Conference submissions

A fractal study of Al thin films prepared by RF magnetron sputtering

fredrick fredrick1

1University of Johannesburg, APK Campus, Mechanical Engineering Science, South Africa

Abstract

Al thin films find applications in various microelectronic systems. In this article, both mono- and multi-fractal approaches have been employed to study the micromorphology of aluminium thin films prepared by RF magnetron sputtering technique. The films were prepared at various powers and temperatures on substrates. Their surface topography were imaged using atomic force microscopy (AFM) and optical surface profilometer (OSP). The images were then subjected to different fractal computations techniques to understand the influence of the processing parameters and the possibility of depositing ordered (fractal) structures through RF magnetron sputtering of Al thin films. The technique presented is shown to be very useful in characterizing Al and other films for microelectronics and sensor applications.


Giant Magnetoelastic effect in Tb1-xCox amorphous thin films.

Mohamed Larbi Soltani1

1Annaba University, Dpt of Physics, Algeria

Abstract

Magnetostrictive thin films are currently of great interest for use as active materials in integrated microactuators. In this field, much research is done on amorphous materials of the type (Tb, Dy) Fe2.But in these compounds the order temperature is not high enough for certain applications and consequently the magnetostriction of these materials is also limited. We have studied a series of Tb1-x Cox amorphous thin film samples and found large magnetostriction at room temperature with ordering temperatures up to about 600 K. Here we present the magnetic and magnetostrictive investigations for Tb1-x Cox in a range of 0.4 < x < 0.8. Indeed, the amorphous alloy of Tb and Co (a Tb-Co) has a higher order temperature than that of its competitor at Tb-Fe and also a slightly higher magnetostriction. A maximum in magnetostriction was found with values of b γ,2 = - 24.5 MPa ; λ γ,2 = 400ppm) which is close to the result observed with the crystalline bulk materials of the Laves RFe2 phase. For the ferromagnetic samples at room temperature (x>0.62) the intrinsic anisotropy is analyzed in terms of a biaxial anisotropy model. No saturation was observed for fields up to 8T, due to the sperimagnetic nature of such materials. Also the biaxial anisotropy was analyzed. The compressive stresses at the origin of the perpendicular anisotropy component could be released by annealing at 250°C. Moreover, as the magnetic field applied in the plane of the layer during the annealing, It was able to induce a uniaxial anisotropy whose axis of easy magnetization is in the plane. After annealing, we observed enormous changes in magnetization and magnetostriction, and a much lower susceptibility to low field, following stress relaxation. The optimization of the composition and the annealing conditions gave giant magnetoelastic effects up to bγ,2 = 60 MPa (λγ,2 = 1020 ppm) with lower saturation fields than for massive like Terfenols-D for example.


Property Characterization of Soft Magnetic Materials for developing Advanced Electromagnetic Devices

Youguang Guo1

1University of Technology Sydney, School of Electrical and Data Engineering, Australia

Abstract

This paper investigates the properties of soft magnetic materials for advanced design of electromagnetic devices. The material property characterization is a crucial issue for designing high performance devices, but the data are usually obtained with conditions different from real ones. For example, the property data provided by manufacturers are usually measured in one-dimensional alternating magnetic excitations. However, the magnetic fields in many electromagnetic devices such as electrical machines, are two-dimensional or even three-dimensional and rotational, and the properties under these excitations may be very different from those under one-dimensional excitations. This paper will present the works in the property measurement and characterization of soft magnetic materials, and their application for developing high performance electromagnetic devices.


Gas sensing properties of heterojunctions-based CuO-TiO2 thin films

Pavel Horák1 , Giovanni Ceccio2 , Alfio Torrisi3 , Jiří Vacík4 , Přemysl Fitl5 , Jan Vlček6 , Martin Vrňata7

1Nuclear Physics Institute, Academy of Sciences, Czech Republic, Neutron physics department, Czech Republic
2Nuclear Physics Institute, Academy of Sciences, Czech Republic, Neutron physics department, Czech Republic
3Nuclear Physics Institute, Academy of Sciences, Czech Republic, Neutron physics department, Czech Republic
4Nuclear Physics Institute, Academy of Sciences, Czech Republic, Neutron physics department, Czech Republic
5University of Chemistry and Technology, Prague, Department of Physics and Measurements, Czech Republic
6University of Chemistry and Technology, Prague, Department of Physics and Measurements, Czech Republic
7University of Chemistry and Technology, Prague, Department of Physics and Measurements, Afghanistan

Abstract

The effect of chemisorption of surrounding gases on metal oxide was discovered in 1962, firstly for ZnO, then followed by SnO2. Since then metal oxide-based semiconductor sensors have become an important issue in the industry with many manufacturers [1]. However, the vast majority of investigated chemiresistors have had the sensitive layer based on homogeneous metallic oxides. In the 1990s a new approach, utilizing heterogeneous sensitive layers, appeared [2]. However, only after the nanotechnology techniques have been widely available the application of heterojunctions (HJ) in the sensitive layer became very promising for gas sensing [3-6]. HJs, especially at the nanoscale, can significantly enhance the performance of sensors, mainly their selectivity. In this work, we prepared HJs-based thin films by the combination of CuO-TiO2. The films were prepared by the ion beam sputtering method (using Ar ions) followed by thermal annealing in air for 24 hours at the temperature of 400 °C. The stoichiometry of the films was characterized by the Rutherford Back-scattering (RBS) and Nuclear resonance analysis (NRA) methods utilizing α-particles with energy 2000 and 3046 keV. The ion beams were provided by the Tandetron MC 4130 accelerator within the CANAM research infrastructure framework (canam.ujf.cas.cz). The gas sensing properties of the CuO-TiO2 thin films were analyzed in the atmospheres containing 100 ppm of hydrogen, acetaldehyde or methanol vapors respectively and also in 10 ppm of nitrogen dioxide. For this measurement, the films were deposited on the prefabricated alumina substrate containing heater, Pt 1000 thermocouple and interdigital system of electrodes. The sensors were operated at elevated temperatures of 300 °C. A poster summarizing results of gas sensing measurement for several thin films with different Cu/Ti stoichiometric ratios will be presented. References: [1] Bochenkov, V.E., Sergeev, G.B., Advances in Colloid and Interface Science 116 (2005) 245 – 254 [2] Vasiliev, R.B., et al., Materials Science and Engineering, 1999. B57: p. 241-246. [3] Miller, D., et al., Sensors and Actuators: B. Chemical, 2014. 204: p. 250-272. [4] Kim, J.-H., et al., Sensors and Actuators: B. Chemical, 2017. 248: p. 500-511. [5] Gao, X., et al., Sensors and Actuators: B. Chemical, 2018. 258: p. 1230-1241. [6] Zhou, T., et al., Sensors and Actuators: B. Chemical, 2018. 255: p. 745-753.


A review of magnetron sputtering of AlN thin films for extreme condition sensing

fredrick fredrick1

1University of Johannesburg, APK Campus, Mechanical Engineering Science, South Africa

Abstract

In this work, an overview of the published works on the deposition of AlN thin films for harsh condition applications is presented. The harsh environments include petrochemical, automobile/engine, marine, aerospace applications, health monitoring, etc. Harsh environments may be defined as the operating conditions exhibiting high shock loads, high temperature, high pressure/forces and corrosive media. 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. 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 304L 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.


Effect of Nickel Powder Grains on Corrosion Resistance of Cold Sprayed Coatings

Mieczyslaw Scendo1 , Katarzyna Staszewska-Samson2

1Jan Kochanowski University in Kielce, Institute of Chemistry, Poland
2Jan Kochanowski University in Kielce, Institute of Chemistry, Poland

Abstract

Corrosion resistance of nickel coatings on the Al7075 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 Al7075 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.


Biomimetic sensors for determining trace concentrations of H2O2 in aqueous and aqueous-alcohol solutions

Tofik Nagiev1

1Research Center of Azerbaijan National Encyclopedia, , Azerbaijan

Abstract

Biomimetic sensors based on semiconductor (Si), metal (Al) and smart material (TPhPFe(III)/Al2O3) have been developed. 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 10-6wt.%. When using metal (Al) as an electrode, despite its very high sensitivity to the environment, the threshold of sensitivity also amounted to 10-6 wt.%.


Assessing the changes in dynamic bearing forces and shifts in rotor’s stability regions as a result of defects in ball bearings

Harry Ngwangwa1

1University of South Africa, Department of Mechanical and Industrial Engineering, South Africa

Abstract

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.


PORPHYRIN-BASED HYBRID MATERIALS. SEARCHING FOR THE BEST PARTNER TO IMPROVE OPTOELECTRONIC PROPERTIES

Eugenia FAGADAR-COSMA1

1Institute of Chemistry "Coriolan Dragulescu" of Romanian Academy, Organic Chemistry-Porphyrins, Romania

Abstract

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 [1-6]. 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) [1-3] or magnetic particles [5], 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 [1]; a methoxy-substituted Pt-porphyrin in PVC membrane is able to potentiometrically detect bromide [2] or to optically detect hydrocortisone; a water soluble Zn-porphyrin in complex with AgNPs is used for recognition and monitoring of p-aminosalicylicacid drug [3]; trace oxygen sensing were realized by using a newly porphyrin heterodimeric complex [4]; 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 [6]. 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.

Acknowledgements:

The authors are grateful for the support from UEFISCDI, because this work has been financed by 76 PCCDI/2018 Project belonging to PNIII-Future and Emerging Technologies, and from Institute of Chemistry “Coriolan Dragulescu” of Romanian Academy, Programme 3-2018.


PORPHYRIN-BASED HYBRID MATERIALS. SEARCHING FOR THE BEST PARTNER TO IMPROVE OPTOELECTRONIC PROPERTIES

Eugenia FAGADAR-COSMA1 , Anca LASCU2 , Nicoleta PLESU3 , Gheorghe FAGADAR-COSMA4

1Institute of Chemistry "Coriolan Dragulescu" of Romanian Academy, Organic Chemistry-Porphyrins, Romania
2Institute of Chemistry “Coriolan Dragulescu”, Organic Chemistry-Porphyrins, Romania
3Institute of Chemistry “Coriolan Dragulescu”, Organic Chemistry-Programme 2, Romania
4”Politehnica” University Timisoara, , Faculty of Industrial Chemistry and Environmental Engineering, Romania

Abstract

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 [1-6]. 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) [1-3] or magnetic particles [5], 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 [1]; a methoxy-substituted Pt-porphyrin in PVC membrane is able to potentiometrically detect bromide [2] or to optically detect hydrocortisone; a water soluble Zn-porphyrin in complex with AgNPs is used for recognition and monitoring of p-aminosalicylicacid drug [3]; trace oxygen sensing were realized by using a newly porphyrin heterodimeric complex [4]; 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 [6]. 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.

Acknowledgements:

The authors are grateful for the support from UEFISCDI, because this work has been financed by 76 PCCDI/2018 Project belonging to PNIII-Future and Emerging Technologies, and from Institute of Chemistry “Coriolan Dragulescu” of Romanian Academy, Programme 3-2018.


Optimization of the complex sensors system used to control the electrochemical metals recovery process from waste printed circuit boards

Sorin-Aurel Dorneanu1 , Albert Fazakas2 , Eniko Covaci3 , Graziella Liana Turdean4

1"Babes-Bolyai" University Cluj Napoca, Department of Chemical Engineering, Romania
2Technical University of Cluj Napoca, Bases of Electronics Department, Romania
3"Babes-Bolyai" University Cluj Napoca, Department of Chemical Engineering, Romania
4"Babes-Bolyai" University Cluj Napoca, Department of Chemical Engineering, Romania

Abstract

Literature data [1] and our preliminary results [2] 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. In this context, our previous work [3] proved that a complex sensors system, based on pH, oxidation/reduction potential (OPR), temperature and voltammetric sensors, can be effectively used for the recovery process management. 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. L.A. Diaz, T.E. Lister, Waste Manag., 2018, 74, 384-392. 2. S.A. Dorneanu, A.A. Avram, A.H. Marincas, N. Cotolan, T. Frentiu, P. Ilea, Studia UBB Chemia, 2018, LXIII(4), 147-158. 3. S.A. Dorneanu, G.L. Turdean, "Complex sensors system for controlling the process of electrochemical recovery of metals from waste printed circuit boards", Poster, IC-MAST, September 24-27, 2018, Bratislava, Slovakia.

Acknowledgements:

This work was supported by a grant of the Romanian Ministry of Research and Innovation, CCCDI-UEFISCDI, project number PN-III-P1-1.2-PCCDI-2017-0652 / 84PCCDI ⁄ 2018, within PNCDI III.


Design and analysis of the amorphous silicon metamaterial in the terahertz band

XIA ZHANG1

1Communication University of China, Department of Photo-electronics, , China

Abstract

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 0.1 to 10 terahertz is obtained by mean of designing, to meet the requirement for the terahertz functional device development. 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.


Test Benches for Aerodynamic Testing of Rotors and Propellers for Small Unmanned Aerial Vehicles

Filip Panayotov1 , Vladimir Serbezov2 , Ivan Dobrev3 , Michael Todorov4

1Technical University of Sofia, Department of Aeronautics, Bulgaria
2Technical University of Sofia, Department of Aeronautics, Bulgaria
3Arts et Metiers ParisTech, , France
4Technical University of Sofia, Department of Aeronautics, Afghanistan

Abstract

The recent massive introduction of small unmanned aerial vehicles (UAVs) brought the problem of absence of reliable aerodynamic data and models for propulsion systems that work at low Reynolds numbers. At the same time the new capabilities of modern measuring equipment permit detailed experimental investigations of the aerodynamic characteristics of such systems. This paper presents the results of work in this direction, carried out at, or with serious contribution of the Department of Aeronautics at Technical University of Sofia. Two test benches are presented. The first one is for static testing of small helicopter rotors. It is designed also with provisions for installation in suitable wind tunnels. The second one is a test stand for evaluation of electric power plants for unmanned aircraft vehicles. It can be used statically, or may be installed on the roof of an automobile for mobile testing. As an illustration experimental results are given for a specific model helicopter rotor and a small airplane propeller.


Estimate the elastic constants of a horizontal transversely isotropic (HTI) phenolite by ultrasonic critical angle reflectometry technique

Young-Fo Chang1 , Tsung-Chih Chi2

1National Chung Cheng University, Department of Earth and Environmental Sciences, Taiwan
2National Chung Cheng University, Department of Earth and Environmental Sciences, Taiwan

Abstract

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. However, five independent elastic constants are needed to express the material’s elastic behavior for a transversely isotropic medium (TIM). 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. Study results show that the average errors are 4% and 3% for measuring the velocities of longitudinal (or elastic constants C11, C13 and C33) and transverse (or elastic constants C44 and C66) waves by this technique, respectively. That indicates this technique is an effective method to estimate the elastic constants of anisotropic media.


Influence of copper layer thickness on 2G HTS tape steady functioning at alternating current

Pavel Degtyarenko1

1Joint Institute for High Temperature Russian Academy of Science, Superconductivity, Russian Federation

Abstract

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 [1] 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 1.5 – 3 times (vs. the cable design version) by decreasing of copper amount in a cable. 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 [2]. And for the most of actual HTS power transmission lines a reversed situation takes place, i.e. the cable stability against overheating increases with the drop of copper amount. 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.e. a combination of this function with the power transmission. 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 50-60 Hz is considered and discussed. Now, there is an opportunity of decreasing this thickness from 40 to 14 µm what is demonstrated by the experimental results obtained and reached by the improvement of coating technology.


Junctionless Double-Gate SOI magneto-sensitive FET

Uladzimir Nahnoiny1 , Victor Mordkovich2 , Alexey Leonov3

1Moscow Institute of Physics and Technology (State University), Physical and Quantum Electronics, Russian Federation
2Institute of Microelectronics Technology and High Purity Materials, , Russian Federation
3Institute of Microelectronics Technology and High Purity Materials, , Russian Federation

Abstract

Construction of the magneto-sensitive junctionless transistor (MJLT} contain n+-n-n+ channel, formed in thin (20 nm) silicon layer of SOI wafer. 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. Was shown, that SOI MJLT significantly superior both traditional Si Hall elements and magneto-sensitive Si MOS transistors with the inversion channel ( so called MagFET.) [1] In particular, MJFET exceeds threshold sensitivity by an order of magnitude and has a record wide range of operation temperature (from few K to, at least, 500˚C). MJFET much more sustained to impact of impulse, corpuscular and ionizing radiation. Applying of double-gate system for modulating channel current provide significant improvement in signal/noise ratio, allows frequency spectroscopy and measuring magnitude of alternating magnetic field. Besides double gates MOS system provides feed backs between Hall signal and/or MOS gates or power source which provides stable measuring in case of changing temperature or radiation conditions of environment.


MULTIBAND PHOTOELECTRONIC TRANSMITTER FOR OPTICAL SENSOR

Maria Ivakh1

1Lviv Polytechnic National University, Electronic devices department, Ukraine

Abstract

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-62 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. The optical sensor structural diagram based on the PSoC microcontroller CY8C5888LTI-LP097 was developed for measuring amino acids concentrations. 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.


Multi-Parametric Interactions in a Single Organic Electrochemical Transistor for a Bio-Inspired Chemo-Recognition

Sébastien Pecqueur1 , Fabien Alibart2

1IEMN, NCM, France
2Université de Sherbrooke, , Canada

Abstract

In this study, we report on the exploitation of an organic electro-chemical transistor as a high-order chemical sensor in water, for which its multi-parametricity at the single-device device already suffices to mimic basic principles of complex biological chemosenses such as taste, aiming for integration in a neuromorphic sensory network. We show that multiple transistor properties can be specifically affected from the composition of the gating-electrolyte, so that alkali chlorides, Brønsted acids and polyols footprints can be separated by principal component analysis: qualitatively and semi-quantitatively. We validated the capability of this elementary structure to discriminate salts from acids from sugars by testing the system using unexperienced liquid food as electrolytes after training. In association with recent findings on the neuromorphic properties of these same devices, we show that organic electrochemical transistors can potentially be used at all layers of a homo-technological neural network hardware to achieve complex chemorecognition of highly multi-parametric iono-molecular environments, paving the way of integrated artificial chemosensory systems.

Acknowledgements:

We acknowledge financial supports from the EU: ERC-2017-COG project IONOS (# GA 773228). We thank the French National Nanofabrication Network RENATECH for financial support of the IEMN clean-room. We thank also the IEMN cleanroom staff of their advices and support.


Study of phase transformations in Al-Ge-Ni ribbons

Oleksandr Roik1 , Olexiy Yakovenko2 , Volodymyr Kazimirov3 , Volodymyr Sokolskii4

1Taras Shevchenko National University of Kyiv, Chemistry, Ukraine
2Taras Shevchenko National University of Kyiv, Chemistry, Ukraine
3Taras Shevchenko National University of Kyiv, Chemistry, Ukraine
4Taras Shevchenko National University of Kyiv, Chemistry, Ukraine

Abstract

The Al-Ge-Ni amorphous alloys with low Ni content are known to have a good ductility and bend by a 180° without fracture [1]. We report the results of obtaining by melt spinning technique and subsequent annealing of ribbons with nominal compositions Al79Ge15Ni6, Al61Ge29Ni10 and Al61Ge15Ni24. The as-quenched Al79Ge15Ni6 ribbon consists of fine crystalline α-Al, an unknown metastable intermetallic and amorphous phase. The as-quenched Al61Ge29Ni10 ribbon contains only metastable phase Al6Ge5. The decrease of cooling rate increases the grain size in the ribbon, which was obtained from Al61Ge29Ni10 melt, but does not change phase composition. Aluminium, germanium, and the metastable phase were identified in the as-quenched Al61Ge15Ni24 ribbon. After annealing of the ribbons only thermodynamically equilibrium phases were detected. [1] A. Inoue, M. Yamamoto, H.M. Kimura, T. Masumoto, Ductile aluminium-base amorphous alloys with two separate phases, J. Mater. Sci. Lett. 6 (1987) 194–196.


Optical Fiber Surface Plasmon-Coupled Emission as a method for fluorescence sensing

Dawid Jankowski1 , Simeonika Rangełowa-Jankowska2 , Mateusz Śmietana3 , Sebastian Maćkowski4

1Baltic Institute of Technology, , Poland
2Baltic Institute of Technology, Al. Zwyciestwa 96/98, 81-451 Gdynia, , Poland
3Institute of Microelectronics and Optoelectronics, Warsaw University of Technology, Koszykowa 75, 02-093 Warsaw, , Poland
4Baltic Institute of Technology, Al. Zwyciestwa 96/98, 81-451 Gdynia, , Poland

Abstract

Optical Fiber Surface Plasmon Controlled Emission (OFSPCE) as a new method for sensing is presented. OFSPCE phenomenon is the directional emission associated with non-localized surface plasmons [1-3], which emerges at the dielectric / metal film / optical fiber core interface. The functional interface of the device is fabricated on a side surface of an optical fiber core. Excitation of fluorophores deposited on the top of the layout system in dielectric layer is mediated with surface plasmons propagating in the metal film, and is possible due to the wave vectors matching of the incident wave through the optical fiber silica core and plasmonic wave in total internal reflection configuration. As a consequence, the excitation and emission of fluorophores occur at certain angles with respect to the side surface of the optical fiber core. The OFSPCE method combines the advantages of Surface Plasmon Resonance, fluorescence and optical fibers [4,5], providing sensitivity, selectivity, and portability, respectively, giving thus the opportunity to create new generation of diagnostic tools like „all-in-needle” [6,7].

Acknowledgements:

The research was financed by the project 3/DOT/2016 funded by the City of Gdynia


Influence on immunosensor performance with different antibody immobilization procedures

Pasqualina Liana Scognamiglio1 , Filippo Causa2 , Paolo Antonio Netti3

1Istituto Italiano di Tecnologia, Center for Advanced Biomaterials for Health Care, Italy
2Università degli studi di Napoli Federico II, , Italy
3Università degli studi di Napoli Federico II , , Italy

Abstract

Immunosensors are affinity-based assays whose performance mainly depends on the selectivity and specificity of molecular recognition between antigens and antibodies (Abs). The antibodies immobilization is a critical step in the development of such devices as it could alter their specificity and immunological activity. Poly(ethylene glycol)-based hydrogel particles serve as a sensitive, non-fouling and bio-inert suspension array for the detection of biomarkers. Acrylated antibodies provide a facile means for their immobilization within the poly (ethylene) glycol diacrylate (PEGDA) hydrogel network via photo-polymerization. This strategy is widely employed in many studies, but it has not been found whether the immunosensor performance can be improved by following a simpler way that does not require this non-site-specific chemical modification of the antibody. Here, a systematic evaluation of the effects of antibody immobilization strategy on the binding efficiency and selectivity of immunosensors prepared with Anti-tumor necrosis factor (Anti-TNFalpha) is described. Polyethylene-glycol-based hydrogels have been functionalized with Anti-TNFalpha either (1) through a physical entrapment (2) directly via free sulphydryl groups or (3) indirectly through a bifunctional linker containing a polyethylene glycol spacer. Firstly, the binding affinity of acrylated Anti-TNFalpha towards TNFalpha has been measured using isothermal titration calorimetry (ITC) to confirm recognition abilities even after chemical modification. Then, photo-polymerized hydrogels were prepared according to standard procedures, employing a pre-polymer solution containing PEGDA, antibody, and photoinitiator. Different degrees of bio-functionalization within hydrogel matrices were obtained at different immobilization strategies and at different antibody concentrations. Anti-TNFalpha/TNFalpha specific interaction was registered through a fluorescence output using a Atto647-labeled TNFalpha. It was determined that the highest antibody immobilization density and the highest sensitivity was exhibited by Anti-TNFalpha immobilized through the reduction of disulphide bridges of its hinge region. Specific TNFalpha interaction with Anti-TNFalpha and non-specific binding to bovine serum albumin modified hydrogels were also compared.


Two sections of short waveguides for fiber Mach-Zehnder interferometer construction

Dongning Wang1

1China Jiliang University, College of Optical and Electronic Technology, China

Abstract

We demonstrate a fiber Mach-Zehnder interferometer by use of two sections of short waveguides inscribed by femtosecond laser. One short waveguide directs light from the fiber core to the cladding-air interface, where it experiences multiple total internal reflections, and the other collects the light back into the fiber core. The device is robust in structure, easy and fast in fabrication, and has the capability of ambient refractive index sensing.

Acknowledgements:

We would like to acknowledge financial support from National Natural Science Foundation of China (Grant No. 61661166009).


High volume, low cost production of nanobiosensors using flexographic printing technique

Kar Seng Teng1 , Abdulaziz Assaifan2 , Jonathan Lloyd3 , Siamak Samavat4 , Davide Deganello5

1Swansea University, College of Engineering, United Kingdom
2Swansea University, College of Engineering, United Kingdom
3Swansea University, College of Engineering, United Kingdom
4Swansea University, College of Engineering, United Kingdom
5Swansea University, College of Engineering, United Kingdom

Abstract

The use of nanoscale electronic materials as sensing elements in biosensors offer many advantages, such as ultra-high sensitivity, excellent specificity, rapid response time and minimal sample volume for detection. The sensitivity of such nanobiosensor allows early detection of diseases, which could enhance the chances for successful treatments. There has been much research interest and effort in developing nanobiosensors as point-of-care diagnostic devices that has an expected market value of US$37 billion by 2021 globally. However, one of the major challenges in bringing the technology to mass-market is the cost of manufacturing these nanobiosensors. For example, most nanobiosensors are fabricated using expensive cleanroom facilities and complex processes, which lead to high production cost and hence making them commercially unviable. Therefore, the ability to scale-up production of nanobiosensors at very low cost is commercially attractive. In this talk, the novel use of flexographic printing technique for the fabrication of nanobiosensors will be presented. Such roll-to-roll printing technique is ideal for volume production of nanobiosensors at very low cost. The technique enables high-speed direct-patterning of nanomaterials on to a surface [1]. Furthermore, it allows the use of organic substrates, which would significantly reduce the cost of these devices. Metal-oxide nanowire chemiresistive gas sensor and metal nanoparticle electrochemical biosensor were fabricated using the printing technique [2-4]. An intricate nanotextured surface at flexographic printed ZnO thin film, which exhibited high specific surface area, was developed for biosensing applications. Such nanobiosensors is ideal for large scale screening of diseases at very low cost with excellent sensitivity [5]. References 1. J.S. Lloyd, C.M. Fung, D. Deganello, R.J. Wang, T.G.G. Maffeis, S.P. Lau and K.S. Teng, ‘Flexographic printing-assisted fabrication of ZnO nanowire devices’, Nanotechnology 24, 195602 (2013) 2. J. Benson, C.M. Fung, J.S. Lloyd, D. Deganello, N.A. Smith and K.S. Teng, ‘Direct patterning of gold nanoparticles using flexographic printing for biosensing applications’, Nanoscale Research Letters 10, 127 (2015). 3. J.S. Lloyd, C.M. Fung, E.J. Alvim, D. Deganello and K.S. Teng, ‘UV photodecomposition of zinc acetate for the growth of ZnO nanowires’, Nanotechnology 26, 265303 (2015). 4. C.M. Fung, J.S. Lloyd, S. Samavat, D. Deganello and K.S. Teng, ‘Facile fabrication of electrochemical ZnO nanowire glucose biosensor using roll to roll printing technique’, Sensors and Actuators B: Chemical 247, 807 (2017). 5. A.K. Assaifan, J.S. Lloyd, S. Siamak, D. Deganello, R.J. Stanton and K.S. Teng, ‘Nanotextured surface on flexographic printed ZnO thin films for low-cost non-faradaic biosensors’, ACS Applied Materials and Interfaces 8, 33802 (2016).


Stress dependent electrochemical hysteresis for the applications in Lithium ion batteries

A.K. Soh1

1Monash University Malaysia, Mechanical Engineering, Malaysia

Abstract

Intercalation of lithium ions into the electrodes of lithium ion batteries is affected by the stress of active material, leading to energy dissipation and stress dependent voltage hysteresis. A reaction- diffusion-stress coupling model has been established to investigate the stress effects under galvanostatic and potentiostatic operations. It is found a compressive stress in the electrode surface layer would impede lithium intercalation. Therefore, a higher overpotential is needed to overcome the intercalation barrier induced by stresses. The stress difference between charge and discharge made contribution to the voltage hysteresis which depends on charge rate, electrode particle radius, as well as a combined parameter that reflects the influence of material properties including elastic modulus, partial molar volume, capacity and diffusivity. Simulations also found stress hysteresis contributed to voltage hysteresis and led to energy dissipation. The stress induced voltage hysteresis is small in low rate galvanostatic operations but extraordinarily significant in high rate cases. In potentiostatic operation, the stresses and stress induced overpotentials increase to a peak value very soon after operation commences and decay all the left time. Therefore, a combined charge-discharge operation is suggested, i.e., galvanostatic first and potentiostatic follows. This combined operation can not only avoid extreme stress during operations so as to prevent electrode from failure but also reduce the voltage hysteresis and energy dissipation due to stress effects.

Acknowledgements:

The work was supported by the 2017 Monash University Malaysia Strategic Large Grant Scheme (Project code: LG-2017-04-ENG) and the Cluster Fund of Advanced Engineering Programme, Monash University Malaysia.


AN APPLICATION OF THERMAL ANALOGY IN ACTIVE CONTROL PROBLEMS

Evgeny Barkanov1 , Andrejs Kovalovs2 , Aleksandr Anoshkin3 , Pavel Pisarev4

1Riga Technical University, Institute of Materials and Structures, Latvia
2Riga Technical University, Institute of Materials and Structures, Latvia
3Perm National Research Polytechnic University, Department of Mechanics of Composite Materials and Structures, Russian Federation
4Perm National Research Polytechnic University, Department of Mechanics of Composite Materials and Structures, Russian Federation

Abstract

Nowadays, lightweight structures with integrated piezoelectric materials (PZT and MFC) used as actuators or sensors have obtained considerable spread in transport and aerospace engineering for the purpose of geometry control, vibration and noise reduction, as well as for overall performance improvement. To design such constructions, different numerical analyses have been developed in the last three decades. The piezoelectric response could be modelled with 2D and 3D coupled-field solid elements widely presented in finite element software. However, in the case of complex structures with large dimension of the numerical problem to be solved, the thermal analogy could be examined as an effective methodology. In this case piezoelectric coefficients characterising PZT or MFC patches are introduced as thermal expansion coefficients. In the present study an application of thermal analogy for the solution of active control problems is successfully demonstrated for static and dynamic analyses of simple beam and plate structures, and studying an active twist of smart helicopter rotor blades. Validation of the numerical results is carried out examining an active quasi-static behaviour of aluminium beam with adhesively bonded MFC (M8528-P1). In time of experiment beam deflection has been measured with PANASONIC laser sensor (HL-G108-A-C5). Rigorous convergence study using different finite element types and modelling approaches has been executed. Initially, the material properties of MFC in the finite element analysis have been described with the data presented by Smart Material Corporation. Later, to improve an accuracy of the numerical model, they have been changed with PZT fibre material properties and their equivalent volume. To control the structural vibrations in the low frequency range, the problem of optimal location of MFC actuators has been solved for a variety of isotropic and orthotropic panels. An effectiveness of application of MFC actuators for the vibration damping has been estimated with the factor describing the amplitude reduction related to the applied energy (voltage). Numerous parametric studies have shown that the optimal location can be defined knowing the form of a separate mode. The thermal analogy has been successfully applied also for the design of an active twist of smart helicopter rotor blades. To validate the developed 3D finite element model and corresponding analysis, the demonstration rotor blade with MFC actuators has been designed, produced and tested in quasi-static conditions. The main characteristics of the demonstrator are taken from the well-known BO 105 model rotor blade consisting of unidirectional GFRP C-spar, laminated composite skin and foam core. To twist the rotor blade, 12 MFC actuators with operating voltage of -500 … +1500 V have been implemented from both sides of the blade and then cured together with GFRP. The final results show that the difference between active twist angles obtained experimentally and numerically is negligible that confirms high accuracy of the developed 3D finite element model and corresponding analysis.

Acknowledgements:

This work was supported by the Russian Science Foundation (project No. 18-19-00722) and the European Regional Development Fund, measure 1.1.1.5 “Support to international cooperation projects in research and innovation of RTU” (project No. 1.1.1.5/18/I/008).


Specialized alarm-initiating device for early detection of coal self-ignition

Smirnov Grigory1

1Irkutsk National Research Technical University, Industrial Ecology and Life Safety Department , Russian Federation

Abstract

The existing methods of fire detection are based on the registration of physical phenomena associated with the processes of combustion or smouldering, such as elevated temperature, the release of combustion products, changes in the chemical composition of the air, thermal radiation. Sensor elements of the devices detecting those features stay at a distance from the source of ignition. This result in postponed time of fire registration in comparison with its occurrence. Accordingly, the more time it takes, the more significant damage a fire can cause. The work studies the design of alarm-initiating device developed at Irkutsk National Research Technical University. The device is to detect the evidence of incipient self-ignition at the stage of self-heating before a fire starts, and it is applicable to coal and other substances that a likely to ignite spontaneously. The main feature of the invention is that the temperature measurement and air sampling are carried out directly in the places that are at more risk of self-ignition. In addition, the device is energy-independent due to the original design of the power supply element. Moreover, the measurement of several parameters of the fire environment significantly increases the reliability and credibility of the self-ignition detector.


Using Thermal Imagers for Monitoring Landslide Stability: Monitoring and Analysis in Mudstone Area

Chien-Yuan Chen1 , You-Yi Liu2 , Jing-Wen Chen3 , Ho-Wen Chen4

1National Chiayi University, Civil and Water Resource Engineering, Taiwan
2National Chiayi University, Civil and Water Resources Engineering, Taiwan
3National Cheng Kung University, Department of Civil Engineering, Taiwan
4Tunghai University, Department of Environmental Science and Engineering, Taiwan

Abstract

Thermal imagers are characterized by noncontact and long-distance detection capabilities, rendering them suitable for landslide monitoring. A thermal imager can reveal changes in surface radiation temperatures and can be used for monitoring landslide-induced surface temperature changes. The purpose of the study was to understand the landslide mechanism by analyzing surface infrared temperature changes. A landslide case in a mudstone area in southern Taiwan was monitored for this pilot study. Thermographs obtained by a handheld thermal imager from various times were analyzed for monitoring the surface temperature changes on slope faces. In addition, an unmanned-aerial-system-mounted thermal imager was used to capture digital orthophoto thermal images for setting up a three-dimensional monitoring net. These images indicated that wet soil had higher water content and exhibited a lower surficial infrared temperature change. Infrared temperature changes per unit time served as monitoring variables and were compared with isotherms for detecting potentially unstable areas. The results demonstrated that a potentially unstable area could be detected through the thermal images. Accordingly, landslide monitoring could be improved by thermal imagers.


Surface morphology effect on the wetting behavior of nanostructured ZnO

Andrejs Ogurcovs1 , Marina Krasovska2 , Vjaceslavs Gerbreders3 , Irena Mihailova4 , Eriks Sledevskis5 , Edmunds Tamanis6

1Daugavpils University, Institute of Life Sciences and Technologies, Latvia
2Duagavpils University, Institute of Life Sciences and Technologies, Latvia
3Duagavpils University, Institute of Life Sciences and Technologies, Latvia
4Daugavpils University, Institute of Life Sciences and Technologies, Latvia
5Daugavpils University, Institute of Life Sciences and Technologies, Latvia
6Daugavpils University, Institute of Life Sciences and Technologies, Latvia

Abstract

Peculiarities of the wetting process in case of each surface are determined by surface fill and morphology of nanostructures. Six morphologies were chosen for the determination of the specific wetting processes of the ZnO nanostructures: nanoneedles, small diameter rods, large diameter rods, tubes, plates, homogeneous magnetron sputtered 150 nm layer. The experiment was performed using standard optical method and novel approach based on electrochemical impedance spectroscopy (EIS). EIS with great accuracy allows describes not only surface wetting but also processes occurring at the volume of the nanostructured sample. This method makes it possible to describe the dynamics of the wetting process and allows determining the saturation value (time moment when nanostructures are completely wetted. Using this technique, it is also possible to describe the dynamics of the intermediate process that occurs when Cassie-Baxter wetting model at the beginning of the process is gradually replaced with a Vensel model at the end of the process when all the graves between the nanostructures are completely filled with water. During the measurement certain amount of distilled water was dropped to the surface of the sample and an image of the drop was taken every 1 min. In case of hydrophilic ZnO nanostructure morphologies, the wetting process is uneven and non-linear: in the first few minutes there is a large difference between the phases of adjacent curves, but over time this step decreases until the phase difference becomes minimal and the curves coincide. This moment can be defined as the moment of saturation, which characterizes the complete wetting of the nanostructured sample. In the case of hydrophobic surfaces, the dynamics of phase change is more expressed and saturation state is characterized by a longer time interval (7-9 min). In the case of hydrophilic surfaces, the saturation occurs much faster (2-4 min) and the phase value changes are smaller.

Acknowledgements:

This work is supported by European Regional Development Fund (ERDF), Measure 1.1.1.1 “Industry-Driven Research”, Project No. 1.1.1.1/16/A/001 „ Development of the analytical molecular recognition device based on the nanostructures of metal oxides for biomolecules detection”.


Evaluation of Aluminum alloy 1050-H4 Micro-hardness after Accumulative Roll Bonding Process (ARB)

MOTHIBELI PITA1

1UNISA & UNIVERSITY OF JOHANNESBURG, MECHANICAL & INDUSTRIAL ENGINEERING, South Africa

Abstract

In this study, experimental investigations of micro-hardness of Al- 1050-H4 material after accumulative roll bonding (ARB) process at different passes were studied. ARB process enhances material properties. Samples of three ARB passes as well as un-rolled samples of AL-1050-H4 were used for micro-hardness experiment. Samples were cut on rolling direction (RD), mounted and polished before commencing with the test. Each sample was tested using Vickers microhardness tester at five different positions with a load of 20g and the holding time taken for each indentation was 10seconds. The results revealed that the highest hardness value was obtained on the first pass of ARB process and it was reported as 47.62 HV. It was observed that the decrease in grain size increase the hardness of material. It was also noticed that the increase in grain size decrease the hardness of aluminium 1050-H4.


Investigation of Tensile strength of Aluminum alloy 1050-H4 during Accumulative roll bonding process

MOTHIBELI PITA1

1UNISA & UNIVERSITY OF JOHANNESBURG, MECHANICAL & INDUSTRIAL ENGINEERING, South Africa

Abstract

Accumulative roll bonding process (ARB) was performed on commercially available AL-1050-H4 aluminium alloy. Samples were rolled for three passes. In ARB process, thickness is reduced by 50% for each pass. The aim of performing ARB process was to refine the grain structure of aluminium 1050-H4 to increase its tensile strength. Tensile test was performed at room temperature with the aim of determine whether ARB increase mechanical properties of aluminium 1050-H4 and at which pass did material experience high tensile strength. Samples were cut according to standard test methods for tension testing of metallic material (ASTM) at rolling direction (RD). information about the microstructure of samples was obtained using optical microscope (OM). From the results, sample with highest tensile strength was identified as well as the percentage elongation.