Pontifical Catholic University of Rio de Janeiro, Brazil
Jesus Anselmo Tabares
Universidad del Valle, Colombia
Chungnam National University, South Korea
National Institute for Environmental Studies, Japan
Md Salah Uddin
University of Texas Permian Basin, United States
CNRS University of Rouen UMR 6634 GPM laboratory, France
Pedro Paulo Medeiros Ribeiro
UFRJ Federal University of Rio de Janeiro, Brazil
Interdisciplinary Science and Engineering Laboratory, University of Delaware, United States
Nini Rose Mathews
Instituto de Energias Renovables -UNAM , Mexico
Brigham Young University, Provo, Utah, United States
Ioffe Institute, Russia
University of Calabria (UNICAL), Italy
National Autonomous University of Mexico, Mexico
The Catholic University of America, United States
Cristiano Ceron Jayme
University of Sao Paulo, Brazil
School of Mechanical and Design Engineering, University of Portsmouth, United Kingdom
Peking university third hospital, China
Luxembourg Institute of Science and Technology, Luxembourg
Joana A. Silva
IFIMUP, University of Porto, Portugal
Institute for microelectronics and microsystems (IMM) - CNR, Italy
Institute of Construction and Building Materials / TU Darmstadt, Germany
Hokkaido University, Japan
Dr Kajari Dutta
Amity University Kolkata, India
ITMO University, Russia
Korea Institute for Advanced Study, South Korea
Kumamoto University, Japan
Kent State University, United States
General Electric Research, Niskayuna, NY, USA
East China University of Science and Technology, China
National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute"', Ukraine
JFE Techno-Research Corp., Japan
The Pennsylvania State University, USA
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.
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.
Emmanuel Péres de Araújo Military Institute of Engineering, Brazil
Laboratory scale production method of composite fuels for hybrid propulsion
Fuel formulation is one of the chief strategies in hybrid propulsion studies1. In this context,
polyethylenes-paraffins compositions have been suggested as a trade-off solution to attain
both mechanical quality and ballistic performance2,3. In parallel, mixed hybrids have proven
their capacity to enhance regression rates of thermoset polymers in mixture-modelled
experiments4. Ammonium perchlorate replacement by ammonium nitrate could turn mixed
hybrids into environmentally benign materials5. Meanwhile, the preparation of fuels based on
paraffins6,7 and thermoplastic polymers8 could benefit from an application-oriented approach,
capable to generate macroscopically homogeneous and symmetrical samples, compatible
with both instrumental and ballistic measurements. Therefore, a laboratory scale batch
method for the preparation of composite fuels for hybrid propulsion comprising low density
polyethylene (LDPE), paraffin and ammonium nitrate was successfully developed, yielding a
protocol consisting of two major steps, i.e., vigorous mixing at high temperature and natural
cooling centrifugal casting. This method allowed the repetitive production of single circular
port cylindrical grains (Figure), with a volumetric contraction in the 7% - 18% range, prone
to be used both in static firings and in instrumental analysis9. TGA and DSC results suggested
that the attained partial miscibility level between LDPE and paraffin, yielding a
crystallization enthalpy in the -320 J/g range, was enough to provide a good compositional
uniformity in the radial axis of the grains and a crystallization behavior compatible with the
inexistence of major cracks. Under the overall experimental conditions adopted, the
volumetric contraction of pure paraffin, i.e., 9.9%, was found to be lower than literature data,
as well as crystallization enthalpy results suggested a synergistic interaction between LDPE
and macrocrystalline paraffin, away from the additive rule9. The devised preparation method
and its macroscopic and microstructural findings are expected to be useful in hybrid
propulsion studies, regarding particularly the proper definition of novel LDPEmacrocrystalline
paraffin-NH4NO3 composite fuels’ formulations.
Mario Nogueira Barbosa Junior Pontifical Catholic University of Rio de Janeiro, Brazil
Mechanical Properties analysis of a pigment free epoxy novolac reduced graphene oxide composite coating through TD-NMR technique
Industrially, carbon steel is the most used among metallic materials, and, consequently, the one that suffers the most from corrosion processes. About half of the metallic failures that have occurred have been attributed to the corrosion phenomenon, encouraging the search for new solutions to its reduction . The degradation of metallic materials by corrosion is a problem for the industry due to forced production stops, and as a consequence, loss or waste of valuable sources and resources, loss or contamination of products, less efficiency in industrial processes, and additional costs in process maintenance. The use of protective coatings on carbon steel is one of the main techniques for the prevention of corrosion. Epoxy resins are one of the most commercialized coatings in industry, given their thermal and chemical resistances, compatibility with a large number of materials, good adhesion and others. Graphene has been widely explored in scientific studies as a nanofiller in polymer-based composites, to increase the efficiency of coatings in anti-corrosive action. For a better understanding of the results obtained in the corrosion tests of the work of M.N.B. Junior and coworkers , mechanical tests were performed on the neat polymeric material and nanocomposites with graphene. TD-NMR experiments, through the OW4 pulse sequence, were performed on the samples both prior and after the mechanical deformations. The pulse sequence employed can discriminate molecular dynamics of intermediate mobility, thus revealing changes occurring inside the relevant scale of polymer chains conformation. The results showed clear changes in molecular dynamics, clearly correlated with the presence and concentration of the graphene filler. The graphene sheets increase the molecular mobility (mainly for the EP0.5GL sample) of the samples, suggesting that the bulk of the sheets can be located in the semirigid (of intermediate mobility) fraction of the polymer chains.
Jesus Anselmo Tabares Universidad del Valle, Colombia
Optimized route for the fabrication of MnAlC permanent magnets by arc melting
The τ-MnAlC is a face-centered tetragonal structure of the near equiatomic MnAl alloy, stabilized with a very low concentration of C which is currently considered a very promising candidate for permanent magnet applications due to its high anisotropy field (~ 4 T), relatively high saturation magnetization (MS = 96 Am2/kg) and Curie temperature (TC = 380 °C) [1-3], besides being a low-cost and rare-earth-free alloy. This ferromagnetic τ-MnAlC phase is usually obtained from a quenched high-temperature hcp ε-phase (ε-MnAlC) which is then annealed at temperatures between 500 and 700 °C [1,2]. Throughout the fabrication process of the metastable τ-MnAlC phase, some equilibrium phases (β-Mn and γ2-Al8Mn5 phases ) can appear, deteriorating its magnetic properties. In this work, we present a simple fabrication route that allows obtaining magnetically enhanced bulk τ-MnAlC magnet. In the fabrication process, an electric arc-melting method is carried out to melt ingots of Mn54.3Al44C1.7 alloys. A two-step heat treatment at 1200 and 1100 °C allowed us getting a very high concentration ε-MnAlC alloy after performing the quenching process in room temperature water. By reducing the formation of secondary phases, we allowed obtaining a bulk τ-MnAlC alloy with improved magnetic properties. Room-temperature hysteresis loops showed that our bulk τ-MnAlC alloy exhibits values of saturation magnetization, remanence magnetization and coercive field higher than those reported in previous works [4,5]. Experimental evidences demostrate that the two-step heat treatment to homogenize the ε-MnAlC plays an important role in the suppression of undesirable phases that deteriorate the permanent magnet properties of the τ-MnAlC. In addition, TEM-based magnetic imaging techniques were performed to locally inspect the magnetic microstructure of the improved MnAlC permanent magnet.
Soon-Gil Yoon Chungnam National University, South Korea
Unprecedented Flexibility of In-Situ Layer-by-Layer Stacked Graphene with Ultralow Sheet Resistance
Although graphene has been extensively studied as a candidate transparent conducting electrode (TCE) material for next-generation flexible devices, transferred large-scale graphene inevitably suffers from wrinkles, ripples, and metallic residues, which significantly lowers its quality by increasing its resistance and reducing its flexibility under tensile strain. As a result, many studies have looked to decrease the sheet resistance and increase the flexibility of graphene, but the complicated fabrication processes and high costs involved are barriers to commercialization. In the present study, 4-inch scale monolayered graphene and layer-by-layer stacked graphene that do not require a transfer process were designed to exhibit high flexibility and ultra-low sheet resistance. Three-layered stacked graphene film grown in situ on a polyethylene terephthalate substrate had an ultra-low sheet resistance of ~ 16 sq-1 at an optical transmittance of ~93% and superior flexibility for 104 cycles under a tensile strain of 5%. However, the plastic deformation of the PET substrate considerably reduced the flexibility of the monolayered graphene. In contrast, monolayered graphene on polydimethylsiloxane, which did not undergo plastic deformation, exhibited unprecedented flexibility at a static tensile strain of 15% (radius of curvature: 0.6 mm) and for 3104 bending cycles under a tensile strain of 11% (radius of curvature: 0.9 mm). This study provides an effective approach for the fabrication of TCEs for use in foldable electronic devices.
Kazuo Yamada National Institute for Environmental Studies, Japan
The outline and the background of “Recommendation of RILEM TC 258-AAA: RILEM AAR-13: application of alkali-wrapping for concrete prism testing to assess the expansion potential of alkali-silica reaction”
Various test methods and models have been developed to evaluate the alkali reactivity of aggregates and to estimate the long-term expansion behavior of concrete, and the test results have been compared with the behavior in the field. Since the expansion of ASR is caused by the formation of expansive reaction products of reactive silica in the aggregate and alkali in the pore fluid, the most essential points required for the test method are the alkali content and moisture content. Of course, apart from the properties of the aggregate itself, there are many other factors related to ASR expansion, such as water-to-cement ratio, mixing ratio of reactive and non-reactive aggregates, SCMs, aggregate size, temperature, age of the evaluation, humidity, etc., which result in different micro-textures of cracks, different reaction products, and different pore fluid compositions, and then resulting in different expansion dynamics and deformation characteristics of the structure. In order to investigate these factors and develop models to estimate the performance of structures, the most basic and important point is to first perform tests under controlled conditions of alkali content and moisture supply.
As an example of the influence of alkali leaching, which is considered to be one of the important influencing factors, the influence of specimen size will be explained: cylinders of Φ10 cm and blocks of 40 × 60 × 60 cm were made of the same concrete mixture and placed in different climatic locations in Japan. It was observed that the smaller cylinders showed less expansion. Analysis showed alkali leaching over several centimeters from the surface, which may have been the cause of the reduced expansion. When the same mixtures were tested in the laboratory with RILEM AAR-3 or 4, significant alkali leaching from the specimens and mass loss due to limited moisture supply were also detected.
A vast amount of data has been accumulated in ASR studies so far, but unfortunately, due to this circumstance explained above, it is questionable how reliable the data can be in terms of lab-field correlation. If the test method has a strictly defined procedure and reproducibility has been confirmed, any test method can be used, as long as the purpose of the test is limited to the determination of the harmlessness of aggregate or specific concrete in a certain area, since the criteria for determination are based on engineering experience. However, when trying to scientifically examine the influence of various factors, an appropriate test method is necessary. In order to realize the requirements of keeping the alkali content constant and supplying sufficient water, the authors proposed alkali-wrapping for concrete prism testing, currently published as RILEM AAR-13: application of alkali-wrapping for concrete prism testing to assess the expansion potential of alkali-silica reaction.
Md Salah Uddin University of Texas Permian Basin, United States
Molecular dynamics simulations and experimental characterization of chitosan hydrogel with different crosslinking agents for targeted drug delivery
Chitosan is a water-soluble, non-toxic, biodegradable, cationic, linear polysaccharide that is widely used in targeted drug delivery. In this study, two major cross-linkers Genipin and Disulfide have been selected to crosslink linear chains and investigate their effect on drug distribution with molecular dynamics simulations and loading/releasing rate with experimental characterization. Genipin is a small molecule, acts as a nontoxic linker, and can undergo self-polymerization whereas Disulfide crosslinking is a polymer-polymer crosslinking where the reaction takes place under neutral conditions and provide mucoadhesion. The cross-linking process is heavily impacted by the temperature and the pH conditions. To investigate the drug loading and releasing rate, Thymoquinone, Gefitinib, and Erlotinib have been selected for the linear chitosan along with two other cross-linked systems conducted in Phosphate buffer solution. This experiment guides to observing the drug loading and releasing efficiency of the linear chitosan and the cross-linked chitosans depending upon the amount of cross-linking used. The swelling ratio for the polymeric system is also observed and it is found to be improved with genipin and disulfide crosslinking. A previous study has been conducted to investigate the drug distributions with molecular dynamics simulations. Chitosan hydrogel network is constructed using three different crosslinking agents, soaked with water, and thermal cycles are applied to estimate the critical temperatures. Subsequently, three different drug molecules are incorporated into the models separately and the distributions are observed by analyzing the trajectories of the drug molecules obtained from the simulations performed with canonical ensembles, as the distributions will affect the drug discharge.
Allisson Saiter-Fourcin CNRS University of Rouen UMR 6634 GPM laboratory, France
What about new knowledges on the physical aging process?
Knowing the physical aging process is essential for predicting the time-dependent behavior of glass-forming liquids. The way by which a glass reaches (or not) its equilibrium state after a certain time is still matter of debate in the scientific community 1. Recently, it has been proven that this way is clearly dependent of the gap between the glass transition temperature Tg and the aging temperature Ta in different glass-forming liquids: polymeric systems 2, metallic glasses 3, and chalcogenide glasses 4. When Ta is close to Tg, the kinetics of the enthalpy of recovery occur in one step, whereas for Ta far from Tg, multiple steps can appear.
Recently, the use of the fast scanning calorimetry (FSC) has generated many studies 5-7 proving that the physical aging can accelerate the ability to crystallize by forming nuclei after reaching of the equilibrium state. This phenomenon known from a theoretical point of view is difficult to evidence experimentally because it appears after the complete structural relaxation, but we highlighted it through the study of a Selenium glass.
Pedro Paulo Medeiros Ribeiro UFRJ Federal University of Rio de Janeiro, Brazil
Nickel and cobalt extraction from laterite ores
Nickel is mostly extracted from sulfide ores, however, laterite ores account for over 2/3 of all nickel resources in the world, and despite its predominance, there is no well-established process to extract nickel from such ores. Cobalt is also present in laterite ores. Nickel and cobalt in laterites are hosted in many different compounds such as oxides, hydroxides, and silicates minerals. The sulfation-roasting-leaching process has the potential to change this scenario once it can be applied to all kinds of nickel laterite ores. In this study, it will be presented the results of the experiments conducted using the sulfation-roasting-leaching process for four different laterites ore samples. X-ray diffraction, scanning electron microscopy coupled to energy dispersive spectroscopy, and chemical analyses by atomic absorption spectrometry were the techniques employed to characterize ore samples and leaching solid residues. Phase quantification was carried out by the Rietveld method. Under favorable conditions, nickel and cobalt recoveries were higher than 80 (wt.%) while the iron recovery was only 5.5 (wt.%).
Deb Jaisi Interdisciplinary Science and Engineering Laboratory, University of Delaware, United States
A novel approach for enhancing solubility through structural substitution of ions of a slow-release fertilizer
Modern agriculture has arrived at the crossroad of conflicting problems of keeping up the supplant food production and yet protecting water quality. Slow and controlled release fertilizers are developed towards minimizing the usage of natural resources and maximizing plant uptake. Research efforts on developing next generations of nanofertilizers are aimed to control the rate of release of nutrients and track transfer and transformation in soils and waters. Specifically, two approaches of tuning nanofertilizer are being investigated: altering crystal chemistry via substitution of cations and anions in structural sites in apatite and amorphous calcium phosphate and changing their surface properties including size, shape, and surface morphology. The structural incorporations of soluble ions and carbonate are found to enhance phosphorus release kinetics. Crystal defects created from altering the structural reorganization of a unit cell are likely dominating factors. The changes made in surface properties have counteracting effects. Inability to limit the number of variables among products complicates discrimination of the role of each parameter. Nonetheless, the current success made in optimizing the properties has aided in tuning the temporal need of phosphorus for plants.
Nini Rose Mathews Instituto de Energias Renovables -UNAM , Mexico
Chalcogenide thin films by electrodeposition for photovoltaic applications
The solar cells need to be developed based on low-cost, earth-abundant, stable, and efficient materials for large-scale applications. An emerging family of absorber layers based on metal chalcogenides such as Sb-S/Se, Cu-Bi-S , CZTS are highly interesting due to their abundance, good optical and electrical characteristics. Various film deposition methods are reported for the development of these materials. In this contribution the development of thin films by electrodeposition will be outlined. Electrodeposition is a scalable, and low-cost technique which can be carried out at room temperature. The one-step electrodeposition process of Sb2S3, Sb2Se3, the ternary Sb2(S-Se)3, and the nucleation and growth mechanisms are discussed. The phase purity, structure, and opto-electronic characteristics of the material were studied extensively using experimental tools such as XRD, XPS, SEM, photosensitivity, etc. The energy band diagram of these films with window layers like CdS and ZnS will be explained.
Jason Weaver Brigham Young University, Provo, Utah, United States
Assessing interface joint strength between powder bed fusion parts and wrought substrate in SS316L
Within the field of additive manufacturing (AM), the strength of materials is often a key consideration. Metal powder bed fusion (PBF) is a process of AM that builds metal parts layer by layer by depositing and fusing successive layers of powder upon a substrate material. The strength of this interface between the substrate and the printed material is important to characterize, especially in applications where the substrate is retained and included in the finished part. Ensuring that this interface between the original and printed material has adequate material properties enables the use of this PBF-AM process to repair existing structures and create new parts. We studied the tensile and torsional shear strengths of wrought and PBF-built SS316L specimens and compared them to specimens composed of half wrought material and half PBF material. These specimens were created by building new material via PBF onto existing wrought SS316L blocks, then cutting the specimens to include both materials. The specimens were also examined using optical microscopy and electron backscatter diffraction (EBSD). The PBF specimens consistently exhibited higher strength and lower ductility than the wrought specimens. The hybrid PBF/wrought specimens performed similarly to the wrought material. In none of the specimens did any failure appear to occur at or near the interface between the wrought substrate and the PBF material. Most of the deformation in the PBF/wrought specimens appeared to be limited to the wrought portion of the specimens. These results are consistent with optical microscopy and EBSD showing smaller grain size in the PBF material, which correlates to increased strength in SS316L due to the Hall–Petch relationship. With the strength at the interface meeting or exceeding the strength of the original wrought material, this process shows promise as a method for adding additional features or repairing existing structures using metal PBF-AM.
Alexander Lebedev Ioffe Institute, Russia
Effect of electron irradiation temperature on radiation resistance of SiC.
In this work, we investigated the effect of high-temperature electron irradiation on the characteristics of power semiconductor devices based on silicon carbide. Commercial 4H-SiC integrated Schottky diodes (JBS) with a blocking voltage of 1700 V were irradiated with 0.9 MeV electrons at temperatures from 23 to 500 0C in the fluence range from 1x1016 cm-2 to 1.3x1017 cm-2
It is shown that the radiation resistance of diodes under high-temperature ("hot") irradiation significantly exceeds the resistance of diodes at room temperature ("cold") irradiation. When irradiated at temperatures of 23 to 500 0C, the base resistance at a fluence of 1.3x1017 cm-2 is 106 Ohm and 1 Ohm, respectively; those it decreases by 6 orders of magnitude. However, irradiation even at a temperature of 150 C reduces the resistance in comparison with irradiation at room temperature by ~ 50 times.
In the entire investigated range of temperatures and irradiation fluences, the height of the metal-semiconductor barrier does not change.
It was found that partial annealing of the formed Radiation defects occurs even in the course of DLTS measurements at the temperatures T ≥ 400 K. After annealing, four centers can be distinguished, which are thermally stable at these temperatures.
Conclusions First, an increase in the irradiation temperature leads to an increase in the radiation resistance of silicon carbide. This is important for SiC, since this material is considered primarily as a material for creating high-temperature electronics devices.
Second, the decrease in the rate of removal of carriers in SiC at elevated irradiation temperatures is due to the annealing of the formed RDs at temperatures of 300-450 K
Francesca Alessandro University of Calabria (UNICAL), Italy
Porous Carbon Materials Obtained by the Hydrothermal Carbonization of Orange Juice for low-cost supercapacitors
Porous carbon materials are currently subjected to strong research efforts mainly due to their excellent performances in energy storage devices1,2. A sustainable process to obtain them is hydrothermal carbonization (HTC), in which the decomposition of biomass precursors generates solid products called hydrochars, together with liquid and gaseous products3,4. Hydrochars have a high C content and are rich with oxygen-containing functional groups, which is important for subsequent activation. Orange pomace and orange peels are considered wastes and then have been investigated as possible feedstocks for hydrochars production. On the contrary, orange juice was treated by HTC only to obtain carbon quantum dots. In the present study, pure orange juice was hydrothermally carbonized and the resulting hydrochar was filtered and washed, and graphitized/activated by KOH in nitrogen atmosphere at 800 °C. The resulting material was studied by transmission and scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, nitrogen sorption isotherms. We found porous microspheres with some degree of graphitization and high nitrogen content, a specific surface of 1725 m2/g, and a pore size distribution that make them good candidates for low-cost supercapacitor electrodes.
Joel Antunez-Garcia National Autonomous University of Mexico, Mexico
The effect of chemical composition on the properties of LTA zeolite: A theoretical study
Nowadays, zeolites' commercial, technological, and scientific importance is undeniable. In 2016, the global zeolite market was estimated at $USD 29.08 billion1, with a steady annual growth expected at 2.5%. Zeolites are crystalline and porous materials with a composition based on sodium, aluminum, and silicon. In the zeolites, pores are of nanometric dimension and are interconnected by channels; these characteristics grant to the zeolites a large surface area compared to their volume. Detergents, catalysts, and absorbents are those materials that concentrate more than 80% of commercial needs. Recent studies show that electrochemical performance, flexibility, and stability of zeolite-based Li–air batteries promise high efficency and flexibility compared to others currently on the market2. However, despite the large number of applications known today for zeolites, the correct distribution of the elements that compose them remains unclear. It makes it impossible to understand specific reaction mechanisms and predict unknown electronic properties. The electronic properties of LTA-type zeolites in their siliceous (see Fig. 1), aluminized, and ferric frameworks compositions, all of which were selected in their sodium ion-exchange form and under anhydrous conditions, were studied through DFT computations. In the case of an aluminized framework, it was found that the non-Löwensteinian configuration is energetically more favorable and has better electronic conductivity than the Löwensteinian framework. The two different ferric frameworks under consideration presented a distinct nature and higher acidity than aluminized ones. Furthermore, it was observed that the purely siliceous LTA framework showed an inversion in the Löwdin charge trace behavior, suggesting that it is associated with its hydrophobic nature.
Sepideh Akhbarifar The Catholic University of America, United States
Thermoelectric Properties of Lead Ruthenate Derevatives
The derivatives of lead ruthenate pyrochlores were investigated by varying the Pb/Ru ratio in lead ruthenate (Pb2Ru2O6.5). All ceramic compounds were synthesized by solid state synthesis and the thermoelectric properties were measured between 298 and 573 K. All compounds were isomorphic. Reducing the number of Pb2+ ions create more vacancies in the Pb2O′ sublattice and changes the properties of the already existing oxygen vacancies, which are occupied by Pb 6s2 electron lone pairs in pure lead ruthenate. Decreasing the concentration of Ru4+ affects electrical conductivity, which is mainly governed by the RuO6 backbone structure of ruthenate pyrochlore. The underlying scattering mechanisms of electrical (σ) and thermal conductivity (κ), the Seebeck coefficients (S) of all ceramics were analyzed in terms of carrier concentrations, using existing quantum physical models. All ceramics were p-type and showed metal-like electrical conductivity and glass-like thermal conductivity. Therefore, the same scattering mechanisms were seen for all pyrochlores. Electrical conductivity σ(T) and electronic thermal conductivity κe(T) were governed by ‘electron impurity scattering’. The 3-phonon resistive process (Umklapp scattering) controlled the lattice thermal conductivity κL(T), which supports the electron-impurity scattering mechanism. In all compounds, the Seebeck coefficients were inversely proportional to the carrier concentration.
Cristiano Ceron Jayme University of Sao Paulo, Brazil
Preparation, characterization, and in vitro evaluation DNA-based polymer films for tissue engineering
The deoxyribonucleic acid (DNA) is one of the most important biopolymers present in living organisms, in addition to carbohydrates and proteins. The use of DNA as a functional biomaterial for therapeutic, diagnostic, and drug delivery applications have been prominent in recent years, but its use as scaffold for tissue regeneration is still limited. The aim of this study was to evaluate the biocompatibility and interaction of DNA-based polymeric films (DNA-PFs) with primary human fibroblasts (PHF) for regenerative medicine and wound healing purposes. Cell viability, cell cycle kinetics, oxidative stress, and migration studies were carried out at 48 and 72 hours of incubation and compared to control cells. The morphological characterization of the films was performed by SEM, SEM-EDX and AFM analysis. Cell adhesion was impaired in the first 24 hours, explained by the difference in topography and roughness of DNA-PFs, but it was overcome after 48 hours of incubation. PHF seeded on DNA films showed higher proliferation and migration rates than the control after 48 hours of incubation, with maintenance of cell morphology and lower cytotoxicity and oxidative stress during the evaluation time. These results indicate that DNA-PFs are not only highly biocompatible but provide a suitable microenvironment for dermal fibroblasts to maintain its activity, which could help to build new and more complex biomaterials for future tissue repair application.
Sarinova Simandjuntak School of Mechanical and Design Engineering, University of Portsmouth, United Kingdom
Combining Residual Stresses and Fluid-Structure Interaction FE Analysis for Induction Bending Pipes’ Integrity Assessment at elevated temperature
The bending process of pipes for engineering applications such as those of the power
generation plant’s bent pipes will introduce residual stresses (RS) within the pipes. Following
this, pipe manufacturers often perform heat treatments (stress-relief), especially for those
pipes that will be used under high pressure and high temperature. All these steps in
manufacturing bent pipes will ultimately influence the stress levels along the pipes, which will
also have an impact in their structural integrity or life.
A finite element (FE) method by coupling structural and thermal analysis to simulate bending
and heating has been used to predict the stress levels present in bent pipes. For more realistic
approach in this prediction, fluid motion and temperature inside a bent pipe which could exert
pressure (in-service loading) and thermal loading will be considered and incorporated in the
model and analysis. This aims to understand the overall effect on the stress level of the pipes
that are subjected to room and elevated temperature. The study will focus on the final stress
level conditions at locations where geometry varied the most.
Jia-Kuo Yu Peking university third hospital, China
Fabrication of 3D-Printed PEGDA-GelMA-CSMA Hydrogel Scaffolds for Promoting Chondrogenic Differentiation
The limited self-healing ability of cartilage necessitates the application of alternative tissue engineering strategies for repairing the damaged tissue and restoring its normal function. Compared to conventional tissue engineering strategies, three-dimensional (3D) printing offers a greater potential for developing tissue-engineered scaffolds. Herein, we prepared a novel photo-crosslinked printable cartilage ink comprising of polyethylene glycol diacrylate (PEGDA), gelatin methacryloyl (GelMA), and chondroitin sulfate methacrylate (CSMA). Unlike direct 3D (bio)printing methods, we used an alternative strategy called sacrificial templating mediated by 3D printed templates[1-4]. Briefly, we used the conventional Fused deposition modeling (FDM) to print a poly (lactic acid) (PLA) porous scaffold as a mold, followed by mixing gel precursors and pouring it into the mold, leaving the liquid level a little above those. After exposure to 405 nm blue light for 10 s and removal of pre-mold, high-resolution 3D-printed hydrogel scaffolds were obtained with uniform interconnected pores. FDM enables the rapid fabrication of highly interconnected pore geometries and channel sizes[5, 6]. Moreover, it is a cost-effective approach to print high-resolution constructs compared to other 3D (bio)printing techniques which are often overwhelmed by the viscosity, yield stress and shear thinning behavior of bio-ink. The 3D scaffolds possessed favorable compressive elastic modulus and degradation rate. In vitro experiments showed good adhesion, proliferation, and F-actin and chondrogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) on the scaffolds. When the CSMA concentration was increased, the compressive elastic modulus, GAG production, and expression of F-actin and cartilage-specific genes (COL2, ACAN, SOX9, PRG4) were significantly improved while the osteogenic marker genes of COL1 and ALP were decreased. The findings of the study indicate that the 3D-printed hydrogel scaffolds possessed not only adequate mechanical strength but also maintained a suitable 3D microenvironment for differentiation, proliferation, and extracellular matrix production of BMSCs.
Clement Mugemana Luxembourg Institute of Science and Technology, Luxembourg
Ionic Polydimethylsiloxane-Silica Nanocomposites: From Synthesis and Characterization to Self-Healing Property
Polydimethylsiloxane (PDMS) is the most widely explored and utilized polysiloxane, possessing an extremely low glass transition temperature, excellent thermal stability, high permeability, and good biocompatibility. As a liquid at room temperature, most applications require PDMS to be chemically crosslinked and / or combined with nanofillers to realize the requisite mechanical properties. While mechanical reinforcement of PDMS by nanofillers is well-known, the realization of consistently high levels of dispersion of nanofillers in a PDMS matrix remains a challenge. One strategy to control nanoparticle dispersion involves grafting ionic functional groups to the nanoparticle surface (thus creating so-called nanoparticle ionic materials, or NIMs1) and combining these charged nanoparticles with a polymer matrix containing functional groups with the opposite charge. Following such an approach, we describe ionic PDMS-silica nanocomposites from (cationic) ammonium-functionalized PDMS and (anionic) sulfonate-functionalized silica nanoparticles formulated with the aim of influencing the distribution and dispersion of the nanoparticles. The impact of the PDMS molecular weight, charge density and charge location on the distribution, dispersion of ionic silica nanoparticles and on the mechanical reinforcement of the resultant nanocomposites is explored. The potential for self-healing arising from reversible ionic interactions located at the interface between polymer matrix and highly dispersed silica nanoparticles is investigated by studying the impact of ionic nanoparticles loading and the PDMS molecular weight under different healing conditions, i.e., temperature and humidity.2 Finally, coarse-grained molecular dynamics simulations are carried out to calculate the lifetimes of temporary ionic crosslinks between the nanoparticles and the polymer matrix comprising these nanocomposites3.
Joana A. Silva IFIMUP, University of Porto, Portugal
Giant magnetostriction in magnetorheological elastomers
Magnetorheological elastomers (MREs) are composite materials, consisting of magnetic
particles embedded in a polymer matrix, whose magnetoelastic properties can be tuned by a
magnetic field. These materials can be applied as vibration attenuators and absorbers,
magnetic switches and valves. In this work we produced low concentration MREs composed
of PDMS (silicone rubber) with helicoidal particles of FeCo-2V. The main goal was to
achieve high strain and large elasticity.
The FeCo-2V alloy is a widely available inexpensive soft ferromagnet. To produce the
MREs, we used a commercial grade of this material, Hiperco 50 (Carpenter Technologies).
Four different volume fractions were used, between 0.6vol% and 3.4vol%. Additionally, the
MREs were produced in isotropic and anisotropic geometry.
Physical characterization was performed, showing that the MREs have ferromagnetic
behavior. The crystallography shows that the elastomer and the particles retain two
independent phases. Additionally, the anisotropic energy of the anisotropic MREs was
measured and it is shown to increase with the volume fraction. The elasticity moduli were
determined, and we show that, in isotropic MREs, the Young’s modulus is unchanged by the
external magnetic field (200 Oe) and small variations of volume fraction. However, in
anisotropic MREs, the Young’s modulus increases with the volume fraction, and it takes
larger values under a magnetic field intensity of 200 Oe. This shows that the magnetization
state of the MREs directly influences the mechanical elasticity. The magnetorheological
(MR) effect is reported in anisotropic MREs with low volume fraction. We show that the MR
effect reduces with increasing volume fraction. The magnetostriction of the MREs was
determined at 3.5k Oe, and giant magnetostriction values were obtained in MREs with
volume fraction as low as 1.2vol%. The results were compared to reported values and we
show that the magnetostriction of low concentration MREs is increased by more than 2-fold,
while reducing the volume fraction of magnetic particles.
Giuseppe Tranchida Institute for microelectronics and microsystems (IMM) - CNR, Italy
DIRECT SYNTHESIS AND CHARACTERIZATION OF MIL-101 (Fe) CRYSTALS ON CARBON-BASED SUBSTRATE
Metal–organic frameworks (MOFs) have recently received large attention in the field of
heterogeneous catalysis, gas storage, drug delivery, and fuel cells because of their versatility,
large surface area, well-ordered porous structure, and tunable organic linkers/metal clusters.
MOFs are hybrid inorganic-organic crystalline materials formed by metal ions coordinated
through specific functional groups, such as carboxylated groups, to rigid organic ligands in
order to form one-dimensional, two-dimensional or three-dimensional porous structures. MIL
is a subclass of MOFs formed by trivalent metal centers and carboxylate ligands. In this work
we focus on the development of synthetic strategies to grow and optimize the chemical and
structural properties of MIL-101(Fe) on a conductive carbon-based porous substrate, which is
usually adopted as gas diffusion layer in electrolyzers and fuel cells. Nanostructured MIL
crystals were directly grown on the carbon substrate in mild conditions from a solution of
FeCl3·6H2O and terephthalic acid in DMF. The deposition was conducted at 110°C,
atmospheric pressure and varying the reaction time from 2 to 22 hours. The influence of the
reaction time on growth and nucleation of the MOFs in terms of crystallinity, crystal size and
surface coverage has been investigated. Infrared Spectroscopy (FT-IR), Energy Dispersion Xray
(EDX) and scanning electron microscope (SEM) analyses were performed to study the
chemical, compositional and morphological properties. The crystallographic structure was
investigated by X-ray Diffraction (XRD). The electrochemical properties were tested by Cyclic
Voltammetry (CV) experiments. The good crystalline properties and the stability upon
electrochemical testing of the MOFs synthetized on carbon-based substrates make these
nanostructures a promising material for catalytic processes related to iron, such as for example,
oxygen reduction or electrochemical reduction of nitrogen, to produce ammonia at low
temperature and pressure.
Neven Ukrainczyk Institute of Construction and Building Materials / TU Darmstadt, Germany
Geopolymer materials: acid resistance measurements and modeling
Geopolymers are inorganic nanomaterials that provide a promising environmental friendly alternative to mineral binders, used to cement construction and building materials. Well deigned geopolymers exhibit excellent resistance to acid attacks, outperforming conventional cement-based materials. This can be explained by geopolymers zeolite-like amorphous molecular structure that exhibits lower solubility than calcium-rich cementitious hydration products. Degradation of concrete structures by acid attack is of great interest in numerous applications, such as biogas, biowaste, power plant cooling tower, sewer and wastewater treatment plants.
This keynote lecture comparatively reviews the findings of our publications as well as presents experimental results analysed in a new manner, which enabled to perform novel calibrations of our mathematical modeling approach. The lecture makes comparative overview on a progress made concerning geopolymers binders leaching and acetic acid attack degradation mechanisms. Results are compared from a broader perspective to a parallel research that revealed geopolymers acid attack mechanisms when exposed to sulfuric acid in lab and biogenic field conditions. Most importantly, this synthesis enabled to further evaluate the diffusion-based models for alkali leaching from geopolymers on additional measurement results related to both sulfuric and acetic acid scenarios.
Under sulfuric acid case, precipitation of expansive sulfate salts further accelerates the damage process by cracking. Existing experimental methods for leaching in pure water were proposed for more aggressive conditions in acidic solutions. Tests under laboratory conditions combined analyses of both liquid and solid samples. In the exposure solutions, the eluted elements were measured over time by inductively coupled plasma (ICP) mass spectroscopy (MS) or optical emission spectroscopy (OES) and from elemental distributions at different depths determined on cross-sections of solid samples using scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS)
Bunsho Ohtani Hokkaido University, Japan
Design, preparation and characterization of functional nanomaterials based on energy-resolved distribution of electron traps
How can we design functional solid materials, such as catalysts and photocatalysts? What is the decisive structural parameters controlling their activities, performance or properties? What is obtained as structural properties by popular conventional analytical methods, such as X-ray diffraction (XRD) or nitrogen-adsorption measurement, is limited to bulk crystalline structure and specific surface area, i.e., no structural characterization on amorphous phases, if present, and surface structure has been made so far. This is because there have been no macroscopic analytical methods to give surface structural information including possibly-present amorphous phases. Recently, we have developed reversed double-beam photoacoustic spectroscopy (RDB-PAS) which enables measure energy-resolved distribution of electron traps (ERDT) for semiconducting materials such as metal oxides [1,2]. Those detected electron traps (ETs) seem to be predominantly located on the surface for almost all the metal oxide particles, and therefore they reflect macroscopic surface structure, including amorphous phases, in ERDT patterns. Using an ERDT pattern with the data of CB bottom position (CBB), i.e., ERDT/CBB pattern, it has been shown that metal oxide powders, and the other semiconducting materials such as carbon nitride, can be identified without using the other analytical data such as XRD patterns or specific surface area, and similarity/differentness of a pair of metal-oxide samples is quantitatively evaluated as degree of coincidence of ERDT/CBB patterns. An approach of material design based on the ERDT/CBB analyses is introduced .
 Chem. Commun. 2016, 52, 12096-12099.  Electrochim. Acta 2018, 264, 83-90.  Catal. Today 2019, 321-322, 2-8.
Dr Kajari Dutta Amity University Kolkata, India
Room temperature synthesis of GO/Ag2O nanocomposite: Broad spectral ranged solar photocatalyst and high efficacy antibiotic for waste water treatment
With the worldwide industrial growth, major concern is rapid surge in water pollution. Notably, the water is contaminated by strong industrial dyes and pathogenic microorganisms. To address the issue, a simple heterostructure GO/Ag2O was synthesized in room temperature, which can serve the purpose of industrial waste management. In general, Ag2O nanostructures with absorptivity in NIR range is able to absorb 57% of solar spectrum, but our synthesized Ag2O nanowires can absorb Visible-NIR spectral range (peak ~ 850 nm) due to presence of multiple energy states, confirmed by the density of states (DOS) of Ag2O using density functional theory (DFT) analysis. Developing a nanocomposite with graphene oxide exhibited blue shifting of absorption maximum at 700 nm and improved absorptivity covering the entire solar spectrum (200-1800 nm). The DFT analysis of designed geometrical relaxed structure of GO/Ag2O approved the unique optical properties of nanocomposite. The nanocomposite degraded a very strong medical dye (Safranin-O) for 40 minutes white light exposures. In addition, our nanocomposite also showed antibacterial activity against E. coli with an MBC ~ 0.01 mg/ml. Molecular Docking analysis also established the improved interaction of an E.coli ribosomal and membrane protein with GO in nanocomposite in comparison with that of pure GO, which supports the experimental results. Fast charge transfer between Ag2O and GO increases the super oxide and hydroxide radicals in our synthesized hetero-system, which results excellent solar photocatalytic activity and ROS species to destroy the bacterial colonies.
Sadykov Dinislam ITMO University, Russia
Influence of low temperature on mechanical properties of UFG Al-Cu-Zr alloy
Ultrafine-grained (UFG) aluminum alloys are promising functional materials for use in various industries. However, for practical application, it is necessary to understand the influence of temperature regimes on their physical and mechanical characteristics. Recently  it was shown that additional alloying of HPT-processed Al-Zr by Cu leads to a dramatic increase in strength at room temperature while maintaining high level of conductivity. It has been shown that such enhancement of strength is associated with grain refinement and formation of nanoprecipitates of Al2Cu phase at grain boundaries during HPT processing. In this report, we studied the influence of low temperature in a range of 77–300 K on mechanical behavior of HPT processed Al-1.47Cu-0.34Zr (wt. %) alloy in comparison with such behavior of similarly structured UFG commercially pure (CP) Al and Al-0.4Zr (wt. %) alloy.
It is shown that yield stress and ultimate tensile strength increases with decreasing temperature for all three materials, however the rate of change of σ0.2 with decreasing temperature is nearly the same for all three material in the range 77–223 K and lower than in the range 223–293 K. The mechanical behavior of ultrafine-grained CP Al and Al-0.4Zr alloy are very similar in the whole temperature range 77-300 К. Alloying with Cu leads to substantial increase in the rate of the enhancement of σ0.2 with decreasing temperature in the range 223–293 K.
Accelerated strengthening with decreasing temperature in the range 223–293 K and influence of Cu on such strengthening is explained by using the concept of nonequilibrium grain boundaries in the UFG state and their influence on the emission of dislocations from grain boundaries, as well as considering the presence of Al2Cu precipitates at grain boundaries in the Al-Cu-Zr alloy.
Eunjung Ko Korea Institute for Advanced Study, South Korea
ferromagnetic Fe3GeTe2/CrGeTe3 moiré heterobilayer
Owing to unique fundamental physics and device applications, twisted moiré physics in two-dimensional (2D) van der Waals (vdW) layered magnetic materials has recently received particular attention. We investigate magnetic vdW Fe3GeTe2 (FGT)/CrGeTe3 (CGT) moiré heterobilayers with twist angles of 11o and 30o from first-principles. We show that the moiré heterobilayer is a ferromagnetic metal with an n-type CGT layer due to the dominant spin-majority electron transfer from the FGT layer to the CGT layer, regardless of various stacked structures. The spin-majority hybridized bands between Cr and Fe bands crossing the Fermi level are found regardless of stacking. The band alignment of the CGT layer depends on the effective potential difference at the interface. We show that an external electric field perpendicular to the in-plane direction modulates the interface dipole and band edges. Our study reveals a deeper understanding of the effects of stacking, spin alignment, spin transfer, and electrostatic gating on the 2D vdW magnetic metal/semiconductor heterostructure interface.
Taiga Yamasaki Kumamoto University, Japan
Bayesian spectroscopy of synthesized X-ray magnetic circular dichroism spectra at the Ni-L3, -L2 edges
X-ray magnetic circular dichroism (XMCD)1) measurement is an effective way to extract information about microscopic spin states of magnetic materials. Conventionally, the XMCD measurements at the L3 and L2 edges of magnetic elements have been performed to evaluate the spin and orbital magnetic moments based on the sum rule2). On the other hand, we applied Bayesian spectroscopy3) (BS), which allows us to trace back the causality by using Bayesian theorem4), to the analysis of the XMCD spectra. As a result, we succeeded in extracting spin state splitting for the respective helicities from the XMCD spectrum only and reconstructing the original −/+helicity X-ray absorption (XA) spectra5).
In this contribution, we also discuss the noise tolerance of BS on synthesized XMCD spectra prepared by mimicking the Ni-L3 and -L2 edges in NiFe2O46). Gray spectra in the Figure are the original −/+helicity XA spectra, and the superimposed noise in the right panels is two-times intense compared to the left panels. The analyzed XMCD spectra are the difference spectra between those −/+helicity XA spectra.
In BS on the XMCD spectra, the number of spectral components in each of the original −/+helicity XA spectra can be estimated by using Bayes free energy3) as the information criterion. Dashed curves represent decomposed components from XMCD spectra, and blue and red curves are their sum spectra. As seen both panels with different noise intensities, the reconstructed curves from the XMCD spectra well reproduce the original −/+helicity XA spectra. This result demonstrates that the BS for XMCD has high tolerance for noise.
Rabindra Dubadi Kent State University, United States
mechanochemical incorporation of metal oxide species on γ−alumina
Mechanochemistry has been used for the synthesis of γ-alumina with incorporated metal oxide (MO) species (M=Fe, Cu, & Zn). This synthetic route affords porous alumina with MO species having a large amount of interfacial defects on the alumina surface1. Various metal percentages (5, 10) were used to tune the composition of the resulting hybrid materials2. Boehmite used as alumina precursor and Pluronic P123 as a pore generating agent were grinded with suitable metal salts. The synthesized samples were calcined in air at 600 °C for 4 hours with a heating rate of 1°C/min because the γ phase of alumina is formed at 450-750 °C3. Commercial γ−alumina (SBET = 96 m2/g, VT = 0.54 cm3/g), and boehmite (SBET = 282 m2/g, VT = 0.34 cm3/g) were used as reference samples. γ-Alumina obtained after 3 hours of one-pot milling showed higher SBET 320 m2/g and VT 1.21 cm3/g. The synthesized samples were characterized by TGA/DTG, SEM, XRF, and N2 adsorption techniques. The intensity of XRF peaks increases with increasing dopant concentration showing an effective incorporation of MOs into alumina. Similarly, the synthesized sample with 5% metal content was tested for selective catalytic reduction (SCR) of NOx3,4. The highest NOx conversion rate (70%) was observed for the Fe modified sample at 450 °C and (71 %) for the Cu modified sample at 300 °C. For all MO modified samples, the N2O production did not exceed 20 ppm at the given temperature window, while the unmodified alumina showed the highest N2O production, indicating better catalytic performance of MO modified samples. This study shows that one-pot ball milling of boehmite along with P123 and metal salts affords porous γ−alumina with large surface area and high pore volume. The MO incorporated samples show higher efficiency for the NOx conversion without producing harmful N2O as a byproduct.
Radislav Potyrailo General Electric Research, Niskayuna, NY, USA
Industrial perspective on innovations in gas sensors: from one year's fundamental science to another year’s product
Reliable diagnostics of viral infections from breath, ambient air quality, industrial safety, homeland security – are some examples of unmet gas monitoring needs in unobtrusive formats because existing concepts of gas sensors reach their fundamental performance limits.
This plenary talk will stimulate your senses by (1) posing fundamental questions on principles of gas sensing and (2) showing earlier unthinkable sensor capabilities delivered by modern multidisciplinary research. We will discuss design principles of our multi-gas sensors that operate across the electromagnetic spectrum ranging from radio to optical frequencies.
In our radio-frequency sensors we introduced a dielectric excitation scheme of semiconducting metal oxide materials on the shoulder of their dielectric relaxation region. Our scheme provided unexpected boost in performance of these popular sensing materials over their chemiresistor readout . Our excitation scheme based on contemporary electronics brought highly desired features, e.g. linear sensor response, dynamic range of six decades of gas concentrations, and 50-fold improvement in the limit of detection versus chemiresistors. We lab-tested our excitation scheme with numerous gases, performed field validations on drones and in wearable formats and launched a commercial product with our partners.
In our photonic sensors, multi-gas selectivity is achieved within a single nanostructured sensing unit that produces a bright visible light iridescence [2-4]. By utilizing individual nanostructured sensors rather than sensor arrays we have improved sensor stability by eliminating independent aging factors in separate sensors in their arrays. Our existing and new machine learning (a.k.a. chemometrics) tools further advanced our sensor designs and performance in detection of multiple gases.
Wei-Hong Zhu East China University of Science and Technology, China
Sterically Hindered Diarylethenes with Benzobis(thiadizole) Bridge: Enantiospecific Transformation and Reversible Photo-Superstructures
Photochromic diarylethenes feature the reversible regulation by external photo irradiation which have attracted increasing attentions due to the bistability and outstanding fatigue resistance. To date, most studies focus on side aryl groups instead of central ethene bridge. However, the aromaticity and steric hindrance of ethene bridge can greatly affect the photochromic performance of diarylethene on bistability, quantum yields and chirality. In the presentation, we introduce our unique sterically hindered diarylethene system as a star photochromic or photoresponsive building block with excellent bistability, high photocyclization quantum yields and enantiospecific transformation, which provides a widely potential application in non-destructive information encoding, self-assembled systems, liquid crystal modulation and so on.
Tetiana Roik National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute"', Ukraine
Self-lubricating mechanism of new copper-based composite
The article analyzes the tribological properties of a new composite antifriction material based on copper, alloyed with nickel, aluminum and silicon, with the addition of calcium fluoride (CaF2) solid lubricant. In this work, the structure and its effect on antifriction properties were studied during tribological tests under friction conditions at loads of 1.0–3.0 MPa and a rotation speed of 1200–2000 rpm in air. The effect of manufacturing technology on the formation of the copper-based composite structure has been studied. The contribution of nickel, aluminum and silicon alloying elements to phase formation in the material structure has been analyzed. Research focuses on the calcium fluoride distribution in a composite with a copper matrix, its role in the self-lubricating process of the material, the distribution of the friction pair’s chemical elements and solid lubricant CaF2 in the contact zone under severe operating conditions. It was shown the solid lubricant is evenly distributed over the contact surfaces, and it covers the entire friction area. It has been established that anti-seize films formed in the presence of CaF2 solid lubricant provide high wear resistance. Solid lubricant CaF2 promotes the antifriction films formation during the friction process and provides a self-lubricating mode for the high-speed friction unit. Such films defend the contact surfaces against the intensive wear and stabilize a work of the friction unit. Studies have illustrated the developed antifriction copper-based composite is 5-6 times more wear resistant than the well-known composite operating under similar conditions. The developed composite can be recommended for use in friction units of high-speed equipment, electric motors, and speed reducers.
Toshio Fujimura JFE Techno-Research Corp., Japan
Analysis of the Solidus Temperature of Multicomponent Steel
Is the assumption of a constant solidus temperature—which has been empirically adopted in general steel solidification analysis without firm validation—valid in all solidification stages? This long-standing query has still remained owing to the difficulties in achieving the reliable measurements of the solidus temperature while the measurements of the liquidus temperature reasonably agree with phase diagrams.
To examine this assumption of a constant solidus temperature in all solidification stages for multicomponent steels, heat- and solute-transfer equations were simultaneously solved using the finite thickness model1), which focuses on early-to-late stage solidification except final stage solidification. In early-to-middle stage solidification, the model provides a constant solidus temperature, as predicted by the previously reported semi-infinite thickness model2),3) by the present authors wherein the solidification front was far from the strand center. In late stage solidification, however, the present model exhibited a slightly decreased solidus temperature—almost within the temperature measurement accuracy range. This suggests that the assumption of a constant solidus temperature does not exactly hold in late stage solidification, but is not unreasonable from a practical viewpoint. The obtained solutions agree well with numerical analyses and are in reasonable agreement with thermo-analytical measurements and industrial findings. Thus, the present model supports the assumption of a constant solidus temperature and estimates the solidus temperature in early-to-late stage solidification, which can play a role in search of an adequate solidus temperature as an approximate analytical solution for multicomponent steels.
Chetan Nikhare The Pennsylvania State University, USA
Reduction of Young’s modulus and effect on springback
Sudden increase of fuel consumption and resulting air pollution is due to the higher usage of automotive vehicles. To control the pollution and its impact on the environment, the National Highway Transportation Safety Administration (NHTSA) and Environmental Protection Agency (EPA) issued new rules called the Safer Affordable Fuel-Efficient (SAFE) vehicles which sets stricter standards for fuel economy and carbon dioxide . The new set values for miles per gallon as per the SAFE for model year 2021 to 2026 are 44.6 to 54.6 . But even the bestselling car is not able to reach the target of year 2021 . Thus, the automotive industry is facing an ongoing challenge to reduce the vehicle weight to reduce the fuel usage per mile and to avoid the environmental regulation penalty. Therefore, the innovation related to light-weighting became a mandatory necessity. To reach this target, the industry has been looking option to manufacture parts from high strength to ultra-high strength steels. With the usage of advanced high strength steels, the lightweight was achieved by reducing the thickness of the material without compromising on strength. However, due to their high strength property often challenges occurred are higher machine tonnage requirement, sudden fracture, geometric defect, etc. The geometric defect comes from recovery of the original geometry due to material elasticity. This defect is called as springback. Springback is commonly known as a manufacturing defect due to the geometric error in the part. Due to this error the deviated part would not be able to fit in the assembly without opt-in for secondary operations. Traditionally, it was believed that the elasticity remains constant at any plastic strain. However, during testing advanced high strength steels it was found that the elastic recovery increases during loading and unloading with increase in plastic strain.