Academic literature on the topic 'Non-spherical nanoparticles'
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Journal articles on the topic "Non-spherical nanoparticles"
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Singh, Himanshi, Debes Ray, Joachim Kohlbrecher, and Vinod K. Aswal. "Interaction of nanoparticles with non-spherical micelles and bilayers." Journal of Applied Physics 131, no. 15 (April 21, 2022): 154701. http://dx.doi.org/10.1063/5.0084795.
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Interaction of different-sized anionic silica nanoparticles with non-spherical micelles and bilayers of non-ionic surfactant C12E10 has been studied by small-angle neutron scattering (SANS). The non-ionic surfactant C12E10 in aqueous solution self-assembles to form core–shell spherical micelles. Different means (temperature, salts, and alcohols) have been examined to induce the structural transition of micelles from spherical to non-spherical and bilayer formation. The dehydration from micellar shell leads to such transition in the cases of increasing temperature and selective salt (e.g., KF). On the other hand, for alcohols, spherical to non-spherical micellar transition or bilayer formation arises for long-chain length alcohols CnOH ( n > 5) because of the mixed micelles formation of alcohol with surfactant. From the different ways to alter the micellar morphology, transitions obtained by alcohols were found to be the best suited for nanoparticle–surfactant solution as they do not influence the interactions between nanoparticle and surfactant and among nanoparticles. It is found that the shorter chain length alcohols (CnOH, n ≤ 5) interact with nanoparticles via the adsorption of individual micelles while the non-spherical micelles and bilayers of surfactant formed in the presence of long-chain length alcohols rearrange themselves to attach onto the nanoparticles. SANS with an advantage of contrast variation (contrast matching silica nanoparticles with solvent) provides the evidence of bilayer formation around nanoparticles. The concentration effect of long-chain length alcohol on micelle morphology and subsequently on the nanoparticle–surfactant system is also examined. It is found that the adsorption of surfactant bilayer structures is prominent in the case of larger particle size due to flattened curvature.
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Li, Xiaoyin, Fangyang Yuan, Wenma Tian, Chenlong Dai, Xinjun Yang, Dongxiang Wang, Jiyun Du, Wei Yu, and Huixin Yuan. "Heat Transfer Enhancement of Nanofluids with Non-Spherical Nanoparticles: A Review." Applied Sciences 12, no. 9 (May 9, 2022): 4767. http://dx.doi.org/10.3390/app12094767.
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This article reviews the heat transfer enhancement of nanofluids with non-spherical nanoparticles. We divided the non-spherical nanoparticles suspended in nanofluids into three categories based on the dimension of geometric particle structure. Based on the measured data in experimental studies, we then evaluated the shape effect of non-spherical nanoparticles on thermal conductivity and convective heat transfer enhancement of nanofluids. Recent studies explored the numerical predictions and related heat transfer mechanisms. Due to large aspect ratios, thermal conductivity is abnormally enhanced only for nanofluids with carbon nanotubes/nanofibers/nanowires. The approximate enhancement effect exerted by three types of non-spherical nanoparticles on thermal conductivity was 4.5:2.5:1. Thermal conductivity enhancement per concentration was larger for nanorods/ellipsoids with small aspect ratios. The convective heat transfer coefficient was increased by suspending non-spherical nanoparticles in the base fluid. Consequently, no significant thermohydraulic performance was discovered for convective heat transfer of non-spherical nanoparticle nanofluid flow, specifically for turbulent flows, due to increased pumping power. However, the temperature and particle concentration effect on convective heat transfer remains unclear. In addition, no perfect model for predicting the thermal conductivity and convective heat transfer of non-spherical nanoparticle nanofluids has been reported.
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Tréguer-Delapierre, M., J. Majimel, S. Mornet, E. Duguet, and S. Ravaine. "Synthesis of non-spherical gold nanoparticles." Gold Bulletin 41, no. 2 (June 2008): 195–207. http://dx.doi.org/10.1007/bf03216597.
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Niaz, Saad, Ben Forbes, and Bahijja Tolulope Raimi-Abraham. "Exploiting Endocytosis for Non-Spherical Nanoparticle Cellular Uptake." Nanomanufacturing 2, no. 1 (February 1, 2022): 1–16. http://dx.doi.org/10.3390/nanomanufacturing2010001.
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Several challenges exist for successful nanoparticle cellular uptake—they must be able to cross many physical barriers to reach their target and overcome the cell membrane. A strategy to overcome this challenge is to exploit natural uptake mechanisms namely passive and endocytic (i.e., clathrin- and caveolin-dependent/-independent endocytosis, macropinocytosis and phagocytosis). The influence of nanoparticle material and size is well documented and understood compared to the influence of nanomaterial shape. Generally, nanoparticle shape is referred to as being either spherical or non-spherical and is known to be an important factor in many processes. Nanoparticle shape-dependent effects in areas such as immune response, cancer drug delivery, theranostics and overall implications for nanomedicines are of great interest. Studies have looked at the cellular uptake of spherical NPs, however, fewer in comparison have investigated the cellular uptake of non-spherical NPs. This review explores the exploitation of endocytic pathways for mainly inorganic non-spherical (shapes of focus include rod, triangular, star-shaped and nanospiked) nanoparticles cellular uptake. The role of mathematical modelling as predictive tools for non-spherical nanoparticle cellular uptake is also reviewed. Both quantitative structure-activity relationship (QSAR) and continuum membrane modelling have been used to gain greater insight into the cellular uptake of complex non-spherical NPs at a greater depth difficult to achieve using experimental methods.
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Zhu, Xingjun, Chau Vo, Madelynn Taylor, and Bryan Ronain Smith. "Non-spherical micro- and nanoparticles in nanomedicine." Materials Horizons 6, no. 6 (2019): 1094–121. http://dx.doi.org/10.1039/c8mh01527a.
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Köhler, Johann, and Andrea Knauer. "The Mixed-Electrode Concept for Understanding Growth and Aggregation Behavior of Metal Nanoparticles in Colloidal Solution." Applied Sciences 8, no. 8 (August 10, 2018): 1343. http://dx.doi.org/10.3390/app8081343.
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The growth and aggregation behavior of metal nanoparticles can be modulated by surfactants and different other additives. Here the concept of how open-circuit mixed electrodes helps to understand the electrical aspects of nanoparticle growth and the consequences for the particle geometries is discussed. A key issue is the self-polarization effect of non-spherical metal nanoparticles, which causes a local decoupling of anodic and partial processes and asymmetry in the local rates of metal deposition. These asymmetries can contribute to deciding to the growth of particles with high aspect ratios. The interpretation of electrochemical reasons for particle growth and behavior is supported by experimental results of nanoparticle syntheses supported by microfluidics which can supply high yields of non-spherical nanoparticles and colloidal product solutions of high homogeneity.
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Smith, Gregory N., Laura L. E. Mears, Sarah E. Rogers, and Steven P. Armes. "Synthesis and electrokinetics of cationic spherical nanoparticles in salt-free non-polar media." Chemical Science 9, no. 4 (2018): 922–34. http://dx.doi.org/10.1039/c7sc03334f.
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The electrokinetics of cationic sterically-stabilized diblock copolymer nanoparticles prepared in salt-free non-polar media depend on whether the charge is located in the stabilizer shell or in the nanoparticle core.
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Zhu, Xingjun, Chau Vo, Madelynn Taylor, and Bryan Ronain Smith. "Correction: Non-spherical micro- and nanoparticles in nanomedicine." Materials Horizons 7, no. 5 (2020): 1436. http://dx.doi.org/10.1039/d0mh90013c.
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Wautelet, M., J. P. Dauchot, and M. Hecq. "On the phase diagram of non-spherical nanoparticles." Journal of Physics: Condensed Matter 15, no. 21 (May 16, 2003): 3651–55. http://dx.doi.org/10.1088/0953-8984/15/21/313.
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Little, Christopher A., Christopher Batchelor-McAuley, Neil P. Young, and Richard G. Compton. "Shape and size of non-spherical silver nanoparticles: implications for calculating nanoparticle number concentrations." Nanoscale 10, no. 34 (2018): 15943–47. http://dx.doi.org/10.1039/c8nr06062b.
Full textDissertations / Theses on the topic "Non-spherical nanoparticles"
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Wood, Christopher. "Non-spherical plasmonic nanoparticles." Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/48485.
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The field of nanotechnology has grown exponentially in recent years. As advancements are made in synthetic technology, this allows for their implementation into new research areas, industries, and potential applications. Nanoparticles are an extensively studied area in nanotechnology, with a plethora of constituent materials providing a vast array of potential properties. Plasmonic nanoparticles in particular have the ability to absorb light, leading to enhancements in many applications, for example surface enhanced Raman spectroscopy. Many plasmonic nanoparticle studies are focused on spherical nanoparticles, but significantly less is known of their non-spherical counterparts. Non-spherical plasmonic nanoparticles possess unique optical and behavioural properties that are of significant technological interest. However, their relatively unknown formation mechanisms typically result in polydisperse samples and little being known of their specific behaviour. The work in this thesis is centred on three areas of non-spherical plasmonic nanoparticles. The first is based on silver nanoprisms, synthesised from the photo-conversion of silver seeds. A blue-shift of their dipole excitation after illumination was noted and investigated using UV-Vis and TEM. Nanoprism analogues were synthesised and investigated, including gold-coated, and hollowed prisms. The second area is based on the size-selection of silver nanoprism solutions using ultraconcentration through a liquid-liquid interface. These investigations were to determine whether such methods and which conditions could be used to increase monodispersity of such nanoparticle samples. An increase in mean size indicated a more monodispersed sample was achieved, and if progressed further could significantly improve the results of other sections or future research. The final section studies magnetic nanoparticles, and using magnetism to direct nanoparticles to points of interest on large multifunctional plasmonic substrates. Through these investigations, magnetic trapping was observed of single nanoparticles on pyramidal substrates.
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Mathäs, Roman Willi. "Non-spherical micro- and nanoparticles." Diss., Ludwig-Maximilians-Universität München, 2015. http://nbn-resolving.de/urn:nbn:de:bvb:19-185114.
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Ahmed, Zeeshan. "Diffusivity of non-spherical nanomaterials in intestinal mucus." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASS136.
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RésuméL'administration orale est souvent préférée au recours au voies parentérales invasives. Toutefois, pour que l’administration orale soit efficace, il est nécessaire que les caractéristiques physico-chimiques et pharmacocinétiques des molécules soient favorables. Ainsi, le caractère fragile et/ou l’absorption intestinale incomplète de nombreuses molécules ne permettent pas leur administration par la voie orale en raison notamment : (i) d’une grande dilution de la molécule active et / ou sa destruction dans les liquides biologiques, (ii) d’un temps de séjour insuffisant devant la muqueuse en raison des mécanismes de péristaltisme et de clairance, ce qui aboutit à une absorption incomplète. (iii) d’une faible perméabilité apparente de la membrane intestinale.L'association des molécules actives à des nanoparticules conçues de manière à permettre l'augmentation du temps de séjour et de la concentration locale de médicament au contact direct de la muqueuse digestive durant la phase d’absorption permet de résoudre ces différents problèmes. Ainsi, l'effet de la taille des nanoparticules et leurs propriétés de surface sur leurs caractéristiques muco-adhésives a été largement étudié. Alors que jusqu’à présent les nanoparticules étudiées étaient sphériques, la possibilité récemment introduite de produire des nanoparticules non-sphériques à partir de polymères pharmaceutiquement acceptables a ouvert de nouvelles perspectives. Dans ce contexte, l'objectif principal de cette thèse a été d'étudier l'impact des la morphologie des nanoparticules sur leur comportement mucoadhésif. Le travail expérimental a compris les étapes suivantes: (i) la production et la caractérisation d'une bibliothèque de nanoparticules de morphologie contrôlée et (ii) l’étude de l'impact de leur morphologie sur leur diffusivité dans le mucus qui tapisse l'épithélium intestinal. Dans cet objectif, des nanoparticules oblongues ou en forme de disque ont été fabriquées par une technique de déformation physique de nanoparticules parentes constituées de poly(cyanoacrylate d'alkyle) et de géométrie sphérique. Dans ce procédé, les nanoparticules sphériques étaient déformées de manière contrôlée après leur dispersion dans un film de poly (alcool vinylique) suivi de son étirage. Des nanoplaquettes hexagonales ont également été préparées, mais par une technique d’auto-association de polysaccharides hydrophobisés et d’alpha-cyclodextrine. Quelle que soit leur forme, ces particules ont été décorées en surface par du chitosane, du chitosane thiolé ou de l'acide hyaluronique. Leur comportement diffusif dans le mucus a été étudiée par micoscopie de fluorescene permettant le suivi individuel des particules préalablement marquées et l'analyse détaillée de leurs trajectoires dans différentes milieux. La conclusion générale de cette étude est que la décoration de surface par les polysaccharides et la morphologie des nanoparticules jouent conjointement un rôle dans leur diffusion au sein du mucus. Ainsi, l'analyse des trajectoires suggère que la diffusion se produit essentiellement au sein d’espaces confinés présents au sein de la microstructure hétérogène du mucus. Il en résulte que l’immobilisation des nanoparticules dans le mucus dépend à la fois de leur géométrie et de la nature du polysaccharide à leur surface. Les particules décorées par le chitosane et le chitosane thiolés, tous deux connus pour leurs caractéristiques mucoadhésives, ont été la plupart du temps immobilisées, tandis que les plaquettes constituées d’acide hyaluronique présentaient une plus grande diffusivité en comparaisonAbstractOral delivery is often preferred to invasive parenteral routes, provided that drug physicochemical and pharmacokinetics characteristics are adequate. However, effective delivery of many fragile and/or poorly absorbed drugs still represents unfulfilled challenge for the pharmaceutical community because at least one of the following drawbacks: (i) large drug dilution and/or destruction in biological fluids. (ii) insufficient residence time in front of the absorptive due to peristaltism and clearance mechanisms. (iii) low apparent permeability of the intestinal membrane.Encapsulation of drugs in adequately engineered nanoparticles showed its ability to partially solve some aspects of these drawbacks, thanks to increases in residence time and local drug concentration in vicinity of the mucosal wall. While the effect of NP size and surface properties on their mucoadhesive characteristics has been extensively studied, the production of non-spherical nanoparticles from pharmaceutically acceptable polymers has recently been made feasible. In this context, the main objective of this thesis was to investigate the impact of Nps shape on their mucoadhesive behaviour. The experimental work consisted in : (i) producing and characterizing a library of NPs with controlled shape and (ii) to study the impact of NP morphology on their diffusivity into the intestinal mucus lining the intestinal epithelium. Elongated and disc shape NPs were designed by stretching of spherical poly(alkylcyanoacrylate) NPs using a poly(vinyl alcohol) film stretching method. Alternatively, flattened hexagonal platelets were obtained by self-association of hydrophobically-modified polysaccharides and alpha-cyclodextrin. Whatever their shape, these particles were surface decorated with chitosan, thiolated chitosan and hyaluronic acid. Their diffusive behaviour in mucus has been investigated by single particle tracking after fluorescent-labelling and detailed analysis of their trajectories. As a general picture, both polysaccharidic surface decoration and shape had an impact on NPs diffusion. In accordance with the heterogenous microstructure of the mucus, analysis of particles trajectories suggested that diffusion occurred mostly in confined spaces. As well, immobilization in the mucus depended both on polysaccharidic shape and surface decoration. Mucoadhesive chitosan and thiolated chitosan particles were mostly immobilized, while hyaluronic acid decorated platelets where more diffusive in comparison
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Mathäs, Roman Willi [Verfasser], and Gerhard [Akademischer Betreuer] Winter. "Non-spherical micro- and nanoparticles : fabrication, characterization, and in-vitro investigations / Roman Willi Mathäs. Betreuer: Gerhard Winter." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2015. http://d-nb.info/107545669X/34.
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Diaz, salmeron Raúl. "Directed-mobility and enhanced-adhesion nano-platelets for local drug delivery : towards a new treatment of bladder diseases." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS458.
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Titre : Nano-plaquettes à mobilité dirigée et adhésion amplifiée pour l’administration locale: vers un nouveau traitement des maladies vésicalesAbstract : L’administration locale des médicaments, définie comme une voie d’administration où la substance active est directement administrée sur ou proche de la cible ou tissus souhaités, permet d’apporter des grandes quantités des médicaments avec moins d’effets secondaires, et permet une simplification du système nanoparticulaire du fait de la non-extravasation des médicaments. Dans ce contexte, le projet de recherche de cette thèse s’est focalisé sur la voie intra-vésicale comme voie d’administration locale car il existe un besoin clinique de la part des patients, n’étant pas encore résolu. Malgré les hypothétiques avantages fournis par l’administration locale des médicaments, la voie intra-vésicale présente certaines limitations qui diminuent l’efficacité des traitements et l’observance des patients. La plupart des médicaments pour le traitement des maladies vésicales, notamment pour le cancer de la vessie et les cystites interstitielles, sont sous forme de solutions ou suspensions administrées de manière intra-vésicale via un cathéter qui passe à travers l’urètre. Dès leur arrivée à la vessie, les substances actives sont fortement diluées par les urines et éliminées rapidement lors de la miction. Cela conduit à une diminution des concentrations des substances actives au plus proche de l’épithélium, nécessitant plusieurs instillations intra-vésicales, réalisées par des praticiens hospitaliers, pour atteindre des concentrations thérapeutiques. Il y a donc un réel besoin de développer des nouvelles formulations permettant de contrecarrer les phénomènes décrits au préalable.L’objectif de cette thèse de doctorat est de créer un nouveau système nanoparticulaire de morphologie non-sphérique qui serait susceptible d’avoir un mouvement diffèrent et dirigé ainsi qu’une adhésion amplifiée. En conséquence, nous attendons de ces systèmes qu’ils apportent des concentrations en substances actives plus importantes que les systèmes nanoparticulaires sphériques et formulations galéniques traditionnelles.Aux cours de nos travaux expérimentaux, nous avons réussi à développer un système nanoparticulaire de morphologie hexagonale et aplatie. Ces nanoparticules, appellées nano-plaquettes, sont conçues à partir de l’auto-assemblage des molécules d’α-CD et des chaines alkyles greffées sur les squelettes de polysaccharides tels que l’acide hyaluronique, la chondroïtine sulfate ou l’héparine. Ces systèmes présentent l’originalité de ne pas avoir de substance active encapsulé parce que les molécules de polymère elles mêmes agissent à la fois en tant que substance active et de véhicule. Ces nano-plaquettes ont montré un mouvement en milieu isotrope et statique très diffèrent des nano-sphères utilisées comme contrôle. En effet, la majorité d’entre elles diffuse de manière plus importante et dirigée, avec des trajectoires rectilignes. Grâce à leur mouvement et aux propriétés inhérentes liées à leur forme, ces systèmes se sont montrés particulièrement intéressants vis-à-vis des interactions avec des cellules. Ils adhèrent mieux et plus longtemps à la muqueuse vésicale, elles sont mieux internalisées par des cellules et sont éliminées plus lentement une fois adhérées à la surface de l’urothélium.Un modelé in vivo de Syndrome de la Vessie Douloureuse / Cystite Interstitielle développé chez le rat nous a permis de montrer l’efficacité thérapeutique des nano-plaquettes, notamment celle constituées d’acide hyaluronique. En effet, elles présentent une meilleure bioaccumulation dans la vessie et une meilleure activité anti-inflammatoire et de régénération de la muqueuse urothéliale.Ces systèmes nanoparticulaires, conçues lors de nos travaux de thèse, constituent une approche innovante, rationnelle et efficace pouvant ouvrir de nouvelles voies de recherche pour le traitement des maladies vésicalesTitle: Directed-mobility and enhanced-adhesion nano-platelets for local drug delivery: towards a new treatment of bladder diseases.Abstract: Local drug delivery, defined as the administration route where the drug is delivered directly or very close to its target or tissue, allows to bring large amounts of drugs with reduced side effects, in comparison with systemic administration. In this context, our research project has been focused on the intravesical drug delivery as local administration route, because there is a real need to develop new pharmaceutical formulations to thwart several limitations. Despite the advantages provided by the local drug delivery, intravesical drug delivery exhibited some issues which are decreasing the therapeutic efficacy and the patient compliance to the treatment. Most of therapies for the treatment of bladder diseases are simple drug solutions or suspensions administered intravesically by using a catheter through the urethra in order to reach easily the bladder and, consequently, the urothelium. Since the drug is administered into the bladder, drug dilution is occurring because the continuous production of urine. Furthermore, active substances are being eliminated during washout when bladder urine voiding is happening. These two processes lead to the decrease of local drug concentration close to the urothelium. Patients need repeated catheterization, performed by health care practitioners, to reach therapeutic dose of the drug. Therefor, there is a need of new drug formulations to avoid these main limitations.The main goal of this PhD thesis was to create and design a new nanoparticulate system with non-spherical shape susceptible to move in a different manner compared to spherical nanoparticles. These systems may exhibit an amplified mucoadhesion allowing to bring more important amounts of drug than classical and nanoparticle administration.During this thesis, we developed a new nanoparticulate system presenting non-spherical, hexagonal and flattened shape. The driven force for the design of these nanoparticles was the self-assembling of α-cyclodextrin molecules with alkyl chains grafted on the polymer skeleton. Polymers used belong to a polysaccharide family called glycosaminoglycans including hyaluronic acid, chondroitin sulfate or heparin. This original and innovative nanoparticulate system does not encapsulate an active drug. Our polysaccharide will act, at the same time, as the active drug and the carrier. These nanoparticles, called now nano-platelets have shown different movement behavior than the spherical ones. Indeed, they diffuse more rapidly in a straight-line way. Thanks to their oriented and directed motion and to their intrinsic properties, due to the shape, these systems have shown a better mucoadhesion on the bladder tissue, a better uptake in different cell lines and they were far less rapidly eliminated from the urothelium mucosa.An in vivo model of Bladder Painful Syndrome / Interstitial Cystitis in rats demonstrated the therapeutic efficacy of nano-platelets, especially for hyaluronic acid nanoparticles. Indeed, they demonstrated a better bioaccumulation into the bladder and a better therapeutic efficacy as anti-inflammatory and urothelium regenerating agents.These nanoparticulate systems, designed during this work, represent a new innovative, rational and effectiveness approach allowing to open new research pathways for the treatment of bladder diseases
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Park, Chan Hyun. "Thermal Performance of Poly Alpha Olefin Nanofluid with Spherical and Non-spherical Nanoparticles." Thesis, 2011. http://hdl.handle.net/1969.1/ETD-TAMU-2011-05-9177.
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Research on nanofluids has been undertaken for several years because of the reported enhancements of thermal properties such as thermal conductivity and enhanced heat transfer performance in laminar flow. Nanofluid is the fluid where nanoparticles are dispersed in a base fluid. Thermal conductivity and viscosity are considered to be the most prominent factors in the efficient use of nanofluids. A change in thermal conductivity and viscosity also changes the convective heat transfer coefficient. Nanoparticles can be metallic or non-metallic and also can have different shapes. In this study, Poly-Alpha-Olefin (PAO) has been used as a base fluid with Alumina (Al2O3) nanoparticles. Poly-Alpha-Olefin is commonly used for engine lubrication in military
applications and cooling in electronic and industrial devices. Several nanofluid samples were made by METSS Corp. in Ohio, USA using different dispersants, different base fluids and different morphology of alumina nanoparticles. The mass fraction of nanoparticles is from 2.5 to 20 percent. The thermal properties of each sample such as thermal conductivity and viscosity have been measured. Thermal conductivity of nanofluids and pure base fluids were both measured and the thermal conductivity enhancement has been calculated. Also, the heat transfer coefficient has been determined for laminar flow under constant heat flux conditions.
Results indicate that all the tested nanofluids and base fluid samples show a Newtonian behavior. Among the nanofluid samples, NF-048, which contains non-spherical Alumina nanoparticles exhibits the greatest thermal conductivity enhancement when compared to pure PAO. Heat transfer tests were conducted with pure PAO and NF-048, and an enhancement in convective heat transfer coefficient was observed. The thermal conductivity of NF-048 increases with temperature, which is consistent with heat transfer results. Furthermore, the percentage enhancement in convective heat transfer coefficient was shown to increase non-linearly with the axial distance in the heat transfer section. NF-048 exhibits a lower Re (Reynolds number)*Ra (Rayleigh number) than pure PAO under laminar flow constant heat flux conditions indicating that nanoparticle morphology and composition are the two main factors responsible for convective heat transfer enhancement at low Reynolds number.
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Jung, Bong-Su 1972. "Fabrication and characterization of a plasmonic biosensor using non-spherical metal nanoparticles." Thesis, 2007. http://hdl.handle.net/2152/3614.
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Label-free detection techniques have an important role in many applications, such as situations where few molecules -- rather than low molarity -- need to be detected, such as in single-cell screening. While surface plasmon resonance (SPR) scattering from metal nanoparticles has been shown to achieve significantly higher sensitivity in gene arrays, such an approach has not been demonstrated for protein arrays. SPR-based sensors could either use simple absorption measurement in a UV-Vis spectrometer or possibly surfaceenhanced Raman spectroscopy as the detection mechanism for molecules of interest. However, non-spherical particles are needed to achieve high sensitivity and field enhancement that is a requirement in both techniques, but these shapes are not easy toproduce reproducibly and preserve for extended periods of time. Here I present a carbonbased template-stripping method combined with nanosphere lithography (NSL). This fabrication allows to preserve the sharp features in atomically flat surfaces which are a composite of a non-spherical metal nano-particle (gold or silver) and a transparent embedding material such as glass. The stripping process is residue-free due to the introduction of a sacrificial carbon layer. The nanometer scale flat surface of our template stripping process is also precious for general protein absorption studies, because an inherent material contrast can resolve binding of layers on the 2 nm scale. These nanocomposite surfaces also allow us to tailor well-defined SPR extinction peaks with locations in the visible or infrared spectrum depending on the metal and the particle size and the degree of non-symmetry. As the particle thickness is reduced and the particle bisector length is increased, the peak position of the resonance shifts to the red. Not only the peak position shifts, but also the sensitivity to environmental changes increases. Therefore, the peak position of the resonance spectrum is dependent on the dielectric environmental changes of each particle, and the particle geometries. The resulting silver or gold nanoparticles in the surface of a glass slide are capable of detecting thiol surface modification, and biotin-streptavidin protein binding events. Since each gold or silver particle principally acts as an independent sensor, on the order of a few thousand molecules can be detected, and the sensor can be miniaturized without loss of sensitivity. UNSL-Au metal nanoparticle (MNP) sensors achieve the sensitivity of close to 300 nm/RIU which is higher than any other report of localized surface plasmon resonance (LSPR) sensors except gold nanocrescents. Finite-difference-time-domain (FDTD) and finite-element-method (FEM) numerical calculations display the influence of the sharp features on the resonance peak position. The maximum near-field intensity is dependent on the polarization direction, the sharpness of the feature, and the near-field confinement from the substrate. 3D FDTD simulation shows the local refractive index sensitivity of the gold truncated tetrahedron, which is in agreement with our experimental result. Both experimental and numerical calculations show that each particle can act as its own sensor.
Book chapters on the topic "Non-spherical nanoparticles"
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Vital, A., U. Klotz, T. Graule, R. Mueller, H. K. Kammler, and S. E. Pratsinis. "Synthesis of Spherical, Non-Aggregated Silica Nanoparticles." In Nanostructured Materials and Coatings for Biomedical and Sensor Applications, 203–10. Dordrecht: Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-010-0157-1_21.
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Rubín, J., F. Jiménez-Villacorta, J. Bartolomé, and C. Prieto. "CEMS spectra of non-spherical nanoparticles in oxidized iron thin films." In ICAME 2007, 713–18. Berlin, Heidelberg: Springer Berlin Heidelberg, 2008. http://dx.doi.org/10.1007/978-3-540-78697-9_97.
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Li, Xiao, Weidong Zhang, and Gaojian Chen. "Synthesis of Non-spherical Glycopolymer-Decorated Nanoparticles: Combing Thiol-ene with Catecholic Chemistry." In Methods in Molecular Biology, 149–55. New York, NY: Springer New York, 2016. http://dx.doi.org/10.1007/978-1-4939-3130-9_12.
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"Filling Nanoparticles in Dielectrics." In Design and Investment of High Voltage NanoDielectrics, 169–200. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-3829-6.ch006.
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This chapter contains the new technologies for filling nanoparticles inside dielectrics that handled the computational solid state physics of nanodielectrics. This chapter draws attention also to modeling and simulation techniques, bare spherical nanoparticles, non-spherical nanoparticles, and physical process analysis. Also, this chapter presents recent nanodielectrics technology and fillers in commercial dielectric. In this chapter, the structural examination of two-dimensional small-angle x-beam diffusing SAXS designs are examined for polymer-inorganic nanocomposites loaded with platelet-shaped mineral crystals demonstrating favored introduction. Also, this chapter displays an audit from starting later DFT requisitions to spectroscopic issues dependent upon a particular PC code, CASTEP. The precision of spectra computed by utilizing DFT is another addition to qualitative investigations.
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Rickard, David. "Framboid Sizes." In Framboids, 21–46. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780190080112.003.0002.
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Framboid size-frequency plots show log-normal distributions with a geometric mean diameter of 6.0 μm and with 95% of framboids ranging between 2.9 and 12.3 μm. The largest framboids may be 250 μm in diameter, although spherical aggregates of framboids, known as polyframboids, may range up to 900 μm in diameter. Various spherical clusters of nanoparticles have been described which are less than 0.2 μm in diameter. These do not form a continuum with framboids. There is no evidence for any significant change in framboid diameters with geologic time, and the differences in mean sizes between hydrothermal and sedimentary framboids do not, at present, appear to be statistically significant. By contrast, it appears that the mean diameters of framboids from non-marine sediments are significantly larger (7.6 μm) than marine framboids (5.7 μm). There is some evidence that framboids formed in the water column are smaller than those formed in sediments, but the non-critical use of this possible difference as a proxy for paleoenvironmental reconstructions is not robust. So-called microframboids and nanoframboids are discrete entities which are distinct from framboids. They are nanoparticle clusters and are not produced by the same processes as those involved in framboid formation, nor do they behave in the same way. They are more akin to atomic clusters, which form similar constructs.
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Guzmán, Katherine, Brajesh Kumar, Marcelo Grijalva, Alexis Debut, and Luis Cumbal. "Ascorbic Acid-assisted Green Synthesis of Silver Nanoparticles: pH and Stability Study." In Green Chemistry - New Perspectives [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.107202.
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In this chapter, eco-friendly in situ synthesis of silver nanoparticles (AgNPs) using a mixture of ascorbic acid and citric acid is introduced. The synthesis conditions of the AgNPs were optimized by adjusting the pH of the reaction mixture. Different spectroscopic and microscopic techniques have been used to characterize the physico-chemical properties of AgNPs. The synthesis of AgNPs was primarily identified by the appearance of yellow colour and confirmed by showing λmax = 409 nm in UV-visible spectroscopy. All characterization techniques reveal that the generated AgNPs were non-aggregated, quasi-spherical shapes with an average size of 22.4 ± 13.2 nm, and face-centred cubic crystalline structures. Infrared spectroscopy confirms the surface of AgNPs covered with -COOH group and shows peaks at 1733, 1759, 3262 and 3633 cm−1. Moreover, synthesized AgNPs at pH 10 were stable for one month with a slight change in size. A straightforward, facile and environmentally-friendly synthesis of highly stable AgNPs may contribute to future engineering applications.
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Cassagnau, Philippe. "Rheology of Carbon Nanoparticle Suspensions and Nanocomposites." In Rheology of Non-Spherical Particle Suspensions, 59–75. Elsevier, 2015. http://dx.doi.org/10.1016/b978-1-78548-036-2.50003-4.
Full textConference papers on the topic "Non-spherical nanoparticles"
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Park, Chan Hyun, and Jorge L. Alvarado. "Thermal Performance of Poly Alpha Olefin Nanofluid With Spherical and Non-Spherical Nanoparticles." In ASME 2012 Heat Transfer Summer Conference collocated with the ASME 2012 Fluids Engineering Division Summer Meeting and the ASME 2012 10th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/ht2012-58319.
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In this study, several heat transfer fluids consisting of Poly-Alpha-Olefin (PAO) as base fluid and non-spherical alumina (Al2O3) nanoparticles such as nanorods and nanoplatelets have been used to formulate thermally enhanced nanofluids. Thermal properties such as thermal conductivity and viscosity have been measured, and the corresponding thermal conductivity enhancement has been calculated. The heat transfer coefficient under laminar flow under constant heat flux conditions has been measured experimentally. Results indicate that nanofluids containing spherical and non-spherical nanoparticles depict a Newtonian behavior at low concentrations. Nanofluids containing non-spherical alumina nanoparticles exhibit the greatest thermal conductivity enhancement when compared to pure PAO. Moreover, heat transfer enhancement was also observed when non-spherical nanoparticles were used. Likewise, the percentage enhancement in convective heat transfer coefficient was shown to increase non-linearly with axial distance (x/Di) in a circular heat transfer section. Nanofluids containing non-spherical nanoparticles exhibits a lower Re*Ra (Reynolds number*Rayleigh number) than pure PAO under laminar flow constant heat flux conditions indicating that nanoparticle morphology and composition are the two main factors responsible for convective heat transfer enhancement at low Reynolds number. Convection and axial conduction can explain the increase in Nusselt number when x/Di is greater than 400. The expected radial movement of nanoparticles within the fluid at relatively low Reynolds number could explain the enhanced convection when factoring in changes in viscosity and the effect of buoyancy.
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Brzobohatý, Oto, Martin Šiler, Lukáš Chvátal, Vítezslav Karásek, and Pavel Zemánek. "Optical trapping of non-spherical plasmonic nanoparticles." In SPIE OPTO, edited by David L. Andrews, Enrique J. Galvez, and Jesper Glückstad. SPIE, 2014. http://dx.doi.org/10.1117/12.2041199.
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Yu, Leyuan, Dong Liu, and Frank Botz. "Laminar Convective Heat Transfer of Alumina-Polyalphaolefin Nanofluids Containing Spherical and Non-Spherical Nanoparticles." In ASME 2011 Pacific Rim Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Systems. ASMEDC, 2011. http://dx.doi.org/10.1115/ipack2011-52256.
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As a promising candidate for advanced heat transfer fluids, nanofluids have been studied extensively during the past decade. In contrast to the early reports of dramatic heat transfer enhancement even at extremely low particle concentrations, the most recent studies suggest the laminar convective heat transfer of nanofluids is only mildly augmented and can be predicted by the conventional Navier-Stokes equations. The majority of the past studies were limited to water-based nanofluids synthesized from spherical nanoparticles. No systematic information is yet available for the convective heat transfer of nanofluids containing non-spherical particles, especially those formulated with the base fluid other than water. An experimental study was conducted in this work to investigate the thermophysical properties and convective heat transfer characteristics of Al2O3-Polyalphaolefin (PAO) nanofluids containing both spherical and rod-like nanoparticles. The effective viscosity and thermal conductivity were measured and compared to predictions from the effective medium theory. The friction factor and local Nusselt number were also measured for the laminar flow regime. It was found that established theoretical correlations can satisfactorily predict the experimental data for nanofluids containing spherical nanoparticles; however, they are less successful for nanofluids with nanorods. The possible reasons may be attributed to the shear-induced alignment of non-spherical nanoparticles and its subsequent influence on the development of the thermal boundary layer. The results suggest that the hydrodynamic interactions between the non-spherical nanoparticles and the surrounding fluid medium have a significant impact on the thermophysical properties as well as on the thermal transport characteristics of nanofluids.
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Sar, D. K., P. Nayak, K. K. Nanda, Shyamalendu M. Bose, S. N. Behera, and B. K. Roul. "Size-Dependent Cohesive Energy and Melting Of Non-Spherical Nanoparticles." In MESOSCOPIC, NANOSCOPIC AND MACROSCOPIC MATERIALS: Proceedings of the International Workshop on Mesoscopic, Nanoscopic and Macroscopic Materials (IWMNMM-2008). AIP, 2008. http://dx.doi.org/10.1063/1.3027186.
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Liu, Fang, and Yang Cai. "Effects of Particle Shape on Nanofluids Laminar Forced Convection in Helically Coiled Tubes." In ASME 2017 Heat Transfer Summer Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/ht2017-4722.
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In this study, effects of particle morphology (shape and size) on nanofluids laminar forced convection in helically coiled tubes are investigated numerically using Eulerian-Lagrangian two-phase approach. The laminar forced convective heat transfer and pressure drop of Al2O3-water nanofluids containing nanoparticles with various particle shapes (sphere, platelet, blade, cylinder and brick) and sizes at different volume fractions in the developing and fully developed regions are investigated using the validated two-phase model. It is found that the nanofluids containing platelet particle shape has the highest heat transfer enhancement, which is followed by nanofluids containing cylinder, blade, sphere and brick nanoparticle shapes, respectively. Non-spherical nanoparticles with larger aspect ratio, small particle size and a suitable particle volume concentration are beneficial for heat transfer enhancement of forced convection. Heat transfer efficiency reaches minima at Re of 1250 for laminar forced convection with 1% volume fraction. The correlations of Nusselt number and pressure drop with nanoparticle shape and size were developed to predict convective heat transfer of nanofluids containing spherical nanoparticles and non-spherical nanoparticles.
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Öhman, Johan, and Mikael Sjödahl. "Identification and Size Estimation of Non-Spherical Nanoparticles using Polarization-Resolved Holography." In Digital Holography and Three-Dimensional Imaging. Washington, D.C.: OSA, 2020. http://dx.doi.org/10.1364/dh.2020.hth4h.8.
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Juve, Vincent, M. Fernanda Cardinal, Anna Lombardi, Aurelien Crut, Paolo Maioli, Luis M. Liz-Marzan, Natalia Del Fatti, and Fabrice Vallee. "Size dependent surface plasmon resonance broadening in non-spherical nanoparticles: Single gold nanorods." In 2013 Conference on Lasers & Electro-Optics Europe & International Quantum Electronics Conference CLEO EUROPE/IQEC. IEEE, 2013. http://dx.doi.org/10.1109/cleoe-iqec.2013.6801889.
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Terekhov, Pavel D., Kseniia V. Baryshnikova, Yuriy A. Artemyev, Alina Karabchevsky, Alexander S. Shalin, and Andrey B. Evlyukhin. "Optical multipole resonances of non-spherical silicon nanoparticles and the influence of illumination direction." In Optical Components and Materials XV, edited by Michel J. Digonnet and Shibin Jiang. SPIE, 2018. http://dx.doi.org/10.1117/12.2289894.
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Liu, Yaling, Kytai Nguyen, Manohara Mariyappa, Soujanya Kona, and Jifu Tan. "A Coupled Particle-Continuum Model of Nanoparticle Targeted Delivery Under Vascular Flow With Experimental Validation." In ASME 2010 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2010. http://dx.doi.org/10.1115/sbc2010-19035.
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Nanomedicine poses a new frontier in medical technology with the advantages of targeted delivery and patient specific design. In applications of nanoparticle targeted drug delivery, the delivery efficiency is controlled by the physical properties of the nanoparticle such as its size, shape, ligand density, as well as external environmental conditions such as flow rate and blood vessel diameter. Proper drug dosage choice relies on determination of the attachment and detachment rates of the nanoparticles at the active region and the understanding of the complex process of targeted drug delivery. A few particulate models have been proposed to study the adhesion individual spherical or non-spherical nanoparticles on receptor coated wall. Meanwhile, continuum convection-diffusion-reaction models have been widely used to calculate the drug concentration under various conditions, which usually assumes specific binding and de-binding constants. In reality, these binding and de-binding rates largely vary with physical properties of the particles and local flow conditions. However, there has not been any study that links the particulate level nanoparticle size and shape information to the system level bounded particle concentration. A hybrid particle binding dynamics and continuum convection-diffusion-reaction model is presented to study the effect of shear flow rate and particle size on binding efficiency. The simulated concentration of bounded nanoparticles agrees well with experimental results in flow chamber studies.
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Li, L., C. Leung, Y. Du, C. Wong, and P. Pong. "Capping-ligands-induced synthesis of non-spherical magnetite nanoparticles for hyperthermia and their biocompatibility study." In 2015 IEEE International Magnetics Conference (INTERMAG). IEEE, 2015. http://dx.doi.org/10.1109/intmag.2015.7157201.
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