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Journal of Visualized Experiments : JoVE Sep 2016Different metallic materials have different polarization characteristics as dictated by the open circuit potential, breakdown potential, and passivation potential of the...
Different metallic materials have different polarization characteristics as dictated by the open circuit potential, breakdown potential, and passivation potential of the material. The detection of these electrochemical parameters identifies the corrosion factors of a material. A reliable and well-functioning corrosion system is required to achieve this. Corrosion of the samples was achieved via a potentiodynamic polarization technique employing a three-electrode configuration, consisting of reference, counter, and working electrodes. Prior to commencement a baseline potential is obtained. Following the stabilization of the corrosion potential (Ecorr), the applied potential is ramped at a slow rate in the positive direction relative to the reference electrode. The working electrode was a stainless steel screw. The reference electrode was a standard Ag/AgCl. The counter electrode used was a platinum mesh. Having a reliable and well-functioning in vitro corrosion system to test biomaterials provides an in-expensive technique that allows for the systematic characterization of the material by determining the breakdown potential, to further understand the material's response to corrosion. The goal of the protocol is to set up and run an in vitro potentiodynamic corrosion system to analyze pitting corrosion for small metallic medical devices.
Topics: Biocompatible Materials; Corrosion; Electrodes; Equipment and Supplies; Materials Testing; Stainless Steel
PubMed: 27683978
DOI: 10.3791/54351 -
Global Challenges (Hoboken, NJ) Feb 2023Photovoltaic silicon converts sunlight in 95% of the operational commercial solar cells and has the potential to become a leading material in harvesting energy from... (Review)
Review
Photovoltaic silicon converts sunlight in 95% of the operational commercial solar cells and has the potential to become a leading material in harvesting energy from renewable sources, but silicon can hardly convert clean energy due to technologies required for its reduction from sand and further purification. The implementation of the novel materials into photovoltaic systems depends on their conversion efficiency limited by the material's inherent properties, longevity dependent on internal stability, and ease of manufacturing process. A major challenge is discovering a multilayered set of different photovoltaic materials capable of converting clean energy from a wider spectra range since emerging materials and technologies such as dye-sensitized and quantum dots suffer from low conversion efficiencies while perovskite and organic cells have short longevity in atmospheric conditions. Presently, improving technologies for commercialized materials and creating multijunction solar cells enhanced by new photovoltaic materials is a path toward cleaner energies. With the rapid development of the integrative technologies and challenges that photovoltaics for clean energy conversion are facing, the entire clean photovoltaic industry could arise by bottom-up course as a part of integrative technologies rather than erecting large power plants.
PubMed: 36778780
DOI: 10.1002/gch2.202200146 -
Polymers Dec 2021This article attempts to introduce a simple and robust way for the classification of soft magnetic material by using multivariate statistics. The six magnetic properties...
This article attempts to introduce a simple and robust way for the classification of soft magnetic material by using multivariate statistics. The six magnetic properties including coercive magnetic field, relative magnetic permeability, electrical resistivity magnetic inductions, i.e., remanence and saturation along with Curie temperature are used for the classification of 16 soft magnetic materials. Descriptive statistics have been used for defining the prioritization order of the mentioned magnetic characteristics with coercive magnetic field and Curie temperature as the most and least important characteristics for classification of soft magnetic material. Moreover, it has also justified the usage of cluster analysis and principal component analysis for classifying the enlisted materials. After descriptive statistics, cluster analysis is used for classification of materials into four groups, i.e., excellent, good, fair and poor while defining the prioritization order of materials on a relative scale. Principal component analysis reveals that the relative permeability is responsible for defining 99.69% of total variance and is also negatively correlated with the coercive magnetic field. Therefore, these two characteristics are considered the responsible factors for categorically placing the enlisted materials into four clusters. Furthermore, principal component analysis also helps in figuring out the fact that a combined influential consequence of relative permeability, coercive magnetic field, electrical resistivity and critical temperature are responsible for defining prioritization ordering of materials within the clusters. The material's suitability index is identified while making use of adjacency and decision matrices obtained from material assessment graph and relative importance of magnetic properties, respectively. Afterward this material suitability index is used to rank the enlisted materials based on selected attributes. According to the suitability index, the best choice among enlisted soft magnetic materials is Supermalloy, Magnifer 7904 which is present in group 1 labeled as excellent by multivariate analysis. Therefore, the results of graph theory are in accordance with cluster analysis and principal component analysis, thus confirming the potential of this intelligent approach for the selection application specific magnetic materials.
PubMed: 34960877
DOI: 10.3390/polym13244328 -
Science Advances Dec 2019Disordered materials are often out of equilibrium and evolve very slowly in a rugged and tortuous energy landscape. This slow evolution, referred to as aging, is deemed...
Disordered materials are often out of equilibrium and evolve very slowly in a rugged and tortuous energy landscape. This slow evolution, referred to as aging, is deemed undesirable as it often leads to material degradation. However, we show that aging also encodes a memory of the stresses imposed during preparation. Because of inhomogeneous local stresses, the material itself decides how to evolve by modifying stressed regions differently from those under less stress. Because material evolution occurs in response to stresses, aging can be "directed" to produce sought-after responses and unusual functionalities that do not inherently exist. Aging obeys a natural "greedy algorithm" as, at each instant, the material simply follows the path of most rapid and accessible relaxation. Our experiments and simulations illustrate directed aging in examples in which the material's elasticity transforms as desired because of an imposed deformation.
PubMed: 32064313
DOI: 10.1126/sciadv.aax4215 -
Journal of Environmental Management May 2022A critical review of the articles dealing with biochar in terms of the reuse of biomass waste in building materials and its impact on material properties was conducted... (Review)
Review
A critical review of the articles dealing with biochar in terms of the reuse of biomass waste in building materials and its impact on material properties was conducted using five different electronic databases; thirteen articles were selected for this critical review. Biochar was used as a replacement for cement and aggregate in cementitious composites and as an addition in wood polypropylene composites and plasters. The biochar dosages ranged from 0.5% to 40%; in most composites, the addition of biochar increased strength and reduced thermal conductivity and the bulk density of fresh mortars. Also, biochar dosages of 0.5-2% decreased, while dosages of 10-40% increased water absorption and penetration on cementitious composites. The selected studies mainly introduced biochar use in building materials as a means of biomass waste reduction and its reuse for various purposes, while carbon footprint reduction was addressed in only a few of them. Biochar-containing building material's capability of capturing CO from the air was also observed (0.033 mmol CO g to 0.138 mmol CO g). The results also showed that mortars with CO-unsaturated biochar had better mechanical and physical properties than mortars with CO-saturated biochar. Selected studies showed biochar-containing building materials have a great potential for carbon footprint reduction. However, there is a lack of comprehensive studies about biochar use in building materials concerning climate change mitigation.
Topics: Biomass; Charcoal; Construction Materials; Wood
PubMed: 35176567
DOI: 10.1016/j.jenvman.2022.114704 -
International Dental Journal Feb 2023The term bioactivity is being increasingly used in medicine and dentistry. Due to its positive connotation, it is frequently utilised for advertising dental restorative... (Review)
Review
The term bioactivity is being increasingly used in medicine and dentistry. Due to its positive connotation, it is frequently utilised for advertising dental restorative materials. However, there is confusion about what the term means, and concerns have been raised about its potential overuse. Therefore, FDI decided to publish a Policy Statement about the bioactivity of dental restorative materials to clarify the term and provide some caveats for its use in advertising. Background information for this Policy Statement was taken from the current literature, mainly from the PubMed database and the internet. Bioactive restorative materials should have beneficial/desired effects. These effects should be local, intended, and nontoxic and should not interfere with a material's principal purpose, namely dental tissue replacement. Three mechanisms for the bioactivity of such materials have been identified: purely biological, mixed biological/chemical, or strictly chemical. Therefore, when the term bioactivity is used in an advertisement or in a description of a dental restorative material, scientific evidence (in vitro or in situ, and preferably in clinical studies) should be provided describing the mechanism of action, the duration of the effect (especially for materials releasing antibacterial substances), and the lack of significant adverse biological side effects (including the development and spread of antimicrobial resistance). Finally, it should be documented that the prime purpose, for instance, to be used to rebuild the form and function of lost tooth substance or lost teeth, is not impaired, as demonstrated by data from in vitro and clinical studies. The use of the term bioactive dental restorative material in material advertisement/information should be restricted to materials that fulfil all the requirements as described in the FDI Policy Statement.
Topics: Humans; Dental Restoration, Permanent; Dental Caries; Policy; Dental Materials; Composite Resins
PubMed: 36577639
DOI: 10.1016/j.identj.2022.11.012 -
Frontiers in Bioengineering and... 2021The integrity of soft tissue seal is essential for preventing peri-implant infection, mainly induced by established bacterial biofilms around dental implants. Nowadays,...
The integrity of soft tissue seal is essential for preventing peri-implant infection, mainly induced by established bacterial biofilms around dental implants. Nowadays, graphene is well-known for its potential in biocompatibility and antisepsis. Herein, a new titanium biomaterial containing graphene (Ti-0.125G) was synthesized using the spark plasma sintering (SPS) technique. After material characteristics detection, the subsequent responses of human gingival fibroblasts (HGFs) and multiple oral pathogens (including , , and ) to the graphene-reinforced sample were assessed, respectively. Also, the dynamic change of the bacterial multispecies volume in biofilms was evaluated using absolute quantification PCR combined with Illumina high-throughput sequencing. Ti-0.125G, in addition to its particularly pronounced inhibitory effect on at 96 h, was broadly effective against multiple pathogens rather than just one strain. The reinforced material's selective responses were also evaluated by a co-culture model involving HGFs and multiple strains. The results disclosed that the graphene-reinforced samples were highly effective in keeping a balance between the favorable fibroblast responses and the suppressive microbial growth, which could account for the optimal soft tissue seal in the oral cavity. Furthermore, the underlying mechanism regarding new material's bactericidal property in the current study has been elucidated as the electron transfer, which disturbed the bacterial respiratory chain and resulted in a decrease of microbial viability. According to the Kyoto Encyclopedia of Genes and Genomes (KEGG) database, the PICRUSt tool was conducted for the prediction of microbial metabolism functions. Consequently, it is inferred that Ti-0.125G has promising potentials for application in implant dentistry, especially in enhancing the integrity of soft tissue and improving its resistance against bacterial infections around oral implants.
PubMed: 33928075
DOI: 10.3389/fbioe.2021.665305 -
Periodontology 2000 Feb 2017Despite decades of titanium as the gold standard in oral implantology, the search for alternatives has been growing. High esthetic standards and increasing incidence of... (Review)
Review
Despite decades of titanium as the gold standard in oral implantology, the search for alternatives has been growing. High esthetic standards and increasing incidence of titanium allergies, along with a rising demand for metal-free reconstructions, have led to the proposal of ceramics as potential surrogates. Following numerous experimental studies, zirconium dioxide (zirconia) has earned its place as a potential substitute for titanium in implantology. Yet, despite zirconia's excellent biocompatibility and tissue integration, low affinity to plaque and favorable biomechanical properties, early failures were significantly higher for zirconia implants than for titanium implants. Technical failure as a result of fracture of the material is also a major concern. So far, zirconia implants have been mainly manufactured as one-piece implant systems because of the material's limitations. Nevertheless, various two-piece systems have been progressively emerging with promising results. Screw-retained abutments are desirable but present a major technical challenge. Innovation and technical advances will undoubtedly lead to further improvement in the reliability and strength of zirconia implants, allowing for novel designs, connections and reconstructions. Additional clinical studies are required to identify all relevant technical and biological factors affecting implant success and patients' satisfaction. However, the evidence for a final verdict is, at present, still incomplete.
Topics: Animals; Biocompatible Materials; Dental Implants; Dental Materials; Dental Prosthesis Design; Dental Restoration Failure; Dental Stress Analysis; Humans; Zirconium
PubMed: 28000266
DOI: 10.1111/prd.12180 -
Shanghai Kou Qiang Yi Xue = Shanghai... Dec 2022To analyse the effect of restoration and tooth tissue stress distribution under different occlusal preparation thickness, based on three-dimensional finite element modal...
PURPOSE
To analyse the effect of restoration and tooth tissue stress distribution under different occlusal preparation thickness, based on three-dimensional finite element modal of the mandibular second molar with root canal therapy and endocrown restorations.
METHODS
A mandibular second molar was scanned by cone-beam CT (CBCT) and a three-dimensional finite element model with endocrown restortions was established. Three kinds of endocrown restorations materials with different elastic modulus (glass ceramic, lithium disilicate ceramic and zirconia), and three types of occluscal thickness (1, 2 and 3 mm) were adopted. With a 200 N force loaded vertically and obliquely, the distribution and magnitude of stress in the tooth tissue and endocrown restorations were investigated by three-dimensional finite element analysis. RESULTS: The restoration and tooth tissue maximum stress values were increased firstly and then decreased with the increasing of occlusal thickness; the base material maximum stress values were decreased with the increasing of occlusal thickness; the maximum stress values of tooth tissue and base material were increased with the increasing of restoration material's Young's modulus. Compared to the loading in vertical direction, the maximum stress values were increased with loading in oblique direction.
CONCLUSIONS
It's beneficial for tooth tissue to reduce the stress concentration under 2mm thickness. The stress on endocrown will be more concentrated with the increasing of restoration material's Young's modulus.
Topics: Finite Element Analysis; Dental Stress Analysis; Dental Porcelain; Dental Materials; Molar; Root Canal Therapy; Materials Testing
PubMed: 36970798
DOI: No ID Found -
IEEE Transactions on Visualization and... 2007The properties of virtually all real-world materials change with time, causing their bidirectional reflectance distribution functions (BRDFs) to be time varying....
The properties of virtually all real-world materials change with time, causing their bidirectional reflectance distribution functions (BRDFs) to be time varying. However, none of the existing BRDF models and databases take time variation into consideration; they represent the appearance of a material at a single time instance. In this paper, we address the acquisition, analysis, modeling, and rendering of a wide range of time-varying BRDFs (TVBRDFs). We have developed an acquisition system that is capable of sampling a material's BRDF at multiple time instances, with each time sample acquired within 36 sec. We have used this acquisition system to measure the BRDFs of a wide range of time-varying phenomena, which include the drying of various types of paints (watercolor, spray, and oil), the drying of wet rough surfaces (cement, plaster, and fabrics), the accumulation of dusts (household and joint compound) on surfaces, and the melting of materials (chocolate). Analytic BRDF functions are fit to these measurements and the model parameters' variations with time are analyzed. Each category exhibits interesting and sometimes nonintuitive parameter trends. These parameter trends are then used to develop analytic TVBRDF models. The analytic TVBRDF models enable us to apply effects such as paint drying and dust accumulation to arbitrary surfaces and novel materials.
PubMed: 17356224
DOI: 10.1109/TVCG.2007.1013