Search results

The purpose of this paper is to investigate the electrical transport mechanism of the Al‐doped ZnO nanorods at different temperatures by employing impedance spectroscopy.

Al‐doped ZnO nanorods were grown on silicon substrate using step sol‐gel method. For the seed solution preparation Zinc acetate dihydrate, 2‐methoxyethanol, monoethanolamine and aluminum nitrite nano‐hydrate were used as a solute, solvent, stabilizer and dopant, respectively. Prior to the deposition, P‐type Si (100) wafer was cut into pieces of 1 cm×2 cm. The samples were then cleaned in an ultrasonic bath with acetone, ethanol, and de‐ionized (DI) water for 5 min. The prepared seed solution was coated on silicon substrate using spin coater at spinning speed of 3000 rpm for 30 s and then dried at 250°C for 10 min followed by annealing at 550°C for 1 h. The hydrothermal growth was carried out in a solution of zinc nitrate hexahydrate (0.025M), Hexamethyltetramine (0.025M) in DI water.

Al‐doped ZnO nanorods were characterized using scanning electron microscope (SEM), X‐ray diffraction (XRD) and impedance spectroscopy. The impedance measurements were carried out at various temperatures (100°C‐325°C). The impedance results showed that temperature has great influence on the impedance; the impedance value decreased as the temperature increased. This decrement is attributed to the increase of the mobility of the defects, especially the oxygen vacancies. The surface morphology of the samples was measured by SEM and X‐ray diffraction. The SEM images show that the high density of Al‐doped ZnO nanorods covers the silicon substrate, whereas the XRD pattern shows the (002) crystal orientation.

This paper demonstrates the electron transport mechanism of Al‐doped ZnO nanorods, at different temperatures, to understand the charge transport model.

The purpose of this paper is to examine the passive layer on 1050A aluminium alloy in non‐stationary conditions of linearly raised and lowered temperatures by means of dynamic electrochemistry impedance spectroscopy (DEIS).

The oxide passive layer on aluminium was examined using DEIS under non‐stationary conditions of linearly raised and lowered temperatures. In total, five heating‐cooling cycles were performed.

A significant change of impedance was observed only during the first cycle, which was called the forming one. During the subsequent cycles, the impedance of the system changed in a reversible manner.

The analysis using a equivalent circuit allowed us to determine a change of electric parameters of the circuit in the temperature function. Obtained changes of the electric parameters were correlated with layer structure.

This paper aims to presents a new method of investigation of local properties of conformal coatings utilized in microelectronics.

It is based on atomic force microscopy (AFM) technique supplemented with the ability of local electrical measurements, which apart from topography acquisition allows recording of local impedance spectra, impedance imaging and dc current mapping. Potentialities of the proposed AFM-assisted approach have been demonstrated on commercially available epoxy-coated electronic printed boards in as-received state and after six-year service.

The technique proved to be capable of identification, spatial localization and characterization of conformal coating defects.

The proposed approach can be utilized for assessment of protective film state in such demanding fields as electronics or electrotechnics where the classical techniques of anticorrosion coatings investigation cannot be employed due to small element dimensions and relatively low coating thickness.

The approach adopted by the author is novel in the field of organic coatings investigation.

Organic solar cells have potential as an alternative to conventional inorganic solar cell due to low processing cost, flexibility and easy fabrication technique.

The goal of this paper is to study the characteristics of the CuPc and PCBM based organic solar cell by introducing a thin layer of Ag at the interface of donor (CuPc) and Acceptor (PCBM), their photovoltaic and optical properties were investigated. The heterojunction solar cells with and without silver inter layer were fabricated through thermal deposition in HR vacuum. The OPV solar cells were characterized using current-voltage graphs, absorbance spectrum and Impedance spectroscopy. Impedance spectroscopy was taken to identify the traps using series resistance, parallel resistance, and Impedance spectrums under different frequencies. Optical behaviors of these devices have been investigated with absorbance spectrum.

Introducing Ag to interfacing point produced traps and these traps causes to decreased Voc, Isc, FF, and efficiency. The effect of silver layer at donor acceptor interface was studied.

Modern meat processing requires automation and robotisation to remain sustainable and adapt to future challenges, including those brought by global infection events. Automation of all or many processes is seen as the way forward, with robots performing various tasks instead of people. Meat cutting is one of these tasks. Smart novel solutions, including smart knives, are required, with the smart knife being able to analyse and predict the meat it cuts. This paper aims to review technologies with the potential to be used as a so-called “smart knife” The criteria for a smart knife are also defined.

This paper reviews various technologies that can be used, either alone or in combination, for developing a future smart knife for robotic meat cutting, with possibilities for their integration into automatic meat processing. Optical methods, Near Infra-Red spectroscopy, electrical impedance spectroscopy, force sensing and electromagnetic wave-based sensing approaches are assessed against the defined criteria for a smart knife.

Optical methods are well established for meat quality and composition characterisation but lack speed and robustness for real-time use as part of a cutting tool. Combining these methods with artificial intelligence (AI) could improve the performance. Methods, such as electrical impedance measurements and rapid evaporative ionisation mass spectrometry, are invasive and not suitable in meat processing since they damage the meat. One attractive option is using athermal electromagnetic waves, although no commercially developed solutions exist that are readily adaptable to produce a smart knife with proven functionality, robustness or reliability.

This paper critically reviews and assesses a range of sensing technologies with very specific requirements: to be compatible with robotic assisted cutting in the meat industry. The concept of a smart knife that can benefit from these technologies to provide a real-time “feeling feedback” to the robot is at the centre of the discussion.

This paper aims to enhance the barrier properties and active protection of a water-based silane coating on mild steel through nanoclay and zinc acetylacetonate simultaneously included into the formulation.

The corrosion protection performance of the silane sol-gel coatings with no additive, zinc acetylacetonate, nanoclay and nanoclay + zinc acetylacetonate was monitored using electrochemical impedance spectroscopy during 5 h of immersion in a sodium chloride solution. Moreover, the surface of coatings was analyzed using a field emission scanning electron microscopy equipped with an energy dispersive X-ray spectrometer (FESEM-EDX) and water contact angle measurements.

In electrochemical impedance spectroscopy analysis, the impedance at low frequencies, coating resistance and charge transfer resistance were the parameters considered which indicated the superiority of silane coating formulated with both nanoclay and zinc acetylacetonate. According to the results of FESEM/EDX and water contact angle measurements, the superiority was linked with the enhancement in the barrier properties in the presence of nanoclay, as well as function of the corrosion inhibitor at coating–substrate interface.

According to the literature, there is no research conducted to study the impact of the simultaneous use of nanoclay and zinc acetylacetonate on the barrier properties and active protection of an eco-friendly silane sol-gel coating including glycidyloxypropyltrimethoxysilane, tetraethoxysilane and methyltriethoxysilane on mild steel in a sodium chloride solution.

When coatings are applied to industrial equipment, they have to be able to stand the heat produced by solar energy and/or by different conditions on the process. Therefore, the purpose of this paper is to study the effect of temperature on the protective properties of coatings since this parameter degrades the polymer structure. In addition, the temperature effects on dry coating can also be specified.

In order to know the behaviour of an organic coating at different temperatures, a drying aging cycle was performed by heating on substrate steel and free‐of‐substrate films during ten uninterrupted days at three and different temperatures: 65, 85 and 100°C. At the end of this period, the aged films were analyzed by means of electrochemical impedance spectroscopy (EIS) measurements, thermal analysis (DSC and TGA), Fourier transform infrared spectroscopy (FTIR), and scanning electronic microscopy (SEM).

The most critical temperature for the aging was 85°C and “over‐cured” phenomenon were observed on the aged films which were reported by EIS, thermal and IR analyses.

These aging conditions were tested on a very strong and rigid resin containing a barrier pigment. Thus, it can also be applied to other plastic coatings, such as vinyl or alkyd ones, by modifying the temperatures according to glass transition temperature (T_g), as well as the ageing time depending on the hardness and resistance of such coatings and, of course, the protective effect of the pigment. In addition, another aggressive electrolyte, such as synthetic sea water, chloride, sulphide media, as well as inhibitors or ecological pigments could be used in order to predict its behaviour in different corrosive media.

The value of this work is on the specific temperatures used for the aging method applied to a rigid resin which revealed the over‐cured phenomena and the behaviour of the pigment; so if it is applied to a more plastic and flexible coating, it may reveal other phenomena and promote other kind of degradation, maybe even more aggressive ones.

To evaluate the inhibition efficiency of 1‐methyl 2‐mercapto imidazole (MMI) in controlling the corrosion of carbon steel in sulphuric acid and to study its action mechanism.

The effect of concentration, immersion time and temperature on the behaviour of this inhibitor has been studied using weight loss, d.c. polarisation and a.c. polarisation techniques.

The results show that MMI is a mixed type inhibitor. Changes in impedance parameters (charge transfer resistance, R_t; and double layer capacitance, C_dl) were indicative of adsorption of MMI on the metal surface, leading to the formation of a protective film that grew with the increasing exposure time. Adsorption of MMI on the carbon steel is found to obey the Langmuir adsorption isotherm. The inhibition efficiency of MMI is temperature‐independent and its addition leads to a small increase in activation corrosion energy.

Surface analytical techniques such as X‐ray photoelectron spectroscopy and Auger spectroscopy can enlighten more on the mechanism of corrosion inhibition.

A survey of literature has shown that no work using electrochemical techniques has yet been done on MMI as corrosion inhibitor for carbon steel in sulfuric acid.

This paper aims to present an approach based on electrical impedance tomography spectroscopy (EITS) for the determination of water and ice fraction in low-power applications such as autarkic wireless sensors, which require a low computational complexity reconstruction approach and a low number of electrodes. This paper also investigates how the electrode design can affect the reconstruction results in tomography.

EITS is performed by using a non-iterative method called optimal first order approximation. In addition to that, a planar electrode geometry is used instead of the traditional circular electrode geometry. Such a structure allows the system to identify materials placed on the region above the sensor, which do not need to be confined in a pipe. For the optimization, the mean squared error (MSE) between the reference images and the obtained reconstructed images was calculated.

The authors demonstrate that even with a low number of four electrodes and a low complexity reconstruction algorithm, a reasonable reconstruction of water and ice fractions is possible. Furthermore, it is shown that an optimal distribution of the sensor electrodes can help to reduce the MSE without any costs in terms of computational complexity or power consumption.

This paper shows through simulations that the reconstruction of ice and water mixtures is possible and that the electrode design is a topic of great importance, as they can significantly affect the reconstruction results.

The purpose of this paper is to study the susceptibility to corrosion processes of X60, X65 and X70 steels immersed in sand-clay soil with pH 3.0, using electrochemical techniques, scanning electron microscopy (SEM), energy dispersive spectroscopy and X-ray diffraction (XRD).

Natural acidic soil sample was collected as close as possible to buried pipes (1.2 m in depth) in a Right of Way from south of Mexico. Both steels and soil were characterized through SEM and XRD. Then, open circuit potential was recorded for all steels exposed to soil at different exposure times. Thus, the electrochemical impedance spectroscopy (EIS) was traced, and anodic polarization curves were obtained.

The steel corrosion processes started when the active sites were exposed to natural acidic soil. However, corrosion rates decreased for three steels as immersion time increased, obtaining the highest corrosion rate for X60 steel (0.46 mm/year for 5 h). This behavior could be attributed to corrosion products obtained at different exposure times. While, 5 h after removing corrosion products, X65 steel was more susceptible to corrosion (1.29 mm/year), which was corroborated with EIS analysis. Thus, corrosion products for the three steels exposed to natural acidic soil depended on different microstructures, percentage of pearlite and ferrite phases, in which different corrosion processes could occur. Therefore, the active sites for carbon steel surfaces could be passivated with corrosion products.

The paper identifies the any implication for the research.

Some anodic peaks could be caused by metallic dissolution and was recorded using high positive polarization (high field of perturbation). In addition, the inductive effects and diffusion process were interpreted at low frequency ranges using EIS. According to X-ray diffraction (XRD), acidic soil had Muscovite containing aluminum and iron phases that were able to generate hydrogen proton at the presence of water; it might be promoted at the beginning of deterioration on low carbon steels. Steel surface cleaning after removing corrosion products was considered to study the possible diffusion phenomena on damaged steel surfaces using EIS.