxide of SOI structure in conjunction with Si substrate.
A pair of ohmic opposite contacts formed on lateral sides of channel which are normal to the current flow serves for measure the Hall effect. This work held for explore features of characteristics of normally closed magneto-sensitive FMJLT in accumulation regime enrichment of the channel SiSiO2 near interfaces regions with electrons. TCAD modelling in this work made for achieve maximum of magneto-sensing in depending of device form, property of SOI structure channel width and length, donor concentration in active layer, charge in SiO2 films, density of states on SiO2-Si interface , electrical regimes of operation supply voltage, gate potentials.
Experimentally explored I-V characteristics in presence and absence of magnetic field in a wide range of temperature and in depending of different types of radiation exposure. Also investigated possibility to improve characteristics of magneto-sensitive JLT due to double-gate control system. MJFET much more sustained to impact of impulse, corpuscular and ionizing radiation. Maria Ivakh 1. For biological substances researches the optical sensors are used in wide applications range form medical diagnostics to surrounding medium monitoring. The sensitive material is a main element of optical sensors and provide the corresponding response from tested substauce.
Cholesteric liquid crystals can be applied to such kind of sensitive materials based on spectral characteristic changes versus biological influence. In paper the pure BLO cholesteric liquid crystal and as mixture with 5CB nematic liquid crystal have been researched as sensitive material medium for amino acids optical sensor. There are three areas in spectral characteristics diagram can be observed at the amino acids interacting. The first area that correspond to small amino acids concentrations is characterized by wavelength minimum transmittance shifting to long range of spectrum, then the saturation area is observed second area , and with following amino acids concentration increasing the wavelength minimum transmittance shift to short range of spectrum third area.
To expand the concentration measurement range, we suggest to use the first and third areas of spectral characteristic. We propose to use the several narrow-band optical sources and one photoelectronic converter for optimal designing structure of optical sensor. Such configuration will provides a wide range of optical parameters measurements with minimizing of hardware costs for sensors implementation.