Combination Of Material Properties Research Articles

Methyl-methacrylate based aluminum hybrid film grown via three-precursor molecular layer deposition

Molecular layer deposition (MLD) processes involving two precursors are commonly employed for the growth of conformal thin films. However, the use of two precursors limits the combinations of material properties that can be accessed during film synthesis. Here, we develop a robust, three-precursor MLD process for a hybrid film that incorporates a desirable acrylate, methyl-methacrylate (MMA), together with aluminum into its repeating structure. We report a film growth rate of 3.5 Å/cycle at 110 °C, constant growth per cycle between 100 and 130 °C, and good stability of the film when exposed to ambient. We propose reaction pathways for the incorporation of MMA into the film, and by using infrared spectroscopy and x-ray photoelectron spectroscopy, we identify the reaction pathway as a non-zwitterionic aminoacrylate reaction. This study offers new insight into the use of more than two precursors in the design of an acrylate-based MLD film and provides a framework that can be adopted for subsequent three-precursor film designs.

Influence of Electrical and Thermal Conductivity of Cemented Carbides on the Wire EDM Process

Wire electrical discharge machining (WEDM) is suitable for manufacturing fine blanking punches made of cemented carbides, because it is independent of the mechanical material properties. Nevertheless, the process is influenced by electrical and thermal properties of the machined workpiece and the properties of the used dielectric. Cemented carbides differ in their thermal and electrical properties depending on grain size and binder content. This leads to instabilities or wire breakages during the machining when using standard machining technology. To avoid this, the electrical machine settings must be adapted to the respective material. So far, there is no physical material-property-based approach, which allows a material-specific adaptation of the machine settings. Therefore, in this paper, the influence of the material properties in combination with the used dielectric on the process conditions during WEDM is investigated. For this purpose, nine carbides with different electrical and thermal conductivities (varying binder content and grain size) are investigated in two oil-based and in two water-based dielectrics. It could be observed, that with increasing thermal and electrical conductivity of cemented carbides the cutting rate decreases, when not adapting the machine settings. Individual adaptation of the machine settings to the respective cemented carbides composition significantly increased the cutting rate. Furthermore, when using a high viscosity dielectric with low thermal conductivity, the highest cutting rate is observed. The resulting higher heat concentration is assumed to be the cause based on the measured discharge craters and the rim zone thicknesses.

Experimental assessment of packaging paper properties effect in combination with storage conditions on the adhesion performance of automotive glass

Abstract The aim of this work was an experimental comparison of different types of packaging paper, determining the effect of packaging material properties in combination with storage conditions on the purity of glass surface and the related quality of adhesion of bonded materials. In the automotive industry, the quality of adhesion is a key factor, as automotive glass must meet the safety requirements. During the experiments, the glass sheets were wrapped in four types of paper and stored according to the conditions that are common in a real production. The research was focused on the influence of different composition of packaging papers on the resulting adhesive properties of glass sheets. According to the results obtained in this work, it can be stated that during the storage there is an interaction between paper and glass. According to XRF analyzes, ongoing corrosion of the glass can be inferred. The resulting adhesion was assessed based on a peel test, which took place under defined conditions given by standard customer specifications. It has been observed that the negative effect of unsuitable paper increases over time. For optimal adhesion it is necessary to emphasize the packaging materials and the storage conditions of the glass. The results and knowledge achieved in this work can significantly improve the quality of production in which a material is glued to the glass surface.

Selection of backfill grout for shallow geothermal systems: Materials investigation and thermo-physical analysis

A main aspect of the geothermal well design is the selection of grouts backfilling the space between a geothermal probe and the surrounding ground, taking into consideration the mineralogical, thermo–physical, mechanical and flowability properties. The EU GEO4CIVHIC project aimed at developing efficient and cost-effective geothermal systems suitable for the air-conditioning refurbishment of urban buildings. A selection of different grouts was performed to ensure the whole efficiency of shallow geothermal heat exchangers designed within the project. Experimental tests were executed to identify flowable grouts with the best possible combination of different material properties, while also fulfilling a competitive cost target set forth in the preliminary project cost analysis. Grout acceptance criteria were defined: a working time of at least 4 h, a water bleeding target of 2% and a volumetric shrinkage upper bound of 4%, a thermal conductivity in water saturated conditions of at least 1.4 to 1.5 Wm−1K−1, a compressive strength range of 1 to 2.1 MPa, a flow time range of 60 ± 15 s. Two out of six commercial grouts were selected for installations onsite.

NUMERICAL STUDY OF THE EFFECT OF GEOMETRY AND BOUNDARY CONDITIONS ON THE COLLAPSE BEHAVIOUR OF STOCKY STIFFENED PANELS

This study aims at studying different configurations of the stiffened panels in order to identify robust configurations that would not be much sensitive to the imprecision in boundary conditions that can exist in experimental set ups. A numerical study is conducted to analyze the influence of the stiffener’s geometry and boundary conditions on the ultimate strength of stiffened panels under uniaxial compression. The stiffened panels with different combinations of mechanical material properties and geometric configurations are considered. The four types of stiffened panels analysed are made of mild or high tensile steel and have bar, ‘L’ and ‘U’ stiffeners. To understand the effect of finite element modelling on the ultimate strength of the stiffened panels, four types of FE models are investigated in FE analysis including 3 bays, 1/2+1+1/2 bays, 1+1 bays and 1 bay with different boundary conditions.

Approaching new biomaterials: copolymerization characteristics of vinyl esters with norbornenes, allyl esters and allyl ethers

AbstractVinyl ester‐based monomers for radical photopolymerization have recently been shown to be promising alternatives to (meth)acrylates through lower irritancy and cytotoxicity. Vinyl ester monomers are becoming increasingly important on account of new, more cost‐efficient synthetic production methods, not to forget their increased reactivity and improved material properties in combination with thiol–ene polymerization. Due to their biocompatibility and degradability, these monomers are more frequently used in tissue engineering. Nevertheless, the material properties can be improved by possible copolymerizations with other monomers. Therefore, the copolymerization behavior of vinyl ester with norbornene, allyl ether and allyl ester has been studied fundamentally in a photoreactor via free radical photopolymerization. Here, the consumption of double bonds of the monomers has been identified using NMR spectroscopy. Copolymerization parameters have been determined using the Kelen–Tüdös method. Results show equal consumption of vinyl ester and co‐monomer double bonds leading to alternating copolymerizations. The double bond conversion was confirmed via in situ real‐time near‐infrared photorheology. Mono‐ and difunctional vinyl esters with co‐monomers have also provided further insight into the polymer network of these copolymers. © 2021 The Authors. Polymer International published by John Wiley & Sons Ltd on behalf of Society of Industrial Chemistry.

FUNDAMENTAL INVESTIGATIONS ON THE MACHINABILITY OF ADDITIVELY MANUFACTURED MULTI-MATERIALS

Additively manufactured multi-materials promise unique combinations of different material properties. However, the machining behavior of these materials is widely unknown. In this study, fundamental investigations on chip formation and morphology, cutting force, workpiece temperature after cutting and surface quality were conducted in orthogonal cutting experiments. Additively manufactured test specimens made out of 316L stainless steel processed by Laser Powder Bed Fusion (LPBF), and the nickel-based alloy Inconel 718 processed by wire-based Laser Metal Deposition (LMD-w) were machined. Investigations were conducted with single- and multi-material combinations as well as porous 316L material. Besides, conventional cast material was machined in order to draw a relative comparison. The results showed significant changes in chip formation and cutting forces between cast and additively manufactured materials, especially for Inconel 718. These differences can be attributed to the changed microstructure and material properties. For two-component multi-materials, the connection area between the materials acted as a defect only to a limited extent. It was shown that the main influence evoke from the cutting direction in relation to the build-up direction of the specimen.

Hygrothermal performance assessment of split insulated cork wall assemblies under various moisture load conditions

Every year along with the implementation of energy-saving, energy conservation and other green energy initiatives the demand for effective, but sustainable, renewable insulation materials in the construction industry increases. It is worth mentioning that the selection of insulation materials nowadays is not limited to its cost and technical characteristics only, but health-related aspects and carbon footprint are also taken into consideration. However, there are not many insulation materials that have competitive technical characteristics, are sustainable, renewable and do not pose risk for health. Cork and cork-based materials like insulation cork boards (ICB) are of these types of materials which have unusual combination of material properties, have low to negative carbon footprint and have low to almost zero negative impact on the ecology and human health during the whole life cycle and later on. That is why with the increasing demand for sustainable, renewable and ecological materials the interest toward cork in North America is expected to increase. However, there are not so many researches performed on lightweight wall assemblies common in North America with cork insulation applications. In this paper, the hygrothermal performance of natural cork insulation used in split wall assemblies is compared against similar, commonly used mineral wool and expanded polystyrene (EPS) wall assemblies for three different Canadian climates, using WUFI hygrothermal analysis computer simulation tool. The relative performance of seven wall assemblies, with various combinations of insulation type and vapor control strategies, exposed to different moisture loads including elevated indoor humidity, air leakage and rain penetration are presented. The simulation results suggest that, in general, assemblies with cork have a slight advantage in performance against the EPS assemblies, especially when the amount of moisture affecting the assemblies is high. In most cases, assemblies with mineral wool perform better than that of with cork and EPS insulations.

Customizing biohybrid cryogels to serve as ready-to-use delivery systems of signaling proteins

Macroporous cryogels have recently gained increasing interest for the controlled administration of signaling proteins in tissue engineering due to an advantageous combination of material properties. However, most of the previously reported cryogel systems did not allow for tunable, sustained protein release. We therefore designed a set of ready-to-use multi-armed polyethylene glycol (starPEG)-heparin cryogel systems containing different amounts of the protein-affine glycosaminoglycan component heparin to enable systematically tunable long-term delivery of different signaling proteins without affecting other cell-instructive properties. Experimental data and mathematical modeling indicate that the macroporous structure causes local differences in the concentration of proteins released into the pores and in the surrounding of the cryogels. As a proof-of-concept for their ready-to-use potential, cryogels pre-functionalized with signaling proteins and cell adhesion-peptides were demonstrated to induce the neuronal differentiation of colonizing pheochromocytoma cells. The elaborated approach opens up new perspectives for cryogels as easily storable and applicable systems for the precision delivery of signaling proteins.

The evolution of material stock research: From exploring to rising to hot studies

AbstractMaterial stocks in buildings, infrastructure, and durable products play multiple roles in environmental and socioeconomic systems throughout their life cycle. After half a century of exploration, the study of material stocks has led to the development of a knowledge system. However, an overall picture of the evolution of knowledge in this field is lacking. With the aid of CiteSpace, a science mapping tool, we review 395 publications and find that the study of material stock experienced three obvious stages: initial exploration (1973–2005); rising period (2006–2016); and a hot period (2017–2020). The evolution of material stock research shows a clear objective‐oriented mode. As research objectives evolved from macroscopic observation to refined management of materials, the main research content changed from observational accounting to exploring the application, role, and service functions of material stocks, especially from the perspective of systematic metabolism under the complex background of social transformation. Accounting items shifted from an initial focus on metallic materials to a broader set of materials and product stocks, and from accounting of a single category to multi‐category accounting. The scale of research correspondingly shifted from the national and global scale to the urban and community scale which can serve refined management. These changes also led to in‐depth and detailed study of the role and function of stocks. In the future, scholars should continue to explore and apply microscale models, “whiten” the black box in large scale research; focus on recycling of urban minerals and electronic wastes. Mapping the transformation of raw materials into products by combining material properties and product functions is crucial to concretely implement a circular economy. Differentiation, specialization, combination of approaches, and sub‐categorical and sub‐regional coefficients will be the key to future refined, lean, and precise accounting.

Solid coin-like design activated carbon nanospheres derived from shallot peel precursor for boosting supercapacitor performance

Thin porous carbon nanospheres based on natural materials, characterized by abundant availability, facile synthesis without templates, and heteroatom doping have confirmed the enhanced high performance of electrochemical energy storage devices. However, these potentials are difficult to obtain, and further poses a serious challenge. This work, activated carbon nanosphere was obtained from the biomass precursor shallot peel through a solid coin-like design with different chemical impregnations with high-temperature pyrolysis. The three different activators used were KOH, ZnCl2, and NaOH, selected to optimize the precursor's potential to produce porous carbon nanospheres. All the carbons prepared exhibited potential nano-sized morphological structures with a high carbon content of 77.71–90.11%. Furthermore, the oxygen content of 24.60% indicated a doping heteroatom for the electrode material. Surprisingly, the KOH impregnation exhibited a nanosphere-rich morphological structure with a diameter of 102–124 nm adhering to the nanofiber surface. This combination of material properties has the benefit of improving the supercapacitor's performance with a high specific capacitance of 170.12 F g−1 in a 1 M H2SO4 aqueous electrolyte. Meanwhile, the maximum specific energy reached 16.67 Wh kg−1 with a maximum specific power of 86.40 W kg−1 at a constant current density of 1.0 A g−1, in a two-electrode system. Therefore, the activated carbon with a solid coin-like design derived from shallot peel waste is a potential source of a rich nanospheres structure with a facile strategy for large-scale commercial electrochemical energy storage applications.

Nanotube Sheet and Yarn Manufacturing and Commercialization

Nanotube macroscale materials such as yarns, tapes, and sheets provide combinations of material properties that are unique relative to existing materials. Although nanotube sheet and yarn commercialization is still an emerging activity, these materials may become important in the future Business and Economics of societies. Therefore, this paper surveys current worldwide efforts toward manufacturing and commercialization of nanotube macroscale materials. The survey will help researchers, investors and economists consider how the new materials might be used in new applications and how the materials might spur economic development. Nanotube macroscale materials consist of yarn, tapes, and sheets, and exclude powdered forms of nanotubes used as filler materials. Both Carbon Nanotube (CNT) and Boron Nitride Nanotube (BNNT) materials are considered. It is anticipated that macroscale sheet and yarn with customizable properties will have broad applications. This paper is organized to provide ideas for possible areas of applications of nanotube yarn and sheet, followed by a survey of current commercialization efforts. Manufacturing barriers that must be overcome to push the development of nanotube macroscale materials toward large scale commercialization are also discussed. The paper also provides references for researchers and industry professionals who may want to further develop and put nanotube macroscale materials into their own applications.

Global Inverse Design across Multiple Photonic Structure Classes Using Generative Deep Learning

AbstractUnderstanding how nano‐ or micro‐scale structures and material properties can be optimally configured to attain specific functionalities remains a fundamental challenge. Photonic metasurfaces, for instance, can be spectrally tuned through material choice and structural geometry to achieve unique optical responses. However, existing numerical design methods require prior identification of specific material−structure combinations, or device classes, as the starting point for optimization. As such, a unified solution that simultaneously optimizes across materials and geometries has yet to be realized. To overcome these challenges, a global deep learning‐based inverse design framework is presented, where a conditional deep convolutional generative adversarial network is trained on colored images encoded with a range of material and structural parameters, including refractive index, plasma frequency, and geometric design. It is demonstrated that, in response to target absorption spectra, the network can identify an effective metasurface in terms of its class, materials properties, and overall shape. Furthermore, the model can arrive at multiple design variants with distinct materials and structures that present nearly identical absorption spectra. The proposed framework is thus an important step towards global photonics and materials design strategies that can identify combinations of device categories, material properties, and geometric parameters which algorithmically deliver a sought functionality.

TPLS as predictive platform for twin-screw wet granulation process and formulation development

In recent years, the interest in continuous manufacturing techniques, such as twin-screw wet granulation, has increased. However, the understanding of the influence of the combination of raw material properties and process settings upon the granule quality attributes is still limited. In this study, a T-shaped partial least squares (TPLS) model was developed to link raw material properties, the ratios in which these raw materials were combined and the applied process parameters for the twin-screw wet granulation process with the granule quality attributes. In addition, the predictive ability of the TPLS model was used to find a suitable combination of formulation composition and twin-screw granulation process settings for a new API leading to desired granule quality attributes. Overall, this study helped to better understand the link between raw material properties, formulation composition and process settings on granule quality attributes. Moreover, as TPLS can provide a reasonable starting point for formulation and process development for new APIs, it can reduce the experimental development efforts and consequently the consumption of expensive (and often limited available) new API.

Three dimensional atmospheric entry simulation of a high altitude cometary dustball meteoroid

Aims. The break-up of a dustball meteoroid is investigated numerically based on fluid dynamics simulations of the meteoroid’s atmospheric entry flow. Both thermal and mechanical break-up mechanisms are implemented, in order to investigate dustball meteoroid disintegration. Methods. A three dimensional model of a dustball meteoroid composed of thousands of small spherical grains was used in the atmospheric entry flow simulation, performed with the direct simulation Monte Carlo (DSMC) method. The dynamics of each meteoroid grain were calculated by means of the discrete element method (DEM), which models contact dynamics between grains. By coupling DEM with DSMC, the dynamics of a dustball meteoroid were calculated during atmospheric entry. In addition, thermal computations were also carried out taking into account the incoming atmospheric heat flux, thermal radiation, and grain ablation. Thus, this methodology is able to compute mechanical as well as thermal dustball meteoroid disintegration. Results. To test this novel multi-physics simulation framework, a prototypical dustball meteoroid, namely a Draconid meteoroid, was simulated. Using typical material properties from the literature, the Draconid meteoroid was compressed due to aerodynamic forces to roughly half its size immediately after the start of the simulation at 200 km altitude. Later, aerodynamic-induced meteoroid rotation occured until the meteoroid disintegrated mechanically at 120 km altitude. The fact that the meteoroid disintegrated mechanically is directly related to the combination of material properties used in the simulation.

Multiscale temperature-dependent ceramic matrix composite damage model with thermal residual stresses and manufacturing-induced damage

This work presents a multiscale thermomechanical simulation framework to capture the temperature-dependent damage behavior of woven ceramic matrix composites (CMCs). The framework consists of cooldown simulations, which capture a realistic material initial state, and subsequent mechanical loading simulations to capture temperature-dependent nonlinear stress–strain behavior. The cooldown simulations result in a realistic material initial state with thermal residual stresses and damage hotspots that occur due to constituent property mismatch and post-manufacturing cooldown. A fracture mechanics-informed thermomechanical progressive damage model is extended to capture the manufacturing-induced damage that occurs because of the high thermal residual stresses and to simulate the mechanical response of two-dimensional (2D) plain weave carbon (C) fiber, silicon carbide (SiC) matrix (C/SiC) CMCs at temperatures ranging from room temperature (RT) to 1200 °C. A combination of temperature-dependent material properties and damage model parameters are included in the model to simulate the effects of temperature on deformation and damage behavior. Model calibration was conducted using quasi-static tensile experimental data from the literature for RT, 700 °C, and 1200 °C and the nonlinear, temperature-dependent predictive capabilities of the reformulated model are demonstrated for 1000 °C. The model is also applied to simulate the temperature-dependent thermomechanical response of a 2D woven five harness satin (5HS) SiC/SiC CMC at RT and 1200 °C and shows excellent agreement with experiments.

Bioactivity Experimental Studies of Composite Materials Promising for Use in Traumatology and Orthopedics: Review

The aim of the study — to determine the properties of modern bioactive composite materials that have the greatest advantage for use in traumatology and orthopedics, particularly in spine surgery.Material and Methods. We performed a comprehensive literature search using PubMed, Medline, eLIBRARY and Semantic Scholar. The keywords “implants”, “biomaterials”, “composites”, “tissue engineering”, “scaffolds”, “graphene”, “hydrogels”, “3D bioprinting” were used to identify papers examining the topic of interest. We included comparative studies published from 2010 to 2020 in our review. The following properties were evaluated in papers: biotolerance, bioactivity, osteoconductivity, osteoinductivity, osteostimulation, mechanical strength.Results. Special attention is paid to the creation of composites. Composites are made by combining two or more materials to achieve biochemical and biomechanical properties. In composites production, a certain place is occupied by the technology of 3D bioprinting, thanks to which it is possible to develop an individual implant according to a given situation.Conclusion. The combination of composite materials properties indicating on their bioactivity and mechanical strength, as well as the use of 3D techniques to design the geometric forms of implants, provide a high potential for use in traumatology and orthopedics, particularly in spinal surgery.

Flexural behavior of PVA‐FRC GFRP reinforced concrete beams

AbstractFiber reinforced concrete beams are a popular research topic because of the improvement in the performance of concrete beams with fibers. PVA‐FRC GFRP reinforced concrete beams have better mechanical properties than those of ordinary reinforced concrete beams when considering the combination of multidirectional material properties. This article presents the results of an experimental study on the flexural behavior of PVA‐FRC GFRP reinforced concrete beams. Seven GFRP concrete beams were tested. The test variables included the PVA fiber content and GFRP diameter. The test results indicated that the existence of GFRP bars is effective for enhancing the load‐carrying capacity of RC beams and that PVA fibers can substantially inhibit the development of cracks in PVA‐FRC GFRP reinforced concrete beams and increase the midspan deflection. The experimental midspan deflection and maximum crack widths are also compared with theoretical predictions using new guidelines from the American Concrete Institute. Finally, the maximum crack correction formula for PVA‐FRC GFRP reinforced concrete beams is proposed.

The influence of spatially varying materials and buckling instabilities on elastic band gaps

The behavior of band gaps is often important to the design of architected materials. One aspect of interest is the ability to tune the band gap via an external stimulus. The use of elastic deformation is a popular method within the field of mechanical metamaterials to achieve band gap switching. Another design feature is the width of the band gap. Structures with variations in the physical or geometric properties may exhibit wider band gaps than uniform designs. This work combines the study of lattices that achieve buckling induced band gaps with spatially varying material properties to leverage both effects. The example lattice design contains super-unit cells of circular voids within a soft elastomeric matrix arranged with different combinations of discrete material properties. The present numerical study compares the simulated transmission through several example designs and demonstrates both band gap widening due to the multiple materials and switching as a function of mechanical deformation.

Prediction of Rotor Burst Using Strain-Based Fracture Criteria to Comply With the Engine Airworthiness Regulation

Abstract Relative to the rotor overspeed compliance governed by civil aviation airworthiness regulation, nowadays the Area-Average Stress method is commonly used approach. However, in order to effectively apply the Area-Average Stress method in analyzing burst speed, large amount of testing data is needed to define an important element of this method: a correction factor. This prerequisite hinders the use of this method for many companies that have limited test data. Meanwhile, analysis of rotor burst speed based on Strain-based Fracture Criteria using true stress–strain curves and burst tests has been done on the low-pressure turbine (LPT) rotor, and a work procedure obtaining the most critical burst speed for certification is proposed. The analysis results, which had a good correlation with test results, showed that Strain-based Fracture Criteria can accurately predict the burst speed considering the most adverse combination of dimensional tolerances, temperature, and material properties, and rotor dimensional growth under the overspeed condition. Both are required by the aircraft engine airworthiness overspeed regulation. Compared to the Area-Average Stress method, Strain-based Fracture Criteria reflects the physical essence of the rotor burst more realistically and can be simply verified without requiring too much test data, therefore it has a good application prospect in the aircraft engine airworthiness.