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Artykuły w czasopismach na temat "Material testing- Nanomaterials"
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Harish, Vancha, Devesh Tewari, Manish Gaur, Awadh Bihari Yadav, Shiv Swaroop, Mikhael Bechelany i Ahmed Barhoum. "Review on Nanoparticles and Nanostructured Materials: Bioimaging, Biosensing, Drug Delivery, Tissue Engineering, Antimicrobial, and Agro-Food Applications". Nanomaterials 12, nr 3 (28.01.2022): 457. http://dx.doi.org/10.3390/nano12030457.
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In the last few decades, the vast potential of nanomaterials for biomedical and healthcare applications has been extensively investigated. Several case studies demonstrated that nanomaterials can offer solutions to the current challenges of raw materials in the biomedical and healthcare fields. This review describes the different nanoparticles and nanostructured material synthesis approaches and presents some emerging biomedical, healthcare, and agro-food applications. This review focuses on various nanomaterial types (e.g., spherical, nanorods, nanotubes, nanosheets, nanofibers, core-shell, and mesoporous) that can be synthesized from different raw materials and their emerging applications in bioimaging, biosensing, drug delivery, tissue engineering, antimicrobial, and agro-foods. Depending on their morphology (e.g., size, aspect ratio, geometry, porosity), nanomaterials can be used as formulation modifiers, moisturizers, nanofillers, additives, membranes, and films. As toxicological assessment depends on sizes and morphologies, stringent regulation is needed from the testing of efficient nanomaterials dosages. The challenges and perspectives for an industrial breakthrough of nanomaterials are related to the optimization of production and processing conditions.
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Qu, Juntian, i Xinyu Liu. "Recent Advances on SEM-Based In Situ Multiphysical Characterization of Nanomaterials". Scanning 2021 (9.06.2021): 1–16. http://dx.doi.org/10.1155/2021/4426254.
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Functional nanomaterials possess exceptional mechanical, electrical, and optical properties which have significantly benefited their diverse applications to a variety of scientific and engineering problems. In order to fully understand their characteristics and further guide their synthesis and device application, the multiphysical properties of these nanomaterials need to be characterized accurately and efficiently. Among various experimental tools for nanomaterial characterization, scanning electron microscopy- (SEM-) based platforms provide merits of high imaging resolution, accuracy and stability, well-controlled testing conditions, and the compatibility with other high-resolution material characterization techniques (e.g., atomic force microscopy), thus, various SEM-enabled techniques have been well developed for characterizing the multiphysical properties of nanomaterials. In this review, we summarize existing SEM-based platforms for nanomaterial multiphysical (mechanical, electrical, and electromechanical) in situ characterization, outline critical experimental challenges for nanomaterial optical characterization in SEM, and discuss potential demands of the SEM-based platforms to characterizing multiphysical properties of the nanomaterials.
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Tan, Qiaoyin, Cuicui Wu, Lei Li, Weide Shao i Min Luo. "Nanomaterial-Based Prosthetic Limbs for Disability Mobility Assistance: A Review of Recent Advances". Journal of Nanomaterials 2022 (31.03.2022): 1–10. http://dx.doi.org/10.1155/2022/3425297.
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The emergence of new hybrid nanomaterial has enabled prosthetic devices to have more performance and significantly improved the quality of life of the disabled. Due to the biosensing properties of prosthetic limbs made of nanomaterials, a large number of nanocomposites have been designed, developed, and evaluated for various prosthetic limbs, such as e-skin, e-skin’s neurotactility sensing, human prosthetic interface tissue engineering, bones, and biosensors. Nano-based materials are also considered to be the new generation of scientific and technological materials for the preparation of various prosthetic devices for the disabled, which can effectively improve the sense of use of the disabled and achieve functional diversity. The study described various nanomaterials for prosthetic devices, and introduced some basic components of nanocomposites; their applications are in three areas, such as bone, skin, and nerve, and evaluated and summarized the advantages of these applications. The results show that (1) carbon-based nanomaterials as neural materials have been studied most deeply. Due to that strong stability of the carbon-based material and the simple transmission mechanism, the cost can be controlled in manufacturing the artificial limb. Materials with human-computer interaction function are the research focus in the future. (2) Skin nanomaterials are mainly composite materials, generally containing metal- and carbon-based materials. Ionic gels, ionic liquids, hydrogels, and elastomers have become the focus of attention due to the sensitivity, multimodal, and memory properties of their materials. (3) Outstanding nanomaterials for bone are fibrous materials, metallic synthetic materials, and composite materials, with extremely high hardness, weight, and toughness. Of the skeletal materials, the choice of prosthetic socket material is the most important and is typically based on fiber laminate composites. Some of these materials make sensors for durability and performance that can be used for large-scale clinical testing.
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Kim, Sung-Hyun, So-Hye Hong, Jin Hee Lee, Dong Han Lee, Kikyung Jung, Jun-Young Yang, Hyo-Sook Shin, JeongPyo Lee, Jayoung Jeong i Jae-Ho Oh. "Skin Sensitization Evaluation of Carbon-Based Graphene Nanoplatelets". Toxics 9, nr 3 (17.03.2021): 62. http://dx.doi.org/10.3390/toxics9030062.
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Graphene nanoplatelets (GNPs) are one of the major types of carbon based nanomaterials that have different industrial and biomedical applications. There is a risk of exposure to GNP material in individuals involved in their large-scale production and in individuals who use products containing GNPs. Determining the exact toxicity of GNP nanomaterials is a very important agenda. This research aimed to evaluate the skin sensitization potentials induced by GNPs using two types of alternative to animal testing. We analyzed the physicochemical characteristics of the test material by selecting a graphene nanomaterial with a nano-size on one side. Thereafter, we evaluated the skin sensitization effect using an in vitro and an in vivo alternative test method, respectively. As a result, we found that GNPs do not induce skin sensitization. In addition, it was observed that the administration of GNPs did not induce cytotoxicity and skin toxicity. This is the first report of skin sensitization as a result of GNPs obtained using alternative test methods. These results suggest that GNP materials do not cause skin sensitization, and these assays may be useful in evaluating the skin sensitization of some nanomaterials.
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Akono, Ange-Therese. "Fracture toughness of one- and two-dimensional nanoreinforced cement via scratch testing". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 379, nr 2203 (21.06.2021): 20200288. http://dx.doi.org/10.1098/rsta.2020.0288.
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Cement is the most widely consumed material globally, with the cement industry accounting for 8% of human-caused greenhouse gas emissions. Aiming for cement composites with a reduced carbon footprint, this study investigates the potential of nanomaterials to improve mechanical characteristics. An important question is to increase the fraction of carbon-based nanomaterials within cement matrices while controlling the microstructure and enhancing the mechanical performance. Specifically, this study investigates the fracture response of Portland cement reinforced with one- and two-dimensional carbon-based nanomaterials, such as carbon nanofibres, multiwalled carbon nanotubes, helical carbon nanotubes and graphene oxide nanoplatelets. Novel processing routes are shown to incorporate 0.1–0.5 wt% of nanomaterials into cement using a quadratic distribution of ultrasonic energy. Scratch testing is used to probe the fracture response by pushing a sphero-conical probe against the surface of the material under a linearly increasing vertical force. Fracture toughness is then computed using a nonlinear fracture mechanics model. Nanomaterials are shown to bridge nanoscale air voids, leading to pore refinement, and a decrease in the porosity and the water absorption. An improvement in fracture toughness is observed in cement nanocomposites, with a positive correlation between the fracture toughness and the mass fraction of nanofiller for graphene-reinforced cement. Moreover, for graphene-reinforced cement, the fracture toughness values are in the range of 0.701 to 0.717 MPa m . Thus, this study illustrates the potential of nanomaterials to toughen cement while improving the microstructure and water resistance properties. This article is part of a discussion meeting issue ‘A cracking approach to inventing new tough materials: fracture stranger than friction’.
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Wohlleben, Wendel, Bryan Hellack, Carmen Nickel, Monika Herrchen, Kerstin Hund-Rinke, Katja Kettler, Christian Riebeling i in. "The nanoGRAVUR framework to group (nano)materials for their occupational, consumer, environmental risks based on a harmonized set of material properties, applied to 34 case studies". Nanoscale 11, nr 38 (2019): 17637–54. http://dx.doi.org/10.1039/c9nr03306h.
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Kumpati, Ramesh, Wojciech Skarka i Sunith Kumar Ontipuli. "Current Trends in Integration of Nondestructive Testing Methods for Engineered Materials Testing". Sensors 21, nr 18 (15.09.2021): 6175. http://dx.doi.org/10.3390/s21186175.
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Material failure may occur in a variety of situations dependent on stress conditions, temperature, and internal or external load conditions. Many of the latest engineered materials combine several material types i.e., metals, carbon, glass, resins, adhesives, heterogeneous and nanomaterials (organic/inorganic) to produce multilayered, multifaceted structures that may fail in ductile, brittle, or both cases. Mechanical testing is a standard and basic component of any design and fabricating process. Mechanical testing also plays a vital role in maintaining cost-effectiveness in innovative advancement and predominance. Destructive tests include tensile testing, chemical analysis, hardness testing, fatigue testing, creep testing, shear testing, impact testing, stress rapture testing, fastener testing, residual stress measurement, and XRD. These tests can damage the molecular arrangement and even the microstructure of engineered materials. Nondestructive testing methods evaluate component/material/object quality without damaging the sample integrity. This review outlines advanced nondestructive techniques and explains predominantly used nondestructive techniques with respect to their applications, limitations, and advantages. The literature was further analyzed regarding experimental developments, data acquisition systems, and technologically upgraded accessory components. Additionally, the various combinations of methods applied for several types of material defects are reported. The ultimate goal of this review paper is to explain advanced nondestructive testing (NDT) techniques/tests, which are comprised of notable research work reporting evolved affordable systems with fast, precise, and repeatable systems with high accuracy for both experimental and data acquisition techniques. Furthermore, these advanced NDT approaches were assessed for their potential implementation at the industrial level for faster, more accurate, and secure operations.
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Wang, Jingang, Xijiao Mu i Mengtao Sun. "The Thermal, Electrical and Thermoelectric Properties of Graphene Nanomaterials". Nanomaterials 9, nr 2 (6.02.2019): 218. http://dx.doi.org/10.3390/nano9020218.
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Graphene, as a typical two-dimensional nanometer material, has shown its uniqueapplication potential in electrical characteristics, thermal properties, and thermoelectric propertiesby virtue of its novel electronic structure. The field of traditional material modification mainlychanges or enhances certain properties of materials by mixing a variety of materials (to form aheterostructure) and doping. For graphene as well, this paper specifically discusses the use oftraditional modification methods to improve graphene’s electrical and thermoelectrical properties.More deeply, since graphene is an atomic-level thin film material, its shape and edge conformation(zigzag boundary and armchair boundary) have a great impact on performance. Therefore, thispaper reviews the graphene modification field in recent years. Through the change in the shape ofgraphene, the change in the boundary structure configuration, the doping of other atoms, and theformation of a heterostructure, the electrical, thermal, and thermoelectric properties of graphenechange, resulting in broader applications in more fields. Through studies of graphene’s electrical,thermal, and thermoelectric properties in recent years, progress has been made not only inexperimental testing, but also in theoretical calculation. These aspects of graphene are reviewed inthis paper.
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Gandhi, Mansi, i Khairunnisa Amreen. "Emerging Trends in Nanomaterial-Based Biomedical Aspects". Electrochem 4, nr 3 (4.08.2023): 365–88. http://dx.doi.org/10.3390/electrochem4030024.
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Comprehending the interfacial interaction of nanomaterials (NMs) and biological systems is a significant research interest. NMs comprise various nanoparticles (NPs) like carbon nanotubes, graphene oxides, carbon dots, graphite nanopowders, etc. These NPs show a variety of interactions with biological interfaces via organic layers, therapeutic molecules, proteins, DNA, and cellular matrices. A number of biophysical and colloidal forces act at the morphological surface to regulate the biological responses of bio-nanoconjugates, imparting distinct physical properties to the NMs. The design of future-generation nano-tools is primarily based on the basic properties of NMs, such as shape, size, compositional, functionality, etc., with studies being carried out extensively. Understanding their properties promotes research in the medical and biological sciences and improves their applicability in the health management sector. In this review article, in-depth and critical analysis of the theoretical and experimental aspects involving nanoscale material, which have inspired various biological systems, is the area of focus. The main analysis involves different self-assembled synthetic materials, bio-functionalized NMs, and their probing techniques. The present review article focuses on recent emerging trends in the synthesis and applications of nanomaterials with respect to various biomedical applications. This article provides value to the literature as it summarizes the state-of-the-art nanomaterials reported, especially within the health sector. It has been observed that nanomaterial applications in drug design, diagnosis, testing, and in the research arena, as well as many fatal disease conditions like cancer and sepsis, have explored alongwith drug therapies and other options for the delivery of nanomaterials. Even the day-to-day life of the synthesis and purification of these materials is changing to provide us with a simplified process. This review article can be useful in the research sector as a single platform wherein all types of nanomaterials for biomedical aspects can be understood in detail.
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Konstantopoulos, Georgios, Elias P. Koumoulos i Costas A. Charitidis. "Digital Innovation Enabled Nanomaterial Manufacturing; Machine Learning Strategies and Green Perspectives". Nanomaterials 12, nr 15 (1.08.2022): 2646. http://dx.doi.org/10.3390/nano12152646.
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Machine learning has been an emerging scientific field serving the modern multidisciplinary needs in the Materials Science and Manufacturing sector. The taxonomy and mapping of nanomaterial properties based on data analytics is going to ensure safe and green manufacturing with consciousness raised on effective resource management. The utilization of predictive modelling tools empowered with artificial intelligence (AI) has proposed novel paths in materials discovery and optimization, while it can further stimulate the cutting-edge and data-driven design of a tailored behavioral profile of nanomaterials to serve the special needs of application environments. The previous knowledge of the physics and mathematical representation of material behaviors, as well as the utilization of already generated testing data, received specific attention by scientists. However, the exploration of available information is not always manageable, and machine intelligence can efficiently (computational resources, time) meet this challenge via high-throughput multidimensional search exploration capabilities. Moreover, the modelling of bio-chemical interactions with the environment and living organisms has been demonstrated to connect chemical structure with acute or tolerable effects upon exposure. Thus, in this review, a summary of recent computational developments is provided with the aim to cover excelling research and present challenges towards unbiased, decentralized, and data-driven decision-making, in relation to increased impact in the field of advanced nanomaterials manufacturing and nanoinformatics, and to indicate the steps required to realize rapid, safe, and circular-by-design nanomaterials.
Rozprawy doktorskie na temat "Material testing- Nanomaterials"
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Gupta, Prakhar. "Elasticity of one-dimensional nanostructures - a multiscale approach". Thesis, 2018. http://localhost:8080/xmlui/handle/12345678/7621.
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Mahlangu, Thembisile Patience. "Synthesis of smart nanomaterials for preconcentration and detection of E.coli in water". Diss., 2015. http://hdl.handle.net/10500/19941.
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It is common knowledge that water is one of the basic needs for human beings. However, the consumption of contaminated water can lead to waterborne diseases and fatalities. It is, therefore imperative to constantly monitor the quality of potable water. There are numerous technologies used for water quality monitoring. These technologies are relatively effective however these tests are expensive and complex to use, which then require experienced technicians to operate them. Other tests are not rapid, making consumers of water susceptible to waterborne diseases. In this study, dye-doped, surface functionalized silica nanoparticles (SiNPs) and surface-functionalized magnetic nanocomposites (MNCs) were proposed as materials that can be applied in order to reduce the time taken to get results as well as to make the processes less complex and portable.
The aim of this study was to synthesize and characterize surface functionalized dye-doped SiNPs and surface functionalized MNCs for detection and preconcentration of in water. Additionally, proof of concept had to be shown using the synthesized materials.
SiNPs were the materials of choice due to their easily functionalized surfaces and their strong optical properties. SiNPs are photostable and they do not leach in solution due to the inert nature of the silica matrix in aqueous media. MNCs were chosen as materials of choice for preconcentration of E. coli in water because they are easy to synthesize and they can be applied in various biological applications due to their functional groups. SiNPs were synthesized using the water-in-oil microemulsion. The SiNPs were further functionalized with amine and carboxyl groups and avidin. Thereafter, they were bioconjugated with biotinylated anti-E. coli antibodies. The pure and surface functionalized SiNPs were characterized using ATR-FTIR spectroscopy, FE-SEM, HR-TEM, Zeta Sizer, UV-vis spectroscopy and spectrofluorometry. The application of the dye—doped surface functionalized SiNPs in E. coli detection was characterized using the fluorescence plate reader. The SiNPs were spherical and uniform in size. They increased in size as they were being functionalized, ranging from 21.20 nm to 75.06 nm. The SiNPs were successfully functionalized with amine and carboxyl groups as well as with avidin and antibodies. Two methods were investigated for carboxyl group attachment (direct and indirect attachment) and the direct attachment method yielded the best results with a surface charge of -31.9 mV compared to -23.3 mV of the indirect method. The dye loading was found to be 1% after particle synthesis. The optical properties of the Ru(Bpy) dye were enhanced 3 fold when they were encapsulated in the Si matrix. The SiNPs were binding to the E. coli cells and enabled detection.
MNCs were synthesized through in-situ polymerization. The MNCs were characterized using ATR-FTIR spectroscopy, SEM, TEM and XRD. The MNCs were successfully functionalized with carboxyl groups. The increase in size of the nanocomposites as seen in SEM images proved that the Fe3O4 was successfully encapsulated in the polymer matrix. The MNCs were proven to be magnetic by a simple magnetism test whereby they were separated in an aqueous solution using an external magnetic field. The antibody-labelled MNCs were binding to the E. coli cells as shown in TEM images. E. coli cells were removed from water at varying concentrations of 1x106 CFU/mL to 1x109 CFU/mL at 10 mL volumes.
This study has demonstrated that dye-doped SiNPs amplify the signal of E. coli cells using fluorescence. The study has also demonstrated that the MNCs can be applied in sample preconcentration and enrichment for E. coli detection. However, further studies should investigate and optimize the combination of the two techniques in a point of use device for water quality testing of 100 mL-samples as per the requirement of the SANS 241 standard.Civil and Chemical Engineering
M. Tech. (Chemical Engineering)
Książki na temat "Material testing- Nanomaterials"
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Diamond, Steve. Review of OECD/OPPTS-harmonized and OPPTS ecotoxicity test guidelines for their applicability to manufactured nanomaterials. Duluth, Minn: U.S. Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, 2009.
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Takebayashi, Toru, Robert Landsiedel i Masashi Gamo. In Vivo Inhalation Toxicity Screening Methods for Manufactured Nanomaterials. Springer, 2020.
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Takebayashi, Toru, Robert Landsiedel i Masashi Gamo. In Vivo Inhalation Toxicity Screening Methods for Manufactured Nanomaterials. Springer, 2019.
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Handbook of Safety Assessment of Nanomaterials: From Toxicological Testing to Personalized Medicine. Taylor & Francis Group, 2014.
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Fadeel, Bengt. Handbook of Safety Assessment of Nanomaterials: From Toxicological Testing to Personalized Medicine. Pan Stanford Publishing, 2014.
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Fadeel, Bengt. Handbook of Safety Assessment of Nanomaterials: From Toxicological Testing to Personalized Medicine. Jenny Stanford Publishing, 2014.
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(Editor), Norbert Meyendorf, George Y. Baaklini (Editor) i Bernd Michel (Editor), red. Nondestructive Evaluation and Reliability of Micro and Nanomaterial Systems (Proceedings of SPIE). SPIE Society of Photo-Optical Instrumentation Engi, 2002.
Znajdź pełny tekst źródłaCzęści książek na temat "Material testing- Nanomaterials"
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Doddamani, Mrityunjay, H. S. Bharath, Pavana Prabhakar i Suhasini Gururaja. "Mechanical Testing". W Materials Horizons: From Nature to Nanomaterials, 53–110. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-1730-3_5.
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Belaid, Walid, Amina Houimi, Shrouk E. Zaki i Mohamed A. Basyooni. "Sol-Gel Production of Semiconductor Metal Oxides for Gas Sensor Applications". W Sol-Gel Method - Recent Advances [Working Title]. IntechOpen, 2023. http://dx.doi.org/10.5772/intechopen.111844.
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As they are widely utilized in industries including the food packaging industry, indoor air quality testing, and real-time monitoring of man-made harmful gas emissions to successfully combat global warming, reliable and affordable gas sensors represent enormous market potential. For environmental monitoring, chemical safety regulation, and many industrial applications, the detection of carbon monoxide (CO), carbon dioxide (CO2), nitrogen dioxide (NO2), and methane (CH4) gases is essential. To reliably and quantitatively detect these gases, much-improved materials and methods that are adaptable to various environmental factors are needed using low-cost fabrication techniques such as sol–gel. The advantages of employing metal oxide nanomaterials-based chemoresistive for creating high-performance gas sensors are shown by key metrics such as selectivity, sensitivity, reaction time, and detection. The primary sensing methods are also grouped and thoroughly covered. In light of the current constraints, anticipated future developments in the field of sol–gel nanomaterial-based chemoresistive gas sensors are also highlighted.
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Rallini, Marco, Maurizio Natali i Luigi Torre. "An Introduction to Ablative Materials and High-Temperature Testing Protocols". W Nanomaterials in Rocket Propulsion Systems, 529–49. Elsevier, 2019. http://dx.doi.org/10.1016/b978-0-12-813908-0.00014-9.
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Van Miert, Sabine, Jan Creylman i Geert R. Verheyen. "Mining a Nanoparticle Dataset, Compiled Within the MODENA-COST Action". W Research Anthology on Synthesis, Characterization, and Applications of Nanomaterials, 1706–24. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-8591-7.ch071.
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Engineered nanomaterials (ENM) have new or enhanced physico-chemical properties compared to their micron-sized counterparts, but may also have an increased toxic potential. Animal and in vitro testing are typically employed to investigate the toxic effects of (nano)materials. The sheer number of ENMs and their physico-chemical parameters make it impossible to only use in vivo and in vitro testing, and modelling technologies are also deployed to find relationships between ENM parameters and toxicity. A heterogenous dataset containing information on 192 nanoparticle endpoints was compiled within the MODENA COST-Action consortium. Here, the available data was mined to identify relationships between nanoparticle properties and cell-death as measured with four cytotoxicity assays. ANOVA, collinearity analyses and classification and regression trees gave indications on potential relations between the NP-properties and toxicity, but could not deliver a robust model. More information and datapoints are necessary to build well-validated models.
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Munene Mwaniki, Joseph. "Adsorption and Its Applications: Using Zinc Adsorption on Water Hyacinth to Elaborate the Kinetics and Thermodynamics of Adsorption". W Sorption - From Fundamentals to Applications. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.104293.
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Adsorption is a technique for removing adsorbate from the liquid or gas phase using adsorbents. The adsorbent is solid while the adsorbate can either be dissolved in liquid or gas. Adsorption has attracted the attention of many researchers because of its wide applicability in water and air purification, environment friendly, effectiveness, and ease to design as compared with the other methods. Activated carbon has been used as an effective adsorbent. However, its application is limited since it’s expensive. This has necessitated research interest in other materials that are safe and economical instead of commercial activated carbon. Some of the materials that have been successfully tested include sawdust, silica gel, zeolites, clay minerals and oxides, nanomaterial, agricultural by-products, biological waste, ion exchange resins and water hyacinth, etc. Although some of these materials are effective, they are not readily available. The kinetics of adsorption is done through testing the adsorption data against standard kinetic models and the model with the best line of fit, based on the values of coefficient of determination (R2) is selected. The adsorption process is described using isotherms such as Freundlich and Langmuir. This chapter sheds more light on adsorption, the most common adsorbents, kinetic models, isotherms, and adsorption applicability.
Streszczenia konferencji na temat "Material testing- Nanomaterials"
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Kujawski, Mark P., Leela Rakesh, Stanley Hirschi, Brad D. Falhman, Joana C. Finegan, Ekmagage Don N. Almeida, Nicole M. Bullard, Jason Hiller, Michael P. Lalko i Jeremy V. Miller. "Steady Shear and Linear Viscoelastic Properties of Melt Mixed and Injection Molded Samples of Polypropylene, Polystyrene, and Polyethylene Nanocomposites With Carbon Black, Vapor Grown Carbon Fibers, and Carbon Nanotubes". W ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-15814.
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Tailoring the rheological properties of polymers is important for practical applications such as the stabilization of polymer emulsions, blends, and foams. Nanomaterial (i.e. Carbon Nanotubes, Carbon Nanofibers, Dendrimers, and Carbon Black) are an excellent way to modify the mechanical, thermal, electrical, and optical properties of materials. This paper presents steady shear and linear viscoelastic oscillation testing of three polymers: Polyethylene (PE); Polypropylene (PP); and Polystyrene (PS). These polymers were studied in bulk form and as composites containing designated volume fractions of nanomaterials over a range of processing temperatures and conditions. The nanomaterials investigated in this study include Carbon Black, Vapor Grown Carbon Nanofibers, Multiwalled Carbon Nanotubes, Single Walled Carbon Nanotubes, and COOH functionalized Single Walled Carbon Nanotubes. The nanocomposite samples used for rheological experimentation were manufactured by melt mixing and injection molding. We will address whether the melt rheological measurements can unequivocally detect the co-continuous composition range in such systems. We will also investigate the melt flow rate through nanomaterial concentration variations, as well as discuss the storage modulus (G'), viscous modulus (G"), and complex viscosity of homogeneous polymer materials versus carbon nanocomposite material at various frequencies.
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Gernand, Jeremy M. "Limitations on the Reliability of In Vitro Predictive Toxicity Models to Predict Pulmonary Toxicity in Rodents". W ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-67151.
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Given the rapidly proliferating varieties of nanomaterials and ongoing concerns that these novel materials may pose emerging occupational and environmental risks, combined with the possibility that each variety might pose a different unique risk due to the unique combination of material properties, researchers and regulators have been searching for methods to identify hazards and prioritize materials for further testing. While several screening tests and toxic risk models have been proposed, most have relied on cellular-level in vitro data. This foundation enables answers to be developed quickly for any material, but it is yet unclear how this information may translate to more realistic exposure scenarios in people or other more complex animals. A quantitative evaluation of these models or at least the inputs variables to these models in the context of rodent or human health outcomes is necessary before their classifications may be believed for the purposes of risk prioritization. This paper presents the results of a machine learning enabled meta-analysis of animal studies attempting to use significant descriptors from in vitro nanomaterial risk models to predict the relative toxicity of nanomaterials following pulmonary exposures in rodents. A series of highly non-linear random forest models (each made up of an ensemble of 1,000 regression tree models) were created to assess the maximum possible information value of the in vitro risk models and related methods of describing nanomaterial variants and their toxicity in rat and mouse experiments. The variety of chemical descriptors or quantitative chemical property measurements such as bond strength, surface charge, and dissolution potential, while important in describing observed differences with in vitro experiments, proved to provide little indication of the relative magnitude of inflammation in rodents (explained variance amounted to less than 32%). Important factors in predicting rodent pulmonary inflammation such as primary particle size and chemical type demonstrate that there are critical differences between these two toxicity assays that cannot be captured by a series of in vitro tests alone. Predictive models relying primarily on these descriptors alone explained more than 62% of the variance of the short term in vivo toxicity results. This means that existing proposed nanomaterial toxicity screening methods are inadequate as they currently stand, and either the community must be content with the slower and more expensive animal testing to evaluate nanomaterial risks, or further conceptual development of improved alternative in vitro screening methodologies is necessary before manufacturers and regulators can rely on them to promote safer use of nanotechnology.
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Prabhu, Rasika, Juan-Carlos Santamaria, Nirupama Vaidya, Patrice Abivin, Valerie Lafitte i Balkrishna Gadiyar. "Nanomaterials Improve Polymer-Based Gravel-Packing Fluids at High Temperature". W Offshore Technology Conference. OTC, 2021. http://dx.doi.org/10.4043/30967-ms.
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Abstract A gravel packing fluid system was developed for elevated temperature applications above 290°F comprised of xanthan gum and a high-temperature gravel suspension additive. This fluid system has been successfully pumped in four openhole gravel packing operations so far, validating its suitability for Alternate Path gravel packing technology involving shunt tubes. Laboratory qualification testing for this fluid showed excellent gravel suspension, rheology, and breaking profiles for cleanup and minimal damage during production. Xanthan gels have been used in gravel packing applications for many years. However, by itself, xanthan was unable to suspend gravel at temperatures above 290°F possibly due to onset of thermally activated polymer degradation. This paper demonstrates that gravel suspension ability can be vastly improved with the addition of a recently developed nano-additive. This additive is a specially designed versatile nanosized material that has a proven track record with visco-elastic surfactant fluids in the past. In the present study, we show the successful application of this additive with polymer-based carrier fluids such as xanthan, effectively increasing their application range to 325°F. With the inclusion of this suspension additive, xanthan concentration in the fluid system can also be reduced, which has other potential benefits such as better cleanup after gel break. Extensive laboratory evaluation for fluid qualification was performed prior to the job. High-pressure/high-temperature (HP/HT) rheology measurements were performed using industry-standard rheometers at various shear rates to match specific viscosity requirements for shunt tube applications. Gravel suspension tests performed using special pressurized cells immersed in oil bath at the required bottomhole static temperature showed improved gravel suspension with the nano-additive. Fluid breaking with conventional oxidative breaker was also demonstrated with viscosity measurements. Formation response tests showed very good fluid cleanup with 90% regained permeability. Laboratory testing and successful field applications have proven the effectiveness of this new fluid system.
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Tanguay, Robert L., Lisa Truong, Tatiana Zaikova i James E. Hutchison. "Rapid In Vivo Assessment of the Nano/Bio Interface". W ASME 2013 2nd Global Congress on NanoEngineering for Medicine and Biology. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/nemb2013-93153.
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Recent advances in nanoscience offer great promise for the nanomedicine sector. These advances in the nanotechnology field will undoubtedly increase both human and environmental exposures to engineered nanomaterials. Whether these exposures pose a significant risk remains uncertain. Despite recent collective progress there remain gaps in our understanding of the nanomaterials physiochemical properties that drive or dictate biological compatibility. The development and implementation of rapid relevant and efficient testing strategies to assess these emerging materials prior to large-scale exposures could help advance this exciting field. I will present a powerful approach that utilizes a dynamic in vivo zebrafish embryonic assay to rapidly define the biological responses to nanomaterial exposures. Early developmental life stages are often uniquely sensitive to environmental insults, due in part to the enormous changes in cellular differentiation, proliferation and migration required to form the required cell types, tissues and organs. Molecular signaling underlies all of these processes. Most toxic responses result from disruption of proper molecular signaling, thus, early developmental life stages are perhaps the ideal life stage to determine if nanomaterials perturb normal biological pathways. Through automation and rapid throughput approaches, a systematic and iterative strategy has been deployed to help elucidate the nanomaterials properties that drive biological responses.
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Atwater, Mark A., i Roger J. Welsh. "Direct Synthesis of Nanofibrous Nonwoven Carbon Components: Initial Observations, Capabilities and Challenges". W ASME 2016 11th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/msec2016-8662.
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Wide-spread adoption of carbon nanomaterials has been hindered by inefficient production and utilization. A recently developed method has shown possibility to directly synthesize bulk nanostructured nonwoven materials from catalytically deposited carbon nanofibers. The basic manufacturing scheme involves constraining carbon nanofiber growth to create three-dimensionally featured, macroscale products. Although previously demonstrated as a proof of concept, the possibilities and pitfalls of the method at a larger scale have not yet been explored. In this work, the basic foundation for using the constrained formation of fibrous nanostructures (CoFFiN) process is established by testing feasibility in larger volumes (as much as 2000% greater than initial experiments) and by noting the macroscale carbon growth characteristics. It has been found that a variety of factors contribute to determining the basic qualities of the macroscale fiber collection (nonwoven material), and there are tunable parameters at the catalytic and constraint levels. The results of this work have established that monolithic structures of nonwoven carbon nanofibers can be created with centimeter dimensions in a variety of cross-sectional shapes. The only limit to scale noted is the tendency for nanofibers to entangle with one another during growth and self-restrict outward expansion to the mold walls. This may be addressed by selective placement of the catalyst in the mold.
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Gernand, Jeremy M., i Elizabeth A. Casman. "Selecting Nanoparticle Properties to Mitigate Risks to Workers and the Public: A Machine Learning Modeling Framework to Compare Pulmonary Toxicity Risks of Nanomaterials". W ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-62687.
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Due to their size and unique chemical properties, nanomaterials have the potential to interact with living organisms in novel ways, leading to a spectrum of negative consequences. Though a relatively new materials science, already nanomaterial variants in the process of becoming too numerous to be screened for toxicity individually by traditional and expensive animal testing. As with conventional pollutants, the resulting backlog of untested new materials means that interim industry and regulatory risk management measures may be mismatched to the actual risk. The ability to minimize toxicity risk from a nanomaterial during the product or system design phase would simplify the risk assessment process and contribute to increased worker and consumer safety. Some attempts to address this problem have been made, primarily analyzing data from in vitro experiments, which are of limited predictive value for the effects on whole organisms. The existing data on the toxicity of inhaled nanomaterials in animal models is sparse in comparison to the number of potential factors that may contribute to or aggravate nanomaterial toxicity, limiting the power of conventional statistical analysis to detect property/toxicity relationships. This situation is exacerbated by the fact that exhaustive chemical and physical characterization of all nanomaterial attributes in these studies is rare, due to resource or equipment constraints and dissimilar investigator priorities. This paper presents risk assessment models developed through a meta-analysis of in vivo nanomaterial rodent-inhalational toxicity studies. We apply machine learning techniques including regression trees and the related ensemble method, random forests in order to determine the relative contribution of different physical and chemical attributes on observed toxicity. These methods permit the use of data records with missing information without substituting presumed values and can reveal complex data relationships even in nonlinear contexts or conditional situations. Based on this analysis, we present a predictive risk model for the severity of inhaled nanomaterial toxicity based on a given set of nanomaterial attributes. This model reveals the anticipated change in the expected toxic response to choices of nanomaterial design (such as physical dimensions or chemical makeup). This methodology is intended to aid nanomaterial designers in identifying nanomaterial attributes that contribute to toxicity, giving them the opportunity to substitute safer variants while continuing to meet functional objectives. Findings from this analysis indicate that carbon nanotube (CNT) impurities explain at most 30% of the variance pulmonary toxicity as measured by polymorphonuclear neutrophils (PMN) count. Titanium dioxide nanoparticle size and aggregation affected the observed toxic response by less than ±10%. Difference in observed effects for a group of metal oxide nanoparticle associated with differences in Gibbs Free Energy on lactate dehydrogenase (LDH) concentrations amount to only 4% to the total variance. Other chemical descriptors of metal oxides were unimportant.
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Novikov, L. S., V. N. Mileev, E. N. Voronina i Jacob I. Kleiman. "Modeling and Testing of Nanomaterials for Space Applications". W PROTECTION OF MATERIALS AND STRUCTURES FROM SPACE ENVIRONMENT: Proceedings of the 9th International Conference: Protection of Materials and Structures From Space Environment. AIP, 2009. http://dx.doi.org/10.1063/1.3076869.
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Wu, Guodong, Yanchi Liu, Maieryemuguli Anwaier, Erdong Yao, Hongda Ren i Yuan Li. "Small Sizes of Molybdenum Disulfide Nanosheets As Heavy Oil Viscosity Reducers". W ASME 2022 41st International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/omae2022-78776.
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Abstract The high content of asphaltenes and colloids in heavy oil lead to their high viscosity, making it difficult to exploit and transport. Nanomaterials have become an important additive in reducing viscosity of crude oil. In this work, a series of amphiphilic molybdenum dioxide (MoS2) nanosheets are developed to reduce the viscosity of crude oil by an ultralow concentration aqueous solution. Firstly, nanosheets were synthesized by the hydrothermal methods. The influence factors such as raw material ratio, temperature and time were investigated. Then, SEM are used to systemically characterize the morphology and structure of MoS2 nanosheets. Then, the properties (i.e., size, viscosity reduction, and interfacial activity) of MoS2 nanosheets are tested. The relationship between these properties and viscosity reduction abilities were studied. Finally, based on viscosity reduction testing results, optimal MoS2 nanosheets formulation and dosage are determined. By controlling the stirring and temperature, hydrophilic MoS2 nanosheets with sizes from 40 nm to 160 nm were synthesized, respectively. Modifying them with oleyl amine, the amphiphilic nanosheets can be obtained. SEM show that they are materials with layered nano-structure and commonly composed of 8–10 layers. These nanosheets have good interfacial activity, wetting and emulsifying ability. By adding 100 ppm of MoS2 nanosheets to the mixture of heavy oil and water, the viscosity of these system can fall from > 880 mPa·s to 9 mPa·s. The smaller the size of the MoS2 nanosheets is, the better the viscosity reduction ability will be. The optimal using dosage of these nanosheets is 300–400 ppm, and the optimal size is 40–60 nm. It is predicted that nanosheets will gradually become a new field for the development of heavy oil.
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Abuali Galehdari, Nasim, i Ajit D. Kelkar. "Characterization of Nanoparticle Enhanced Multifunctional Sandwich Composites Subjected to Space Radiation". W ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-66774.
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One of the major concerns in long duration space exploration is to minimize the exposure of crew and equipment to space radiation. High energy radiation not only can be hazardous to the health but also can damage the materials and electronics. Current designs are contained heavy metals to avoid occupational hazards from radiation exposures. As a result the shielding structures are heavy and not effective to attenuate all types of radiation. Therefore, the proposed lightweight sandwich composites are designed to effectively shield high energy radiations while providing structural integrity. In the manufactured hybrid sandwich composite, High Molecular Weight Poly Ethylene (HMWPE) woven fabrics are selected as face sheets due to their advanced mechanical properties and excellent physical properties along with effective shielding properties. Basically polymers due to high hydrogen content are considered as effective materials to attenuate high energy radiations. In addition, the core material is epoxy composites incorporating three weight percentages of three different nanoparticles viz. Boron Carbide, Boron Nanopowder and Gadolinium. In fact if polymers as low Z materials are used alone, they usually are not successful to attenuate highly penetrative rays. Therefore, one solution is known to infuse polymer matrix with high radiation absorption properties nanoparticles. Among several different nanomaterials, the three aforementioned nanofillers were chosen because of their good radiation absorption properties. Gadolinium has the highest thermal neutron cross section compare to any other known element and 10B-containing materials are known as excellent radiation absorbers and the composite filled with them have the advantage of convenient and safety in construction, operation and reintegration. The sandwich composites were manufactured using Heat-Vacuum Assisted Resin Transfer Molding method (H-VARTM), which is a cost effective method for high volume production of sandwich structures. To evaluate the shielding performance of manufactured sandwich panels the neutron attenuation testing was performed. The results from neutron radiation tests show more than 99% shielding performance in all of the sandwich panels. In comparison with other nanofillers, Boron Nanopowder showed highest radiation shielding efficiency (99.64%), which can be attributed to its lowest particle size and better dispersion ability into epoxy resin. The flatwise compression testing was performed on all four sandwich panels to determine the mechanical strength of materials before and after being exposure to radiation. The results demonstrate that proposed hybrid sandwich panels can preserve their mechanical integrity while being exposed to the radiation.
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Kockerbeck, Zachary, Majid TabkhPaz, Simon Park i Ron Hugo. "Robust Nanocomposite Coatings Inspired by Structures of Nacre". W 2018 12th International Pipeline Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/ipc2018-78178.
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Carbon steel piping can be exposed to environments that contain various chemical and organic elements that induce corrosion and cracking events. This can lead to the loss of fluid into surrounding sensitive and remote environments. To minimize this inherent risk, various coating technologies have been utilized over the years in industry. These coatings typically suffer from complex application methods, high application cost, and vulnerabilities to environmental effects such as mechanical damage and cathodic disbondment. To overcome these challenges, a novel epoxy based composite coating that utilizes the properties of various nano-particulates such as graphene nanoplatelets (GnP), multi-walled carbon nanotubes (MWCNTs), chitosan, and hBN (Hexagonal boron nitride) is developed. These nanoparticles create a nano-scale “brick and mortar” type effect that is analogous to various natural structures such as the abalone shell (nacre). These nano-structures also enhance coating performance by increasing mechanical strength and anti-bacterial properties while simultaneously decreasing gas permeability. This performance enhancement serves to reduce overall corrosion-induced disbondment area. The dispersion of nanoparticles is verified using various microscopy methods such as scanning election microscopy and an optical 3D profilometer. To confirm the role of nanoparticles in the epoxy composite, the samples undergo rigorous testing to determine both mechanical properties as well as the feasibility of coating application, in particular, for use on girth welds. Using a dynamic mechanical analysis (DMA), the material strength of each combination of nanocomposites is tested and used to determine the glass transition temperature. The testing also includes abrasion, and both long-term mechanical and thermal behaviors of the coating. To test the feasibility of the coating, cathodic protection tests in an accelerated corrosive environment, and gas permeability tests are carried out. The results show that the composite coating made from these nanomaterials had a decrease in cathodic disbondment area and gas permeability and an increase the glass transition temperature and scratch resistance. Therefore, the nanocomposite coatings are found to be a significant improvement over standard epoxy-based coating.
Raporty organizacyjne na temat "Material testing- Nanomaterials"
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Kennedy, Alan, Jonathon Brame, Taylor Rycroft, Matthew Wood, Valerie Zemba, Charles Weiss, Matthew Hull, Cary Hill, Charles Geraci i Igor Linkov. A definition and categorization system for advanced materials : the foundation for risk-informed environmental health and safety testing. Engineer Research and Development Center (U.S.), wrzesień 2021. http://dx.doi.org/10.21079/11681/41803.
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Novel materials with unique or enhanced properties relative to conventional materials are being developed at an increasing rate. These materials are often referred to as advanced materials (AdMs) and they enable technological innovations that can benefit society. Despite their benefits, however, the unique characteristics of many AdMs, including many nanomaterials, are poorly understood and may pose environmental safety and occupational health (ESOH) risks that are not readily determined by traditional risk assessment methods. To assess these risks while keeping up with the pace of development, technology developers and risk assessors frequently employ risk-screening methods that depend on a clear definition for the materials that are to be assessed (e.g., engineered nanomaterial) as well as a method for binning materials into categories for ESOH risk prioritization. In this study, we aim to establish a practitioner-driven definition for AdMs and a practitioner-validated framework for categorizing AdMs into conceptual groupings based on material characteristics. The definition and categorization framework established here serve as a first step in determining if and when there is a need for specific ESOH and regulatory screening for an AdM as well as the type and extent of risk-related information that should be collected or generated for AdMs and AdM-enabled technologies.
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Choudhary, Ruplal, Victor Rodov, Punit Kohli, Elena Poverenov, John Haddock i Moshe Shemesh. Antimicrobial functionalized nanoparticles for enhancing food safety and quality. United States Department of Agriculture, styczeń 2013. http://dx.doi.org/10.32747/2013.7598156.bard.
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Original objectives The general goal of the project was to utilize the bactericidal potential of curcumin- functionalizednanostructures (CFN) for reinforcement of food safety by developing active antimicrobial food-contact surfaces. In order to reach the goal, the following secondary tasks were pursued: (a) further enhancement of the CFN activity based on understanding their mode of action; (b) preparing efficient antimicrobial surfaces, investigating and optimizing their performance; (c) testing the efficacy of the antimicrobial surfaces in real food trials. Background to the topic The project dealt with reducing microbial food spoilage and safety hazards. Cross-contamination through food-contact surfaces is one of the major safety concerns, aggravated by bacterial biofilm formation. The project implemented nanotech methods to develop novel antimicrobial food-contact materials based on natural compounds. Food-grade phenylpropanoidcurcumin was chosen as the most promising active principle for this research. Major conclusions, solutions, achievements In agreement with the original plan, the following research tasks were performed. Optimization of particles structure and composition. Three types of curcumin-functionalizednanostructures were developed and tested: liposome-type polydiacetylenenanovesicles, surface- stabilized nanoparticles and methyl-β-cyclodextrin inclusion complexes (MBCD). The three types had similar minimal inhibitory concentration but different mode of action. Nanovesicles and inclusion complexes were bactericidal while the nanoparticlesbacteriostatic. The difference might be due to different paths of curcumin penetration into bacterial cell. Enhancing the antimicrobial efficacy of CFN by photosensitization. Light exposure strengthened the bactericidal efficacy of curcumin-MBCD inclusion complexes approximately three-fold and enhanced the bacterial death on curcumin-coated plastic surfaces. Investigating the mode of action of CFN. Toxicoproteomic study revealed oxidative stress in curcumin-treated cells of E. coli. In the dark, this effect was alleviated by cellular adaptive responses. Under light, the enhanced ROS burst overrode the cellular adaptive mechanisms, disrupted the iron metabolism and synthesis of Fe-S clusters, eventually leading to cell death. Developing industrially-feasible methods of binding CFN to food-contact surfaces. CFN binding methods were developed for various substrates: covalent binding (binding nanovesicles to glass, plastic and metal), sonochemical impregnation (binding nanoparticles to plastics) and electrostatic layer-by-layer coating (binding inclusion complexes to glass and plastics). Investigating the performance of CFN-coated surfaces. Flexible and rigid plastic materials and glass coated with CFN demonstrated bactericidal activity towards Gram-negative (E. coli) and Gram-positive (Bac. cereus) bacteria. In addition, CFN-impregnated plastic material inhibited bacterial attachment and biofilm development. Testing the efficacy of CFN in food preservation trials. Efficient cold pasteurization of tender coconut water inoculated with E. coli and Listeriamonocytogeneswas performed by circulation through a column filled with CFN-coated glass beads. Combination of curcumin coating with blue light prevented bacterial cross contamination of fresh-cut melons through plastic surfaces contaminated with E. coli or Bac. licheniformis. Furthermore, coating of strawberries with CFN reduced fruit spoilage during simulated transportation extending the shelf life by 2-3 days. Implications, both scientific and agricultural BARD Report - Project4680 Page 2 of 17 Antimicrobial food-contact nanomaterials based on natural active principles will preserve food quality and ensure safety. Understanding mode of antimicrobial action of curcumin will allow enhancing its dark efficacy, e.g. by targeting the microbial cellular adaptation mechanisms.
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Rycroft, Taylor, Sabrina Larkin, Alexander Ganin, Treye Thomas, Joanna Matheson, Tessa Van Grack, Xinrong Chen, Kenton Plourde, Alan Kennedy i Igor Linkov. A framework and pilot tool for the risk-based prioritization and grouping of nano-enabled consumer products. Engineer Research and Development Center (U.S.), sierpień 2021. http://dx.doi.org/10.21079/11681/41721.
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The use of engineered nanomaterials (ENMs) in consumer products has expanded rapidly, revealing both innovative improvements over conventional materials, and the potential for novel risks to human health and the environment. As the number of new nano-enabled products and the volume of toxicity data on ENMs continues to grow, regulatory agencies like the U.S. Consumer Product Safety Commission (CPSC) – a small, independent federal agency responsible for protecting consumers from unreasonable risks associated with product use – will require the ability to screen and group a diverse array of nano-enabled consumer products based on their potential risks to consumers. Such prioritization would allow efficient allocation of limited resources for subsequent testing and evaluation of high-risk products and materials. To enable this grouping and prioritization for further testing, we developed a framework that establishes a prioritization score by evaluating a nano-enabled product's potential hazard and exposure, as well as additional consideration of regulatory importance. We integrate the framework into a pilot version software tool and, using a hypothetical case study, we demonstrate that the tool can effectively rank nano-enabled consumer products and can be adjusted for use by agencies with different priorities. The proposed decision-analytical framework and pilot-version tool presented here could enable a regulatory agency like the CPSC to triage reported safety concerns more effectively and allocate limited resources more efficiently.
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Ramos, Nuno M. M., Joana Maia, Rita Carvalho Veloso, Andrea Resende Souza, Catarina Dias i João Ventura. Envelope systems with high solar reflectance by the inclusion of nanoparticles – an overview of the EnReflect Project. Department of the Built Environment, 2023. http://dx.doi.org/10.54337/aau541621982.
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High reflectance materials constitute an attractive idea to reduce cooling loads, which is crucial for attaining the Nearly Zero Energy Buildings goal, also presenting the benefit of broadening the range of colours applicable in building facades. The EnReflect project intended to re-design envelope systems by increasing their solar reflectance through nanotechnology. The main idea was to produce novel nanomaterial-based coatings with high near-infrared (NIR) reflectance by tuning their optical properties and testing their compatibility with typical insulation technologies such as ETICS. As such, this project focused on the synthesis of nanoparticles with improved NIR reflectance, the evaluation of the hygrothermal-mechanical behaviour of thermal insulation systems with the application of the improved coating solutions, the characterization of the more relevant material properties and the durability assessment. One of the main achievements was the development of a facile synthesis of a nanocomposite with improved performance in the NIR region that allowed the reflectance improvement of a dark-finishing coating. Also, the incorporation of such nanoparticles had a positive effect on keeping their optical properties after accelerated ageing cycles. The development of numerical simulations allowed the estimation of the maximum surface temperature in Mediterranean climates under different optical parameters. The study of the hygrothermal behaviour of thermal enhanced façades led to the development of a new durability assessment methodology which contributed to closing a standardization gap.
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Huang, Dan, Mirian Velay-Lizancos i Jan Olek. Improving Scaling Resistance of Pavement Concrete Using Titanium Dioxide (TiO2 ) and Nanosilica. Purdue University, 2022. http://dx.doi.org/10.5703/1288284317583.
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This project focused on the evaluation of the influence of nanoadditives on the hydration kinetics, mechanical properties, and durability of concretes with and without supplementary cementitious materials (SCMs). The types of nanomaterials used in the course of this study included nano-titanium dioxide (nano-TiO2) and two forms of nanosilica. A series of experimental tasks, including fabrication, curing, and conditioning of specimens, microstructure analysis, mechanical strength testing, and durability testing were conducted in the laboratory. Based on experimental results, it can be concluded that the addition of nanoparticles can accelerate the early-age hydration process of cementitious pastes, especially those containing fly ash and cured at low temperatures. Both the compressive and flexural strength of mortars and concretes were also enhanced by the addition of nanoparticles. In addition, incorporation of nanoparticles reduced the total amount and connectivity of pores present in concretes. That resulted in lowering the water permeability of concretes, regardless of the cementitious systems and curing temperatures used. The resistance of concretes to freeze-thaw cycles and scaling was also improved by the addition of nanoparticles, especially those containing fly ash. However, an excess of nanoparticles additions may reduce the scaling resistance of concretes.
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Chefetz, Benny, Baoshan Xing, Leor Eshed-Williams, Tamara Polubesova i Jason Unrine. DOM affected behavior of manufactured nanoparticles in soil-plant system. United States Department of Agriculture, styczeń 2016. http://dx.doi.org/10.32747/2016.7604286.bard.
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The overall goal of this project was to elucidate the role of dissolved organic matter (DOM) in soil retention, bioavailability and plant uptake of silver and cerium oxide NPs. The environmental risks of manufactured nanoparticles (NPs) are attracting increasing attention from both industrial and scientific communities. These NPs have shown to be taken-up, translocated and bio- accumulated in plant edible parts. However, very little is known about the behavior of NPs in soil-plant system as affected by dissolved organic matter (DOM). Thus DOM effect on NPs behavior is critical to assessing the environmental fate and risks related to NP exposure. Carbon-based nanomaterials embedded with metal NPs demonstrate a great potential to serve as catalyst and disinfectors. Hence, synthesis of novel carbon-based nanocomposites and testing them in the environmentally relevant conditions (particularly in the DOM presence) is important for their implementation in water purification. Sorption of DOM on Ag-Ag₂S NPs, CeO₂ NPs and synthesized Ag-Fe₃O₄-carbon nanotubebifunctional composite has been studied. High DOM concentration (50mg/L) decreased the adsorptive and catalytic efficiencies of all synthesized NPs. Recyclable Ag-Fe₃O₄-carbon nanotube composite exhibited excellent catalytic and anti-bacterial action, providing complete reduction of common pollutants and inactivating gram-negative and gram-positive bacteria at environmentally relevant DOM concentrations (5-10 mg/L). Our composite material may be suitable for water purification ranging from natural to the industrial waste effluents. We also examined the role of maize (Zeamays L.)-derived root exudates (a form of DOM) and their components on the aggregation and dissolution of CuONPs in the rhizosphere. Root exudates (RE) significantly inhibited the aggregation of CuONPs regardless of ionic strength and electrolyte type. With RE, the critical coagulation concentration of CuONPs in NaCl shifted from 30 to 125 mM and the value in CaCl₂ shifted from 4 to 20 mM. This inhibition was correlated with molecular weight (MW) of RE fractions. Higher MW fraction (> 10 kDa) reduced the aggregation most. RE also significantly promoted the dissolution of CuONPs and lower MW fraction (< 3 kDa) RE mainly contributed to this process. Also, Cu accumulation in plant root tissues was significantly enhanced by RE. This study provides useful insights into the interactions between RE and CuONPs, which is of significance for the safe use of CuONPs-based antimicrobial products in agricultural production. Wheat root exudates (RE) had high reducing ability to convert Ag+ to nAg under light exposure. Photo-induced reduction of Ag+ to nAg in pristine RE was mainly attributed to the 0-3 kDa fraction. Quantification of the silver species change over time suggested that Cl⁻ played an important role in photoconversion of Ag+ to nAg through the formation and redox cycling of photoreactiveAgCl. Potential electron donors for the photoreduction of Ag+ were identified to be reducing sugars and organic acids of low MW. Meanwhile, the stabilization of the formed particles was controlled by both low (0-3 kDa) and high (>3 kDa) MW molecules. This work provides new information for the formation mechanism of metal nanoparticles mediated by RE, which may further our understanding of the biogeochemical cycling and toxicity of heavy metal ions in agricultural and environmental systems. Copper sulfide nanoparticles (CuSNPs) at 1:1 and 1:4 ratios of Cu and S were synthesized, and their respective antifungal efficacy was evaluated against the pathogenic activity of Gibberellafujikuroi(Bakanae disease) in rice (Oryza sativa). In a 2-d in vitro study, CuS decreased G. fujikuroiColony- Forming Units (CFU) compared to controls. In a greenhouse study, treating with CuSNPs at 50 mg/L at the seed stage significantly decreased disease incidence on rice while the commercial Cu-based pesticide Kocide 3000 had no impact on disease. Foliar-applied CuONPs and CuS (1:1) NPs decreased disease incidence by 30.0 and 32.5%, respectively, which outperformed CuS (1:4) NPs (15%) and Kocide 3000 (12.5%). CuS (1:4) NPs also modulated the shoot salicylic acid (SA) and Jasmonic acid (JA) production to enhance the plant defense mechanisms against G. fujikuroiinfection. These results are useful for improving the delivery efficiency of agrichemicals via nano-enabled strategies while minimizing their environmental impact, and advance our understanding of the defense mechanisms triggered by the NPs presence in plants.