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Journal ArticleDOI
C.P. Doǧan, J.A. Hawk 
01 Oct 2001-Wear
51 Citations
Nonetheless, characteristics of the ceramic microstructure do influence its hardness and fracture toughness and must, therefore, play an active role in determining how a ceramic will respond to the specific stress states imposed upon it by the wear environment.
Therefore, when making a restoration using a leucite-based heat-pressed ceramic crown, it is advisable to use tooth-coloured materials such as a porcelain veneered cast post, if you will not be able to make the ceramic more than 1.6 mm thick.
The archaeological and technological evidence from the site provides a unique perspective on how a deliberate imperialistic policy can affect local ceramic traditions, including the pottery and silicate industries.
This example from prehistory illustrates how controlling for formation-process variability enhances estimates of the rate of ceramic change.
The experimental results show that the system can effectively glaze defects on the surface of ceramic pot products.
As such, ceramic assemblages speak to how boundaries were enacted differently depending on the status of the actors engaged in these transactions.
The simulations show how propagating complexion transitions can explain the AGG observed in certain ceramic systems.

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Dog bone shape different ASTM standards with dimensions for plastics
4 answers
Dog-bone shaped specimens are commonly used in mechanical testing of materials, including plastics. ASTM standards provide guidelines for preparing and testing these specimens. ASTM D638-14 specifies the preparation of dog-bone shaped specimens for testing tensile properties of plastics, mentioning machining, die cutting, or molding methods. Additionally, ASTM E1820-2013 and ISO12135:2016 standards focus on fracture toughness testing, with differences in data processing methods and material constitutive models affecting the choice of standard based on material properties. Furthermore, a novel MEMS resonator-based probe with a dog-bone shape was developed for atomic force microscopy, showcasing enhanced resonance frequency and quality factor compared to traditional cantilever probes. These standards and innovations highlight the importance of standardized testing procedures and specimen shapes in evaluating the mechanical properties of plastics.
What causes or contributes to the formation of oxygen vacancies in TiO2 in CO2 hidrogenatiion?
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The formation of oxygen vacancies in TiO2 during CO2 hydrogenation can be attributed to various factors. One significant contributor is the application of an electric field, which promotes the creation of oxygen vacancies in TiO2 films, leading to enhanced photocatalytic efficiency. Additionally, interfacial strain induced by coating can energetically favor the generation of oxygen vacancies in TiO2, resulting in improved material properties and performance. Moreover, the reduction of Rhodium salt by electrons in an electric field during catalyst preparation can lead to the production of oxygen vacancies and Ti3+ on the catalyst surface, enhancing the interaction between Rh and TiO2 for improved CO hydrogenation to ethanol. Furthermore, defect engineering, particularly the presence of oxygen vacancies, plays a crucial role in enhancing the photocatalytic activity of TiO2, especially when combined with specific crystal facets.
In which temperature bearing bronze starts to soften?
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Bronze can start to soften at various temperatures depending on the specific type of bronze alloy. For instance, beryllium bronzes can undergo softening due to reverse solution when heated to 500°C. In contrast, the high-temperature-resisting ferro-bronze demonstrates good high-temperature-softening resistance, maintaining its hardness above 130 HV even after being held at 500°C for 5 minutes. Additionally, the QAl10-4-4 aluminum bronze alloy experiences changes in hardness during aging treatments at different temperatures, with hardness decreasing as certain phases decompose. Therefore, the softening temperature of bronze alloys can vary based on their composition and treatment processes.
What are the current technological applications of cuprate superconductors?
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Cuprate superconductors, known for their high-temperature superconductivity, find applications in various technological fields. They are crucial for applications in medical imagery, motors, generators, power cables, levitation trains, and fusion magnets. Additionally, advancements in rare-earth, cuprate-based bulk superconductors have led to their use in hybrid trapped field magnetic lensing, high-performance magnetic shields, large-gradient magnetic separation, and bench-top NMR/MRI ring-shaped stacks. The crystal structures and properties of cuprate superconductors like YBCO, Bi-2212, and Bi-2223 are essential for their applications, including creating flux pinning sites to increase critical current density. Moreover, the discovery of iron-based high-temperature superconductors has expanded the range of applications for cuprate superconductors.
What is electrobiocorrosion?
5 answers
Electrobiocorrosion is a complex process where the degradation of metal surfaces is influenced by both electrochemical reactions and the presence of microorganisms. This phenomenon involves the initiation, facilitation, or acceleration of corrosion reactions by microorganisms, particularly bacteria like anaerobic sulphate-reducing bacteria (SRB) and other acid-producing bacteria. The biofilms formed by these microorganisms alter the local environment at the metal surface, affecting factors such as pH, pressure, and nutrient levels, thus impacting the corrosion rate. Electrobiocorrosion is a significant concern in various industries due to the economic losses it can cause, highlighting the importance of implementing prevention and control measures that involve the evaluation of both biological and abiotic parameters.
What is the Interplay between anisotropy and heterogeneity in material behavior?
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The interplay between anisotropy and heterogeneity in material behavior is a complex phenomenon influenced by various factors. Anisotropy, affected by crystal orientation and processing parameters, is present in heterogeneous materials due to individual phase properties and microstructural configuration. Existing anisotropy measures have been re-interpreted to consider effective elastic properties in heterogeneous materials, highlighting the role of constituent volume fractions and phase characteristics in determining anisotropy levels. In materials like calendered nonwovens, anisotropy is influenced by the fibrous matrix, bond-areas, and interface regions, showcasing the impact of material heterogeneity on anisotropic behavior. Understanding this interplay is crucial for predicting and controlling material responses in various applications.
What is the matrix base material?
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A matrix base material is a foundational component in the creation of composite materials, serving as the binder that holds the reinforcement materials together, thereby providing the composite with its shape and structural integrity. These matrices can be composed of various substances, including polymers, metals, ceramics, and cement, each offering distinct advantages and limitations based on their physical properties and the application requirements. For instance, polymer matrices are known for their flexibility and can be either hard or rubbery, while metal matrices offer higher strength and ductility. Ceramic matrices, on the other hand, are valued for their high-temperature resistance, though they typically exhibit poor tensile strength. Innovative matrix base materials have been developed for specific applications, such as cold chain transporting devices that utilize a base material filled with a functional adjusting material to keep products fresh over long periods. Similarly, braking friction materials incorporate a base matrix combined with chemical additives and a stable epoxy resin to achieve desired performance characteristics. The surface roughness of ceramic matrix base materials can be specifically engineered to enhance the adhesion of coating layers, extending the service life of tools. Moreover, advancements in matrix materials include the incorporation of silicon carbide ceramics and oxide phases to improve heat and oxidation resistance, as well as mechanical characteristics in ceramic-based composites. The development of ceramic matrix materials that bond stably with metal base coatings has also been noted, offering stable expansion coefficients and resistance to thermal shock. Additionally, matrices have been innovatively used in road-base construction, utilizing recycled vehicle tires to contain aggregate materials and facilitate drainage. Recent research has also focused on modifying epoxy resin base materials with additives like carbon nanotubes to improve mechanical properties and interlayer shearing performance in composite materials. Collagen base materials have been explored for cell culture applications, allowing for the proliferation of cells in complex shapes. Lastly, in the medical field, matrices combining I-typed collagen and Ca minerals have been developed for bone filling, restoration, and replacement, showcasing excellent biological compatibility. In summary, matrix base materials are crucial in the development of composite materials, with their selection and formulation tailored to meet the specific needs of various applications, ranging from industrial and construction uses to advanced medical applications.
How does FTIR contribute to the understanding of corrosion mechanisms in Mg alloys?
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Fourier Transform Infrared Spectroscopy (FTIR) plays a crucial role in enhancing the comprehension of corrosion mechanisms in Mg alloys. FTIR aids in the analysis of corrosion products and surface films, providing insights into the chemical composition and structure. By utilizing FTIR, researchers can identify specific corrosion inhibitors and study their release mechanisms for potential self-healing properties. Moreover, FTIR enables the examination of corrosion films formed on Mg alloys, contributing to a deeper understanding of the protective layers and their effectiveness in preventing corrosion. The application of FTIR in corrosion studies allows for a detailed investigation of the interactions between the alloy surface and corrosive environments, shedding light on the degradation processes and facilitating the development of strategies to mitigate corrosion in Mg alloys.
Amount of percentage for replacement of sand and cement in concrete
4 answers
The research studies provide insights into the replacement percentages for sand and cement in concrete. For sand replacement, studies suggest that 30 to 40% of natural sand can be effectively replaced with crushed stone waste. Additionally, replacing 25% of natural fine aggregate with used foundry sand is found to be successful, with a decrease in compressive strength beyond this percentage. Furthermore, replacing 50% of river sand with M-sand in concrete mixtures has shown excellent strength parameters and economic benefits. When it comes to cement replacement, one study recommends not exceeding 25% replacement with fly ash to achieve desired strength levels. Another study indicates that sawdust can replace up to 20% of sand in concrete, with a recommended water-cement ratio not exceeding 0.5 for optimal properties.
How do the properties of CNT-reinforced polymer nanocomposites for prosthetics vary with the fabrication method used?
10 answers
The properties of Carbon Nanotube (CNT)-reinforced polymer nanocomposites, which are pivotal for prosthetics applications, significantly vary with the fabrication method employed. The solution casting approach, for instance, has been utilized to fabricate multiwalled carbon nanotubes (MWCNTs)-mediated polyvinyl alcohol (PVA) composite films, demonstrating enhanced dispersion of MWCNTs, improved tensile strength, and decreased bandgap, which are desirable for optoelectronic applications that could be relevant in prosthetic sensors. Similarly, the compression molding technique used in preparing polystyrene (PS)-based carbon fabric-reinforced polymers (CFRPs) containing elastomer showed that the mechanical properties and electrical resistivity of the composites could be significantly influenced by the nanocomposite preparation technique, affecting the shape memory behavior crucial for adaptive prosthetics. Additive Manufacturing (AM), particularly the fused filament fabrication (FFF) method, offers a novel approach to producing CNT-reinforced filaments that simultaneously increase mechanical, thermal, and electrical properties, essential for creating customized prosthetic parts with enhanced performance. The surface modification method, among other fabrication strategies like melt mixing and solution mixing, has been identified to improve the dispersion of CNT in the polymer matrix, thereby enhancing the composite's overall properties. The microstructure of CNT-reinforced polymer composites, including volume fraction and alignment of CNTs, significantly influences their electro-mechanical properties, which can be tailored through specific fabrication methods for desired prosthetic functionality. Furthermore, the tribological behavior of CNTs-reinforced composites, which is crucial for the durability and wear resistance of prosthetics, can be optimized through specific dispersion techniques such as ultrasonication and functionalization before ball milling. Molecular and atomic layer deposition (M/ALD) techniques have been shown to tailor CNT interfacial interactions effectively, enhancing the strength and toughness of polymer composites, which are vital for high-performance prosthetics. For biomedical applications, including prosthetics, the physicochemical and mechanical properties of CNT-reinforced polymer nanocomposites can be significantly improved through surface modification of CNTs to enhance their dispersion and distribution within various polymeric matrices. The superior mechanical properties of CNT-based nanocomposites, such as elastic modulus and tensile strength, are well-documented, underscoring their suitability for prosthetic applications. Lastly, the optical properties of polymer nanocomposites, which might be relevant for prosthetic applications requiring aesthetic considerations, depend on the nanoparticle size and distribution, which are influenced by the fabrication technique. In summary, the fabrication method plays a crucial role in determining the properties of CNT-reinforced polymer nanocomposites for prosthetics, affecting their mechanical strength, electrical and thermal conductivity, tribological behavior, and even optical properties, thereby influencing their suitability and performance in prosthetic applications.
What are the current challenges and future directions in the development of CNT-reinforced polymer nanocom?
10 answers
The development of carbon nanotube (CNT)-reinforced polymer nanocomposites faces several challenges, primarily centered around the optimization of CNT dispersion, toxicity concerns, and the scalability of production methods. A significant hurdle is achieving uniform dispersion and alignment of CNTs within the polymer matrix to maximize mechanical and functional properties, as agglomeration and poor dispersion can severely compromise the composite's performance. Techniques such as magnetic field alignment have been explored to control CNT orientation and improve composite properties, but further research is needed to fully understand and optimize these processes. Another challenge is the toxicity associated with CNTs, which poses health risks during production and handling, necessitating comprehensive studies to understand and mitigate these effects, especially for applications in biomedical fields. Additionally, the current production methods for CNTs, such as arc discharge, laser ablation, and chemical vapor deposition (CVD), limit the ability to meet large-scale demands due to cost, efficiency, and environmental concerns. Future directions in the development of CNT-reinforced polymer nanocomposites include the exploration of green, solvent-free synthesis methods to address environmental and scalability issues. Advances in surface modification techniques, such as molecular and atomic layer deposition (M/ALD), offer promising avenues for improving interfacial interactions between CNTs and polymer matrices, enhancing composite strength and toughness. Furthermore, the exploration of novel functionalization methods to improve CNT solubility and compatibility with polymers is critical for expanding the range of applications and performance of these composites. In summary, overcoming the challenges of CNT dispersion, toxicity, and production scalability is crucial for the advancement of CNT-reinforced polymer nanocomposites. Future research should focus on developing environmentally friendly production techniques, improving CNT-polymer interface interactions, and ensuring safe handling and use of CNTs to fully realize the potential of these advanced materials.