Conference submissions

Microscale Insight into Oxidation of Single MoS$_2$ Crystals in Air

Robert Szoszkiewicz1 , Wojciech Spychalski2 , Marcin Pisarek3

1University of Warsaw, Chemistry, Poland
2Warsaw University of Technology, Materials Science and Engineering, Poland
3Institut of Physical Chemistry of the Polish Academy of Sciences, , Poland

Abstract

Because of profound applications of MoS$_2$ crystals in electronics, their oxidation is the subject of substantial interest. We report on oxidation of the surface of single MoS$_2$ crystals, which were heated within a precision muffle furnace at a series of increasing temperatures up to 500$^°$C. Using electron dispersion X-ray spectroscopy (EDS) at ambient conditions, we observed an increase of oxide content with increasing heating temperature and obtained an apparent activation energy for the oxidation process of the order of 1 kcal/mol. This value is at least 8 times smaller than an activation energy for surface formation of MoO$_3$ and according to the literature points rather to physisorbed oxygen species. Our Auger electron spectroscopy (AES) results also pointed out toward the physisorbed oxygen, similarly as our further heating studies within elevated relative humidity conditions. The Mo oxide leftovers on the sample were investigated using atomic force microscopy (AFM) and showed dendritic structures. Surface appearance of those dendrites, their fractal dimension between 1.61 and 1.66, and their surface distribution were reminiscent of the diffusion-limited aggregation (DLA) growth. On the basis of analysis of AFM topographs, we hypothesized that the DLA process was controlled by a surface diffusion of the initially physisorbed oxygen, which had to diffuse to reaction centers in order to facilitate the subsequent chemical conversion of MoS$_2$ layers to volatile Mo oxides.


Optical, and electronic study of Ceramic scintillators within the framework of density functional theory (DFT)

Abderrahim Hadj Larbi1 , Said Hiadsi2 , Moufdi HADJAB3 , Fayçal Bouzid4 , Ammar Haboussi5

1Research Center in Industrial Technologies CRTI, P. O. Box 64, Cheraga 16014, Algiers, Thin Films Development and Applications Unit - (UDCMA) -Setif- Algeria, Algeria
2Laboratoire de Microscope Electronique et Sciences des Matériaux, Université d’Oran des Sciences et de la Technologie Mohamed Boudiaf, Département de Génie Physique, BP 1505 El m’naouar, Oran, Algerie, , Algeria
3Research Center in Industrial Technologies CRTI, P. O. Box 64, Cheraga 16014, Algiers, , Algeria
4Research Center in Industrial Technologies CRTI, P. O. Box 64, Cheraga 16014, Algiers, , Algeria
5Research Center in Industrial Technologies CRTI, P. O. Box 64, Cheraga 16014, Algiers, , Algeria

Abstract

Inorganic halide perovskites show a great potential utilization in ceramic scintillators. In this study, we predict the electronic, and optical properties of ABCl3 (A=alkali, B=alkali-earth) perovskite compounds using the full potential linearized augmented plane wave (FP-LAPW) method, based on density functional theory (DFT), implemented in Wien2k code. The exchange and correlation potential was applied using GGA-PBE approximation to relax the internal atomic positions and to calculate the structural properties. In addition, the modified Becke-Johnson (TB-mBJ) potential was used for calculating the electronic and optical properties. Our results are in good agreement with the experimental data, and other theoretical calculations. In the case of orthorhombic phase, the compound reveals that Cl-p states dominate the valence band. The present study of the optical properties shows the isotropic nature of the compounds, the dielectric function, refractive index, energy loss spectra, and absorption coefficient are plotted.


Investigation of the Influence of the Preparation of the Adhesive Joint of Concrete Surfaces for Distributed Fiber Optic Strain Sensors Based on Rayleigh Backscattering

Martin Weisbrich1

1Structural Concrete Institute, HTWK Leipzig, Germany

Abstract

Fiber optic sensors have been used increasingly in SHM in recent years, especially in concrete construction. New measuring techniques, based on backscattering methods, can measure strain over the entire length of the fiber. The Rayleigh backscattering method also have a spatial resolution in the millimeter range. This article deals with some preliminary tests to investigate the influence of pretreatment of concrete surfaces for distributed measuring and surface applied optical fibers. Three different basic situations are examined compared with six different adhesives on compression cylinders made of fine-grained concrete. The analysis of the test data showed that both a surface pretreatment and a primer have a high influence on the transmission of strain from the concrete surface to the fiber. With the untreated surface, the strain could not be completely transferred to the fiber via the adhesive. After a brief introduction to the measurement methodology, this study presents an option for treating concrete surfaces to obtain realistic strain values with surface-applied distributed optical fiber sensors. Furthermore, it is shown that a primer is required for optimal strain transmission on concrete surfaces and in which areas further investigations are necessary.


Assessment of potential explosiveness of combustible gas mixture without the gas identification

Ivan Ivanov1 , Alexander Baranov2 , Elena Karpova3 , Sergey Mironov4

1Moscow Aviation Institute (National Research University), Aerospace science intensive technologies and productions, Russian Federation
2Moscow Aviation Institute (National Research University), , Russian Federation
3 “STANKIN”—Moscow State Technological University, 105005 Moscow, , Russian Federation
4LLC “NTC IGD”, 140004 Lyubertsy, Moscow Region, , Russian Federation

Abstract

Nowadays, there are three widely used gas sensing technologies for detecting combustible gases in the environment below the explosive threshold: optical, catalytic and semiconductor [1][2]. Typically, each sensor is calibrated for detecting a separate gas. However in industry the gas mixtures of combustible hydrocarbons and vapors as well as hydrogen are common. In this case multisensor gas detectors, optical spectrometers and other equipment for multigas analysis in the environment should be used [3][4]. This ‘multisensor’ approach complicates the task on gas sensing by exploiting complex gas equipment and measurement. The state-of-the-art approaches for estimating the level of explosiveness of combustible gas mixtures start with the identification of all single gases and their concentrations composing the mixture. This process is followed by the calculation of LEL of gas mixture that is then compared with the theoretical threshold value of particular mixture. Based on the comparison, the level of explosion hazard is already estimated [5]. At the same time the identification of separate gases in the mixture for the inference on potential explosion is an intermediate task which is essential in traditional approaches for calculating LEL of gas mixture. That is why the assessment of potential explosiveness of gas mixture without the identification of separate gases in the mixture is a promising solution in this context. In this paper, we have offered a methodology for assessing the degree of explosiveness of hydrocarbon gas mixtures with hydrogen without recognizing the type of hydrocarbons, their quantity and concentration by controlling the burning process in the typical catalytic sensor. According to its fundamental feature, a catalytic sensor practically reacts on the total gaseous and vapor composition of the environment. This feature opens the way for an assessment of the explosiveness of gas mixtures, regardless of their composition [2]. The proposed method is based on the well-known fact that the combustion heat of various hydrocarbons at a concentration of 100% LEL in air differs less than 10% if the same volume of hydrocarbons is burned. Therefore, it is possible to determine the explosiveness of hydrocarbon gas mixture regardless of its exact composition by measuring the amount of heat released during the mixture burning in a constant volume. In the same time, the combustible heat of hydrogen is strongly different from hydrocarbons. However, the hydrogen starts to burn at a much lower temperature than hydrocarbons. In this paper we investigated the combustion of hydrocarbon mixtures which consist of methane, propane, butane and hydrogen (in the range of 20%–60% lower explosive limit) in the regime of diffusion restriction of gas leakage. This is important in order to ensure the main condition of correct measurements- the burning rate of the mixture should be much greater than the rate of their leakage inside the sensor chamber. Diaphragms with calibrated holes and semitransparent membranes were used for diffusion control of the leakage of gases into the sensor chamber. Determination of the amount of released heat was performed by measuring the integral response of the sensor during the combustion of gas mixture inside the catalytic sensor chamber. The measurements of sensor response were carried out according to the voltage divider circuit. The multi-stage heating profile with different duration and voltage amplitude was developed to heat the sensor and provide the measurements. This allowed to divide the catalytic sensor response onto hydrogen and hydrocarbons mixture. The heating were carried out in the temperature range 0-450 ° C. As well as it is allows to exclude the influence of uncontrolled environmental factors (temperature, humidity and pressure) on the result of sensor response measurements. The obtained results demonstrate a good agreement between the experimental values of LEL for hydrocarbon mixtures and the theoretical values. We also performed the estimation of error and its minimization. It is important to emphasize that the offered methodology can be used for sensing as single gases as well as combustible gas mixtures of unknown composition and allow to isolate the hydrogen from hydrocarbons mixture. 1. J. Leis, D. Buttsworth, “A temperature compensation technique for near-infrared methane gas threshold detection,” IEEE Trans. Ind. Electron., vol. 63, DOI: 10.1109/TIE.2015.2495292, no. 3, pp. 1813-1821, Mar. 2016. 2. A. Somov et al.. “Compact low power wireless gas sensor node with thermo compensation for ubiquitous deployment,” IEEE Trans. Ind. Informat., vol. 11, DOI 10.1109/TII.2015.2423155, no. 6, pp. 1660-1670, Dec. 2015. 3. J. Hodgkinson, R. P. Tatam, “Optical gas sensing: a review,” Meas. Sci. Technol., vol. 24, DOI 10.1088/0957-0233/24/1/012004, no.1, pp. 1-59, Nov. 2012. 4. A. V. Lashkov, V. V. Dobrokhotov, V. V. Sysoev, “The gas-analytical multisensor chip based on monolithic catalyst elements,” Proc. Int. Siberian Conf. on Control and Communications, DOI 10.1109/SIBCON.2015.7147121, May 2015, pp. 1-4. 5. K. Kühn, M. Siegwart, E. P. T. Sauerwald, A. Schütze, “Versatile infrared gas measurement system with tunable microstructured Fabry–Pérot filter,” Proc. IEEE Instrum. Meas. Technol. Conf., DOI 10.1109/I2MTC.2012.6229377, May 2012, pp. 1938-1943.

Acknowledgements:

This work was supported by the grant No. 9.1195.2017/4.6| from the Ministry of Education and Science of Russian Federation


Pt(II)-metalloporphyrin and thin films based on porphyrins and their hybrid nanomaterials destined for electrochemical, optical and fluorescence sensing of biologically active compounds

Eugenia FAGADAR-COSMA1 , Dana VLASCICI2 , Ioan STAMATIN3 , Gheorghe FAGADAR-COSMA4

1Institute of Chemistry Timisoara of Romanian Academy, Organic Chemistry, Romania
2West University of Timisoara, Chemistry-Biology-Geography Faculty, Romania
3University of Bucharest, Bucharest-Magurele, 3Nano-SAE Research Center, Romania
4Politehnica University Timisoara, Faculty of Industrial Chemistry and Environmental Engineering, Romania

Abstract

There is an increased interest for the determination of iodide, bromide and ascorbic acid in therapeutic monitoring, for biogenic amines in foods and for CO2 detection in wet environment. Presenting a very good versatility, Pt(II) 5,10,15,20-tetra(4-methoxy-phenyl)-porphyrin generates two different ion-selective sensors by using different plasticizers, namely: o-nitrophenyloctylether (NPOE) and dioctylphtalate (DOP). The calibration curves were linear in the range 10-5 to 10-1 M. The detection limit is 9×10-6 M for the iodide-selective sensor and 8x10-6 M for the bromide-selective sensor. By EIS method the water absorption of the membranes was determined in MES buffer solution. The performed measurements emphasized the necessity to introduce a membrane conditioning step, before the detection step of minimum immersion time of 25 hours in MES solution. The same Pt-porphyrin was able to optically detect triiodide with a detection limit of 10-9 M and can be applied in fluorescence sensing of hydrogen peroxide. An asymmetrically substituted meso-phenyl porphyrin, 5-(4-carboxyphenyl)-10,15,20-triphenylporphyrin was investigated as sensitive thin layer in electrochemical sensor for the histamine detection, a chemical compound associated with meat products freshness. The sensitive layer was deposited onto the carbon working area of SPE-110 by MAPLE with well preservation of both the structure and functionality of porphyrin, confirmed by AFM and Raman spectrometry. The cyclic voltammetry performed in trichloroacetic acid solution opens a new approach to exploit the porphyrin properties. The oxidations peaks are dependent on the presence or absence of histamine and the detection limit of the sensor for histamine is within the range of (0 – 8) ppm. In another experiment, Mn(III) tetratolyl-porphyrin chloride (MnTTPCl), spherical gold colloid (n-Au) and their hybrid (MnTTPCl/n-Au) were chosen to be comparatively investigated by UV-vis spectroscopy in the presence of ascorbic acid (AA). The hybrid material (MnTTPCl/n-Au) has the best capacity to detect concentrations of ascorbic acid in the range of 2.6 x10-6 M to 4.38 x10-5M. A multifunctional material based on 5-(4-carboxyphenyl)-5,10,15-tris(4-phenoxyphenyl)-porphyrin, iron oxide magnetic nanoparticles and a silica linker, was tested and validated for its capacity to detect CO2 in traces (in the range of 30 µM to 200µM).


Structured and catalytically-modified boron-doped diamond electrodes for electrochemical measurements

Tibor Izak1 , Ondrej Szabo2 , Pavla Stenclova3 , Stepan Potocky4 , Rene Pfeifer5 , Vlastimil Vyskocil6 , Alexander Kromka7

1Institute of Physics, Czech Academy of Sciences, Prague, , Czech Republic
2Institute of Physics of the Czech Academy of Sciences, Cukrovarnická 10, 162 00 Prague 6, Czech Republic, , Czech Republic
3Institute of Physics of the Czech Academy of Sciences, Cukrovarnická 10, 162 00 Prague 6, Czech Republic, , Czech Republic
4Institute of Physics of the Czech Academy of Sciences, Cukrovarnická 10, 162 00 Prague 6, Czech Republic, , Czech Republic
5Faculty of Science, Charles University, Albertov 6, 128 43 Prague 2, Czech Republic, , Czech Republic
6Faculty of Science, Charles University, Albertov 6, 128 43 Prague 2, Czech Republic, , Czech Republic
7Czech Academy of Sciences, Institute of Physics, Czech Republic

Abstract

Boron-doped diamond (BDD) is considered as a promising electrode material for a variety of analytes due to its extremely high chemical stability, a wide potential window in aqueous media with a low background current and stable surface state without the tendency to fouling. In the present study, we introduce various technological approaches for fabrication of structured boron-doped diamond (BDD) electrodes for electrochemical applications. The diamond structuring was done either by reactive ion etching (RIE) in O2 or CF4/O2 gas mixture employing the gold nanoclusters as the masking material or by thermo-catalytically driven reactions of nickel nanoclusters with the diamond surface. In the first case, the gold nanoparticle’s masks were prepared by evaporating a thin Au layer in a thickness of 3 or 12 nm and further annealed in hydrogen plasma to form nanoclusters with different diameters. In the case of the catalytic modification, a thin Ni film (~12 nm) was evaporated onto the diamond surface and subsequently thermally treated in hydrogen rich microwave plasma. As result, the Ni film transformed into clusters (80-100 nm in diameter) and catalytically transformed the diamond surface into graphitic forms which were etched away in hydrogen rich plasma. At certain process conditions, Ni clusters were incorporate into the diamond films. The final electrode morphology varied from nanograss to nanorods with different diameter and density. The samples were characterized in terms of surface morphology (scanning electron microscopy images), chemical composition (Raman spectroscopy) and electrochemical properties (cyclic voltammetry). The basic electrochemical properties of structured BDD electrodes were studied using standard ferrocyanide solution, and their detection properties were tested to heavy metal ions such as Cd2+, Pb2+, Cu2+. Regarding to electrochemical studies using ferrocyanide solution, all structured BDD films revealed a potential window enlargement. Contrary to this observation, the peak separation of [Fe(CN)6]4−/3– increased in some cases up to 900 mV compared to 81 mV for the planar BDD electrodes. Nevertheless, after electrode surface activation (+3 V for 5 min in 2M HNO3) all sensors revealed a comparable (or very similar) electrochemical properties (i.e. comparable potential window and peak separation). In electrochemical studies using solution with heavy metal ions, it was found that the optimal BDD morphology is linked to/coupled with the analyte composition. It means that, for example, as-grown BDD is the best for separate detection of Cd2+, as-grown BDD or nanorods with larger diameter for separate detection of Pb2+, while dense nanograss BDD morhology for simultaneous detection of Cd2+ and Pb2+.

Acknowledgements:

This work was supported by project co-financed by EU “Physics at your service“, number of project: CZ.07.1.02/0.0/0.0/16_023/0000115.


Glassy carbon electrodes modified with ordered mesoporous silica for lead detection

Nicoleta Cotolan1 , Liana Muresan2 , Graziella Turdean3 , Andrea Salis4

1Babes-Bolyai University, Faculty of Chemistry and Chemical Engineering, Cluj-Napoca, Department of Chemical Engineering, Romania
2Babes-Bolyai University, Faculty of Chemistry and Chemical Engineering Cluj-Napoca, Chemical Engineering, Romania
3Babes-Bolyai University, Faculty of Chemistry and Chemical Engineering Cluj-Napoca, Chemical Engineering, Romania
4University of Cagliari, Scienze Chimiche e Geologiche, Italy

Abstract

Ordered mesoporous silica (OMS) from the class of MCM-41 and SBA-15 [1] has attracted the scientists interest due to their large specific surface areas, ordered structure, inert framework, non-toxicity, and hydro/thermal stability, which allow them to be used as catalyst support, as well as adsorption, sensing or drug delivery systems. The environmental pollution with heavy metals, especially with Pb affects seriously the human health (causing cardiovascular, neurological, anemia or kidney problems) and its detection becomes an important concern of the research [2]. Many standardized, but expensive and time consuming methods, such as atomic absorption spectrometry (AAS) and inductively coupled plasma mass spectroscopy (ICP-MS), have been used for Pb measurements. In this context, the use of electrochemical techniques, especially stripping analysis on modified electrodes satisfy the requirements of low cost, rapid results, good analytical parameters. The aim of the work was to prepare a modified glassy carbon electrodes coated with a composite matrix consisting from four types of original and functionalized ordered mesoporous silica and an ion-exchange polymer (Nafion). The role of NH2- functional groups grafted on the silica surface on the electrochemical behavior of the modified electrodes was also investigated. The analytical parameters of the prepared electrodes determined by square wave anodic stripping voltammetry were very promising, recommending the use of the modified electrode for real samples analysis.

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.


Load matching for giant magnetoimpedance sensor in coaxial configuration

Sergei Shcherbinin1 , Stanislav Volchkov2 , Anna Chlenova3 , Galina Kurlyandskaya4

1Ural Federal University, Institute of Natural Science and Mathematics, Russian Federation
2Ural Federal University, Institute of Natural Science and Mathematics, 620002, Ekaterinburg,, Russian Federation
3Ural Federal University named after the first President of Russia B. N. Yeltsin, Institute of Natural Science and Mathematics, Russian Federation
4Universidad del País Vasco UPV/EHU, Depto Electricidad y Electrónica, 48940, Leioa, , Spain

Abstract

Magnetic field detectors based on giant magnetoimpedance (GMI), in addition to the sensitivity with respect to applied field, require the linearity of the signal conversion and reduction of the external electromagnetic interference effect and noise fluctuation. Since the working frequency of such sensor is hundreds of megahertz, the most secure from external interference is the coaxial design. However, when the ferromagnetic wire is placed as a central core of a coaxial cable, the line mismatch along the wave impedance inevitably arises and be taken into account. The sensitivity of GMI sensor based on rapidly quenched CoFeSiB amorphous wire (150 μm in diameter, 6 mm long) was investigated. Wire was installed as a central core in a coaxial cable with a wave impedance of 50 Ohm. The outer diameter of the cable was 1.7 mm, which makes it possible to locate the sensor inside a miniature electromagnet. The study was carried out in the frequency range 0.02-1.02 GHz in the external magnetic field range from 1 to105 Oe with different terminators from 1 to 100 Ohms: the best terminator was the 1 Ohm resistance. This option is preferable from the point of view of the maximum steepness of the characteristics, the GMI sensitivity, and electromagnetic compatibility, despite the greater frequency dispersion than in the coherent regime.

Acknowledgements:

This work was financially supported by Russian Science Foundation grant 18-19-00090.


Fabrication of Gallium Nitride Waveguide for Oral Cancer Raman Spectrum Measurement

Liann-Be Chang1

1Chang Gung University, Graduate Institute of Electro-Optical Engineering, Taiwan, Province Of China

Abstract

Raman spectroscopy technology can detect structure and specificity of bimolecular. It is a well known non-destructive technique and no extra labeling process required, that means we don’t need to go further on the preparation of the measured bio specimen. The waveguide Raman spectroscopy is a branch of Raman spectroscopy which uses guided wave to detect the characteristic of the specimen on the surface of a fabricated dielectric waveguide. The material selection and process fabrication of the waveguide are important issues... In this research, we use wide bang gap compound semiconductor GaN as our optical waveguide Raman device. Since the refractive index of GaN is 2.4, higher than the environment, good enough for the signal light confinement. Furthermore, GaN semiconductor is hardness, non-toxic, transparent and acid/alkali resistance. The oral specimen will not inter-react with GaN material biochemically and ssuitable for our bio-sensing application. We have deposited the oral specimen on our fabricated GaN waveguides, and founded interesting difference between a normal cell and tumor cell by Raman signals.


Potentiometric DNA sensor, based on polythiophene modified with single-stranded DNA probe

Maria Khaydukova1 , Zhanna Boeva2

1Saint Petersburg State University, Chemistry, Russian Federation
2Åbo Akademi University, Science and Engineering, Finland

Abstract

The importance of diagnostic on the earlier stage for a genetically caused disease or cancer cannot be overestimated. Determination of exact DNA sequences can provide valuable information for the diagnosis. However, the price and complexity of such analysis make them available only in special cases. The development of the low-cost, rapid and simple technique for DNA sequence determination could make these tests widely spread and accessible to the ordinary human. The electrochemical sensors become attractive in this context since they possess demanding properties. In our research, we have developed and characterized DNA biosensor based on glassy carbon electrodes modified with polythiophene film and single strand DNA probe. For this purpose, bithiophene was electrochemically polymerized on glassy carbon disk electrode and single stranded oligonucleotide was tethered via alkylthiol spacer to its surface. It was shown that modification of the electrode with polythiophene allows for simple potentiometric detection of the DNA probe hybridization with the complementary single-stranded DNA at the 1 µM concentration.

Acknowledgements:

Maria Khaydukova and Zhanna Boeva are expressing their gratitude to Akademy of Finland for funding research project for bilateral mobility to Finland, project "Functionalized polythiophenes for DNA genosensors" decision 308172 from 21.01.2017. Zhanna Boeva is expressing her gratitude to Jane and Aatos Erkko Foundation for funding project "New electrochemical sensing platforms for personalized medicine".


Multisensor system for treated wastewater quality monitoring

Eugine Legin1 , Maria Khaydukova2 , Dmitry Kirsanov3 , Vladimir Rybakin4 , Anatoly Zagrebin5 , Natalia Ignatieva6 , Andrey Legin7

1Saint Petersburg State University, Chemistry, Russian Federation
2Saint Petersburg State University, Chemistry, Russian Federation
3Saint Petersburg State University, Chemistry, Russian Federation
4Institute of Limnology Russian Academy of Sciences, , Russian Federation
5Institute of Limnology Russian Academy of Sciences, , Russian Federation
6Institute of Limnology Russian Academy of Sciences, , Russian Federation
7Saint Petersburg State University, Chemistry, Russian Federation

Abstract

Post-industrial societies produce huge amounts of the wastewater. Special procedures for wastewater treatment are implemented for safe return water to the environment. The proper analytical control has to be performed before returning water to the natural reservoirs. Nowadays in most of the cases this control is done in offline mode with determination of several analytes: ammonium nitrogen, nitrate nitrogen, phosphates, chemical and biological oxygen demands. Although quite precise these laboratory methods are rather time-consuming and most of them cannot be realized in real-time mode. In this study potentiometric multisensor system was applied for simultaneous assessment of these parameters. For this purpose sample set of treated wastewater was analyzed by traditional methods and with the multisensor system. Sensor responses were correlated with the results of traditional referent measurements using partial least squares regression. It was shown that suggested approach provides an opportunity for simultaneous monitoring of the water quality parameters within one three minutes long measurement instead of laborious traditional methods. Moreover, multisensor measurements can be implemented on-line as they do not require any reagents and complicated sampling.

Acknowledgements:

Authors acknowledge the financial support provided by RSF project #17-73-10284.


Modeling of interdigital electrodes geometrical parameters effects on chemical sensor response

DALLAH KHALID1 , azzedine bellel2 , Omar Lezzar3 , Saleh Sahli4 , Patrice Raynaud5

1Laboratory of Electronic Materials for Medical Application, Faculty of sciences and technology, University of Constantine 1, Constantine 25000, Algeria , Electronique, Algeria
2Laboratory of Electronic Materials for Medical Application, Faculty of sciences and technology, University of Constantine 1, Constantine 25000, Algeria , Electronique, Algeria
3Laboratory of Electronic Materials for Medical Application, Faculty of sciences and technology, University of Constantine 1, Constantine 25000, Algeria , Electronique, Algeria
4Laboratory of Microsystems and Instrumentation, Faculty of sciences and technology, University of Constantine 1, Constantine 25000, Algeria, Electronique, Algeria
5University Paul Sabatier Laboratory Plasma and Conversion of Energy (LAPLACE) 118 route de Narbonne, 31062 Toulouse cedex, France, , France

Abstract

The detection of volatile organic compounds (VOC), humidity and toxic industrial chemicals is important for various environmental and industrial applications. Interdigital capacitors (IDC) are one of the most used transducers in chemical and biological sensors. The design of IDC sensor is carried out in such a way that it would be suitable for microelectronic technology. The basic geometry of an IDC is defined by some parameters such as: number of electrodes N, electrode width W, electrode length L and the separation between electrodes G. The interactions between IDC sensitive coating and analyte induced a change in the sensors capacitance due to the permittivity variation of the sensitive layer and to the change in polymer thickness (swelling). In order to evaluate the effects of IDC geometrical parameters on the sensing properties, the development of theoretical model for the interactions between analyte and sensitive coating has been studied. In this work, a fairly new approach of IDC based sensor in terms of capacitance calculation has been presented. The modeling of the IDC geometrical parameters effects on the VOC sensor properties using 2D and 3D multi-physics simulation software COMSOL has been carried out. The effect of the geometrical parameters has been coupled with the measurements of the polymer swelling. The simulation results are divided into three parts: the first concerns the variations of IDC capacitance as a function of electrode spacing, where the electrode spacing was found to have a strong influence on the device capacitance. The second theoretical analysis concerns the effect of polymer thickness on sensor capacitance. The results show that the capacitance increases with sensitive layer thickness then reaches saturated values. Finally, the IDC based sensor response in terms of capacitance variations, towards the variation of methanol, acetone and ethanol concentration has been also simulated. The kinetic response increase gradually with time then reaches a steady state. The results show that sensor sensitivity increases with increasing electrode width W and decreasing the separation between electrodes G. The effect of the coating layer thickness on the IDC based sensor response in terms of capacitance variation showed that for layer thickness lower than about 200 nm, the sensor response increases significantly than slowly. Beyond the thickness of about 330 nm, electric field distribution in the sensitive layer decreases with increasing layer thickness and the sensor capacity did not change much further. From this observation, we may conclude that the IDCs-based sensor is not sensitive to layer thickness greater than half of its wavelength.

Acknowledgements:

This work is supported by the Algerian Thematic Agency of Research in Sciences and Technology (ATRST)


Hand motion prediction by neural networks using wearable strain sensors based on thin graphite films

Takahiro Kanokoda1 , Yuki Kushitani2 , Moe Shimada3 , Jun-ichi Shirakashi4

1Tokyo University of Agriculture and Technology, Department of Electrical and Electronic Engineering, Japan
2Tokyo University of Agriculture and Technology, Department of Electrical and Electronic Engineering, Japan
3Tokyo University of Agriculture and Technology, Department of Electrical and Electronic Engineering, Japan
4Tokyo University of Agriculture and Technology, Department of Electrical and Electronic Engineering, Japan

Abstract

A human motion prediction system can be used to estimate human gestures in advance to the actual action for reducing delays in interactive system. We have already reported a method of simple and easy fabrication of strain sensors and wearable devices using pyrolytic graphite sheets (PGSs). The wearable electronics could detect various types of human motion, with high durability and fast response. In this study, we have demonstrated hand motion prediction by neural networks (NNs) using hand motion data obtained from data gloves based on PGSs. In our experiments, we measured hand motions of subjects for learning. We created 4-layered neural networks to predict human hand motion in real-time. As a result, the proposed system successfully predicted hand motion in real-time. Therefore, these results suggested that human motion prediction system using NNs is able to forecast various types of human behavior using human motion data obtained from wearable devices based on PGSs.


FexNi100-x thin film systems with slight deviations from zero magnetostriction compositions: focus on pressure sensor applications

Anna Chlenova1 , Iuliia Novoselova2 , Ruslan Salikhov3 , Michael Farle4 , Vladimir Lepalovskij5 , Galina Kurlyandskaya6

1Ural Federal University named after the first President of Russia B. N. Yeltsin, Institute of Natural Science and Mathematics, Russian Federation
2University of Duisburg-Essen, 47057, Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), Germany
3University of Duisburg-Essen, 47057, Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), Germany
4University of Duisburg-Essen, 47057, Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), Germany
5Ural Federal University, 620002, Institute of Natural Sciences and Mathematics, Russian Federation
6Universidad del País Vasco UPV/EHU, Depto Electricidad y Electrónica, 48940, Leioa, , Spain

Abstract

FeNi thin films and multilayered structures are widely used in technical devices, such as inductors, transformers and magnetic sensors. Usually the main characteristics required for applications are high magnetic permeability, small coercivity, well defined magnetic anisotropy and near-zero magnetostriction. Therefore the most studied FexNi100-x system was Fe19Ni81 for which both static and dynamic magnetic properties were considered. Recently, FeNi-based multilayered structures were proposed for pressure measurements in microfluidic devices for biomedical applications using the giant magnetoimpedance effect (GMI) [1]. Magnetic softness of thin FeNi films is a critical condition for high GMI sensitivity. These applications also require incorporation of a sense layer with few microns thickness to insure the high impedance variation [2]. Although thin FeNi films with close to zero magnetostriction were extensively studied, less attention was paid to FexNi100-x thin film systems with slight deviations from zero magnetostriction compositions, especially for a thickness above 100 nm which can be more sensitive to pressure variations. In this work, the structure and magnetic properties, were studied by ferromagnetic resonance and giant magnetoimpedance for FexNi100-x thin film systems with compositions with small deviation from zero magnetostriction in order to find the best conditions for possible applications as microfluidic small pressure sensitive elements based on GMI effect.

Acknowledgements:

This work supported by grant of RFBR mol_a № 18-32-00094 and by the German-Russian Interdisciplinary Science Center (G-RISC) funded by the German Federal Foreign Office via the German Academic Exchange Service (DAAD).


Fabrication of conducting polymer-metal (2T-Pd) thin film modified electrode for electrochemical sensors

Leila Lamiri1 , Belkacem Nessark 2 , Linda Djaouane3 , Leila Hasniou4 , Farid Habelhames5 , Charif Dahchar6 , Ouafia Belgharbi7 , Radhia Yekhlef8 , Samiha Laidoudi9

1Research Center in Industrial Technologies CRTI, P.O. Box 64, Cheraga 16014, Algiers, Thin Films Development and Applications Unit - (UDCMA) -Setif- Algeria, Algeria, Algeria
2Laboratoire d’Electrochimie et Matériaux, Département de Génie des Procédés, Faculté de Technologie, Université Ferhat Abbas, Sétif 19000, Algeria, , Algeria
3Laboratoire d’Electrochimie et Matériaux, Département de Génie des Procédés, Faculté de Technologie, Université Ferhat Abbas, Sétif 19000, Algeria., , Algeria
4Laboratoire d’Electrochimie et Matériaux, Département de Génie des Procédés, Faculté de Technologie, Université Ferhat Abbas, Sétif 19000, Algeria, , Algeria
52Laboratoire d’Electrochimie et Matériaux, Département de Génie des Procédés, Faculté de Technologie, Université Ferhat Abbas, Sétif 19000, Algeria, , Afghanistan
6Research Center in Industrial Technologies CRTI P.O.Box 64, Cheraga 16014 Algiers, Algeria, , Algeria
7Research Center in Industrial Technologies CRTI P.O.Box 64, Cheraga 16014 Algiers, Algeria, , Algeria
8Research Center in Industrial Technologies CRTI P.O.Box 64, Cheraga 16014 Algiers, Algeria, , Algeria
9Research Center in Industrial Technologies CRTI P.O.Box 64, Cheraga 16014 Algiers, Algeria, , Algeria

Abstract

A novel modified electrode based on polybithiophene (2T) film containing palladium (Pd) particles has been synthesized by electrochemical method using a two-step procedure. First, P2T film was deposited on indium thin oxide (ITO) substrate by oxidation of the monomer bithiophene dissolved in acetonitrile (CH3CN) containing lithium perchlorate (LiClO4) as supporting salt. Then, the incorporation of Pd particles on the P2T film was performed by the immersion of the modified electrode in a Pd solution. The obtained electrode (P2T-Pd/ITO) was characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), UV–vis and spectroscopy and scanning electronic microscopy (SEM). Results demonstrate that the proposed 2T-Pd composites act as good catalysts for the oxidation of glucose in 0.1 M NaOH solution.


Design and simulation of the properties of metamaterial compatible with silicon prosess in terahertz spectrum

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 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 a terahertz metamaterial structure and the research on the electromagnetic characteristic of the terahertz metamaterial are valuable. In this paper, a unit structure of terahertz metamaterial base on microelectronics technology is designed; the reflectivity and the transmittance in the terahertz frequency band of the metamaterial corresponding to the designed unit are calculated by using the simulation software of electro-magnetic field; the absorbance of the metamaterial is obtained.


Optimization study of defected ZnO/Si/Cu2O thin film solar cell structure using AMPS-1D modeling simulator

Samah BOUDOUR1 , Idris BOUCHAMA2 , Moufdi HADJAB3 , Samiha Laidoudi4

1Research Center in Industrial Technologies CRTI, Thin Film and Applications Development Unit UDCMA-CRTI, Algeria
2Electronic Department, Faculty of Technology, Mouhamed Boudiaf University, 28000, Msila, Algeria, , Algeria
3Research Center in Industrial Technologies CRTI, P. O. Box 64, Cheraga 16014, Algiers, , Algeria
4Research Center in Industrial Technologies CRTI P.O.Box 64, Cheraga 16014 Algiers, Algeria, , Algeria

Abstract

Intrinsic or doped, either by oxygen vacancies or by substitution of some the atoms, zinc oxide (ZnO, wide energy band gap at 3.3eV) and cuprous oxide (Cu2O, direct energy band gap at 2.1eV) based thin film semiconductors are among present-day partner for the widespread crystalline silicon (Si) semiconductor material in solar cell application. In the present work, we highlight a simulation study on performance of defected ZnO/Si/Cu2O solar cell using Analysis of Microelectronic and Photonic Structures (AMPS-1D) computer simulator under solar spectrum AM1.5. We explain the current-voltage (J-V) characteristics like open circuit voltage (Voc), short circuit current (Jsc), fill factor (FF) and efficiency (η). The band alignment ideality of the heterojunction, the high defects within layers, the quantum efficiencies (QE) and the temperature effects are also investigated based on the device design and the input parameters such as thickness, doping densities, etc of layers. The optimized defected ZnO/Si/Cu2O three-layer structure showed an appreciable performance.


APPLICATION OF THERMAL SENSORS FOR DETERMINATION OF MASS FLOW RATE AND VELOCITY OF FLOW IN PIPES OF HERMETIC SYSTEMS

Yurii Baidak1

1Odessa National Academy of Food Technologies, Thermodynamics and Renewable Energetics, Ukraine

Abstract

The paper relates to the field of measuring technology and deals with the enhancement of the thermoconvective method when it is applied for the experimental determination of such hydrodynamics indicators as mass flow rate and velocity of flow by their indirect parameters - the temperatures of two thermal sensors and the heater power provided that they are located directly on the surface of the hermetic piping system. The issue of determination of correction factor on heterogeneity of liquid temperature distribution in the pipe cross section depending on pipe diameter and the velocity of the flow was clarified. According to the results of numerical calculations, the dependencies of temperature gradient on the pipe surface and the correction factor on the heterogeneity of the temperature distribution along the pipe cross section under the heater in the function of the velocity of flow in pipes of different diameters are plotted. These dependencies specify the thermal method of studying the fluid flow in the pipes, simplify the experiment, are useful in processing the obtained results and can be applied in measuring equipment.


Influence of the length-to-width ratio on the ΔE effect of amorphous magnetoelastic ribbons for actuation applications

Ariane Sagasti1 , Miguel Llano2 , Andoni Lasheras3 , Ana Catarina Lopes4 , Jorge Feuchtwanger5 , Jon Gutierrez6

1UPV/EHU, Electricity and electronics, Spain
2BCMaterials, , Spain
3UPV/EHU, , Spain
4BCMaterials (Basque Center for Materials, Applications & Nanostructures), Bldg. Martina Casiano, 3rd. Floor, Barrio Sarriena s/n, 48940, Leioa, Spain, , Portugal
5UPV/EHU, , Mexico
6Universidad del País Vasco UPV/EHU, Departamento de Electricidad y Electrónica, Spain

Abstract

Fe-rich amorphous magnetoelastic alloys show outstanding magnetic and magnetoelastic properties that make them excellent candidates for very simple detection and actuation devices. The origin of such applicability arises from the coupling between elastic and magnetic properties of those materials, and reflects directly in the dependence of Young modulus with the applied external magnetic field, a property that is useful and allows to control the response of such materials under applied external parameters as mass loading, stress, temperature and so on. We present an extensive study of the variation of the Young modulus with the applied magnetic field and the so called ΔE effect on amorphous magnetoelastic ribbons of Fe-Ni-Co-Si-B composition. Strips with different length-to-with ratios (from 4 to 21) have been analyzed, varying both the length (L = 35, 30, 25, 20 mm) and width (w = 5, 3.3, 2.5, 1.7 mm) From our observations, depth of the ΔE effect reduces and applied magnetic bias field for minimum Young modulus value (Emin) increases continuously as the length of the strips shortens. With our measured values of Young modulus at applied zero magnetic field (E0) and Emin, we have also performed simulations by using FEM (Finite Elements Method), in order to estimate the maximum deviation of the end of such a strip when working under applied constant pressure or stress, a situation that can be similar to one open/close simple design valve application. Obtained values of such deviation range between 4 mm and 18 mm, telling us about its feasibility.


Analysis of surface relief gratings on azo-copolyimide films by atomic force microscopy and high-resolution scanning electron microscopy

Ion Sava1 , Iuliana Stoica2 , Ilarion Mihaila3 , Ionut Topala4 , George Stoian5

1"Petru Poni" Institute of Macromolecular Chemistry, Polycondensation, Romania
2"Petru Poni" Institute of Macromolecular Chemistry, , Romania
3Integrated Center of Environmental Science Studies in the North-Eastern Development Region (CERNESIM), Alexandru Ioan Cuza University of Iasi, , Romania
4Alexandru Ioan Cuza University of Iasi, Faculty of Physics, Iasi, , Romania
5National Institute of Research and Development for Technical Physics, Iasi, , Romania

Abstract

Free-standing, transparent, flexible films of azo-copolyimides were investigated regarding surface relief gratings formation under the action of pulsatory laser irradiation. Aromatic azo-copolyimide films have been obtained from polyamidic acids based on benzophenonetetracarboxylic dianhydride and a mixture of 2,2-bis{3-amino-4-[(p-oxyalkyloxy–p’-methyl) azobenzene]-phenylene}-hexafluoropropane (0.25mol) and 4,4’-diamino-3,3’dimethyldiphenyl methane (0.75mol) by thermal imidization. The studied azo-copolyimides showed a good surface structuration capacity irrespective of pulsess number (10 or 100) using a laser field with an energy density of 45 mJ/cm2. According to atomic force microscopy investigations, by using a high number of pulses, the surface relief became much more regular and the modulation depths were around 140-250 nm, while by using only 10 pulses number the modulation depths were in the range of 80-150 nm. The surface morphology has a preferential orientation, indicated by the low value of the texture direction index. The values of the functional volume parameters were larger for all polyimide samples after increasing the number of pulses. For target applications the resulted nanostructures were covered with gold by sputtering deposition and investigated by high-resolution scanning electron microscopy. The best results were obtained for a metal layer thickness of 10 nm, the deposited film being uniform and free from longitudinal cracks.

Acknowledgements:

This work was supported by a grant of Ministery of Research and Innovation, CNCS - UEFISCDI, project number PN-III-P4-ID-PCE-2016-0708, within PNCDI III.


Complex sensors system for controlling the process of electrochemical recovery of metals from waste printed circuit boards

Sorin-Aurel Dorneanu1 , Graziella Turdean2

1"Babes-Bolyai" University Cluj-Napoca, Faculty of Chemistry and Chemical Engineering, Department of Chemical Engineering, Romania
2Babes-Bolyai University, Faculty of Chemistry and Chemical Engineering Cluj-Napoca, Chemical Engineering, Romania

Abstract

With an enormous value (exceeding 50 Mt worldwide in 2018) and a continuous increasing tendency (of ~4%/year) [1], the amount of waste electric and electronic equipment (WEEE) represents a major challenge for industry and the research community in respect to the environmental protection and raw materials preservation. From this amount, the waste printed circuit boards (WPCBs) represent only 3-5% but concentrate more than 40% from the value of the recoverable metals [2]. As a consequence, physico-mechanical, hydrometallurgical and pyrometallurgical techniques for the metals recovery from WPCBs were designed and implemented, but all of them present several disadvantages like high energy consumption, secondary pollution due to the generation large volumes of residual effluents and release of extremely toxic gases in atmosphere, respectively [3]. Based on our preliminary results [4], we conclude that the electrochemical recovery of metals from WPCBs represents an economical and eco-friendly recycling alternative if the operational parameters are well controlled. The process management becomes more difficult due to the high heterogeneity of treated WPCBs, their composition depending on manufacturer, adopted technology, release time and many other factors. In order to evaluate this dispersion, on the beginning of the present work, 10 different generation PC motherboards (PCMBs), released between 1998 and 2008, were partially dismantled and the direct accessible metals were chemically dissolved at a solid:liquid ratio of 1:4, using a bromine/bromide leaching system. For example, the analysis by inductively coupled plasma atomic emission spectrometry (ICP-AES) of the resulted solutions indicates concentrations for Cu, Sn, Pb, Fe and Ni in the next ranges: 18.7÷30.5, 6.3÷10.1, 0.05÷9.7, 1.9÷8.1 and 0.6÷1.1 g/L, respectively. Unfortunately, at these concentrations level, the use of consecrated analytical techniques (e.g. ICP-AES, ICP-mass spectroscopy, flame or graphite furnace atomic absorption spectroscopy and anodic stripping voltammetry) for on-line monitoring and recycling process control becomes unpractical, requiring expensive equipment and significant samples pre-treatments (e.g. 10 to 10000 fold dilution). As an alternative, in the present work, stationary and rotating disk electrodes of glassy carbon were exploited as amperometric sensors by cyclic linear scan and cyclic square wave voltammetry. The obtained results, recorded for the previous mentioned metals in real and undiluted samples, present an acceptable correlation with the values obtained by ICP-AES analysis. In order to increase the monitoring and control accuracy for the metals recovery process, we start to complete the array of amperometric sensor with pH, temperature, conductivity and oxidation/reduction potential sensors, the computerised correlation of the acquired data being also in progress. Moreover, programmable multi-sequences amperometric techniques were designed and will be tested and validated in real and undiluted samples of WPCBs leachate. References: 1. Z. Liu, J. Tang, B.-yi Li, Z. Wang, J. Clean. Prod., 2018, 167, 97-109. 2. F. Cucchiella, I.D’Adamo, S.C. Lenny Koh, P. Rosa, Renew. Sust. Energ. Rev. 2016, 64, 749-760. 3. C. Ning, C.S.K. Lin, D.C.W. Hui, G. McKay, Top. Curr. Chem., 2016, 375(2), 1-36. 4. S.A. Dorneanu, Studia UBB Chemia, 2017, LXII(3), 177-186.

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.


OPTICAL SENSOR WITH LIQUID CRYSTAL ACTIVE ELEMENT FOR AMINO ACIDS DETECTION

Maria Vistak1 , Zinoviy Mykytyuk2 , Hryhoriy Barylo3 , Anatoliy Andrushchak4 , Yulia Horbenko5

1Danylo Halytsky Lviv National Medical University, Biophysics, Ukraine
2Lviv Polytechnic National University, Electronic Devices, Ukraine
3Lviv Polytechnic National University, Electronic Devices, Ukraine
4Lviv Polytechnic National University, Telecomunication, Ukraine
5Ivan Franko National University of Lviv, Chemical, Ukraine

Abstract

The using of liquid crystal (LC) materials in biology and medicine it make the big interest in modern world. We developed an optical sensor with the use of LC materials as an active medium for quantitative and qualitative analysis of amino acids. Such an analysis is required for the study of drugs influence, control of biological processes, the development of pharmaceuticals - biologically active additives, amino acid mixtures and vitamin complexes. In the visible range of wavelengths, we investigated spectral characteristics of the LC mixture with amino acids dopants (valine, asparagine, methionine) with aim to design an active element of amino acid sensors. For analysis, a medicinal product or a standard solution of this agent in distilled water was used. At the dependences of the wavelength at minimum transmittance versus of concentration of amino acids and their aqueous solutions, two plots are observed, the first is increasing, while the second one is passed into the saturation. During the mathematical processing of experimental results, a linear approximation was carried out in a certain concentration range, in which it is possible to achieve the required measurement accuracy. To extend the range of measurements, it is necessary to approximate in the direction of the saturation zone. This makes it possible to extend the range of measured concentrations of amino acids in the LC mixture, but the accuracy of the measurement are decreased. The molecular aspect of the interaction of LC with amino acids is analyzed. Accordingly, to studied results the LC pitch increasing with an increasing of amino acids concentration in the LC mixture are observed. On the base of investigation work, an optical microelectronic sensor of amino acids has been designed. The electronic part of the device is based on the microcontroller family PSoC (Cypress). This microcontroller controls the optical part of the sensor and processes the information signal.


MATERIALS FOR AMINO ACIDS OPTICAL SENSORS

Orest Sushynskyi1 , Olena Aksimentyeva2 , Romana Petrina3 , Semen Khomyak4 , Iryna Kremer5

1Lviv Polytechnic National University, Electronic Devices, Ukraine
2Ivan Franko National University of Lviv, Chemical, Ukraine
3Lviv Polytechnic National University, Technology of Biologically Active Substances, Pharmacy and Biotechnology, Ukraine
4Lviv Polytechnic National University, Technology of Biologically Active Substances, Pharmacy and Biotechnology, Ukraine
5Lviv Polytechnic National University, Electronic Devices, Ukraine

Abstract

Amino acids are a class of organic compounds that combine the properties of amines and acids. The molecules of amino acids consist of the carboxyl group with the amino group. They are monomers of proteins and form a polymer chain to form the peptide bonds. For today, the detection of free amino acids in different biological objects, namely, bacteria, plants, food, urine and blood serum is an actual problem. However, existing methods for controlling amino acids are complex, bulky and require skilled personnel. Medicinal plants containing many amino acids are promising for the creation of new drugs. We investigated the spectral characteristics of mixtures of cholesteric and nematic liquid crystals (LC) with amino acid addition. For analysis, we used the amino acids contained in Arnica montana (glycine, serine, proline, phenylaniline). In contact with amino acids, the cholesteric-nematic mixture (CNM) changes its spectral characteristics, namely, the position of the wavelength at the minimum of optical transmission, which can become the basis of the principle of the optical sensor functioning. Consequently, the proposed LC mixture can be used as the active medium of the sensing element of the sensor. From the standpoint of practical use, solid-state sensitive elements can be created by introducing a LC mixture into porous materials [1]. Let's analyze the results. With the increase in the concentration of amino acids in the CNM, the shift of spectral characteristics to the longwave region to a certain concentration of the amino acid occurs, after which the wavelength of the minimum pass is constant. The concentration value at which a heterogeneous system is formed is established. On the micro photo of obtained CNM the cholesteric textures are observed. The investigated amino acids are characterized by differences in structure and, accordingly, their properties. This causes changes in the configuration of the LC molecules due to the excellent processes of interaction between the CNM and the studied amino acids, especially when the transition is nonpolar (proline) - small polar (serine, glycine) - large polar (arginine). That is can be observed on the obtained experimental dependencies.


Semiconductor Component Fault Assessment and Probability Impact Estimation on Applications Level

Jonas Stricker1 , Clemens Kain2 , Andi Buzo3 , Jerome Kirscher4 , Linus Maurer5 , Georg Pelz6

1Uni BW, EIT4, Germany
2Infineon, , Germany
3Infineon, , Germany
4Infineon, , Germany
5Bundeswehr Universität, , Germany
6Infineon, , Germany

Abstract

Failures at component level can affect the application behavior in many different ways. During product definition it is crucial to know the severity and the probability of such influence. The current methods for dealing with such problems are based on engineering judgment, but these are limited by the complexity of the applications and its components. In this paper, we present an automated approach in which we model the failures at component level, propagate them in application through simulation, cluster the failures and estimate the overall probability that different application failures modes have. This approach is applied on an automotive Electric Power Steering application while the components of interest are an analog-to-digital converter and a current sensor. The results show that the large number of failure modes on component level boils down to a very low number of application failure modes. For each of these failure modes the probability of occurrence is calculated starting from the related root causes on component level.

Acknowledgements:

This research project is supported by the German Government, Federal Ministry of Education and Research under the grant number 16ES0356-61.


Direct fabrication of a β-PVDF piezoelectric film in a 3D-shape

Ana Catarina Lopes1 , Jon Gutierrez2 , Jose Manuel Barandiaran3

1BCMaterials (Basque Center for Materials, Applications & Nanostructures), Bldg. Martina Casiano, 3rd. Floor, Barrio Sarriena s/n, 48940, Leioa, Spain, , Portugal
2Universidad del Pais Vasco UPV/EHU, , Spain
3Universidad del Pais Vasco UPV/EHU and BCMaterials, , Spain

Abstract

Poly(vinilidene fluoride) (PVDF) and its copolymers present the best piezoelectric properties among the restricted number of piezoelectric polymers [1]. However, its crystallization in the piezoelectric β-phase requires the stress ratio of -PVDF sample at a temperature of 80 ºC[2]. Such process limits the production of the film to a flat form and avoids its printing. The production of neat PVDF directly from the melt in the β-phase would represent a huge advance in the area of piezoelectric polymers and lead to an enormous spread of their applications. In this work, a flexible and light film of neat PVDF in the β-phase has been produced, directly from the melt, in the non-flat form that can also be printable. The hydrophilic ionic liquid, C2mim BF4 and C2mim Cl were used to induce the crystallization of PVDF in the piezoelectric β-phase by melt. Since the filler is water soluble, it can be removed by washing. 10%wt of ionic liquid is enough to totally induce the crystallization in the piezoelectric β-phase. The introduction of the film in water at 70 ºC by one hour is enough to completely remove the ionic liquid, what was proved by FTIR. The spherulitic structure, the crystallinity and the degradation temperature is not affected by the previous introduction of ionic liquid. After exposed to a corona discharge polarization, the final sample showed a d33 coefficient of -27 pCN-1. For the first time, a 3D shape film of a neat PVDF in the β-phase was produced. Besides its simplicity, this method is also cheap and ecologically viable, since the IL retained in water can be recovered by distillation, and reused [3]. [1] P. Martins, A.C. Lopes, S. Lanceros-mendez, Prog Polym Sci, 39 (2014) 683-706 [2] J. Gomes, J. S. Nunes, V. Sencadas, and S. Lanceros-Mendez, Smart Mater Struct, 19 (2010) 065010. [3] A.C.Lopes, J. Gutiérrez, J.M. Barandiarán, Eur Polym J, 99 (2018) 111-116.

Acknowledgements:

The Basque Government is acknowledged for funding under project number KK-2015/00094- ACTIMAT and KK-2016/00095-LISOL. A.C.Lopes thanks to MSCA-IF-2015 (Marie Skłodowska Curie Actions) of the European Union's Horizon 2020 Programme for the received funds under grant agreement n° [701852].


INCREASING THE SENSITIVITY OF MAGNETOELASTIC SENSORS BY MODIFYING THE GEOMETRY

Paula GSaiz1 , Andoni Lasheras2 , Ariane Sagasti3 , Iban Quintana4 , Jon Gutierrez5 , María Isabel Arriortua6 , Ana Catarina Lopes7

1BCMaterials (Basque Center for Materials, Applications & Nanostructures), Bldg. Martina Casiano, 3rd. Floor, Barrio Sarriena s/n, 48940, Leioa, Spain, BCMaterials, Spain
2BCMaterials (Basque Center for Materials, Applications & Nanostructures), Bldg. Martina Casiano, 3rd. Floor, Barrio Sarriena s/n, 48940, Leioa, Spain, , Spain
3BCMaterials (Basque Center for Materials, Applications & Nanostructures), Bldg. Martina Casiano, 3rd. Floor, Barrio Sarriena s/n, 48940, Leioa, Spain, , Spain
4IK4-TEKNIKER, Polígono Tecnológico de Eibar, Calle Iñaki Goenaga, 5, Eibar, Spain, , Spain
5Universidad del País Vasco UPV/EHU, Departamento de Electricidad y Electrónica, Spain
6Universidad del País Vasco UPV/EHU, Mineralogía y pretrología, Spain
7BCMaterials (Basque Center for Materials, Applications & Nanostructures), Bldg. Martina Casiano, 3rd. Floor, Barrio Sarriena s/n, 48940, Leioa, Spain, , Portugal

Abstract

The development of miniaturized systems able to specifically detect low amounts of chemical or biological compounds in a wireless, quick, cheap and precise way is a demand, since most of the up to date methods used for that purpose require complex instrumentation and slow treatment processes. In that systems, the sensitivity and the selectivity are two important parameters that define the quality of the sensor. In this way, magnetoelastic resonators, which are gaining interest for sensors applications, could provide an attractive alternative. The detection on these materials is wireless and fast as it is based on the decrease of the magnetoelastic resonance frequency caused by the increase of the mass on the resonant system1. Many investigations have focused on the increase of this shift, however, most of them are based on an increase of the sensitivity by a reduction of the magnetoelastic ribbon size2. Despite the interesting obtained results, it forces to work on high frequency values and with less intensity of the signal which requires a better detector. So, in order to avoid the reduction of magnetoelastic ribbon size, other alternatives should be considered. In this work, a commercial Fe40Ni38Mo4B18 metallic glass (Metglas 2826MB) have been used to study the effect of the geometry of the sensor and of the percentage of the resonator surface covered on the sensitivity and other magnetic properties. Results shows that, changing the geometry of the resonator without change the size, an increase of more than a 1000% on its sensitivity which respect to the traditional rectangular shape could be achieve. References [1] Grimes, C. A., Roy, S. C., Rani, S., & Cai, Q. (2011). Theory, instrumentation and applications of magnetoelastic resonance sensors: a review. Sensors, 11(3), 2809-2844. [2] Sagasti, A., Gutiérrez, J., San Sebastián, M., & Barandiarán, J. M. (2017). Magnetoelastic resonators for highly specific chemical and biological detection: A critical study. IEEE Transactions on Magnetics, 53(4), 1-4.

Acknowledgements:

The research leading to these results has received funding from the MSCA-IF-2015 (Marie Skłodowska Curie Actions) of the European Union's Horizon 2020 Programme under grant agreement n° [701852], from the “Ministerio de Economía, Industria y Competitividad” (MAT2016-76739-R(AEI/FEDER, UE)) and from the “Gobierno Vasco” (Basque University System Research Groups, IT-630-13).


Crown-ether containing polyimides for alkaline ion metals sensing

Adriana-Petronela Chiriac1 , Mariana-Dana Damaceanu2 , Catalin-Paul Constantin3

1"Petru Poni" Institute of Macromolecular Chemistry, Polycondensation and Thermostable Polymers, Romania
2"Petru Poni" Institute of Macromolecular Chemistry, Polycondensation and Thermostable Polymers Department, Romania
3"Petru Poni" Institute of Macromolecular Chemistry , Polycondensation and Thermostable Polymers, Romania

Abstract

Rigid-rod aromatic polyimides constantly attracted large interest due to their unique combination of properties, such as excellent thermo-oxidative stability and tensile properties, along with good dielectric features and dimensional stability. Therefore, they were used in a wide range of applications, such as interlayer dielectrics in microelectronics, optical waveguides in optoelectronics, or thermoresistant components in aircraft industry, among others. Incorporation of specific functionalities into polyimide structural motifs led to various advanced functional materials with unique properties, such as permeability to hot gases, electrochromic, photosensitive, charge-transporting etc. However, their applicability is limited because of processing difficulties arising from the rigid-chain characteristics that induce limited solubility and infusibility. To overcome these problems, modifications of the chemical polymer structures were performed to render beside better solubility and processability other advantageous polymer properties. The common strategy consists in the incorporation of bulky lateral substituents, various flexible or kink units, or non-coplanar moieties into rigid polymer backbones. Along these lines, here we report on the development of some polyimides modified with 15-crown-5 moiety in the side chain for use in sensing of alkaline metal ions. Some properties of the polymers, such as solubility, thermal stability, photo-optical, electrochemical and morphology of the thin films made therefrom were thoroughly investigated.

Acknowledgements:

This work was supported by a grant of Ministry of Research and Innovation, CNCS - UEFISCDI, project PN-III-P4-ID-PCE-2016-0708, contract no. 66/2017 within PNCDI III.


Development of an electromagnetic method as a non-destructive testing to assess the integrity of marine structures

goran Omer1

1Liverpool johnmoors University (LJMU), Built Environment and Sustainable Technologies Research Institute (BEST), United Kingdom

Abstract

Abstract: Corrosion of the reinforcing steel is a main reason for deterioration and damage in reinforced concrete structures such as concrete columns and bridge decks. One such aggressive substance, present predominantly in marine or coastal environments, is chloride and the associated chloride ions. Chloride in the presence of oxygen and water cause pitting corrosion and the measurement of chloride content is a significant issue in the discovery of early corrosion damage induced by chloride attack. However, there is at present, an absence of a dependable non-destructive method to examine the chloride content of the structure. This paper displays the consequences of an experimental study to explore the suitability of a microwave non-destructive method to monitor chloride penetration into the concrete structures. The variations in the electromagnetic properties of concrete specimens with chloride penetration are measured to detect correlation between chloride content and the electromagnetic properties of concrete samples; dielectric constant, loss factor and loss tangent. In this study, five concrete slabs of size 250x250x60mm without reinforcement at water cement ratio (w/c) of 0.4 were prepared. The samples were cured in different salt water concentrations from 0.0M/L, 0.6M/L for 28 days. The electromagnetic (EM) properties of concrete specimens were measured through two ports using a vector network analyser and rectangular waveguide over a microwave frequency range from 2.35GHz to 12GHz at a power of 0dBm. The relationship between the chloride content of concrete specimens and the electromagnetic properties is confirmed by the initial findings, highlighting the potential for development of an EM technique to monitor the chloride content of in situ centre concrete.


Novel triphenylamine-based polyimides for electrochromic applications

Catalin-Paul Constantin1 , Andra-Elena Bejan2 , Mariana-Dana Damaceanu3

1"Petru Poni" Institute of Macromolecular Chemistry , Polycondensation and Thermostable Polymers, Romania
2“Petru Poni” Institute of Macromolecular Chemistry, Polycondensation and Thermostable Polymers , Romania
3"Petru Poni" Institute of Macromolecular Chemistry, Polycondensation and Thermostable Polymers Department, Romania

Abstract

Among the polymers widely studied for applications in advanced techniques, aromatic polyimides have received special attention due to their outstanding thermal stability associated with good electrical and mechanical properties. Polyimides are widely used in high temperature plastics, adhesives, dielectrics, photoresists, nonlinear optical materials or membrane materials for gas separation, among others. The newest applications include electroluminescent devices, electrochromic materials, polymer electrolyte fuel cells or polymer memories. The electrochromic effect occurs when the polymer film color can be alternated by applying a potential. This interesting property led to various technological applications, such as smart windows, automatic antiglazing mirrors, large scale electrochromic screens and chameleon materials. On the other hands, owing to their attractive electroactive and photoactive properties, various triphenylamine-based polymers were developed for optoelectronic applications, such as light-emitting diodes, solar cells, memory or electrochromic devices. Along these lines, here we report on the design, synthesis and investigation of novel electrochromic polyimides. These polymers are based on two substituted triphenylamine diamines and two chromophoric dianhydrides. They were obtained by one-step solution polycondensation reaction at high temperature. The influence of the macromolecular architecture on their thermal, photophysical, electrochemical properties and electrochromic behaviour has been thoroughly explored.

Acknowledgements:

This work was supported by a grant of Ministry of Research and Innovation, CNCS - UEFISCDI, project PN-III-P4-ID-PCE-2016-0708, contract no. 66/2017 within PNCDI III.


Sensitiveness of alumina resistivity to trace concentrations of acetone vapors

Jan Ivanco1

1Slovak Academy of Sciences, Institute of Physics, Slovakia

Abstract

J. Ivančo1, M. Benkovičová1, Y. Halahovets1, J. Kollár2, A. Hološ2, and J. Mosnáček2 1 Institute of Physics, Slovak Academy of Sciences, Dúbravská cesta 9, SK-845 11 Bratislava, Slovakia 2 Institute of Polymers, Slovak Academy of Sciences, Dúbravská cesta 9, SK-845 41 Bratislava, Slovakia Acetone is considered as a biomarker of diabetes since that is manifested by increased concentration of acetone vapours in an exhaled breath of the diabetes patient. Therefore, there has been concern over a simple, affordable detector capable of sensing of acetone vapours-concentration changes around one ppm range. Chemiresistors based on various metal oxides have been widely investigated. We demonstrate that a chemiresistor consisting solely of an alumina wafer, which is often employed in the role of an electrically insulating substrate for sensing films, is sensitive to exposure of trace concentrations of acetone vapours. To illustrate the response, the resistance of the alumina wafer increases by a factor of about 15 upon exposure to 10 ppm acetone diluted in dry air. Unlike metal oxides films, which commonly require operating temperatures of hundred degrees Celsius, the sensitivity of alumina increases with decreasing temperature with the highest sensitivity being at room temperature. Though, a thermal pretreatment of alumina is necessary to precede the room-temperature sensing of acetone vapors. We presume that the sensitivity of alumina to acetone vapors is owing to metastable compositional changes at the alumina surface induced by annealing in air.

Acknowledgements:

We acknowledge the support by (Slovak) Research and Development Agency (grant number APVV-14-0891), the (Slovak) Grant Agency for Science (VEGA 2/0010/15), and CNR-SAS 2016-2018 grants.


Triphenylmethane-based polyimides with chromic response

Mariana-Dana Damaceanu1 , Ion Sava2

1"Petru Poni" Institute of Macromolecular Chemistry, Polycondensation and Thermostable Polymers Department, Romania
2"Petru Poni" Institute of Macromolecular Chemistry, Polycondensation, Romania

Abstract

Polyimides belonging to the class of high performance polymers are very important for the modern technology’s needs, their development beginning in 1960 primarily to satisfy the necessary of electronic and aerospace industries. In the early years the main goal was to preserve their conventional physical and mechanical properties at high temperatures. Recently, some new features as electronic, photo- and electro-optical that are of interest for developing advanced materials are also required to be maintained at high temperatures. Therefore, a growing interest is manifested for the research of polyimides for use in advanced technologies. Although these polymers show interesting properties, research progress in the area of structural modification for fine tuning the properties for specific applications, e.g. smart materials with chromic response is rather slow. Chromism is a reversible color change in response to a process caused by a stimulus. There are numerous chromic materials, including conducting polymers for which the color variation results from different mechanisms, e.g. electrochromic, thermocrhromic, ionochromic or photochromic materials. Here we report on the development of some aromatic polyimides containing triphenylmethane core with multifunctional properties. Our study surveys the correlation between the structural motif and polymer characteristics, with a special concern on the chromic effect in response to the solvent change.

Acknowledgements:

This work was supported by a grant of Ministry of Research and Innovation, CNCS - UEFISCDI, project PN-III-P4-ID-PCE-2016-0708, contract no. 66/2017 within PNCDI III.


ZnO nanostructure-based DNA sensors

Irena Mihailova1

1Daugavpils University, Institute of Life Sciences and Technologies, Latvia

Abstract

Vjačeslavs Gerbreders1, Marina Krasovska1, Irēna Mihailova1, Andrejs Ogurcovs1, Ēriks Sļedevskis1, Inese Kokina2, Inese Gavarāne2, Ilona Mickeviča2, Edmunds Tamanis1, Andrejs Gerbreders1 1Institute of Life Sciences and Technology, Department of Technology, Daugavpils University, Parādes Street 1, Daugavpils LV-5401, Latvia 2Institute of Life Sciences and Technology, Department of Biotechnology, Daugavpils University, Parādes Street 1A, Daugavpils LV-5401, Latvia In recent years, electrochemical deoxyribonucleic acid (DNA) sensors have emerged as a promising alternative to conventional time-consuming, expensive and laborious DNA diagnostic methods. Many different types of DNA sensors have been developed for the rapid detection of tuberculosis, HIV infection, dengue fever, etc. DNA sensor is an analytical device that determines the presence or absence of specific DNA sequences in the analyte by complementary hybridization to probe DNA immobilized on the working electrode surface. Therefore, one of the most important tasks of sensorics is to design a working electrode that participates in the oxidation-reduction reaction during electrochemical studies. Among various electrode materials such as gold, carbon nanotubes, etc., zinc oxide is one of the most promising candidatea because of its low cost, biocompatiblity and chemical stability in simulated physiological solutions. However, ZnO-based thin films and nanostructures with different structures, morphologies, and sizes can be designed using various methods, thus offering new opportunities of increasing the selectivity and sensitivity of the sensors. We developed a novel, label-free and sensitive ZnO nanostructure-based DNA biosensor that allows electrochemical measurements in small volumes (up to three μl) of the analyte. Circular platforms with the diameter of 3 mm coated ZnO nanostructure arrays with different morphology (thin film, nanorods and nanotubes) were used as the transducer substrates (working electrodes), and 0,3 mm Pt/Ir wire as a counter electrode. The experiment was carried out with Trichinella britovi commercial primers and PCR products of Trichinella britovi and Trichinella spiralis, which are the two most common species of Trichinella in Europe. The processes of the immobilization of short DNA primers onto ZnO nanostructures and DNA hybridization were investigated by differential pulse voltammetry technique. We found that that the sensor’s sensitivity strongly depends on the size and morphology of ZnO nanostructures, while the highest sensitivity was achieved in the case of nanotubes. We also found that ZnO nanotubes-based DNA sensor allows not only to unambiguosly distinguish complementary, non-complementary, or semi-complementary DNA sequences to target primer (Trichinella britovi), but also to distinguish between Trichinella britovi and Trichinella spiralis PCR products. This confirms that biosensor is able to detect the presence of the Trichinella parasite in the sample to the accuracy of the parasite species.

Acknowledgements:

This work is supported by 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”


Advanced sensors material properties test among different working conditions

Ziao Zheng1

1Peking University, School of Software and Microelectronics, China

Abstract

There has been several working conditions that we need to put special emphasis where sensors may encounter with the low performance in several properties. In this essay, two conditions are the testing background for the sensors. First condition for the eletro-magnetic sensor is highly humid condition with the room temperature of 17 degrees(celcius). With the improvements of circuit designing and working voltage, the sensor is able to perform as well as the normal non over-humid condition. Second condition presented some of the working devices in high working load with the system requiring non stop working for two days. The srtategy of power supplying here faces challenge that in the result changes the mode of electrical supplying.


Diamond thin film as functional layer in SGFET and QCM bio-sensors

Vaclav Prochazka1 , Tibor Izak2 , Marian Varga3 , Alexander Kromka4

1Czech Academy of Sciences, Prague , Institute of Physics, Czech Republic
2Czech Academy of Sciences, Prague, Institute of Physics, Czech Republic
3Czech Academy of Sciences, Prague , Instittue of Physics, Czech Republic
4Czech Academy of Sciences, Institute of Physics, Czech Republic

Abstract

Recognition of biological or biochemical events using semiconductor devices has been used in many applications. Amongst commonly used materials, a diamond thin film is considered as a promising material for such devices. In this work, we have involved the diamond thin film as a functional layer to recognize different buffer or cultivation solutions. Firstly, we used the hydrogen-terminated diamond film as an optically transparent and electrically conductive channel in solution-gated field effect transistors (SGFET) [1]. We found that loading of the H-diamond channel with buffer solutions (Phosphate PBS, HEPES, and McIlvaine) at equal pH of 7.4 caused diverse voltage shifts in transfer transistor characteristics. The gate voltage shifts after applied different buffers were approx. 50 mV. Repeated measurements with different solutions confirmed the sensing reversibility of the diamond SGFETs. Only the relative value of the voltage (referred to the voltage measured at the first application of sensor) tended to decrease. Secondly, we employed the oxygen or hydrogen terminated diamond coating for the quartz crystal microbalance piezoelectric mass sensor (i.e. H-QCM or O-QCM) [2]. The highest serial resonant frequency (SRF) shifts of 418 and 643 Hz were observed for FBS proteins adsorbed on both sides of O-QCM and H-QCM, respectively. Adsorbed BSA and FN proteins resulted in lower frequency shifts. For FN proteins, the O-QCMs (hydrophilic surface) revealed higher sensitivity than the H-QCMs (hydrophobic surface) as represented by the SRF shit values of 154 and 50 Hz, respectively. This difference is attributed to possible geometrical re-arrangement of molecules adhered on differently terminated diamond surfaces. The work was supported by Czech Science Foundation grant no. P108/12/G108 and Czech Technical University grant no. SGS17/136/OHK4/2T/13. [1] T. Izak et al., Colloid Surfaces B - Biointerfaces 129 (2015) 95 - 99. [2] M. Varga et al., Physical Status Solidi b 252 (2015) 2591 - 2597.


Design and simulation of the properties of metamaterial compatible with silicon process in terahertz spectrum

Dacheng Zhang1

1Peking University, Institute of Micro-nano 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 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 a terahertz metamaterial structure and the research on the electromagnetic characteristic of the terahertz metamaterial are valuable. In this paper, a unit structure of terahertz metamaterial base on microelectronics technology is designed; the reflectivity and the transmittance in the terahertz frequency band of the metamaterial corresponding to the designed unit are calculated by using the simulation software of electro-magnetic field; the absorbance of the metamaterial is obtained.


Response of the ZnO / Fe2O3 sensors to the breath from individuals with combinations of diabetes and smoking at room temperature

IBRAHIM GAIDAN1

1SIRTE UNIVERSITY, Electrical & Electronics Enginering, Libyan Arab Jamahiriya

Abstract

Various studies have shown that human breath analysis can detect presence of different diseases in patients, such as cancer, diabetes, etc. The gases in breath can be different depending upon the disease that the patient is suffering from. The location of affected organ in human body (e.g. lungs, stomach, pancreas, etc.) can also be identified on the basis of breath gas analysis. This encourages the development of advanced sensors that can detect human breath gases which are present in very low concentrations at low pressures. In this study, two sensors were fabricated using pure Fe2O3 powder and ZnO/Fe2O3 mixed powder. The sensors were screen printed on the top of glass substrates that had gold interdigitated electrodes. The sensors were used to detect the breath of three persons (diabetes/none-smoker, none-diabetes/smoker and none-diabetes/none-smoker). The response of the sensors was increased when exposed to breath compared with response to air. A large difference was observed between the response of the sensors to the none-diabetes person’s breath for the smoker and none-smoker conditions. Similar results were observed between the smoking and none-smoking diabetes person. Initial results show that the sensors developed in this study can be used to analyse human breath and may give an indicator to the presence of several diseases.


CAVITATION ASSISTED GENERATION OF NANOMATERIALS AND NANODISPERSIONS TOWARDS THE DEVELOPMENT OF BIOSENSORS

Sivakumar Manickam1

1The University of Nottingham Malaysia Campus, Department of Chemical and Environmental Engineering, Malaysia

Abstract

Much effort is currently being devoted to the study of nanomaterials mainly due to their wide variety of applications. Particularly, nanoparticles have generated a large research effort because of their properties which differ markedly from those of their bulk counterpart. Many different approaches have been applied to the fabrication of nano-entity, such as co-precipitation, microemulsion, supercritical sol-gel processing, hydrothermal synthesis, or high energy ball milling. Directed to the problems of these conventional methods, new synthetic methods have received increased attention in recent years. Cavitation, an approach for synthesizing a variety of compounds at milder conditions is already the rage in materials engineering. The major advantage of this new method is that it affords a reliable and facile route for the control of both the synthetic process and nanostructure in advanced materials. Also, this process provides chemical homogeneity and reactivity through atomic level mixing within the precursor system, and phase pure crystalline materials can be prepared by annealing at reduced temperatures. Various nanomaterials and nanodispersions have been generated using this technique for the development of biosensors. More importantly, novel carbon materials such as Graphene and Fullerene have been exploited for the functionalization and in the development of nanocomposites to be employed in the sensors.


Soft amorphous ferromagnetic alloys: from basic properties to new applications

Jon Gutierrez1

1Universidad del País Vasco UPV/EHU, Departamento de Electricidad y Electrónica, Spain

Abstract

Soft amorphous ferromagnetic alloys: from basic properties to new applications