Conference submissions

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, Research Center, 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.%.


A study of hydrothermally grown ZnO nanorods based MSM UV detectors on SiO2/Si substrates

Rongbin Ye1

1Iwate University, Faculty of Science and Engineering, Japan

Abstract

This study reports hydrothermally grown ZnO nanorods based MSM (metal-semiconductor-metal) UV detectors with Au metal as the electrodes. The zinc oxide nanorods were deposited on SiO2/Si substrates in two steps, seed layer deposition and growth of nanorods. In the first step, approximately 20 nm thick pure ZnO seed layer was grown on Si, then in the second step, main growth of ZnO nanorods were done above seed layer. The structural and crystalline properties of nanorods were examined using scanning electron microscopy and X-ray diffraction, respectively. For MSM devices, interdigited electrodes (IDEs) were deposited above the ZnO nanorod thin films with a shadow mask using a thermal evaporation system. The IDEs of line width 3 mm and span width 65 μm were fabricated and each electrode has 33 lines. The electrical characterization of the Au/ZnO nanorods/Au based detectors was studied under UV light. The values of contrast-ratio and responsivity were calculated from I–V characteristics of MSM UV detectors. These results are expected to be beneficial to fabricating cheap and practical ultraviolet detection applications.


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.


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, Province Of China
3National Cheng Kung University, Department of Civil Engineering, Taiwan, Province Of China
4Tunghai University, Department of Environmental Science and Engineering, Taiwan, Province Of China

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.