Table of contents

The Third International Conference on Materials Engineering and Applications (ICMEA 2020) was held from 6 to 8 January 2020 in Ho Chi Minh City, Vietnam. The conference provided a wide platform for the participants to communicate with each other and to share their research achievements. The distinguished keynote speakers, on the other hand, created a motivational academic atmosphere through the presentation of their outstanding research outputs.

So, on behalf of the organizing committee, we are pleased to present this volume, containing selected contributions to this conference, of authors based in the industry, research institutes and universities. You will find that a variety of subjects around materials is being covered in these proceedings, including material's science, processing and properties, as well as measuring methods and applications. The selection of papers for this volume, we must recognize, was indeed a challenging endeavor for the about fifty specialized researchers that voluntarily took their time for the reviewing process for this IOP Conference proceedings volume.

While we appreciate the efforts of all the author that submitted papers for this conference as well as the key role of the reviewers, we express our gratitude to all the members of the supporting staff, for their enduring effort to make the conference process a smooth one, and to the proceedings editing team, whose time and talent created the present volume from scratches.

Prof. Frank Otremba

Federal Institute for Material Research and Testing, Germany

List of Conference Co-Chairs, Program Co-Chairs, Technical Program Chair, Publicity Chair, Technical Committees are available in this pdf.

List of First Name, Last Name, Institution, Email Address are available in this pdf.

All papers published in this volume of IOP Conference Series: Materials Science and Engineering have been peer reviewed through processes administered by the proceedings Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

The main objective of the present work is to show the superiority in performance of linear thermoelectric generator (TEG) over the conventional Pi shaped thermoelectric generator. Linear thermoelectric generator with various leg lengths as well as different lengths of p-type and n-type semiconductors are modeled. Power and efficiency of the linear thermoelectric generator with various leg lengths and different lengths of p and n legs are compared at the various hot side temperatures numerically using ANSYS 19.1 commercial software. Numerically predicted power of the linear thermoelectric generator is found within 5% error with corresponding theoretical power values. Results presented that, linear thermoelectric generator with a ratio of p leg length to total leg length equal to 0.56 showed higher power output and higher efficiency for all leg lengths as well as all hot side temperatures. Maximum power and maximum efficiency for linear thermoelectric generator with 0.56 length ratio are found 6% higher than maximum power and maximum efficiency of conventional Pi shaped thermoelectric generator with 0.5 length ratio.

In this work, the impact of wire resistance in pure memristor crossbar array is mathematically analysed and verified by the circuit simulation. The memristor crossbar without CMOS device is utilized for application of character image recognition, in which wire resistance is presented. Memristor crossbar circuit is analysed separately with respect to wire resistance on vertical line and wire resistance on horizontal line. The result shows that wire resistance on vertical line can be eliminated because they can be self-compensated. The simulation result agrees with the analysis. The variation of output voltage caused by wire resistance less affect the recognition rate of memristor circuit. On the other hand, when wire resistance on horizontal line is assumed to be 2.5Ω. The output voltages are varied remarkably. Such variation of output voltage degrades the recognition rate of memristor crossbar circuit. The interesting phenomenon is also investigated. The column that is close to the first column has less variation of output voltage, whereas the one that is far from the first column has much variation of output voltage. The result can be used in improving the memristor crossbar architecture, which can tolerate the impact of wire resistance. For example, if we want to increase the size of crossbar, we should increase the number of rows, rather than the number of columns.

In this work, carbon quantum dots (CDs) was successfully synthesized by hydrothermal treatment using dried leaves as green precursor. Graphitic carbon nitride (g-C₃N₄) was combined with CDs to prepare CDs/g-C₃N₄ composites with three different weight percentage at 0.6, 0.8 and 1.0 wt%, respectively. The morphological structure, optical properties and chemical compositions of CDs and composites were characterized using various spectroscopic techniques. CDs solution portrayed a significant fluorescence property that bright blue-green fluorescence can be observed by naked eye under ultraviolet (UV) light irradiation. The highest fluorescence emission was recorded at 320 nm with the optimal excitation wavelength of 423 nm. Ultraviolet-visible diffuse reflectance spectroscopy (UV-DRS) results displayed red-shifted adsorption spectra of CDs/g-C₃N₄ composites from 500 nm to 800 nm. No upconversion photoluminescence (UCPL) was detected in CDs based on the photoluminescence (PL) study. The loading of CDs on g-C₃N₄ reduced the band gap from 2.7 eV to 2.59 eV.

This research focused on the fabrication and characterization of polycaprolactone (PCL)/nanozeolite(NZ) membrane films. PCL/NZ membrane blends were produced at varying amounts of NZ (0 wt. %, 0.5 wt. % and 1.0 wt. %).The membranes produced were characterized using a.) Scanning Electron Microscopy (SEM) in determining the surface morphologies, b.) UTM to evaluate the effect of NZ addition on the tensile strength of PCL, and c.)contact angle goniometer to investigate the effect of NZ on the wettability of PCL/NZ membrane blends. Upon characterization, the SEM result showed that increasing NZ concentration increased the presence of pores and pore-like structures on the PCL/NZ system. Also, the tensile strength of the PCL/NZ blend improved with the addition of NZ. Lastly, the contact angle measurements obtained showed enhanced membrane hydrophilicity because of the hydrophilic NZ present on the matrix. The incorporation of NZ on PCL generally improved its properties based the different characterizations conducted.

Polyvinylidene fluoride membranes have been broadly applied to scientific research and industrial processes due to its excellent property and applications mainly in water treatment. In this study, the effects of lithium chloride (LiCl) on the porosity, morphology, hydrophilicity and permeability of PVDF-halloysites (PVDF-HNT) nanofiber membranes were investigated. It was observed that the incorporation of LiCl improved the electrospinnability of polymersolution and modifes the morphology of fibers from beaded fiber to a uniform fiber structure. The fabricated membrane was used for the separation of oil-water emulsions via gravitational dead end system, in which the 2% concentration of LiCl as additive, bear out the most amount of volume of water collected. As a result, the fabricated membrane offers a new material for practical applications in oil-water separations.

This research was aimed to examine conditions on synthesis of nanoporous carbon materials from durian peel via the process of hydrothermal carbonization (HTC) as an application for delaying durian ripening process. The experiment was conducted by using durian peel as materials for producing nanoporous carbon via the process of hydrothermal at 160-200 °C for 8-24 hours. It also included the process of carbonization at 500-900 °C for 2 hours under nitrogen atmosphere for developing pore structure and removing contaminants to obtain the nanoporous carbon. The properties of nanoporous carbon were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR) and Raman spectrometer analysis. The results indicated that the process of hydrothermal at 200 °C for 12 hours and carbonization at 900 °C for 2 hours was suitable for delaying ripe durian. This is become of the carbon content, porous structure and amorphous structure increased with HTC temperature.

Nanoporous carbon materials have been successfully synthesized from water hyacinth via hydrothermal carbonization (HTC). This research was studied the effect of hydrothermal temperature from 160 - 200 °C and reaction time for 4 - 24 h. Afterwards, carbonization was carried out at the temperature of 600 - 900 °C for 2 h in N₂ atmosphere for developing porosity and even removing contaminants of hydrothermal char to obtain the porous carbon. The physico-chemical properties of nanoporous carbon materials were comprehensively characterized through Scanning electron microscope (SEM), Fourier transforms infrared spectroscopy (FT-IR), CHN elemental analysis, X-ray diffraction (XRD) and BET analysis. The adsorption capacity and carbon content of nanoporous carbon materials from water hyacinth were increased with increased hydrothermal carbonization temperature and time. Performing HTC at 200 °C for 12 h. Is the optimum condition to synthesis of precursor materials for good adsorbent.

N-doped porous carbon materials were produced from palm male flower using hydrothermal carbonization processes at 200 °C for 24 h followed by N-Doping and carbonization at 700°C for 2 h. N-doping was carried out by impregnation using NH₄OH at 0.5, 1.0, 1.5 M and 2 M. Products were characterized by means of chemical composition and morphology using SEM, XPS, and XRD to characterize specific properties such as physical morpholog, porosity, elemental composition on surface and crystalline structure of PMF. After applying hydrothermal carbonization processes, the results showed substantially increased porosity and surface area with suitable microstructure for N-doped electrodes applications. The highest porosity was obtained at NPC–1.5 M.

α-Pinene is a bicyclic compound that is commonly sequestered from coniferous plants like pine trees. Several properties of pinene have been investigated, such as its isomerization capabilities and biological activity. However, the viability of pure pinene as an organic thin film has not yet been explored. In this work, we report the synthesis of an α-pinene-based organic thin film deposited on Al and glass substrates via plasma polymerization and its subsequent surface characterization. It was determined that the film generally became more hydrophobic as the α-pinene loading and the deposition time increased. More importantly, it was shown that specifying a pinene-Ar ratio of 50:50 yielded the highest contact angles at 94.22° and 110.38° for deposition times of 6.0 and 9.0 minutes, respectively. These results signify that a pinene-based organic thin film has been produced through the plasma polymerization synthesis route.

It is well known that the blast affected the explosion and terrorism, not only human life, but also the building structure. In order to prevent these, protective materials are developed. One of them is polyurea. In this work, the elemental composition and microstructure of the selected polyurea sheet samples are characterized. Thermal, dynamic mechanical, tensile, and hardness properties are also studied. It is found that carbon and oxygen are the main compositions, while silicon, fluorine, and titanium are presented as minor ones. The modulus and loss factor increase as the frequency and temperature increase. The elongation property is over 100% and the hardness is around 90 Shore A.

In this research, an automated experimental setup to fabricate high aspect ratio copper micro rods using localized electrodeposition was assembled. Using a custom-made microelectrode, copper micro columns were successfully fabricated on copper substrates from an additive-free electrolyte. To expand the capabilities of localized electrochemical deposition as a potential microfabrication technique, the effect of organic additives including Janus Green B (JGB), Polyethylene Glycol (PEG), 3-mercapto-1-propane sulfonic acid (MPSA) on the uniformity of the fabricated structures was studied. Scanning electron microscopy characterization revealed that organic additives play an important role in achieving a uniform and rigid micro rod across its height. An electrolyte containing all three additives (PEG, JGB, MPSA) appears to produce a micro rod with better structural characteristics compared with the case when only two additives are present (PEG, JGB). From this research, designing an electrolyte with proper chemistry appears to be critical to realize optimized fabrication of micro scale features by localized electrodeposition. It could also contribute to presenting the technique as a competitive and reliable micro fabrication alternative to other complex and high-cost technologies.

Laser metal deposition is of two types: powder bed and metal deposition. Either method is expected to be a breakthrough in innovative design and manufacturing technology development because both methods can form shapes that cannot be formed by conventional removal processing. One metal deposition method is directed energy deposition (DED), in which a laser irradiates the target position on the metal layer to melt it, and metal powder is supplied to the target position to perform molding. DED is expected to produce large parts and repair molds. However, as the lamination mechanism is not sufficiently clarified, relationships between process parameters, material properties, molding accuracy, and molding efficiency are not clear, making stable molding difficult [1]One obstacle to stable molding is that the distance between the head nozzle that supplies the metal powder and the molten pool cannot currently be kept constant. In this study, we measure the distance between the head nozzle and the molten pool using a triangulation method, propose a method to control the position of the head nozzle to keep the distance constant, and experimentally verify the method's usefulness.

This work examined the thermal performance of evaporative cooling of water by an air stream in an equipment wherein the liquid phase is sprayed between two coaxial disks. The contact between the two phases was in a cross-current mode. The performance of the spray bed in terms of thermal efficiency and evaporation rate of liquid were calculated by varying operational parameters like air flow rate, water flow rate, and rotational speed. Both the thermal efficiency (minimum = 0.183, maximum = 0.34) and evaporation rate (minimum = 0.009 kg/min, maximum = 0.032 kg/min) increased with rotational speed and air flow rate. However, the thermal efficiency decreased with liquid flow rate.

The goal of this study was applied on the pulsed light of physical method, to promote the polysaccharide containment of mushroom base of Yellow Flammulina velutipes (Jinhua mushroom). Jinhua mushroom is a specific edible and medicinal mushroom in Taiwan that contains a variety of nutrients and bioactive components such as vitamin, carbohydrate, dietary fiber, protein, ergosterol, amino acid and umami constituents acknowledged to be beneficial for human health. Jinhua mushroom, whose appearance is also similar to white Flammulina velutipes but the functional ingredients are more than it. The polysaccharide of Jinhua mushroom base, which was irradiated the 0–80 pulses of pulsed light. Interestingly, the polysaccharide molecular weight was in the range of 3.56 to 4.30 x 10⁶ Da of base with pulsed light (0–80 pulses), along with increasing pulsed light irradiated pulses, the polysaccharides' viscosity (cPs) was increased. Meanwhile, we determined the moisture adsorption ability and thermal decomposition of the Jinhua mushroom base's polysaccharide, which could be applied to a design during cosmetic materials and biomedicals. Overall, this study is a complete, forward-looking and innovative research project in agricultural waste recycling.

Corrosion fatigue is well known to lower the lifetime expectancy of high alloyed steels. Duplex stainless steel X2CrNiMoN22-5-3 is a promising candidate to withstand both, corrosion and mechanical stress. Therefore, the corrosion fatigue (CF) was investigated in the Northern German Basin electrolyte at 369 K using a specifically designed corrosion chamber. CF damage was clearly related to lateral grain attack within corrosion pit cavities located perpendicular to the load applied. Additionally, multiple fatigue cracks and preferable deterioration of austenitic phase and intact ferritic phase. A delta-like micro crack structure and a curved path characterizes crack termination with little to no base metal deterioration. Crack initiation may be due to early pit formation resulting in depassivation but also due to local depassivation then resulting in pit formation–both initiation mechanisms lead to crack propagation and early failure.

In this study the effect of texture on the wear behavior was investigated in extruded rod of pure zinc. Different loads and temperatures were used to investigate the effect of texture on wear behavior. Formation of chips at higher temperature marked the transition of wear mechanism from micro-ploughing to micro-cutting. Suppression of twinning at high temperature was also observed suggesting a complete slip dominated deformation at high temperature. The effect of texture was evident at high temperature and high loads.

Boron is an alloying element used for increasing the strength of steels, but on the other hand, it sometimes deteriorates heat affected zone (HAZ) weldability and toughness. Although it is widely known that the hardenability of steel is improved due to grain boundary segregation of boron, its details and quantification have not yet been clarified. In this study, boron-free HT590 and boron-added HT780 steels were welded and microstructure and hardness distribution in HAZ were measured, in detail. Furthermore, we calculated and investigated the grain boundary segregation and diffusion of boron during weld thermal cycle by numerical analysis while comparing it with the experiment result. As a result, the present model made it clear that the effect of boron on HAZ hardenability can be expressed by non-equilibrium segregated boron at grain boundary, quantitatively.

Segment thickness is one of the important parameters of shield tunnel structure design. Segment thickness determines the section stiffness and mechanical performance of shield tunnel structure. Considering the load type of overload and unload, a three-dimensional fine shield tunnel numerical model was established. The full-scale test was used to verify the correctness of the numerical model. In the end, the effect of segment thickness on the internal force of shield tunnel structure under abnormal loading conditions was analyzed. The results show that the internal force of each section of the tunnel structure increases with the increase of the thickness of the segment, and the difference of the internal force between the different segment thickness increases with the increase of the overload and the degree of unloading. Increasing the thickness of segment will delay the breakpoint of the bending moment and axial force (critical instability state). The excessive increase of the segment thickness can lead to a large increase in the internal force of the tunnel structure, resulting in a decrease in the crack resistance of the tunnel structure.