New Type Of Material Research Articles

Adsorption characteristics of formaldehyde on nitrogen doped graphene-based single atom adsorbents: A DFT study

Formaldehyde (CH2O) is the most common volatile organic pollutant in the indoor environment, which can directly cause respiratory system diseases of humans. As a new type of material, graphene-based single atom adsorbent has the advantages of large specific surface and high adsorption activity, which can provide a new direction for formaldehyde removal. In this paper, the adsorption characteristics of formaldehyde on graphene-based single atom adsorbents were investigated through density functional theory (DFT) calculations. According to the analysis of geometric structure, electron transfer and density of states (DOS), the adsorption of formaldehyde belongs to a stable chemisorption and the largest adsorption energy of formaldehyde is −2.27 eV, which is a combined action of electron transfer and hybridization effect. Formaldehyde will be preferentially adsorbed on single atom adsorbent in side-on model. The effect of N doping and desorption temperature were studied through searching for linear relationship and Gibbs free energy calculation, respectively. Doping N atoms into graphene plane can significantly improve the adsorption strength of formaldehyde through modulating the charge of metal atoms. The charge of metal atoms can be an efficient descriptor for adsorption energy of formaldehyde. CH2O plays a dominant role in competitive adsorption between O2, N2 and CH2O. We expect that this theoretical study can lay a foundation for the experimental investigations.

Kombucha bacterial cellulose for sustainable fashion

PurposeThe purpose of this paper is to analyse the properties of bacterial cellulose (BC) film, obtained through Kombucha tea fermentation.Design/methodology/approachKombucha fungus was used to produce BC film under static cultivation conditions. Physical and mechanical properties under the influence of drying temperature and durability of BC material were investigated. Tensile properties were estimated by TINIUS OLSEN H10 KT test machine according to ISO 3376:2011, thickness was measured by DPT 60. BC structure was analysed by Scanning Electron Microscopy Quanta 200 FEG.FindingsBC material with excellent deformation properties in wet state were obtained by fermenting Kombucha tea. Due to the presence of fermentation residues, Kombucha film is sensitive to drying temperature. The best deformation properties retain when BC material is dried at low temperature (about 25°C). BC material becomes stiffer and ruptures at lower deformations due to rapid water evaporation at higher drying temperature. It is confirmed that during time, the properties of BC film changes significantly and there may be problems with the durability of products from this material. BC film has an interesting set of properties, therefore its application to fashion industry without further preparation is limited.Originality/valueA new approach is based on the evaluation of Kombucha material properties and investigation of BC as new type of material for fashion industry. Some recommendations for Kombucha BC film production are provided, basing on gained experience, experimental results and analysed literature. The advantages and disadvantages of material are discussed in the paper, in order to search for the ways to adapt the new type of material to fashion business.

Feasibility of predictive assessment of bending performance of CLT plates of Canadian hemlock

The correlation between the bending elastic modulus of lumbers along the primary direction and that of the resultant cross-laminated timber (CLT) plates in the full size suitable for slabs or wallboards was investigated to verify the feasibility of predicting the bending performance during the manufacturing of heavy building structures of this new type of material. A batch of Canada hemlocks lumber was graded based on a vibrational test that measures longitudinal elastic modulus. The elastic modulus and shear modulus in the transverse direction were also measured using the scheme of a torsional modal analysis of a cantilever plate. CLT were fabricated using the graded lumbers in sizes suitable for slabs or wallboards. The elastic moduli of these CLT products were measured using a conventional four-point static bending test. Finally, the static measurements of the elastic moduli of the CLT were compared with their predicted values that were calculated with the aforementioned data collected from the lumber pieces. The predicted elastic modulus along the primary direction of a CLT product agreed with the measured values. Therefore, the mathematical model of the CLT plate and the equation of its elastic modulus are feasible for the bending performance prediction in industrial production of CLT.

Biphenylyl-1,2,4-oxadiazole based liquid crystals – synthesis, mesomorphism, effect of lateral monofluorination

ABSTRACTAiming at developing a new type of materials for functional applications, three series of new compounds were prepared, 3-(biphenylyl)-1,2,4-oxadiazoles, Series I; laterally mono-fluorinated 3-(biphenylyl)-1,2,4-oxadiazoles, Series II; and 5-(biphenylyl)-1,2,4-oxadiazoles, Series III. Liquid crystalline properties of these compounds were studied using differential scanning calorimetry and polarizing optical microscopy. Ten of the thirteen compounds in Series I are mesogenic forming either N or SmA phases depending on the length-to-width molecular ratio. Mesogens of the positional isomers, Series III are both N and SmA. Monofluorination of the biphenylyl group at either the central or the terminal phenylene rings, Series III, resulted in the formation of nematic mesogens with low phase transition temperatures and broad nematic phase range.

Carbon Nanotubes and Carbon Nanotube Structures Used for Temperature Measurement.

Accurate measurement of temperatures with low power consumption with the highest sensitivity and smallest possible elements is still a challenge. The thermal, electrical, and mechanical properties of carbon nanotubes (CNTs) have suggested that their use as a very sensitive sensing element will allow the creation of different sensors, far superior to other devices of similar size. In this paper, we present a short review of different constructive designs of CNTs based resistive sensors used for temperature measurement, available in literature, assembled using different processes, such as self-assembly, drop-casting from a solution, thin films obtained by gluing, printing, spraying, or filtration over a special membrane. As particular cases, temperature sensors obtained from CNT-polymer nanocomposite structures, CNTs filled with uniformly dispersed Fe3O4 nanoparticles or with gallium, and carbon nanotube wires (CNWs) hybrids are presented. Using these preparation procedures, mixtures of CNTs with different dimensions and chirality, as well as with a variable level of impurities and structural defects, can be produced. The sensors’ performance charts are presented, highlighting a number of aspects regarding the applicability of CNT structures for temperature measurement ranging from cryogenic temperatures to high temperatures, the limitations they have, their characteristics and advantages, as well as the special situations that may arise given the particular structure of these new types of materials, together with basic relationships and parameters for CNTs characterization. Further research will be required to develop the techniques of manipulating and depositing individual CNTs on supports and electrodes for the development of temperature sensors.

Analysis of Solid-State Electrolytes for Li-Ion Batteries Using a Multiscale Molecular Dynamics Approach

Metal lithium anodes are excellent alternatives for Li-ion batteries; however, nonuniform plating and swelling of the anode upon lithiation causes the growth of lithium dendrites, among few other problems. One possible solution to this, and perhaps the other problems, is the use of solid-state electrolytes. Our approach to analyze the use of solid-state electrolytes is based on performing a multiscale computational approach using quantum and classical molecular dynamics simulation techniques. We will present our study of the properties of the two above new types of materials for anodes and electrolytes as parts of a full nanobattery,1-4 whereby the properties of their solid electrolyte interphases will be determined. The speciation of several interfaces of lithium-metal anodes with electrolytes such as sulfides, halogenated phosphor-sulfides, halogenated nitrades, and few others of present interest will be presented. Since these simulations require the use of full nanobatteries, thus, they also require the presence of a cathode, and since sulfur and spinel structures are also potential alternatives, we will use related cathodes in our nanobatteries. Selis, L. A.; Seminario, J. M., Dendrite Formation in Anodes of Lithium-Ion Batteries. RSC – Advances, 2018, 8, 5255-5267.Galvez-Aranda, D. E.; Seminario, J. M., Simulations of a LiF Solid Electrolyte Interphase Cracking on Silicon Anodes Using Molecular Dynamics. J. Electrochem. Soc. 2018, 165, A717-A730.Ponce, V.; Galvez-Aranda, D. E.; Seminario, J. M., Analysis of a Li-Ion Nanobattery with Graphite Anode Using Molecular Dynamics Simulations. J. Phys. Chem. C 2017, 121, 12959–12971.Galvez-Aranda, D. E.; Ponce, V.; Seminario, J. M., Molecular Dynamics Simulations of the First Charge of a Li-Ion—Si-Anode Nanobattery. J. Mol. Model. 2017, 23, 120.

BEHAVIOR OF RC BEAM RETROFITTED USING ULTRA HIGH-PERFORMANCE CONCRETE UNDER IMPACT LOADS

Several new types of materials have recently been used as retrofitting materials for structural elements such as ultra-high performance concrete with steel fiber reinforcement (UHPFRC). These materials are used as jacking to enhance the strength and ductility reinforced concrete (RC) beams. Considerable attention has been focused on the response of retrofitted RC beam under static loads but the behavior of such beam under impact loading is somewhat lacking. Therefore, in this study, a 3-D finite element model (FEM) of retrofitted RC beams under impact loading using non-linear finite element software (ABAQUS) was investigated. Since experimental work on this topic is scarce, the FEM is validated using the results of retrofitted RC beam under static loads. The impact load was applied in ABAQUS as equivalent to an initial velocity of 2500 mm/s. A parametric study was carried out to study the flexural response of RC beams retrofitted with different thicknesses and strengthening configurations of UHPFRC under impact loading.

Progress in Nonmetal-Doped Graphene Electrocatalysts for the Oxygen Reduction Reaction.

Owing to energy shortages and environmental pollution, green energy sources such as polymer electrolyte fuel cells and metal-air batteries play a more and more important role, whereby the oxygen reduction reaction (ORR) is the rate-determining step. Development of high-efficiency and stable catalysts to facilitate the ORR is of importance. Graphene is a new type of material with two-dimensional structure and high surface area, which has wide-ranging applications in many fields. However, graphene with zero band gap shows low electrocatalytic activity toward the ORR. Introduction of nonmetal atoms can change the electronic arrangement, generate active sites, and further improve the catalytic activity of graphene. Some nonmetal-doping strategies (e.g., N, S, and P doping) can promote ORR activity. Herein, the recent development of nonmetal-doped graphene catalysts for ORR is reviewed. Some common synthetic methods for nonmetal-doped graphene materials are summarized, and the active sites and possible reaction mechanisms for ORR on various nonmetal-doped graphene catalysts are discussed.

Is Oxidized Zirconium Femoral Head Superior to Other Bearing Types in Total Hip Arthroplasty? A Systematic Review and Meta-Analysis

BackgroundOxidized zirconium (OxZi) is a relatively new type of material that combines the strength of a metal with the surface/wears properties of a ceramic. Our aim was to investigate whether OxZi femoral heads lead to lower polyethylene wear, higher survival rate, and better clinical outcomes than the other bearing types in patients treated with total hip arthroplasty (THA). MethodsTwo reviewers independently conducted a systematic search according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses using the MEDLINE/PubMed database and the Cochrane Database of Systematic Reviews. These databases were queried with the terms: a. “oxidized” AND “zirconium” AND “total” AND “hip” AND “arthroplasty”; b. “oxinium” AND “total” AND “hip” AND “arthroplasty”. The primary outcome measures were the survival rate of the bearing surfaces as well as the polyethylene wear. ResultsThe vast majority (85.7%) of the studies, which reported the mean polyethylene wear rate, showed that there was not any significant difference between OxZi and cobalt-chrome (CoCr) femoral heads (rate ratio: 0.836; 95% confidence interval: 0.362-1.928; P = .674). All studies comparing the survival rate of OxZi and CoCr femoral heads illustrated almost excellent survivorship with both implants. ConclusionOxZi femoral heads did not lead to lower polyethylene wear rate or higher survival rate, when compared with CoCr femoral heads in patients treated with THA. On the basis of these results and taking into account the higher cost of these implants, we would not recommend the routine use of OxZi femoral heads in primary THAs. Level of EvidenceSystematic review and meta-analysis of therapeutic studies I-III.

Investigation of Corrosion Resistance of Alloys with Potential Application in Supercritical Water-cooled Nuclear Reactors

The Supercritical Water Cooled Reactor (SCWR) is one of the Generation IV reactor types, which has improved safety and economics, compared to the present fleet of pressurized water reactors. For nuclear applications, most of the traditional materials used for power plants are not applicable, therefore new types of materials have to be developed. For this purpose corrosion tests were designed and performed in a supercritical pressure autoclave in order to get data for the design of an in-pile high temperature and high-pressure corrosion loop. Here, we are presenting some results, related to corrosion resistance of some potential structural and fuel cladding materials.

Metal Halide Perovskite Nanocrystals: Synthesis, Post-Synthesis Modifications, and Their Optical Properties.

Metal halide perovskites represent a flourishing area of research, which is driven by both their potential application in photovoltaics and optoelectronics and by the fundamental science behind their unique optoelectronic properties. The emergence of new colloidal methods for the synthesis of halide perovskite nanocrystals, as well as the interesting characteristics of this new type of material, has attracted the attention of many researchers. This review aims to provide an up-to-date survey of this fast-moving field and will mainly focus on the different colloidal synthesis approaches that have been developed. We will examine the chemistry and the capability of different colloidal synthetic routes with regard to controlling the shape, size, and optical properties of the resulting nanocrystals. We will also provide an up-to-date overview of their postsynthesis transformations, and summarize the various solution processes that are aimed at fabricating halide perovskite-based nanocomposites. Furthermore, we will review the fundamental optical properties of halide perovskite nanocrystals by focusing on their linear optical properties, on the effects of quantum confinement, and on the current knowledge of their exciton binding energies. We will also discuss the emergence of nonlinear phenomena such as multiphoton absorption, biexcitons, and carrier multiplication. Finally, we will discuss open questions and possible future directions.

Thermal fracture behavior of functionally graded materials – a brief review and some prospects

Functionally graded material (FGM) is a new type of material whose composition and structure vary smoothly in the spatial position, making the properties and functions change continuously. In this paper, the research status on the thermal fracture of FGMs is briefly reviewed, and some future work is also suggested.

Cause Analysis and Countermeasures of Through Shakes in Foamed Concrete Subgrade

The paper presents a new type of material—foamed concrete—adopted for expansion subgrade of the expressway. Intriguingly, the irregular through shakes appear on its top. The method combining the engineering case, theoretical analysis, and numerical simulation is employed to analyze its T‐shaped and tree‐shaped through shake. The research indicates that when the underground water table is high, cracks are easily seen on the top of step‐shape foamed concrete due to buoyancy force. Under the concentrated load effect, the maximum displacement of 27.09 mm is observed on the top of the simply supported beam when elastic modulus is 200 MPa. The maximum principle tensile stress of 0.34 MPa also occurs on the top of the simply supported beam when elastic modulus is 200 MPa and 400 MPa, which is greater than tensile strength of foamed concrete of 0.31 MPa and 0.26 MPa at 7 d and 28 d, respectively. Thus, the adoption of a simply supported beam structure fits site through crack. To avert cracks on the top of foamed concrete in high groundwater table, the antibuoyancy measures should be adopted prior to construction of the upper bearing stratum. The study has expanded the application scope of subgrade and enriched theory of foamed concrete filled in high groundwater table, providing a significant reference to similar projects.

Tuning photoionization mechanisms of molecular hybrid materials for EUV lithography applications

Aromatic structures in organic shell stabilize photoionization products of metal oxo clusters, a new type of materials for EUV lithography.

Laser Based Machining of Aluminum Metal Matrix Composites

Aluminium metal matrix composites (Al MMC) are a relatively new type of material which combine lightweight metallic matrices (aluminium) with hard ceramic reinforcements (like alumina fibre or silicon carbide particles). Al MMCs have excellent potential in various applications from automotive to aerospace; however, their use is currently limited due to their low machinability. Conventional laser processes such as the laser drilling or cutting of monolithic materials (metals/alloys) are well-established processes. However, conventional laser processing of anisotropic materials like metal matrix composites is challenging due to the immense differences in the chemical and physical properties of the matrix and reinforcement. Over the last decade, nanosecond laser based water jet guided (WJG) machining has securely established itself as a novel laser based machining process, especially for the machining of non-monolithic materials like composites. The main investigation of this paper is centred on understanding the performance of WJG laser and conventional high power fibre laser machining of Al MMC. Laser machining of both fibre-based and particle-based Al MMC has been investigated (Al2O3 Fibre–Al MMC; SiC Particle–Al MMC). The WJG laser machining results were compared with the results from conventional long pulse/continuous wave laser process.

Two Approaches to the Problem of High-cycle Fatigue of Materials and Structures

Creation of new types of materials and development of new methods aimed at extending the lifetime of structures are two interconnected approaches to solve the problem of metallic structures fatigue. The paper considers a method for estimating the efficiency of damping implemented in metallic structures by means of energy-intensive materials. The results of comparative calculation are given on the ultimate number of transverse vibration cycles in bridge girders. The calculation uses a linear hypothesis of fatigue-caused damage summation and a model of cyclic material degradation. Notable increase of the vibration decrement for foam-filled metallic structures is predicted, with the lifetime of products lengthening as a result.

Influence of microscopic precipitate structures on macroscopic pattern formation in reactive flows in a confined geometry.

Thanks to the coupling between chemical precipitation reactions and hydrodynamics, new dynamic phenomena may be obtained and new types of materials can be synthesized. Here we experimentally investigate how the characteristic microscopic crystal properties affect the macroscopic pattern obtained. To shed light on such interactions, different reactant solutions are radially injected into a calcium chloride solution at different volumetric flow rates in a confined geometry. Depending on the reactants used and the flow conditions, deformed precipitate membranes have been observed due to reaction-driven viscous fingering. In such cases we show that upon injection a large number of small particles is produced in situ by the reaction at the miscible interface between the two reactant solutions. Therefore, a colloidal gel composed of those tiny particles is pushed forward by the injected aqueous solution giving rise to a viscosity gradient-driven hydrodynamic instability.

Dendrimers and hyper-branched polymers interacting with clays: fruitful associations for functional materials

The interaction of dendrimers or hyper-branched polymers with clays produces different types of new materials.

Numerical study on gas-solid flow characteristics of ultra-light particles in a cyclone separator

Cyclone separator is a widely used mechanical equipment that removes solid materials from transport gas, and the separation characteristics depends heavily on material properties. Most separation objects commonly studied are micron-sized powders or particles of high density with the magnitude ranging from 102 to 103kg/m3. While the particle density of expanded graphite (EG), a new type of material that is widely used in industry, is only a few tenths of conventional materials. However, the cyclone separation of such ultra-light particle has not been studied so far. This paper, based on the computational fluid dynamics and discrete element (CFD-DEM) coupling method, performs simulation experiments of the ultra-light particle cyclone separation at different inlet velocities. The pressure and velocity distribution of the continuous phase in the separator are studied. The effects of ultra-light particles on the flow field are revealed. The particle flow patterns are obtained and the force characteristics of the ultra-light particle are analyzed. Simulation results are verified experimentally. The results show that the separation characteristics of ultra-light particles are different from that of conventional materials: a) the appearance of ultra-light particles has negligible effect on the flow field in the separator; b) the ultra-light particles can be completely separated even if the inlet velocity is low; c) when the inlet velocity is higher than 7.5m/s, "top ash ring" composed of ultra-light particles appears under the roof of the cyclone, and multi-helical particle stream is observed in the cylinder region; besides,some "stagnant" particles rotate horizontally in the cone separation zone; d) particle turbulent diffusions in the upper part of the cyclone become stronger first and then weaker as the inlet velocity increases; e) the gas-particle coupling force and collision force are much larger than the particle gravity, and collisions of particles with different sizes are the main cause of secondary particle breakage.

Thermal characteristics of cement microparticle-stabilized aqueous foam for sealing high-temperature mining fractures

The fractures formed at high temperatures by the heat damage of coal and rock are the main causes for the evolution and spread of coal fires. Cement microparticle-stabilized aqueous foam is a new type of material for preventing and controlling coal and rock fractures at high temperatures. The thermal characteristics of the foam fluid are the most important technical parameters. The morphological changes of the foam fluid under different hot surface temperatures were characterized, and the mechanism of the effect of heating on the stability of the liquid film was studied based on the kinetic energy of the surfactant molecules and particle hydration. Using a homemade testing system, the thermal insulation properties of foam fluid with different bracket heights (2 cm, 7 cm, 12 cm, 17 cm, and 22 cm) and injection thicknesses (20 mm, 40 mm, 60 mm, and 80 mm) were tested. It was concluded that the cold surface temperature of all the foam fluids from 20 mm to 80 mm increased with increasing temperature; however, the rate of temperature increase within 0–90 s was greater than that within 90–300 s. The thermal insulation temperature was distributed on a Gauss cum surface, and the relationship of the thermal insulation temperature with the hot surface temperature and thickness was fitted. On the foundation of the traditional steady-state method, a new effective thermal conductivity measurement apparatus with a half-globular shape was developed, and its principle of operation and experimental setup were described. The effective thermal conductivity fluctuated slowly between 0.1222 and 0.2974 W/m·K within the temperature range of 323–373 K. The empirical correlation to calculate the thermal conductivity of the cement microparticle-stabilized aqueous foam at different temperatures was obtained.