Friedrich Schiller University in Jena, Germany, Germany
Edla Maria Bezerra Lima
Brazilian Agricultural Research Corporation, Embrapa Food Technolology Unit, Brazil
Henrique José da Silva
UNIFRAN - University of Franca, Brazil
University of Arkansas for Medical Sciences (UAMS), Little Rock, Arkansas, USA, Nepal
Marcelo Machado Viana
Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
University of Nebraska-Lincoln, United States
Center for Physical Sciences and Technology, Lithuania
Zhou Bing Chen
The Hong Kong Polytechnic University, China
Israel Institute of Technology, Israel
Dr. Madhumita Mukhopadhyay
Amity University, India
Ana Paula Domínguez Rubio
University of Buenos Aires, Argentina
National Institute for Materials Science, Japan
Katholieke Universiteit Leuven, Belgium
The University of Hong Kong, China
Marcello Rubens Barsi Andreeta
Federal University of São Carlos, Brazil
Institute Polytechnqiue Paris, France
California State University of Northridge, United States
Maharashtra Institute of Technlogy, India
University of Lodz, Poland
Shanghai JiaoTong University, China
Asla Abdullah Al-Zahrani
Imam Abdulrahman Bin Faisal University, Saudi Arabia
The Hong Kong Polytechnic University, Hong Kong
Sivakumar Dhar Malingam
Universiti Teknikal Malaysia Melaka, Malaysia
Bannari Amman Institute of Technology, Sathyamangalam, Tamil Nadu, India
Ronald R. Willey
Willey Optical, Consultants, Charlevoix, MI, USA
Jadavpur University, India
Tarbiat Modares University, Tehran, Iran
Pao Ter Teo
Universiti Malaysia Kelantan (UMK), Malaysia
Zhongyuan University of Technology, China
Youngsan University, South Korea
Budapest University of Technology and Economics, Hungary
University of Bordeaux, France
Vivek Singh Yadav
Indian Institute of Technology Guwahati, India
Tokyo University of Science, Japan
University of Salento, Italy
Fadi Ibrahim Ahmed
Kuwait University, Kuwait
University of Mississippi, USA
University of Reims Champagne Ardenne, France
Ana M.O. Azevedo University of Porto, Portugal
Protein discrimination using erythrosin B-based GUMBOS
In the past years, sensors have attracted increased attention as a facile and cost-effective approach for protein detection and discrimination. Different scaffolds have been employed for construction of sensors, including polymers, substituted porphyrins, and oligopeptide-functionalized resins 1. GUMBOS (Group of Uniform Materials Based on Organic Salts) have emerged as a promising class of materials for accurate identification of protein analytes. These compounds share similar features to those of ionic liquids, but have wide applicability potential due to their melting point range (25-250 ºC) 2. In this context, the usefulness of four novel erythrosin B (EB)-based GUMBOS as recognition elements for proteins with distinct molecular weights and isoelectric points was assessed. GUMBOS were synthesized using a simple metathesis reaction between the anionic dye (EB) and several phosphonium and ammonium cations. The effect of pH and incubation time on the discriminatory power was studied, being the assays performed in aqueous media at pH 3.0, 4.5, and 6.0 for 5, 10, and 15 minutes. Upon exposure to proteins, each sensor generated distinct absorbance response patterns that were analyzed using partial least squares discriminant analysis (PLSDA). The proposed sensing approach offers an interesting alternative to conventional analytical methods since it is simple (label-free) and rapid (only five minutes of equilibration time are required). Moreover, at pH = 6.0, EB-based GUMBOS allowed discrimination of five serum and non-serum proteins with 100% accuracy. The ability of GUMBOS to detect and discriminate between four distinct protein mixtures containing albumin and myoglobin was also studied. These binary mixtures were distinguished from each other with nearly 90% accuracy.
Jagadish Chandra Mahato Assistant Professor of Physics Dep., India
Self-organized endotaxial cobalt disilicides nanowires on Si(110) surfaces: Fabrication and aspect ratio tunning of the nanowires
Self-organized growth of well-ordered endotaxial silicide nanowires (NWs) on clean Si(110) surfaces has been investigated by in-situ scanning tunneling microscopy (STM) and transmission electron microscopy (TEM). Co deposition on clean Si(110) reconstructed surfaces at ~ 600°C produces unidirectional CoSi2 NWs by reaction of cobalt with the hot silicon substrate. STM investigations reveal four types of distinct NWs, all growing along [1-10] in-plane direction except one type growing along in-plane  direction. There are also some nanodots. The cross-sectional TEM measurements show that the unidirectional NWs are of two types, namely flat-top and ridged. The NWs grow not only on the substrate but also into the substrate. CoSi2 in flat top NWs are in the same crystallographic orientation as the substrate Si and the buried interfaces between CoSi2 and Si are A-type. In the ridged NWs CoSi2 and Si are in different crystallographic orientations and the interfaces are B-type. The ridged NWs are in general wider and grow deeper into the substrate.1
The influence of post deposition annealing on the aspect ratio of these self-organized cobalt silicide nanowireson clean Si(110) surfaces has also been investigated by in situ scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) as well as by scanning electron microscopy (SEM). Half a monolayer of cobalt was deposited on the Si(110) surfaces at ∼600°C substrate temperature. Following cobalt deposition, the substrates have been annealed for different durations. Cobalt forms aligned cobalt disilicide nanowires upon reaction with the silicon substrate, following the twofold substrate symmetry. With increasing duration of annealing, the NWs have been found to grow with larger aspect ratio (length/width), eventually producing narrower NWs. These self-organized unidirectional NWs of sub-hundred nanometer width and ∼4–7 nm height produce a Schottky barrier with the silicon substrate and are expected to find applications in nano electronic devices.
Prof. Anatoliy Zavdoveev National Academy of Sciences of Ukraine, Ukraine
The effect of technological operations temperature on the mechanical properties and structure of high-strength steels grade S460M and S355J2
The use of high-strength steels with a yield strength in the range 350-460 MPa allows reducing the metal consumption of structures made for various purposes. These steels are used in bridge construction and other constructions in general, in the manufacture of oil & gas offshore platforms, supports of wind generators, ships, high pressure vessels, as well as in the manufacture of steel rail freight. Considering that the new generation of steels is obtained due to the integrated use of both microalloying and thermo-mechanical control process (TMCP), the properties obtained can be lost as a result of softening during the thermal treatment of steel. The purpose of the present work is to study the effect of high-temperature isothermal heating on the mechanical properties and structure of rolled sheets and simulated heat affected zone metal of micro-alloyed S355J2 and S460M steels obtained using normalization and thermomechanical treatment, respectively. It is shown that at a temperature T≤630 C, characteristic for treatment associated with the welding stress relieving, the mechanical properties of the investigated steels are stable within the limits of error. S460M steel, obtained by TMCP, can be used in the manufacture of welded steel structures that do not require hot straightening and stamping operations. Heating is allowed not higher than Ac1 (714 С), for relieving welding stresses. Steel S355J2 obtained through normalizing may be used in the manufacture of welded steel involving the operation of a temperature of up to 950 C.
Falk Eilenberger Friedrich Schiller University in Jena, Germany, Germany
Scalable Functionalization of Exposed-Core Fibers with CVD-Grown Monolayer Transition Metal Dichalcogenides
Monolayer transition-metal dichalcogenides  (TMDs) are a new and highly interesting material for optics and photonics due to their rich photophysics, their strong interaction with light, and large optical nonlinearities . However, their application is limited by the sub-nanometer interaction length, imposed by their atomic thickness; the enhancement of which is essential for future applications.
Recently, we have demonstrated a novel type of scalable functionalization technique for exposed-cored optical fibers (ECF) , where MoS2 and WS2 crystals are directly grown on the fiber’s core, based on a one-pot chemical vapour deposition CVD-growth process. We show that by adjusting the growing condition, the density of TMDs monolayers can be tuned.
The TMDs interact with the guided light by the evanescent field of the ECF’s guided mode, leading to the exciton formation, photoluminescence (PL) emission, and enhanced nonlinear interaction. The incident light was launched into one facet of the fiber and the PL or nonlinearity generated light was collected from the other face. It exhibits exciton peaks at 678 nm and 622 nm for MoS2 and WS2, as well as enhanced third harmonic generation. Other forms of enhanced nonlinear effects will be discussed in the presentation, as well. We expect that our work may lead to tunable light sources and fiber-based sensors.
Edla Maria Bezerra Lima Brazilian Agricultural Research Corporation, Embrapa Food Technolology Unit, Brazil
Influence of the microstructure on the resistance of PLA biocomposites to food packaging using eco–friendly materials such as mango seed and organo montmorillonite minerals
Biocomposites based on PLA (matrix), organoclays and mango seed as loaded material has been developed by Casting in the present research group since 2015. The ongoing research modified the integument and the kernel of the mango seed by grinding it in a ball mill, reducing the particle size of the mango kernel six times (6X) compared to the original experiment, and fifty times (50x) the mango integument. This process eliminated the effect of elongated shape that the fibers present, increasing the specific surface in contact with the PLA. The samples were characterized in terms of physical-chemical properties (Laser Particle Size, SEM, XRD, Texturometer, FTIR), thermal properties and biodegradability. The SEM results showed that the chloroform output during drying process created bubbles/channels in the biopolymer matrix, which facilitated the access to fluids; weakened the material; and helped the process of biodegradability and decreased mechanical resistance to compression of biocomposites: PLA/integument, PLA/kernel, and PLA/integument/kernel, respectively in 79%, 86% and 84%. In addition, the biodegradability in water and soil was accentuated for the PLA/kernel biocomposite (since 1 week), followed by PLA/integument/kernel biocomposites (5 weeks) and PLA/integument (14 weeks) in a 19-week experiment. These experiments demonstrated that both, the increase in the specific load/matrix contact surface and the creation of bubbles/channels by purging gases during the Casting process, are efficient in accelerating the degradation of these biocomposites in nature and making them highly mechanically fragile. The addition of Bofe and Chocolate organoclay’s accelerated the degradation process of PLA, likely due to the presence of the hydroxyl groups belonging to the silicate layers surface and/or to their organic modifier. The biodegradation of PLA/kernel/integument/Bofe organoclay in water was higher than it was in soil. Furthermore, the materials added to the PLA matrix increased the crystallinity degree and the resistance of the obtained biocomposites.
Henrique José da Silva UNIFRAN - University of Franca, Brazil
Efficiency improvement of photovoltaic cells by coating the protection glass with a silica matrix co-doped with Er3+/Yb3+
This work concerns the power efficiency improvement of polycrystalline silicon photovoltaic cells, by
coating the glass which protects the cells, using thin films. The films were obtained by the Sol-Gel
process, with a silica matrix co-doped with Er3+/Yb3+ lanthanide ions, that promotes upconversion
from infrared to visible light. In this work the films coat the glass instead the cells, like was done in
previous studies1, because the films were treated at 300°C and it is easier to work with the coated
glass. The voltage, current and electrical power were analysed, for seven different samples: only the
photovoltaic cell; the cell protected with a 4 mm common cleaned glass; the cell with a similar glass
coated by one and two layers of thin film, submitted at 200ºC and 300ºC and with two different codoped
concentrations of Er3+/Yb3+. The commercial squared cells with dimensions 156 X 156 mm and
glasses as same dimensions were used. Firstly, the coated glass was submitted to excitation at 980 nm
at 300, 720 and 1090 mW laser power. Typical Er3+ emission bands emerged in the green region (2H11/2
to 4I15/2 and 4S3/2 to 4I15/2) and red regions (4F9/2 to 4I15/2). These results is an indication that the films
are present covering the glass substrate, and the upconversion occurs. After that, the glasses were
placed over the photovoltaic cell and exposed directly to the sun light. Experimental results showed
the efficiency improvement when the glass is coated with the thin film. This improvement is higher
with two layers and with a thermal treatment of 300°C. In conclusion, the photovoltaic cells efficiency
is low due to several factors such as, temperature and non-use of infrared radiation; the solution can
be the use of thin films with system to convert the infrared radiation in visible light.
Bikram Gautam University of Arkansas for Medical Sciences (UAMS), Little Rock, Arkansas, USA, Nepal
Assessment of Bacterial Load in Polyethylene Terephthalate (PET) Bottled Water
Reuse of polyethylene terephthalate (PET) bottles have been done to conserve nature, but due to increasing microbial load in the same reused bottle has been cause of many morbidity across the globe. The aim of this study is to determine any associations between bacterial load and the physical condition of the water bottle.
For this study, parameters like pH, electrical conductivity (EC), total dissolved solids (TDS), heterotrophic plate count (HPC), total coliform count, and Pseudomonas spp were assessed as per the American Public Health Association, 2005. For the extent of polymer degradation the base of the same PET bottle was subjected to FTIR analysis.
The pH value of water samples tested ranged from 5.2 to 6.8. The majority of samples (96%) were found to contain pH values that were unacceptable as per the Department of Food Technology and Quality Control (DFTQC) guideline. Value of electrical conductivity (EC) ranged from 5 to 199 μS/cm. HPC revealed that, out of 100 samples, 48 (48%) samples were found to be acceptable as per the DFTQC guideline value (<25 cfu/mL). Among 100 samples, Pseudomonas spp. was found to be present in 23% of bottled water. Acidic pH and elevated concentrations of TDS and EC may lead to the survival of extremophiles present in HPC which may lead to degradation of PET. FTIR analysis shows that the degradation is under process but has not occurred yet.
Microorganisms survive in bottled water as they have many nutrients required for the microorganism in ionic form. The bacteria that survive in bottled water for a long time rely on several survival mechanisms including evolutionary development (evo-devo) and can solely survive on complex polymers like PET.
Marcelo Machado Viana Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
Polydimethylsiloxanes-modified TiO 2 coatings: The role of structural, morphological and optical characteristics in a self-cleaning surface
The surface modification of TiO 2 thin films with hydrophobic agents has been a good strategy
to modulate the surface energy of this material, allowing it to be compatible with a wider
range of applications . This is a promising approach in the search for self-cleaning
properties, since it is expected that the modified films will exhibit photocatalytic and
superhydrophobic properties. In this work, the synthesis and characterization of TiO 2 thin
films modified with two different types of polydimethylsiloxane (PDMS): hydroxy (AHH)
and vinyl-terminated (AHV) were carried out. PDMS modification of TiO 2 thin films
occurred on two different routes. Route 1 was obtained from the deposition and subsequent
thermal treatment of neat TiO 2 thin films (anatase phase), followed by a surface
functionalization with a solution of PDMS in toluene. Route 2 is based on the preparation and
deposition of a sol-gel solution containing both TiO 2 and PDMS precursors. The thin films
prepared were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM),
X-ray photoelectron spectroscopy (XPS), diffuse reflectance and wettability tests. Vinylic
coatings showed a hydrophobic behavior, while hydroxy coatings proved to be hydrophilics.
PDMS-modification occurred by a covalent functionalization with the formation of Ti–O–Si
bonds to the AHH and Ti–O–C bonds to AHV hydrophobic agent. The wettability test
evidenced significant differences in the contact angle between a water drop and the sample
surfaces and, in the roughness, as evidenced by AFM. This study contributed to a better
understanding of a heterogeneous functionalization of TiO 2 thin films using a non-fluorinated
polymer as a hydrophobic agent and using a faster and environmentally friendlier procedure
for improved the self-cleaning coatings design.
Robert Streubel University of Nebraska-Lincoln, United States
Chiral Spin Textures in Amorphous Iron–Germanium Thick Films
Single-crystals and multilayer heterostructures with global inversion symmetry breaking can promote the formation of topological solitary vector fields owing to a vector spin exchange known as the Dzyaloshinskii-Moriya interaction (DMI). - And so can short-range order. - In this talk, I will present experimental evidence of 3D chiral spin textures, i.e., helical spins and skyrmions with different chirality and topological charge, stabilized in amorphous Fe–Ge thick films. Harnessing Lorentz microscopy with exit wave reconstruction, we observe both isotropic Bloch skyrmions (N = 1), previously found in B20 single-crystals, and anisotropic solitons, i.e., antiskyrmions (N = −1) and N = 2 skyrmions. X-ray magnetic circular dichroism (XMCD) spectroscopy suggests a short-range order similar to B20 FeGe single-crystals despite lacking a global broken chiral symmetry. Our results demonstrate that structurally and chemically disordered materials with a random DMI can resemble inversion symmetry broken systems with similar magnetic properties, moments, and states. Yet, disordered systems are distinct by their degenerate spin chirality that allows for forming isotropic and anisotropic topological spin textures at remanence while offering greater flexibility in materials synthesis, voltage and strain manipulation, and an enhanced spin-orbit coupling relevant to prospective microelectronics applications.
Steponas Ašmontas Center for Physical Sciences and Technology, Lithuania
Impact of cesium concentration on optoelectronic properties of metal halide perovskites
Metal halide perovskites attract considerable attention due to their superior properties having potential applications in optoelectronic devices such as solar cells, photodetectors, light emitting diodes. In solar cells, metal halide perovskites are atractive for their high absorption coefficient allowing to use a thin film, high defect tolerance, high carrier mobility, and long carrier diffusion length. Excellent band gap tunability allows using perovskite layer as a top sub-cell on any bottom cell. Currently, the best solar cells use a mixture of formamidinium (FA) and methylammonium (MA) as the monovalent cations. Addition of cesium makes the triple cation perovskite compositions more thermally stable as they have less phase impurities and are less sensitive to processing conditions.
The triple cation perovskite layers were formed by a one-step deposition method from the produced precursor solution. Anhydrous N,N-dimethylformamide/dimethylsulfoxide (DMF / DMSO), 4:1 by volume, was used as a solvent. Material concentrations of the prepared solution were: 1 M of formamidinium iodide FAI, 1.1-1.3 M of PbI2, 0.2 M of methylammonium bromide MABr, 0.2 M of PbBr. Then CsI solution (1.5 M of CsI in DMSO) was added to the prepared precursor, and CsI concentration was varied from 0 to 50%. The prepared precursor solution was used to form a perovskite compound Csx(MA0.17FA0.83)(100-x)Pb (I0.83Br0.17)3. The layers were deposited by means of programmable centrifuge. FTO glass covered with thin TiO2 film was used as a substrate. The perovskite layers were annealed for 60 min in an inert atmosphere at 100°C temperature.
In this communication, we present experimental study of optical properties of perovskite layers with different cesium concentration as well as photoelectric properties of solar cells fabricated on their base.
Zhou Bing Chen The Hong Kong Polytechnic University, China
Mechanisms for suppressing discontinuous precipitation and improving mechanical properties of NiAl-strengthened steels through nanoscale Cu partitioning
High-strength low-carbon steels are of considerable technological importance in engineering applications such as automotive, shipbuilding, and energy industries. Precipitation strengthening is an effective method for strengthening low-carbon steels. Among various potential precipitates used for precipitation strengthening, NiAl is one of the most effective phases to achieve high strength, and the precipitation of which occurs either continuously or discontinuously. Control of discontinuous and continuous precipitation is crucial for tailoring the microstructure and mechanical properties of NiAl-strengthened steels. In this talk, we will report that Cu is effective in not only promoting the nano-scale continuous NiAl precipitation but also in suppressing the coarse-scale discontinuous NiAl precipitation at grain boundaries, which results in the development of new NiAl-strengthened steels with high yield strength (1400 MPa) and good ductility (10%). Our analyses indicate that the mechanisms for suppressing discontinuous NiAl precipitation are twofold. The main one is the acceleration of continuous NiAl precipitation through Cu partitioning, which swiftly reduces the matrix supersaturation, thereby decreasing the driving force for the growth of discontinuous precipitation. The other is the reduction of grain boundary energy through Cu segregation, which is likely to decrease the nucleation rate of discontinuous precipitation. Consequently, Cu increases the number density of NiAl nanoparticles by more than fivefold, which leads to a twofold enhancement in the strengthening and an improvement in the over-aging resistance of NiAl-strengthened steels.
Yizhaq Engelberg Israel Institute of Technology, Israel
Functional helical fibrils of the human antimicrobial peptide LL37(17-29) present novel architecture and thermal stability
Antimicrobial peptides (AMPs) are canonical part of the innate immune system of many organisms in all kingdoms of life. Interestingly, certain AMPs assemble into well-ordered fibrils that resemble amyloids, which are proteins associated with neurodegenerative and systemic diseases and which bear unique material properties. LL-37 is an AMP which is expressed by various mammalian cells and is considered to play an important role in the first line of defense against pathogens. hLL-37 is cleaved in-vivo into many active derivatives which show a diverse array of selectivity against microbial strains, and additional functions within the immune system. The hLL-3717-29 13-residue derivative was suggested to serve as the active core of hLL-37. Using X-ray micro-crystallography and electron microscopy techniques, we revealed the supra-helical, fibril structure of hLL-3717-29, and correlated between its self-assembly and antibiotic activity. We also determined the high stability of the fibril’s upon heating, and based on these findings, we are working towards the design novel fibril-forming AMPs with improved shelf life and stability. In addition, we are developing an approach to allow the control over their activity and selectivity upon demand.
Dr. Madhumita Mukhopadhyay Amity University, India
Interaction of Macrocyclic Zn (II) Schiff Base cationic Surfactant: A Study using Photometric and Theoretical Approach
A 48 membered macrocyclic tetranuclear Zn (II) complex is reported to be a complex dual anion sensor for fluoride and acetate in aqueous methanolic solution by change in absorption as well as by fluorescence enhancement. In this context, study on the interaction of such Schiff base viz. tetranuclear complex cation [Zn4(LH3)(NO3)5]2+ with a bio-mimicking surfactant is an interesting approach for pursuing detailed study on medicinal industry owing to their antibacterial, antifungal, antiviral activities. A widely used bio mimicking membrane like cetyl trimethyl ammonium bromide (CTAB) is undertaken by the present researchers to study the respective interactions with the functional Zn (II) complex. Steady state absorption and emission studies have been pursued to investigate the course of deciphering the photophysical behaviour of the complex. The extent and mode of binding of the Schiff base with CTAB is analysed using the binding constant magnitude. The extent of interaction among the experimental complex and the biomimicking surfactant is also studied using frontier molecular approach upon engaging ab initio quantum calculations. Hence, analysing the mode of interaction with CTAB, further study is designed for such Schiff base with a suitable bio protein for necessary application in future.
Ana Paula Domínguez Rubio University of Buenos Aires, Argentina
Bacillus subtilis extracellular vesicles can be transported through an in vitro intestinal epithelial cell model
Bacterial Extracellular Vesicles (EVs) have been related to inter-kingdom communication between probiotic/pathogenic bacteria and their hosts. The gastrointestinal tract (GIT) mucosal surface is the primary interface between gut bacteria and internal host tissues. A vital communication between kingdoms in the mammalian GIT is supposed to occur through an exchange of EVs that may interact in a triangular way between gut bacteria and the host. Our aim was to investigate the transcytosis process of B. subtilis EVs using an in vitro intestinal epithelial cell model. In this study, using Confocal Laser Scanning Microscopy, we report that uptake and internalization of CFSE-labeled B. subtilis EVs (115 nm ± 27 nm) by Caco-2 cells are time-dependent. To study the transcytosis process we used a transwell system and EVs were quantified in the lower chamber by Fluorescence and Nanoparticle Tracking Analysis measurements. Intact EVs are transported across a polarized cell monolayer at 60–120 min and increased after 240 min with an estimated average uptake efficiency of 30% and this process is dose-dependent. EVs movement into intestinal epithelial cells was mainly through Z axis and scarcely on X and Y axis. This work demonstrates that bacterial EVs could be transported across the gastrointestinal epithelium. Our findings suggest that this mechanism could be the first step allowing EVs to reach the bloodstream for further delivery up to extraintestinal tissues and organs. The expression and further encapsulation of bioactive molecules into these natural nanoparticles produced by probiotic bacteria EVs of GRAS (Generally Recognized as Safe) bacteria could have practical implications in food, nutraceuticals and clinical therapies.
Liwen Sang National Institute for Materials Science, Japan
Photoelectricity energy conversion devices based on III-V Nitride semiconductors
III-Nitride semiconductor InxGa1-xN has the unique advantage of the widest adjustament
of direct bandgaps from infrared (InN at 0.65 eV) to ultraviolet (UV) (GaN at 3.42 eV) region.
Compared with Si, GaAs, CuInGaSe or Ge systems, it is the only semiconductor system that
can provide the perfect match to the solar spectrum. On the other hand, InGaN-based alloys
also have the favorable physical properties of high absorption coefficient (~105cm-1), high
radiation resistance, high drift velocity, and high carrier mobility. These properties provide
them the promising candidate in the photoelectricity energy conversion devices, not only LED
or LDs, but also the high-performance photodiodes, and solar cells.
In this paper, we will report our work on the photoelectricity devices based on III-Nitride
InGaN film. The word-record visible-blind photodiodes were achieved by using InGaN with
CaF2 as the insulation layer. For the InGaN solar cells, we firstly propose the concept of
intermediate-band transitions based on Nitride, and successfully extend the photoresponse
spectrum from deep UV the near infrared region.
Tailoring diffusive pathways and thermal expansion in Ti-alloys
Ti-alloys are key materials in aerospace and biomedical engineering. Central for the optimization of their mechanical and functional behavior is in-depth knowledge on the complex interplay between diffusive and displacive phase transformations. Recently, 2 intriguing discoveries in relation to orthorhombic α″ phases in β-stabilized Ti-alloys were made: (i) the diffusion-controlled formation of α″iso , α″lean and α″rich phases and ii) the giant and highly anisotropic thermal expansion of martensitic α″. Insight into both phenomena is limited, however needed for the tailoring of (micro)structures across a wide spectrum of configurations.
To address this challenge, I will demonstrate that the thermodynamic energy landscape reveals formation pathways for the diffusional forms of α″ and may lead to a stable β-phase miscibility gap in the binary Ti-Nb alloys. In this way, temperature-composition criteria for the occurrence of α″iso and resolve reaction sequences during thermal cycling are derived. Further, I will revisit the giant (linear) thermal expansion in Ti-Nb alloys and will discuss processing routes to obtain null linear expansion in Ti-alloys. The presented concepts are expected to be transferable to other Ti-alloys and to catalyze new avenues for their tailoring and technological exploitation.
Mao Mao The University of Hong Kong, China
Stable, High-Efficiency Voltage-Dependent Color-Tunable Organic Light-Emitting Diodes with a Single Tetradentate Platinum(II) Emitter Having Long Operational Lifetime
Voltage-dependent, color-tunable organic light-emitting diodes (OLEDs) are appealing tools that can be used for the visualization of electronic output signal of sensors. Nonetheless, the literature reported color-tunable OLEDs that have a simple single-cell device structure suffer from relatively low efficiency, pronounced efficiency roll-off, color-aging, and short operation lifetime, all of which limit practical applications. Here we describe a novel co-host-in-double-emissive-layer (CHIDEL) device, designed to enhance the performance of color-tunable OLEDs with the use of a single tetradentate Pt[O^N^C^N] emitter. When Pt-X-2 was used as a single emitter in an optimized CHIDEL device, a white OLED with CIE tunable coordinates from (0.47, 0.44) at 3 V to (0.36, 0.48) at 11 V, a high color rendering index of 82, and high EQEs of up to 20.75% could be achieved. By using Pt-X-4 as a single emitter, the voltage-dependent color-tunable CHIDEL device, with CIE coordinates shifted from (0.56, 0.43) at 3 V to (0.42, 0.55) at 11 V, demonstrated a high luminance of beyond 90000 cd m-2 and a high EQE of 23.23% at a luminance of 1300 cd m-2. A long lifetime (LT90) of almost 20000 h has been demonstrated for the color-tunable OLED with Pt-X-4 emitting dopant.
Marcello Rubens Barsi Andreeta Federal University of São Carlos, Brazil
Combining single crystal fibers and ceramics to enhance ionic conductivity in solid-state electrolytes
The Laser-Heated Pedestal Growth (LHPG) technique emerged as an attempt to reduce
costs and to enhance the research on solid-state optical devices. The technique allows a fast
way to produce a wide variety of oxide compounds in a fiber-shaped single crystal (known as
single crystal fiber - SCF). Although the main technological applications were regarded to the
optical field, other works were successful in combining SCFs and ceramic materials with
applications ranging from structural reinforcement to textured piezoelectric materials. Another
very important field to be explored, regarding the combination of ceramic materials and SCFs,
is the solid-state electrolytes for low cost, clean and sustainable energy production. Nowadays,
regarding solid-state electrolytes, lithium lanthanum titanate (LLTO) and yttria-stabilized
zirconia (YSZ) are concentrating most of the research efforts. However, several technological
and scientific challenges still remain to be overcome regarding grain boundary engineering
and/or temperature of operation of the devices. In the case of LLTO ceramics, the processing
difficulties and its compositional and crystallographic nature remains a challenge for mass
production. In the case of YSZ, high efficiency of the solid oxide fuel cells (SOFCs) is only
achieved at high temperatures (T>800°C), leading to technological problems regarding the
electrodes. In this work, a new design is presented in order to increase the ionic conductivity
of LLTO and YSZ electrolytes by creating hetero (SCF-LaAlO3:LLTO) and homointerfaces
(SCF-YSZ:YSZ) between SCFs and the polycrystalline ceramic matrix, interconnecting the
two electrodes through those interfaces. The results indicate that it is possible to get an
enhancement of the effective ionic conductivity higher than 200%, which would allow the
production of a more efficient batteries and may provide the decrease in the SOFCs operation
temperature, compared to the conventional ceramics.
Matthew Gleeson Institute Polytechnqiue Paris, France
Quantifying the effect of morphology on second harmonic generation in glycine micro needles
Second harmonic generation (SHG) in crystalline materials can be utilized in nonlinear photonic devices with frequency conversion, multiplexed signal transmission and waveguiding. Organic crystals have useful properties such as ease of synthesis, birefringence, wide transparency range coupled with high molecular polarizability due to a pi-conjugated bond system that allows for large deformation in the presence of an electric field. Isolating the material property responsible for nonlinear optical effects, the second order susceptibility tensor χ(2), is often complicated by crystal growth directions, morphology and frame rotations. Finding and accurately quantifying χ(2) is key for material choice and device design. With recent advances in growing well defined micro and nanoscale structures, the effect of morphology and internal asymmetries on the recovery of χ(2) is relatively unexplored.
We developed a quantitative framework and analytical approach to recover the elements of χ(2) using polarization-resolved SHG microscopy in transmission mode, while illustrating the effect of morphology and birefringence on χ(2) elements. This is applied to non-centrosymmetric β and γ phase microneedles of the amino acid Glycine. Microneedles are grown via droplet evaporation, then characterized with Raman spectroscopy, X-Ray diffraction and Coherent Anti-Stokes Raman Scattering microscopy. The maximum χ(2) elements recovered were d33 = 15 pm/V and d33 = 5.9 pm/V for the β and γ phases respectively. Accounting for the microneedle morphology shows an increased contribution of the longitudinal tensor elements at the expense of others. Our results demonstrate Glycine as a useful bio-compatible nonlinear material.
Anna Bezryadina California State University of Northridge, United States
Nonlinear self-trapping and guiding of light in biological suspensions
The study of nonlinear processes in biological samples is crucial for developing new methods for fabrication of new bio-photonics devices and for developing low-loss transmission for deep-tissue imaging. In the last decade, significant work was to study deep-penetration of light and formation of optical waveguides in dielectric and metallic colloidal suspensions with tunable polarizability. In this work, we discuss formation of waveguide structures in biological suspensions for a range of wavelengths. Specifically, several centimeters long biological waveguides, with no significant photodamage of the cells, have been successfully demonstrated in colloidal suspensions of cyanobacteria, E. coli, and red blood cells (RBCs).
According to the forward-scattering theoretical model, cells in colloidal suspensions get attracted toward the center of the beam due to the optical gradient force, and simultaneously move along the laser beam due to the scattering force. Since living cells usually have a slightly higher index of refraction than the surrounding media, the optical force-induced nonlinearity leads to a self-lensing effect along the beam path, which allows for the formation of a biological "fiber".
Biological samples often have various absorption bands that need to be either targeted or avoided in opto-fluidic micromanipulation or biomedical imaging. However, sometimes the preferred wavelengths may not be suitable to exhibit nonlinear self-guiding and waveguide formation. To overcome this challenge, we implement a pump/probe-type nonlinear coupling, where formed biological waveguides provide effective guidance for a weaker laser beam. Finally, we investigate the conservation of polarization and orbital angular momentum through these scattering bio-soft-matter suspensions. We expect that these studies will help in developing alternative solutions to transmit energy and information through scattering media, as needed in communications, deep-tissue imaging, treatment and diagnostics.
Dr. S.Radhakrishnan Maharashtra Institute of Technlogy, India
Structure development and properties of PBAT-PBS blends and nano composite films
Crystalline structure developed in solution cast films of polybutylene succinate (PBS) blended with polybutylene adipate co-terephthalate (PBAT) was studied in detail with respect to composition of the blend. The effect of nanoparticle ( halloysite nanotubes, HNT) incorporation as well as addition of polyethylene glycol (PEG) plasticizer on crystallization process was also investigated. The samples were cast glasss plate substrate from solution using membrane caster at constant speed and thickness in the range of 100 microns. The composition was varied from 0 to 90 % of PBS in PBAT matrix. Films were air dried in an oven at 50-55 oC for 6 hr. The crystal structure development was studied using wide angle x-ray diffraction, (XRD) differential scanning calorimetry (DSC) and the molecular interaction examined using FTIR. XRD data indicated that PBS crystals were in monoclinic α phase but the relative intensities of the 011 and 020 reflections changed drastically in the blends. Also new reflections which were not reported earlier were seen distinctly in these blends. PBAT phase also showed crystalline nature with few distinct peaks. The DSC analysis revealed that there was preferential growth of PBS α phase crystals with sharp melting at 110 oC. Holloysite nano tubes (HNT) gave distinct nucleation effect with a shift in the temperature of crystallization peak in the DSC cooling curves as well as increase of ΔHc value. The preferential nucleationby HNT could be associated with the close lattice match fo the HNT and the monoclinic phase of PBS. These changes in the crystallinity and crystal phase improved the barrier properties of the films containing HNT which was seen in the decrease if water vapout transmission rate (WVTR) with the addition of HNT.
Magdalena Małecka University of Lodz, Poland
The analysis of Hirshfeld surface as a tool supporting the prediction of new compounds with desired physicochemical properties
Searching for the new materials used in various fields e.g. in pharmacology, biology and material science is very important and attracts more and more attention from researchers. Undoubtedly, crystallographic studies that confirmed the molecular structure of newly designed and invented materials help in these studies. Crystallographer answers not only the question what the molecular structure is, but also gives the information about the arrangement of the molecules in the crystal lattice and intermolecular interactions.
The analysis of Hihrshfeld surface has become an invaluable tool for crystallographers and crystal engineers alike. The new tool, Crystal Explorer program, which uses Hirshfeld Surface approach calculates interaction energies and visualizes the topology of intermolecular interactions are central to modern first-principle approaches to the prediction and designing the molecule with desired properties. This tool was used in our studies in the following cases:
1. the attempt to correlate cytotoxic properties and non-covalent interaction for 14 compounds with experimentally proved cytotoxic potential against cancer cell lines, and for others biologically active compounds,
2. the attempt to find the relation between fluorescence and crystal packing and self-assembly for promising luminescent material,
3. the attempt to discover relationships between lattice energy calculations and energy framework visualization and global reactivity descriptors,
4. quantitative analysis of hierarchy of intermolecular interactions.
The above approach has following outcome: provide useful descriptors for structure-activity relationship studies and give the quantitative analysis of the hierarchy of intermolecular interactions, which could be helpful in the modelling both the cytotoxic activity and luminescence properties.
Asma Iqbal Shanghai JiaoTong University, China
Electroactive triphenylamine based multipurpose polyimides
In recent years packing-disruptive triarylamine based polymeric materials have been greatly investigated for their use in optoelectronics. Aromatic polyimides with reasonably high thermal/mechanical stability, photoluminescence and electroluminescence properties are becoming significantly suitable for optoelectronic applications. Various new diamines (DAs) with different heterocyclic and substituted phenoxy pendent groups were successfully synthesized in high purity and good yield. All the synthesized intermediate and final compounds were characterized by their physical data, FTIR, 1H NMR, 13C NMR spectroscopic techniques. These newly prepared diamines were then used to synthesize polyimides and polyazomethine’s from commercially available dianhydrides and dialdehydes respectively. The photophysical properties of the polymers were explored by UV-visible and photoluminescence spectroscopy which revealed that benzimidazole based PI displayed blue-green emission. Cyclic voltammetry demonstrated reasonably low onset oxidation potential (Eonset 0.47-0.61 V) with high lying HOMO energy level (-4.8 to -5.8 eV) suggesting the hole transport properties of prepared polymer. Besides simple Polyimides we also prepared PI-GO based materials and that work is still in process to be publish. Moreover, we are still working on developing new PI based composites for various electrocatalytic applications.
Keywords: Polyimides, PI- composites, optoelectronics, solution processable, electrocatalysis.
Asla Abdullah Al-Zahrani Imam Abdulrahman Bin Faisal University, Saudi Arabia
Bismuth sulphide decorated ZnO nanorods heterostructure assembly via controlled SILAR cationic concentration for enhanced photoelectrochemical cells
Enhancement of the absorption of visible light spectrum is considered one of the most important elements to improve the photoelectrochemical cell performance of ZnO nanorod arrays (NRAs). In this investigation, throughout ionic layer adsorption and reaction (SILAR), Bi2S3 thin films were deposited on ZnO nanorod arrays with varying cationic concentration. XRD pattern revealed that Bi2S3 was successfully synthesized with orthorhombic structure on the wurtzite ZnO NRAs. Absorbance spectra disclosed that the band gap energy (Eg) of Bi2S3/ZnO NRAs showed a remarkable red shift with increasing the cationic concentration. The photocurrent density increased significantly by increasing the concentration from 1 mM to 3 mM before showing a decrement at higher concentration due to agglomeration of Bi2S3 NPs and formation recombination centres. The hybrid photoanode Bi2S3/ZnO NRAs at 3mM exhibited a significant photocurrent improvement of the highest achieved value (1.92 mA/cm2), which is about six times greater than that of plain ZnO NRAs (0.337 mA/cm2). The high photoconversion efficiency value of 1.65% versus Ag/AgCl was obtained by Bi2S3/ZnO NRAs (3 mM) in comparison with pristine ZnO NRs, mainly because of the stepwise band alignment edge structured and the significant enhancement of morphological and optical properties. The study reveals that controlling of cationic concentration can improve photoconversion efficiency considerably.
Jingyang Wu The Hong Kong Polytechnic University, Hong Kong
Smart bionic morphing leg mannequin for pressure assessment of compression devices
Functional compression devices, that impose accurate dose of compression on human body, have been widely used in medical treatment and rehabilitation. The exerted pressure distribution, including the pressure amplitude and the spatial distribution, plays a significant role on the treatment efficacy. However, human figures vary greatly in terms of shape and size, which causes difficulties in evaluation of compression devices. Hence we present novel solutions for precise evaluation of pressure spatial distribution by developing a smart bionic morphing mannequin with 25 structured-fiber pressure sensors and 4 temperature sensing units. These pressure sensors with a high sensitivity (up to 54.7 pm kPa−1 with an accuracy of ∼0.03 kPa) in the range from 0 to 10 kPa were embedded in the mannequin, at the locations specified by German standard (RAL-GZ 387/1) and anatomical structures of low limbs. Four fiber optical grating temperature sensors were also embedded. This sensing network can provide a precise pressure-mapping rather than a mean pressure obtained from other measurement systems. The fabricated leg mannequin can morph from size 23 (Size M) to 27 (Size L) with an accuracy of 0.125 mm in circumference, reducing the required number of leg mannequins in routine tests of medical compression devices. Furthermore, the measured pressure exerted on the smart mannequin was in good agreement with those exerted on the human leg, showing nonuniform pressure distribution due to the apophysis and local buckles. Therefore, the characteristics of high sensitivity to low-pressure, pressure mapping, bionic, and morphing make the leg mannequins promising to be applied for routine tests in customization of compression garments. To make the leg mannequin morph in the length direction, an improved model is being developed. The work has been focused on realizing vertical deformation of leg mannequin, and replacing expensive fiber pressure sensors with cheaper, high sensitivity electrical force sensors.
Sivakumar Dhar Malingam Universiti Teknikal Malaysia Melaka, Malaysia
Natural fibre metal laminate as car body panel
This work explores the solutions to improve fuel efficiency towards achieving the reduction in CO2 emissions by utilizing the natural fibre metal laminate (nFML) as car front hood. Fibre metal laminate (FML) is a lightweight material that inherits advantages of metal and fibre reinforced composite which have outstanding physical and mechanical properties compared with monolithic metal structures. To date, very little research has been reported related to FML on natural fibre reinforced composite. Natural fibres in FML will enable benchmarking of the performance in FML structure in the product design specifications (PDS) of the car front hood. The research carried out involved concurrent engineering in material selection using Fuzzy VIKOR method, generated inventive solutions through Theory of Inventive Problem Solving (TRIZ) method and investigated the formability and water absorption behaviour of the nFML. Kenaf fibre and polypropylene have been identified as the suitable natural fibre and thermoplastic matrix for fabrication of the nFML using Fuzzy VIKOR method for the car front hood. Identification of problems or contradictions of nFML as car front hood system was constructed using TRIZ method; two layers of fibre reinforced composite has identified as the optimal stacking configuration of the fibre reinforced composite in nFML. This configuration was used to further study the application of nFML as car front hood. Forming analysis was conducted to determine the maximum forming limit of the nFML. Hemispherical punch test was carried out to determine the formability and circle grid analysis was used to determine the forming limit diagram (FLD) and forming limit curve (FLC) of the nFML. The graph revealed that the nFML have a potential to be formed into a complex shapes. This research has successfully demonstrated the capability of nFML in the design of car front hood that satisfies the intended PDS.
Harwinder Singh Bannari Amman Institute of Technology, Sathyamangalam, Tamil Nadu, India
Utilization of Agrowaste as Reinforcement for Epoxy Laminate Composite
Natural lignocellulose based biomass is abundantly available on this planet and another heap is continuously being generated by the agricultural waste and is raising the environmental issues. In order to mitigate this effect in this work, cornhusk film (CHF) is used as reinforcement in epoxy matrix to develop CHF-epoxy laminate composites. The novelty of the work lies in the utility of CHF as reinforcement in the epoxy matrix and to study the influence of CHF loading by weight (3%, 6% and 9%) as well as the angle of orientation (00, 450 and 900) of its ridges on the dynamic mechanical properties of the composites. Alkali treated CHF resulted in better CHF/epoxy interphase and improved composite performance. Strength to weight ratio (SWR) of alkali treated CHF is increased compared to untreated one. DMA test shows best results for 6wt% CHF loaded composites with 372 MPa storage modulus compared to 212 MPa for neat epoxy. The positive shift in tan δ peak of around 8.2 0C for the composites validates the effectiveness of CHF as a reinforcing agent in epoxy matrix. The CHF-epoxy composites retained their homogeneity which is further improved at higher angle of orientation of CHF. The predicted viscoelastic properties of composites from the theoretical expressions are in line with the actual results. Results of statistical analysis show that CHF loading and its orientation in the laminate are significantly affecting the overall properties of the composites. The maximum moisture absorption is around 1.024% for 9wt% CHF loading. CHF based epoxy laminate composite structures can be used for developing partitioning panels, inner lining of doors of automobile decking and similar applications.
Ronald R. Willey Willey Optical, Consultants, Charlevoix, MI, USA
Variation of Indices of Refraction of Nano-Thickness Metal Layers with Thickness, Materials, and Simulation Models
Optical thin film layers of silver and other materials on the order of 10 nm effective optical thickness can vary significantly in index of refraction, n and k. These properties vary with the materials which interface with the thin silver layers and with the processes and post processing used to deposit and treat those layers. Once a given combination of materials and processes have been characterized over a range of thicknesses from 2 to 50 nm, this data can be used to design coatings to most nearly provide the percent reflectance and transmittance versus wavelength desired. Various procedures to extract the n and k of a film from spectrophotometric measurements are provided. Cautions to minimize errors in the procedures are given, and processes to confirm the accuracy of the obtained results are described. Fitting of %T and %R spectral data are often used successfully but tend to provide less than satisfactory results in the presence of large absorptance. In cases of metal films where high absorptance is present, piecewise fitting is beneficial. However, in some cases, there are multiple solutions (similar to the case of a square root), and the proper solution depends upon having starting values for n and k which are close to the real values. A technique for obtaining good starting values is discussed. How well the measured data can be fitted with functions that allow simulation in the design process depends on the models used in the fitting process.
Pubali Das Jadavpur University, India
Effect of synthesis procedure on charge transport analysis of Zinc Oxide
Synthesis process can affect the semiconductor morphology and also its properties. In this work, we report two different synthesis procedure of semiconducting ZnO and its impact in photo sensing Schottky diode. Hydrothermal and co-precipitation method were used to synthesize ZnO which gave rise to rod like (ZnO HT) and particle like (ZnO COP) ZnO respectively. Structural, optical and electrical characterization of the materials were performed. From UV-Vis analysis, ZnO HT exhibited greater optical absorption. Metal semiconductor (MS) junction Schottky diodes were fabricated using ZnO HT and ZnO COP respectively. The photoresponse as well as diode parameters were investigated by current-voltage measurement. The result showed that ZnO HT delivered 121% higher responsivity over ZnO COP. The faster and better charge transport facilitated by rod like morphology of the former. Detail analysis of MS interface proves improvement of interface quality due to rod like ZnO.
Electroactive Biomaterials: Encouraging Tools for Cardiac Tissue Engineering
Cardiovascular diseases, mostly myocardial infarction (MI), are the main reasons of death
worldwide. Millions of cardiac cells and vascular structures are damaged due to the ischemia made
by MI. Adult cardiomyocytes are terminally differentiated cells that cause in a minimal intrinsic
potential of heart to self-regenerate. Innovative approaches based on tissue engineering have been
presented to repair damages from cardiovascular diseases. Recently, conductive biomaterials as
promising bioengineering platforms, have been used to develop scaffolds to return the disrupted
cardiac electrical system and regenerate cardiac tissue. Electrically conductive biomaterials are
likely to recover electromechanical and topographical features of the scaffolds and stimulate the
proliferation, adhesion, and maturation of cardiac cells as well as cardiogenic differentiation of
various types of stem cells.
Here, we review recent advances in conductive biomaterials and mechanisms of their action on
cell functions for cardiac tissue engineering
Pao Ter Teo Universiti Malaysia Kelantan (UMK), Malaysia
From ‘Waste’ to ‘Wealth’: Recycling of Food, Agricultural, and Industrial Wastes as Pore Forming Agents for Sustainable Porous Ceramic Production
Utilizing various wastes in ceramic production has been growing worldwide. This work provides an extensive literature review on the utilization of food, agricultural, and industrial wastes as pore-forming agents (PFAs) in sustainable porous ceramic production. The literature conducted since 2010 indicates that waste-based porous ceramics has versatile properties with excellent performances. Determination of waste material and clay properties as well as processing conditions such as material composition, sintering temperature, and compaction pressure, which influence pore formation in ceramics, has been comprehensively provided. These factors significantly influence the properties of the resulting porous ceramics, including physical, mechanical, and toxicity properties. Recycling food, agricultural, and industrial wastes for increased energy saving and green ceramic production can be realized as an economical and practical approach to sustainable waste management, which align well with achieving sustainability in a circular economy and the UNESCO’s Sustainability Development Goals (SDG). Achieving zero food, agricultural, and industrial wastes can eliminate environmental burdens and pave the way for closed-loop production. In overall, the waste-based porous ceramics can pave the way for sustainable environments, expanding the economic sector, particularly alternative building materials.
Kun Wang Zhongyuan University of Technology, China
Enhanced fill factor and efficiency of ternary organic solar cells by a new asymmetric non-fullerene small molecule acceptor with extended end group
A new asymmetric non-fullerene small molecule acceptor, IDT-TNIC, which is based on a indaceno[1,2-b:5,6-b']dithiophene as central donor unit, thiophene as unilateral bridge, and 2-(3-oxo-2,3-dihydro-1H-cyclopenta[b]naphthalen-1-ylidene)malononitrile as extended end group acceptor unit, as the third component in the PM6:Y6 system. An optimal ternary device based on PM6:Y6:IDT-TNIC (w/w = 1:1.1:0.1) achieved an impressive PCE of 17.0%. The results demonstrated that introduction of IDT-TNIC not only optimize the ladder-type arrangement of energy levels but can also further optimize the morphology of the blend film, leading to balanced charge transport and reduced charge recombination simultaneously. Furthermore, the ternary photovoltaic device still achieved a PCE of 14.15% when the active layer area reached 1.00 cm2. The results indicate that IDT-TNIC is a promising third component of high-efficiency ternary organic solar cells.
Myungsoo Kim Youngsan University, South Korea
Optimization of Woven Fabric Composites Structure for Improvement of Elastic Modulus using Micromechanics and Genetic Algorithm
This study aims to optimize the structure of woven fabric composites to improve the elastic modulus of the composites. In order to implement the woven fabric composites in the numerical analysis, a micromechanics model for woven fabric composites was used and a genetic algorithm was employed as an optimization tool. The structure of the woven fabric composites in the micromechanics can be realized by using the width and thickness of the fill and warp strands, and the waviness of the strands. Therefore, the width and thickness of the strands were used as elements of chromosome strings which were updated during the iterative process in the genetic algorithm to optimize the structure of the composites. Since the strands in woven fabric composites are a kind of unidirectional fiber-reinforced composites, the axial properties of the strands have a greater influence on the properties of the overall woven fabric composites than the transverse properties of the strands. Therefore, in order to increase the in-plane elastic modulus, it has been shown that it is effective to increase the volume of the corresponding strand and decrease the waviness of the strand. However, for the elastic modulus of woven fabric composites in out-of-plane direction, it was found that increasing the size of the waviness of the strands greatly contributed to the improvement of the thickness direction properties of the woven fabric composites.
Róbert Várdai Budapest University of Technology and Economics, Hungary
Improvement of the impact resistance of three-component hybrid PP composites with polymeric fibers
The demand of the industry for newer and better materials increases continuously resulting in constant research and development efforts to satisfy this demand. For structural and automotive applications, the impact resistance, stiffness and strength of composite parts are crucial factors. The requirement is often large stiffness, but good impact resistance at the same time. Glass and carbon fiber reinforced polymers have been used for decades, but increasing environmental awareness and also some economical aspects created much interest for natural fibers and reinforcements. Natural reinforcements have many advantages, they come from renewable resources, they are lighter than glass, cheap and they have positive environmental impact, but there are some drawbacks as well. The quality depends on the origin of the crop, the fibers are sensitive to heat during processing, their adhesion to the polymer matrix is often poor, they absorb moisture, etc. The proper selection of the matrix polymer, the fiber and composition may lead to the required strength and stiffness for most applications. In this study polypropylene (PP) hybrid composites were prepared by the combination of traditional reinforcements (wood, glass, carbon, talc) and polyvinyl alcohol (PVA) fibers. Impact resistance is improved because the presence of the flexible polymeric fibers increases the number of potential energy absorbing mechanisms in the composites. Interfacial adhesion was regulated with the use of maleated PP (MAPP). The aim of this study was the determination of the effect of polymeric fibers on the impact resistance of three-component hybrid PP materials and the identification of the deformation and failure mechanisms occurring during deformation. The results obtained proved that impact modification with polymer fibers works for all reinforcements. The overall properties of the hybrid composites prepared are acceptable, sufficiently large stiffness and impact resistance being achieved for a large number of structural applications.
Valentin Maingret University of Bordeaux, France
Formulation and polymerization of Pickering emulsions stabilized by stimuli-responsive dextran-based nanoparticles
Pickering emulsions offer outstanding kinetic stability, appreciable for storage. It is of great interest to confer them stimuli-responsiveness 1-2 for applications that often require release of the content.
The aim of our work is to formulate Pickering emulsions stabilized by dextran-based stimuli-sensitive nanoparticles. To do so, we modified dextran: a bio-sourced, biocompatible and biodegradable hydrophilic polysaccharide in three different ways. Then, nanoparticles made of modified dextran exhibiting narrow size distribution (PDI<0.2) and average hydrodynamic diameter around 200 nm were produced using nanoprecipitation. The initial modification step provides wettability and ensures stimuli-responsiveness to pH, enzyme or light of these nanoprecipitated particles for their use in Pickering emulsion stabilization. Oil-in-water Pickering emulsions were successfully formulated using these three different types of nanoparticles and limited coalescence phenomenon was studied. Degradation of the nanoparticles and destabilization of the related Pickering emulsions under stimuli (pH 3, enzyme, or light 4 (Figure 1)) were achieved, promoting new bio-friendly vectors for lipophilic substances. The next step is to polymerize the inner phase of simple Pickering emulsions.
Vivek Singh Yadav Indian Institute of Technology Guwahati, India
Rutile Phasic deposition of Titanium dioxide (TiO2) over AZ31 though RF sputtering for biomedical applications
Magnesium alloys like AZ31 offer excellent bio-compatibility with the human bone that has proved their suitability for biomedical implant materials, however, the faster degradation rate remains a challenge. Coating over the AZ31 with bioactive materials helps in controlling the degradation characteristics along with mechanical and interfacial properties. Coated AZ31 also improved the bio-interfacial interactions like protein adsorption and cells attachment. In this study, TiO2 ceramic material is deposited over AZ31 using RF sputtering for different intervals of 7, 8 and 9 hours. The deposition of TiO2 was confirmed using XRD analysis and the formation of the rutile phase of TiO2 was found. The interfacial properties like surface roughness, wettability and surface energy were analyzed. The surface (AZ31) became more hydrophilic after the deposition of TiO2. Degradation studies in the aqueous environment resulted in up to a 40% decrease in the release of Mg2+ ions from TiO2 coated AZ31 samples. Protein adsorption and hemolysis assay were performed to comment on the biological (bio-interfacial) performance.
Shin Aoki Tokyo University of Science, Japan
Combinatorial synthesis of metallosupramolecular phosphatases formed by the self-assembly of functionalized building blocks
Design and synthesis of artificial catalysts that mimic the natural enzymes such as hydrolases and phosphatases remain a great task in the fields of supramolecular chemistry. It is described that artificial enzyme mimics have some disadvantages such as i) lack of long-range interactions between catalysts and substrate and/or between functional groups in their active sites, ii) the requirement of time-consuming synthesis, and iii) being active mostly only in organic solvents. These drawbacks could be overcome by supramolecular methods utilizing the self-assembly of functionalized artificial molecular units.
Herein, we report on the construction of various metallosupermolecular complexes by the self-assembly of bis(zinc(II)-cyclen) complex containing a 2,2’-bipyridyl (bpy) linker, functionalized barbital units and Cu(II) ion as model compounds of alkaline phosphatase that catalyzes the hydrolysis of phosphate monoesters such as mono(4-nitrophenyl)phosphate (MNP).1-3 The formation of these supermolecules and their hydrolysis activity in a single aqueous phase1 and in two-phase solvent system2,3 was studied. It was found that these supramolecular complexes accelerate the MNP hydrolysis in a catalytic manner with the catalytic turnover number (CTN) of 3-4. It was also found that the hydrolysis obeys Michalis-Menten kinetics. In this presentation, these results will be presented.
Francesca Lionetto University of Salento, Italy
Production and characterization of polyethylene terephthalate nanoparticles
Plastic and mainly microplastic (MP) pollution in oceans represents one of the biggest environmental problems further exacerbated by the continuous degradation in marine environment of plastics to MPs and to nanoplastics (NPs). Growing concerns related to MPs adsorption of toxic chemicals can lead to increased bioavailability and impact on organisms of MPs and NPs through the release of these chemicals that, entering the food chain, shift the potential risk from environment to human health. However, due to the complexity of the problem, full knowledge of the negative effects of MPs/NPs on the environment and human health is still missing. It is very hard to carry out reproducible studies due both to the extreme difficulty of collecting NPs from the sea in quantities useful for research and to the great variability of NPs type, size and morphology. Most of the available toxicity studies use commercial polystyrene nanospheres with results not easily correlated with real conditions. It is thus imperative the availability of environmentally relevant nanoparticles for toxicological studies on different organisms and ecosystems. In this work, a reliable method has been set up to produce polyethylene terephthalate (PET) nanoparticles which are relevant for environmental impact studies. Starting from PET pellets, using a procedure based on dry grinding by rotor mill and several steps of wet grinding by planetary mill, aqueous dispersions of PET nanoparticles have been obtained. The size, morphology and chemicalphysical properties of these latter have been characterized laser diffraction, scanning electron microscopy (SEM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) in order to optimize the process parameters and to evaluate their potential to be used as a model NPs for studies on biological tissues
Fadi Ibrahim Ahmed Kuwait University, Kuwait
Novel Virus-like Mesoporous Silica-ZnO-Ag Nanoparticles and Quercetin Synergize with NIR Laser for Covid-19 Infectious Diseases Treatment
This work shows that novel virus-like mesopore silica-zinc oxide/Ag nanoparticles (SZnOAg) synthesized and professionally collected on NIR laser irradiation with quercetin to improve their effectively eliminates the virus as a biomedical application. The properties of the nanoparticles can be tuned with respect to their core diameter, tubular length, and outer diameter. Due to their biomimetic appearance, they can rapidly transform living cells into virus-like particles, this SZnOAg nanomaterials has specific elimination effect on bacteriophage and covid-19. Using epitaxial growth, we can construct virus-like structures that can be used for biomedicine applications. These nanomaterials and NIR laser could open the way to a new range of antiviral materials, due to the low-efficiency cellular uptake of current nanoparticles, their applications in the biomedical field are limited. Herein, it clearly shown that novel mesoporous silica nanoparticles can be easily exhibited superior cellular uptake property.
Arunachalam Rajendran University of Mississippi, USA
Computational modeling of fiber composites under impact loading
In this paper, computational modeling of the response of fiber reinforced composite (FRC) or glass fiber
reinforced plastics (GRP) due to impact loading is considered using two different approaches. The first
approach employs a material point method (MPM) based in-house code to explicitly model the
fiber/matrix architecture (Fig. 1) with the constituents modeled as linear elastic solid and maximum
tensile strain failure criterion1. It appears that the orientation of mesoscopic structure with given fiber
geometry and property in FRC, instead of the matrix material, governs the impact response. The matrix
material failure could be either brittle or ductile with a trivial effect on the impact response. The second
approach employs the Arbitrary-Lagrangian-Eulerian (ALE3D) code along with a hyperelastic
constitutive model to describe the continuum response of the GRP. The shock wave experimental data
for GRP provides an opportunity for the model developers to analyze damage evolutions using advanced
finite element codes in conjunction with appropriate damage models2.
Both approaches modeled the same plate impact configurations described in reference 2. Plate impact
simulations of a metallic flyer impacting a woven glass-fiber reinforced plastic (GRP) at various
velocities are performed using both the MPM and ALE3D codes. GRP VISAR data from a series of onedimensional
strain-based shock wave experiments were utilized in the calibration of a continuum damage
mechanics (CDM) model. The experimental data included D7 Tool Steel and 7075-T6 aluminum flyer
plates and two different GRP thicknesses (6.8 mm or 13.6 mm) at various impact velocities from 8.5 m/s
to 418 m/s. The damage model realistically captured several salient features of the experimental wave
profiles in terms of the shock rise time and the shape of the non-linear portions beyond the Hugoniot
Elastic Limit (HEL) as shown in fig. 2.
Jean Ebothe University of Reims Champagne Ardenne, France
Geometrical impact on Magnetic Properties of Mesoscopic Scale thick Nickel thin films
A real material thin film never exhibits a perfect or ideal geometrical shape, regardless of its
formation conditions. This is mainly depicted by its unavoidable bulk usually represented by
its thickness (d≠0) and its surface irregularities commonly considered in term of surface
roughness (σ≠0), both film characteristics being closely interconnected. Their individual
morphology and microstructure engender different behavior under a particular physical field
(E) effect. Any related film’s property (p) always results from their combined contributions.
The study of p evolution is commonly investigated through its dependence on d as mainly
encountered for macroscopic scale thick samples. However, configuration of real nano-films
and nanostructured thin films is specific most of the time. Consequently, the study of their p
evolution requires an adapted approach reflecting that specificity.
In the present work, our original proposal is illustrated by the study of nanostructured nickel
electrodeposits for which evolution of coercivity (Hc) and magnetic domain size (w) are
precisely investigated. It is then clearly demonstrated that only a new film geometrical
characteristic (τ) defined as τ = (d/σ) can consistently lead to the announced objective.
The study of these properties evolution using the normalization model indicates a
discontinuity in the magnetism of the investigated samples. Bloch magnetic domains (MD)B
are associated with mixed domain walls (DWN + DWB) below a critical position (τ0
-1) ≈ 0.35,
while Néel domain walls (DWN) coexist with mixed magnetic domains (MDB + MDN) beyond that position.