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Artykuły w czasopismach na temat "Potential of nano and micro particles"
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Larpkiattaworn, Siriporn, Wasana Khongwong, Siriporn Tong-On, Chutima Eamchotchawalit i Chaiwat Vorapeboonpong. "Dispersion Stability of Drinking Water Treatment Sludge". Key Engineering Materials 659 (sierpień 2015): 69–73. http://dx.doi.org/10.4028/www.scientific.net/kem.659.69.
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The objective of this study is to improve the particle suspension stability of drinking water treatment sludge (DWTS) and comparable to other silicate powder which are bentonite, micro silica (micro-SiO2), and nano-silica (nano-SiO2). The main dispersion characteristic are related to particle size, and dispersion force. The representative samples of bentonite, micro-SiO2, nano-SiO2, and DWTS were dispersed at the same solid content in water. The particle size distribution and chemical composition of samples were analyzed. The suspended samples were measured for Zeta potential at the controlled pH value. Furthermore, turbidity of suspended samples were investigated at various sedimenting time. The results indicated that nano-SiO2 has the highest Zeta potential value at pH 8-12. The stability of particle dispersion could be implied from turbidity of suspension at various sedimenting time. Bentonite suspension performed more stability than other samples for longer time. However, stability of DWTS particles can be improved by particle size controlling and treatment with dispersion agent to create repulsive force from the charge on the particle surface.
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Ponnamma, Deepalekshmi, Qipeng Guo, Igor Krupa, Mariam Ali S. A. Al-Maadeed, Varughese K. T., Sabu Thomas i Kishor Kumar Sadasivuni. "Graphene and graphitic derivative filled polymer composites as potential sensors". Physical Chemistry Chemical Physics 17, nr 6 (2015): 3954–81. http://dx.doi.org/10.1039/c4cp04418e.
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Odermatt, Reto, Matej Par, Dirk Mohn, Daniel B. Wiedemeier, Thomas Attin i Tobias T. Tauböck. "Bioactivity and Physico-Chemical Properties of Dental Composites Functionalized with Nano- vs. Micro-Sized Bioactive Glass". Journal of Clinical Medicine 9, nr 3 (12.03.2020): 772. http://dx.doi.org/10.3390/jcm9030772.
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Bioactive resin composites can contribute to the prevention of secondary caries, which is one of the main reasons for failure of contemporary dental restorations. This study investigated the effect of particle size of bioactive glass 45S5 on chemical and physical composite properties. Four experimental composites were prepared by admixing the following fillers into a commercial flowable composite: (1) 15 wt% of micro-sized bioactive glass, (2) 15 wt% of nano-sized bioactive glass, (3) a combination of micro- (7.5 wt%) and nano-sized (7.5 wt%) bioactive glass, and (4) 15 wt% of micro-sized inert barium glass. Hydroxyapatite precipitation and pH rise in phosphate-buffered saline were evaluated during 28 days. Degree of conversion and Knoop microhardness were measured 24 h after specimen preparation and after 28 days of phosphate-buffered saline immersion. Data were analyzed using non-parametric statistics (Kruskal–Wallis and Wilcoxon tests) at an overall level of significance of 5%. Downsizing the bioactive glass particles from micro- to nano-size considerably improved their capability to increase pH. The effect of nano-sized bioactive glass on degree of conversion and Knoop microhardness was similar to that of micro-sized bioactive glass. Composites containing nano-sized bioactive glass formed a more uniform hydroxyapatite layer after phosphate-buffered saline immersion than composites containing exclusively micro-sized particles. Partial replacement of nano- by micro-sized bioactive glass in the hybrid composite did not impair its reactivity, degree of conversion (p > 0.05), and Knoop microhardness (p > 0.05). It is concluded that downsizing bioactive glass particles to nano-size improves the alkalizing potential of experimental composites with no negative effects on their fundamental properties.
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Wang, Dan, Yajun Yin, Jiye Wu, Xugui Wang i Zheng Zhong. "Interaction Potential between Parabolic Rotator and an Outside Particle". Journal of Nanomaterials 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/464925.
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At micro/nanoscale, the interaction potential between parabolic rotator and a particle located outside the rotator is studied on the basis of the negative exponential pair potential1/Rnbetween particles. Similar to two-dimensional curved surfaces, we confirm that the potential of the three-dimensional parabolic rotator and outside particle can also be expressed as a unified form of curvatures; that is, it can be written as the function of curvatures. Furthermore, we verify that the driving forces acting on the particle may be induced by the highly curved micro/nano-parabolic rotator. Curvatures and the gradient of curvatures are the essential elements forming the driving forces. Through the idealized numerical experiments, the accuracy of the curvature-based potential is preliminarily proved.
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Miranda López, M. I., M. B. Hernández Hernández, B. S. Vera Barrios, A. Toxqui Teran i J. A. Aguilar Martinez. "A comparative study between the addition of nano and micro-particles of Co3O4 on the electrical and microstructural properties of a ceramic system based on SnO2". Revista Mexicana de Física 66, nr 1 (28.12.2019): 47. http://dx.doi.org/10.31349/revmexfis.66.47.
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A comparative study between the addition of Co3O4 micro-particles and nano-particles as densifying dopant of a SnO2 based varistor system was conducted. The ceramic composition was (99.9-X) %SnO2–X %Co3O4–0.05 %Cr2O3–0.05 %Nb2O5 where X = 0, 0.5, 1.0, 2.0 and 4.0 mol%. Two particle sizes of Co3O4 were used (~5 µm and ~50 nm). The addition of 0.5 mol% of Co3O4 nano-particles promoted an increase of grain size of sintered samples up to 7.9 µm, that is, the maximum value among all variations. Characterization techniques such as TGA, DTA, XRD, and Rietveld analysis revealed a decrease of 16 ºC in the formation temperature of Co2SnO4 as well as an increase of 2.6 wt% in the amount of said phase with the use of 4.0 mol% of Co3O4 nano-particles in comparison with micro-particles. Statistical analysis indicated that the addition of nano-particles of Co3O4 yield better repeatability on densification of ceramic samples. Residual porosity also was decreased. Electrical breakdown and non-linear coefficient values correspond to a non-ohmic behavior with potential application on manufacture of high voltage varistors. The findings of this work can be used as a reference for conducting a later study to improve the electrical properties or even to lower the sintering temperature.
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Duan, Ziyi, Yating Zhao, Xia Liu i Guoxin Li. "Micro (nano) Plastics Released from Plastic Food Containers". E3S Web of Conferences 406 (2023): 01006. http://dx.doi.org/10.1051/e3sconf/202340601006.
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The pollution of micro (nano) plastics is one of the most urgent global environmental problems. Micro (nano) plastics will release from plastic products (e.g., food related products) to the environment, causing potential threats to human health and ecosystem. Therefore, the release of micro (nano) plastics from plastic products (e.g., food containers) deserves more concerns. In the present work, plastic food container was chosen to investigate the release of micro (nano) plastics under two heating methods (100 ℃ hot water and microwave heating) and reuse within nine times were further investigated the release characteristics. The findings demonstrate that: (1) The maximum release amount was 10.3±0.2×1010 particles/L, which was occurred under microwave heating, and it was twice greater than that under hot water heating, indicating that microwave heating could enhance micro (nano) plastics releasing; (2) The amounts of released micro (nano) plastics would fluctuate, and the fluctuation was getting smaller as the use times increasing; (3) The number of use times had no influence on the released particle size, and the amount of nanoplastics (<400 nm) was dominant in the released micro (nano) plastics. Therefore, micro (nano) plastics production from food containers represents a key source of microplastic contamination in the ecosystem.
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Lee, Sun Young, Min Jung Son, Gil Son Khang, Young Suk Son, Chang Kuk You, Suk Young Kim, Hong In Shin, Eui Kyun Park i Shin Yoon Kim. "Stimulatory Effect of Nano-Sized Calcium Metaphosphate Particles on Proliferation and Osteoblastic Differentiation of Human Bone Marrow Mesenchymal Stem Cells". Key Engineering Materials 361-363 (listopad 2007): 1177–80. http://dx.doi.org/10.4028/www.scientific.net/kem.361-363.1177.
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Recently, nanomaterials have received considerable attention because of their potential applications in the biomedical field. In the present study, we investigated the effects of nano-sized calcium metaphosphate (CMP) particles (50 nm) compared with micro-sized CMP particles (200-500 nm and 10 μm) on the proliferation and osteoblastic differentiation of human bone marrow stem cells (BMSCs). BMSCs were challenged with CMP particles with different sizes for 3, 5, and 7 days. An analysis of the proliferation revealed that the nano-sized CMP particles (50 nm) stimulated the proliferation of BMSCs up to 27.79% compared to the untreated control. This stimulatory effect of the nano-sized CMP particle was dose-dependent. CMP particles appeared to adhere on the surface of BMSCs but this did not cause distinguishable morphological changes. Moreover, all CMP particles (50 nm to 10 μm) were capable of stimulating an osteoblastic differentiation of BMSCs as accessed by alkaline phosphatase (ALP) and von Kossa stainings. Further molecular analysis revealed that all the CMP particles induced an expression of osteoblast-related genes such as osteocalcin (OC) and collagen I (Col I). Taken together, our data demonstrate that nano-sized CMP particles have the potential to stimulate the proliferation and osteoblastic differentiation of BMSCs.
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Khitab, Anwar, Sajjad Ahmad, Riaz Akhtar Khan, Muhammad Tausif Arshad, Waqas Anwar, Junaid Tariq, Ali Sikandar Rasheed Khan, Raja Bilal Nasar Khan, Affan Jalil i Zeesshan Tariq. "Production of Biochar and Its Potential Application in Cementitious Composites". Crystals 11, nr 5 (10.05.2021): 527. http://dx.doi.org/10.3390/cryst11050527.
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In cement composites, usually, reinforcement is provided to restrict the crack development and their further propagation under service conditions. Typically, reinforcements utilized in cementitious composites range from nanometer scale to millimeter scale by using nano-, micro-, and millimeter-sized fibers and particles. These reinforcements provide the crack arresting mechanisms at the nano/microscale and restrict the growth of the cracks under service loads, but usually, the synthesis of nano/microfibers, and afterward their dispersion in the cementitious materials, pose difficulty, thus limiting their vast application in the construction industry. Carbonaceous inerts are green materials since they are capable of capturing and storing carbon, thus limiting the emission of CO2 to the atmosphere. In the present study, a comprehensive review of the synthesis of low cost and environmentally friendly nano/micro carbonaceous inerts from pyrolysis of different agricultural/industrial wastes, and afterward, their application in the cementitious materials for producing high performance cementitious composites is presented, which have the potential to be used as nano/micro reinforcement in the cementitious matrix.
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Wang, Zhilong, Zongpu Han, Xiaozhu Liao, Xiao Zhang, Jiachen Liang, Zhe Xing i Zengjie Fan. "3D printing polycaprolactone micro-nano copper scaffolds with a high antibacterial performance for potential sewage treatment". High Performance Polymers 34, nr 1 (31.01.2022): 44–53. http://dx.doi.org/10.1177/09540083211040473.
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Effective application of micro-nano copper particles in elimination of the pathogenic microorganisms in the water remains a challenge. In this study, an optimum structural design was adopted in mathematical models to improve the efficiency of sewage filtration, and polycaprolactone/copper scaffold (PCs) was fabricated through a 3D printing method. The result shows that the micro-nano copper particles were physically embedded into the polycaprolactone scaffolds. In addition, the antibacterial efficiency of PCs against E. coli and S. aureus was up to 100% and the antibacterial performance could be remained in sewage filtration (copper: polycaprolactone = 1:2). The results suggest that PCs is a good candidate for application in the sewage treatment.
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Reichel, Julia, Johanna Graßmann, Oliver Knoop, Jörg E. Drewes i Thomas Letzel. "Organic Contaminants and Interactions with Micro- and Nano-Plastics in the Aqueous Environment: Review of Analytical Methods". Molecules 26, nr 4 (22.02.2021): 1164. http://dx.doi.org/10.3390/molecules26041164.
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Micro- and nanoplastic particles are increasingly seen not only as contaminants themselves, but also as potential vectors for trace organic chemicals (TOrCs) that might sorb onto these particles. An analysis of the sorbed TOrCs can either be performed directly from the particle or TOrCs can be extracted from the particle with a solvent. Another possibility is to analyze the remaining concentration in the aqueous phase by a differential approach. In this review, the focus is on analytical methods that are suitable for identifying and quantifying sorbed TOrCs on micro- and nano-plastics. Specific gas chromatography (GC), liquid chromatography (LC) and ultraviolet-visible spectroscopy (UV-VIS) methods are considered. The respective advantages of each method are explained in detail. In addition, influencing factors for sorption in the first place are being discussed including particle size and shape (especially micro and nanoparticles) and the type of polymer, as well as methods for determining sorption kinetics. Since the particles are not present in the environment in a virgin state, the influence of aging on sorption is also considered.
Rozprawy doktorskie na temat "Potential of nano and micro particles"
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Meehan, Timothy D. Superfine Richard. "Quantitative magnetophoresis of micro and nano particles". Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2008. http://dc.lib.unc.edu/u?/etd,2272.
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Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2008.Title from electronic title page (viewed Jun. 26, 2009). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Chemistry." Discipline: Chemistry; Department/School: Chemistry.
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Li, Xue. ""Cage" Nano and Micro-particles for Biomedical Applications". Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS316/document.
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Les systèmes à délivrance de médicaments sont des technologies conçues pour administrer des molécules actives de façon optimisée afin d’améliorer leurs effets thérapeutiques tout en minimisant les effets secondaires. En effet, ces systèmes permettent une libération au niveau d’une cible thérapeutique. Les particules de type «cage» ont récemment attiré une attention particulière en raison de leur capacité accrue à (co)incorporer et à protéger des molécules actives vis-à-vis de dégradations in vivo. Les cyclodextrines (CDs) sont des exemples type de molécules "cage", possédant une cavité hydrophobe et une surface extérieure hydrophile. Nous avons élaboré tout d’abord des assemblages supramoléculaires à base de CDs d'environ 100 nm par une méthode douce consistant à mélanger deux solutions aqueuses de polymères neutres : 1) polymère de β-CD et 2) dextrane greffé avec la benzophénone, molécule invitée formant des complexes d’inclusion avec les CDs. La procédure de préparation « verte» en une seule étape rend la formulation attractive, malgré sa relativement faible capacité d’encapsulation (5%pds). Afin d'améliorer cete charge, nous avons élaboré des particules hybrides organiques-inorganiques (MOFs) à base de CDs. Avantageusement, les CD-MOF comportent non seulement des cavités de CD, mais aussi de larges pores engendrés lors l’auto-assemblage de CDs. Le lansoprazole a été incorporé avec succès (23%pds) dans les CD-MOFs et nous avons montré que chaque CDs était capable d’accueillir une molécule de principe actif. Cependant, l’inconvénient majeur des CD-MOFs est leur faible stabilité en milieu aqueux, limitant leur domaine d’application. Une modification de surface est apparue donc nécessaire pour améliorer leur stabilité. Notre stratégie a été d’incorporer les CD-MOFs dans des matrices d'acide polyacrylique (PAA). Des microsphères composites d’environ 650 nm ont été élaborées avec succès et ont permis une bonne stabilité et une libération prolongée sur plus de 48 h. Avantageusement, ces particules composites n’étaient pas toxiques in vitro même à des concentrations élevées. Ainsi, nous nous sommes orientés vers l’étude comparative de MOFs plus stables dans l’eau, à base de trimesate de fer. Les MIL-100 (Fe) (Material of Institute Lavoisier) figurent parmi les premiers MOF étudiés en tant que nanomédicaments (nanoMOFs). Ces particules, parfaitement stables dans l'eau, se dégradent dans des milieux contenant des phosphates en perdant rapidement leur caractère cristallin et leurs ligands constitutifs. De façon étonnante, nous avons constaté que malgré leur dégradation, ces MOFs conservent leur taille intacte. Une analyse approfondie basée sur la microscopie de Raman a permis d’obtenir des informations pertinentes sur la morphologie et la composition chimique de particules individuelles. Ainsi, il a été montré qu’un front d'érosion délimitait nettement un cœur intact et une coquillé inorganique érodée. Cependant, ni l’encapsulation ni la modification de surface des MOFs n’altérait leur intégrité. Enfin, nous avons étudié la co-encapsulation de deux molécules actives utilisées en combinaison (amoxicilline et clavulanate de potassium) dans les nanoMOFs stables à base de MIL-100 (Fe). Les antibiotiques ont été incorporées par imprégnation et chaque molécule s’est localisée préférentiellement dans un compartiment (large ou petite cage) corroborant parfaitement les simulations par modélisation moléculaire. De plus, il a été découvert, de manière surprenante, qu’un grand nombre de nanoMOFs se localisait au voisinage des bactéries (S.aureus) dans des cellules infectées. En se dégradant dans ces cellules, les nanoMOFs contenant les antibiotiques ont réduit de manière importante la charge bactérienne intracellulaire. Ces études révèlent le potentiel des particules de type «cage» pour une incorporation efficace de molécules actives et leur libération contrôlée et ouvrent de nombreuses possibilités d’applicationDrug delivery systems are engineered technologies to administer pharmaceutical ingredients to improve their therapeutic effects, aiming at minimizing their side effects by means of targeted delivery and/or controlled release. “Cage” particles recently drew special attention since they could act as “drug containers” which potentially load large amount of drugs, improve their stability and offer the possibilities to co-encapsulate synergetic drugs. Cyclodextrins (CDs) are typical “cage” molecules with a hydrophobic cavity and a hydrophilic outer surface. Taking advantage of the host-guest interactions between β-CD and benzophenone (Bz), CD based nanoparticles (CD-NPs) were the first formulation investigated. CD-NPs of around 100 nm were instantaneously produced by mixing two aqueous solutions of neutral polymers: 1) poly-CD containing β-CDs, and 2) Bz grafted Dex (Dex-Bz). The “green” and facile preparation procedure makes it attractive formulation, whereas its limitation lies on the low drug payloads (~ 5 wt%). In order to improve the drug loading capacity of CDs, porous CD based metal organic frameworks (CD-MOFs) were synthesized, which contain not only CD cavities, but also large pores built up by CDs self-assembly. Lansoprazole (LPZ) was incorporated in CD-MOF microcrystals (~ 6 µm) reaching payloads as high as 23.2 ± 2.1% (wt). Remarkably, each CD cavity was able to host a drug molecule, offering new opportunities for the use of CD-MOFs for drug delivery purposes. However, these particles disassembled in aqueous media, which limits their application for oral and intravenous administration. Surface modification is therefore necessary to improve their stability in water. The drug loaded CD-MOF nanocrystals (~ 650 nm) were successfully embedded in polyacrylic acid (PAA) polymer matrices. The composite microspheres exhibited spherical shapes and sustained drug release over a prolonged period of time (over 48 h). Drug loaded MOF/PAA composite microspheres were not toxic in vitro (cell viability ~ 90%) even at very high concentrations up to 17.5 mg/mL. MOF/PAA composite microspheres constitute an efficient and pharmaceutically acceptable MOF-based carrier for sustained drug release. However, the process of surface modification was complicated and lead to larger particles and reduced drug payloads. Water-stable MOFs are a novel type of hybrid particles, showing a high potential as drug carriers. Iron trimesate MOFs, namely, MIL-100 (Fe) (MIL stands for Material of Institute Lavoisier) was among the first nano-scaled MOFs used for drug delivery. These particles were stable in water but degraded in phosphate buffer saline (PBS) losing their crystallinity and constitutive trimesate linkers. However, it was discovered that they kept their morphology intact. A thorough analysis based on Raman microscopy was carried on to gain insights on both the morphology and chemical composition of individual particles. It was evidenced the formation of a sharp erosion front during particle degradation. Noteworthy, the MOFs did not degrade during drug loading nor surface modification. Co-encapsulation of two synergic antibiotics (amoxicillin and potassium clavulanate) in MIL-100 (Fe) nanoMOFs was achieved following a “green” procedure by soaking nanoMOFs in aqueous solutions of both drugs. Molecular modelling showed that each drug preferentially located in a separate nanoMOF compartment. Surprisingly, nanoMOFs were prone to co-localize with bacteria once internalized in infected macrophages. NanoMOFs acted synergistically with the entrapped drugs to kill intracellular S. aureus, in vitro. These results pave the way towards the design of engineered nanocarriers in which each component synergistically plays a role in fighting the disease. These studies unravel the potential of “cage” particles for efficient drug entrapment and controlled release and open numerous possibilities for applications
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Sergides, M. "Optical manipulation of micro- and nano-particles using evanescent fields". Thesis, University College London (University of London), 2013. http://discovery.ucl.ac.uk/1410938/.
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We present a study of the manipulation of micro-particles and the formation of optically bound structures of particles in evanescent wave traps. Two trapping geometries are considered: the first is a surface trap where the evanescent field above a glass prism is formed by the interference of a number of laser beams incident on the prism-water interface; the second uses the evanescent field surrounding a bi-conical tapered optical fibre that has been stretched to produce a waist of sub-micron diameter. In the surface trap we have observed the formation of optically bound one- and two-dimensional structures of particles and measured the binding spring constant by tracking particle motion and the extent of the particle’s Brownian fluctuations. Additionally, we have measured the inter-particle separations in the one-dimensional chain structures and characterised the geometry of the two-dimensional arrays. In the tapered optical fibre trap we demonstrated both particle transport for long distances along the fibre, and the formation of stable arrays of particles. We present the fabrication of tapered optical fibres using the 'heat-and-pull` technique, and evanescent wave optical binding of micro-particles to the taper. Calculations of the distribution of the evanescent field surrounding a tapered fibre are also presented. We show that the combination of modes can give control over the locations of the trapping sites. Additionally, we show how the plasmon resonance of metallic nano-particles can be exploited to enhance the optical trapping force, and suggest how a bi-chromatic nano-fibre trap for plasmonic particles may be implemented. In both experiments we implement video microscopy to track the particle locations and make quantitative measures of the particle dynamics. The experimental studies are complemented by light scattering calculations based on Mie theory to infer how the geometries of the particle structures are controlled by the underlying incident and scattered optical fields.
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Cockcroft, Stephanie. "VUV 157nm F₂ laser irradiation of micro- and nano-scale particles". Thesis, University of Hull, 2012. http://hydra.hull.ac.uk/resources/hull:7106.
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Micro- and nanoscale particles have recently become the focus of a great deal of research interest due to their wide-ranging potential in a number of applications. This thesis concerns the interaction of small particles with the 157nm wavelength vacuum ultraviolet, VUV, emission from a molecular fluorine gas, F₂, laser. The laser system is introduced and an overview of laser ablation of polymers is presented. Small particles of different materials and sizes, supported on polymeric substrates, are irradiated at a wavelength of 157nm. The silica particles are transparent to the 157nm radiation, which leads to a lens effect. The polystyrene, silicon carbide and silver particles are opaque to the 157nm radiation, leading to a substrate-shielding effect. The lens effect results in the focussing of the incident laser beam into a hotspot at the interface between the particle and the substrate. The enhancement leads to the removal of substrate material underneath the particle to form a dimple on the surface of the substrate. The substrate-shielding effect leads to the removal of the substrate material around the opaque particle while the underlying material is left behind. This forms a polymeric support structure, with the seeding particle attached to the top. The shape of the seeding particle dictates the shape of the support structure, for example spherical particles seed composite conical structures and cylindrical particles seed linear prismatic structures. The polystyrene and silver particles are seen to undergo shape and size transformations as a result of laser irradiation. This is discussed in terms of mass loss through heating. Finite Element Method modelling is used to investigate and support the experimental results. Fluorescent polystyrene particles are also irradiated at a wavelength of 157nm. They retain their fluorescence after irradiation and exhibit Whispering Gallery Mode resonances, ideal for high-sensitivity sensing applications and Lab-on-a-Chip microreactors.
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Spinella-Mamo, Vincent Paul. "Control of micro- and nano- particles with electric and magnetic fields". Connect to Electronic Thesis (CONTENTdm), 2008. http://worldcat.org/oclc/458547540/viewonline.
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Marcetich, Adam Michael. "Ultrasound spectral parameters of micro- and nano- particles: measurement software and modeling". The Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=osu1413384380.
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Othman, Rahimah. "Production of functional pharmaceutical nano/micro-particles by solvent displacement method using advanced micro-engineered dispersion devices". Thesis, Loughborough University, 2016. https://dspace.lboro.ac.uk/2134/22905.
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The rapid advancement of drug delivery systems (DDS) has raised the possibility of using functional engineered nano/micro-particles as drug carriers for the administration of active pharmaceutical ingredients (APIs) to the affected area. The major goals in designing these functional particles are to control the particle size, the surface properties and the pharmacologically active agents release in order to achieve the site-specification of the drug at the therapeutically optimal rate and dose regimen. Two different equipment (i.e. glass capillary microfluidic device and micro-engineered membrane dispersion cell) were utilised in this study for the formation of functional nano/micro-particles by antisolvent precipitation method. This method is based on micromixing/direct precipitation of two miscible liquids, which appear as a straightforward method, rapid and easy to perform, does not require high stirring rates, sonication, elevated temperatures, surfactants and Class 1 solvents can be avoided. Theoretical selection of a good solvent and physicochemical interaction between solvent-water-polymer with the aid of Bagley s two-dimensional graph were successfully elucidated the nature of anti-solvent precipitation method for the formation of desired properties of functional pharmaceutical nano/micro-engineered particles. For the glass capillary microfluidic experiment, the organic phase (a mixture of polymer and tetrahydrofuran/acetone) was injected through the inner glass capillary with a tapered cross section culminated in a narrow orifice. The size of nanoparticles was precisely controlled by controlling phase flow rates, orifice size and flow configuration (two- phase co-flow or counter-current flow focusing). The locations at which the nanoparticles would form were determined by using the solubility criteria of the polymer and the concentration profiles found by numerical modelling. This valuable results appeared as the first computational and experimental study dealing with the formation of polylactide (PLA) and poly(ε-caprolactone) (PCL) nanoparticles by nanoprecipitation in a co-flow glass capillary device. The optimum formulations and parameters interactions involved in the preparation of paracetamol encapsulated nanoparticles (PCM-PCL NPs) using a co-flow microfluidic device was successfully simulated using a 25-full factorial design for five different parameters (i.e. PCL concentration, orifice size, flow rate ratios, surfactant concentration and paracetamol amount) with encapsulation efficiency and drug loading percentage as the responses. PCM-loaded composite NPs composed of a biodegradable poly(D,L-lactide) (PLA) polymer matrix filled with organically modified montmorillonite (MMT) nanoparticles were also successfully formulated by antisolvent nanoprecipitation in a microfluidic co-flow glass capillary device. The incorporation of MMT in the polymer matrix improved the drug encapsulation efficiency and drug loading, and extended the rate of drug release in simulated intestinal fluid (pH 7.4). The encapsulation of MMT and PCM in the NPs were well verified using transmission electron microscopy (TEM), energy dispersive x-ray spectroscopy (EDS), x-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR). PCL drug-carrier nanoparticles were also produced by rapid membrane micromixing combined with nanoprecipitation in a stirred cell employing novel membrane dispersion. The size of the NPs was precisely controlled by changing the aqueous-to-organic volumetric ratio, stirring rate, transmembrane flux, the polymer content in the organic phase, membrane type and pore morphologies. The particle size decreased by increasing the stirring rate and the aqueous-to-organic volumetric ratio, and by decreasing the polymer concentration in the aqueous phase and the transmembrane flux. The existence of the shear stress peak within a transitional radius and a rapid decline of the shear stress away from the membrane surface were revealed by numerical modelling. Further investigation on the PCL nanoparticles loaded immunosuppressive rapamycin (RAPA) drug were successfully synthesised by anti-solvent nanoprecipitation method using stainless steel (SS) ringed micro-engineered membrane. Less than 10 μm size of monohydrate piroxicam (PRX) micro-crystals also was successfully formed with the application of anti-solvent precipitation method combined with membrane dispersion cell that has been utilised in the formation of functional engineered nanoparticles. This study is believed to be a new insight into the development of integrated membrane crystallisation system.
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Simpson, Brian Keith Jr. "Strain engineering as a method for manufacturing micro- and; nano- scale responsive particles". Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34728.
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Strain engineering is used as a means of manufacturing micro- and nano- scale particles with the ability to reversibly alter their geometry from three dimensional tubes to two dimensional flat layers. These particles are formed from a bi-layer of two dissimilar materials, one of which is the elastomeric material polydimethylsiloxane (PDMS), deposited under stress on a sacrificial substrate. Upon the release of the bi-layer structure from the substrate, interfacial residual stress is released resulting in the formation of tubes or coils. These particles possess the ability to dramatically alter their geometry and, consequently, change some properties that are reversible and can be triggered by a stimulus. This work focuses on the material selection and manufacturing of the bi-layer structures used to create the responsive particles and methods for characterizing and controlling the responsive nature of the particles. Furthermore, the potential of using these particles for a capture/release application is explored, and a systematic approach to scale up the manufacturing process for such particles is provided. This includes addressing many of the problems associated with fabricating ultra-thin layers, tuning the size of the particles, understanding how the stress accumulated at the interface of a bi-layer structure can be used as a tool for triggering a response as well as developing methods (i.e. experiments and applications) that allow the demonstration of this response.
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Gun, S. "Electrohydrodynamic atomization forming of micro and nano-scale magnetic particles for biomedical applications". Thesis, University College London (University of London), 2015. http://discovery.ucl.ac.uk/1468713/.
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Production of polymeric magnetic micro and nano-particles is a rapidly emerging area in pharmaceutical and biomedical science. In this thesis, the capability of the electrohydrodynamic atomization (EHDA) process for preparing biodegradable polymeric magnetic particles with different sizes was explored. The EHDA processing method offers several advantages over conventional coprecipitation and emulsification techniques for the preparation of magnetic particles. Most significant are the process efficiency and preservation of the iron oxide nanoparticles and/or therapeutic agents functionality, as complex multistep processing involving harsh solvents, additives and elevated temperatures or pressure are avoided. The first part of the thesis describes a detailed investigation of how the size, morphology and shape of the particles generated can be controlled through the operating parameters; specifically the flow rate and applied voltage. The particle diameter was greatly influenced by flow rate and applied voltage. The mean size of the particles changed from1.6µ m to 17.8µm as the flow rate increased from 100µl/min-1 to 400µl/min-1. The research also focuses on the effects of these parameters on the jetting modes of the E H DA process, in particular the con-jet mode operation. Magnetic nanospheres were also produced using single needle processing with mean size of 56nm with a corresponding polydispersivity index of 16%. Nanospheres exhibited a high saturation magnetization at room temperature (67emu/g). Chlorotoxin, a scorpion venom was chosen as the therapeutic agent model because it is non-toxic, non-immunogenic along with other favourable characteristics such as small size high stability and most importantly only binds to tumour cells and not healthy cells. Scorpion venom loaded magnetic microspheres were produced using single needle processing, with a particle size of 2µm. This work demonstrates a powerful method of generating micro and nano magnetic polymeric particles, with control over the size of particles prepared.
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Qin, Zhenpeng. "Modeling of Ion Transport for Micro/Nano Size Particles in Coulter Counter Application". University of Akron / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=akron1240858653.
Pełny tekst źródłaKsiążki na temat "Potential of nano and micro particles"
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M, Spasic Aleksandar, i Hsu Jyh-Ping 1955-, red. Finely dispersed particles: Micro-, nano-, and atto-engineering. Boca Raton, FL: CRC/Taylor & Francis, 2006.
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Fang, Zhen. Rapid Production of Micro- and Nano-particles Using Supercritical Water. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-12987-2.
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Rapid production of micro- and nano-particles using superficial water. Heidelberg: Springer, 2010.
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Self-Propelled Janus Particles. Materials Research Forum LLC, 2021. http://dx.doi.org/10.21741/9781644901199.
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Design and operation of Janus particles have a great potential for applications in fields such as environmental remediation, electronic engineering, bio-imaging, bio-sensing, drug delivery and other biomedical tasks. Current research aims to imitate the molecular motors of biological systems by creating micro- and nano-scale particles which can exploit chemical energy so as to produce directional motion. The assembling of self-propelled particles and their movement can be controlled by using external fields, especially magnetic fields. The book references 332 original resources and includes their direct web link for in-depth reading.
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Hsu, Jyh-Ping, i Aleksandar M. Spasic. Finely Dispersed Particles: Micro-, Nano-, and Atto-Engineering. Taylor & Francis Group, 2005.
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Hsu, Jyh-Ping, i Aleksandar M. Spasic. Finely Dispersed Particles: Micro-, Nano-, and Atto-Engineering. Taylor & Francis Group, 2005.
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Spasic, Aleksandar M. Finely Dispersed Particles: Micro-, Nano-, and Atto-Engineering. Taylor & Francis Group, 2010.
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Chattopadhyay, Jayeeta, i Rohit Srivastava. Liquid Crystals with Nano/Micro Particles and Their Applications. Taylor & Francis Group, 2023.
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Chattopadhyay, Jayeeta, i Rohit Srivastava. Liquid Crystals with Nano/Micro Particles and Their Applications. Taylor & Francis Group, 2023.
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Chattopadhyay, Jayeeta, i Rohit Srivastava. Liquid Crystals with Nano/Micro Particles and Their Applications. Taylor & Francis Group, 2023.
Znajdź pełny tekst źródłaCzęści książek na temat "Potential of nano and micro particles"
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Chattopadhyay, Jayeeta, i Rohit Srivastava. "Potential Applications of Nanoparticles Aided Liquid Crystals". W Liquid Crystals with Nano/Micro Particles and Their Applications, 84–115. Boca Raton: CRC Press, 2023. http://dx.doi.org/10.1201/9781003093527_3.
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Kaneko, Arata. "Surface Micro-/Nanostructuring Using Self-Assembly of Fine Particles". W Micro/Nano Technologies, 745–71. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-13-0098-1_24.
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Hochepied, Jean-François. "From Oxide Particles to Nanoceramics: Processes and Applications". W The Nano-Micro Interface, 189–204. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2015. http://dx.doi.org/10.1002/9783527679195.ch10.
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Fang, Jiaru, Qin Wang i Ning Hu. "Micro/Nano Cell Potential Biosensors". W Micro/Nano Cell and Molecular Sensors, 97–123. Singapore: Springer Singapore, 2016. http://dx.doi.org/10.1007/978-981-10-1658-5_5.
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Chaurasiya, Akash, Parameswar Patra, Pranathi Thathireddy i Amruta Gorajiya. "PLGA-Based Micro- and Nano-particles". W Micro- and Nanotechnologies-Based Product Development, 83–94. Boca Raton: CRC Press, 2021. http://dx.doi.org/10.1201/9781003043164-6.
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Chattopadhyay, Jayeeta, i Rohit Srivastava. "Micro- and Nano-particles Doped Liquid Crystals". W Liquid Crystals with Nano/Micro Particles and Their Applications, 34–83. Boca Raton: CRC Press, 2023. http://dx.doi.org/10.1201/9781003093527_2.
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Fang, Zhen. "Nano-Structured Coatings". W Rapid Production of Micro- and Nano-particles Using Supercritical Water, 57–62. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-12987-2_4.
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Qian, Jian. "Hollow Micro-/Nano-Particles from Biopolymers: Fabrication and Applications". W ACS Symposium Series, 257–87. Washington, DC: American Chemical Society, 2014. http://dx.doi.org/10.1021/bk-2014-1175.ch014.
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Qiao, R., i N. R. Aluru. "Dispersion Control in Nano-Channel Systems by Localized Zeta-Potential Variation". W Micro Total Analysis Systems 2001, 139–40. Dordrecht: Springer Netherlands, 2001. http://dx.doi.org/10.1007/978-94-010-1015-3_57.
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Fang, Zhen. "Fine Organics Particles by Precipitation of Solute". W Rapid Production of Micro- and Nano-particles Using Supercritical Water, 71–86. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-12987-2_6.
Pełny tekst źródłaStreszczenia konferencji na temat "Potential of nano and micro particles"
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Ahmadniaroudsari, Mani, i Constantinos Mavroidis. "A Cyber-Physical Framework for MRI Guided Magnetic Nano/Micro Particles Called “MAGNASIM”". W ASME 2014 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/detc2014-35504.
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Nano Magnetic Particles drug delivery is a new method of cancer treatment targeting the replacement of current methods such as chemotherapy and radiation to increase the efficiency of treatment. This project aims to design a system including experimental setup and computational platforms that will work parallel to each other developing guidelines for scientists. The Computational platform is able to model the nano particle’s aggregations and movement. Experimental setup will be used to generate results validating the simulations done on the computational platform. Experimental setup has the potential to operate Magnetic nanoparticles drug delivery in different scale and situations. We aim to make the experimental setup as close as possible to human blood properties. This will enable us to come up with guiding trajectories and control algorithms for guidance of different size and shape nano particles in arbitrary capillary shapes. This data can be beneficial for researchers doing experiments on magnetic drug delivery and avoid the In vivo experiments for the sake of animal rights. We present software called MAGNASIM that is being developed to perform simulation, visualization and post-processing analysis of the aggregation and disaggregation processes of magnetic Nano/Micro particles within a fluid environment such as small arteries and arterioles or fluid-filled cavities of the human body. Basically the software would be able: • To examine Self-assembly process and breakup process • To provide design guidelines for fabricating, control and steering the nanocapsules After gathering all the initial conditions, software is able to provide the user the following information: • Forces on each particle in each time-step. • Position of each particle in each time-step. • Interactions between particles. • Control and steer the particles to the considered destination. • Providing visualization of the particles movement.
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Eason, Kwaku, Boris Luk'yanchuk, Yi Zhou, Andrey E. Miroshnichenko i Yuri S. Kivshar. "Magnetic microscopy/metrology potential of metamaterials using nanosized spherical particle arrays". W Smart Nano-Micro Materials and Devices, redaktorzy Saulius Juodkazis i Min Gu. SPIE, 2011. http://dx.doi.org/10.1117/12.904893.
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Cherkasova, A. S., i J. W. Shan. "Impact of Altering Aspect Ratio of the Loading Particles on a Suspension’s Thermal Conductivity". W ASME 2008 International Mechanical Engineering Congress and Exposition. ASMEDC, 2008. http://dx.doi.org/10.1115/imece2008-67854.
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It has been recognized that heat-transfer fluids used to convey thermal energy produced by one device to another can exhibit significant increases in thermal conductivity with the addition of highly conductive particles. Suspensions of nano- and micro-particles have attracted the most recent interest because of their enhanced stability against sedimentation, reduction in potential for clogging a flow system, as well as the tantalizing possibility of unexpected enhancements in thermal conductivity that have been reported in some experiments. Among various suspensions, considerable attention has focused on those containing large-aspect-ratio particles, such as carbon nanotubes. Although recent experiments have demonstrated enormous heat-transfer enhancements in these fluids, such increases were reportedly not in agreement with existing macroscale theories [1–3]. In this research we report on an experimental study of the effects of particle aspect ratio on the effective thermal conductivity of micro- and nano-particle suspensions. The influence of particle aspect ratio on the thermal properties of suspensions was first studied in dispersions of micron-sized, silicon-carbide particles with varying aspect ratio. To carry out a detailed comparison with theoretical predictions, particle aspect ratio and size distributions were measured. It is shown that the conductivity of the silicon-carbide suspensions can be quantitatively predicted by an effective-medium theory (EMT), provided the volume-weighted aspect ratio of the particles is used. The particle-aspect-ratio effect was further studied in the suspensions of multi-walled carbon nanotubes. Experimental data on the thermal conductivity of nanotube suspensions could also be interpreted in terms of the aspect-ratio dependence predicted by EMT if the additional nanoscale effect of interfacial resistance was considered.
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Idrisi, Amir Hussain, i Abdel-Hamid Ismail Mourad. "Fabrication and Wear Analysis of Aluminium Matrix Composite Reinforced by SiC Micro and Nano Particles". W ASME 2017 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/pvp2017-65459.
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Metal matrix composites (MMCs) constitute an important class of weight-efficient structural material which empowering every field of engineering applications. Aluminium based metal matrix composites contains potential for high specific strength and advanced structural applications, as well as good elevated temperature resistance along with light weight application. However, need for improved tribological performance has led to the fabrication of newer variants of the composite. In the present work, aluminium based metal matrix composite (MMCs) developed through stir casting route by reinforcing different weight percentage of SiC micro (5% and 10%) and nano (1% and 2%) particles. In this research, 5083 aluminium alloy is used as matrix phase due its broad range of industrial applications. Wear behaviour of the developed aluminium matrix composite (AMC) was investigated under different conditions of applied load, operation time and speed. The analysis carried out at room temperature for three different loads (10N, 20N, and 30N) with varying four different operation times (30 mins, 60 mins, 90 mins, and 120 mins). The speed was kept constant at 1450 rpm during all experiments. The results of all considered composites are investigated and the composite with 2% SiC nano reinforcement is identified as a superior among all other composition for tribological applications point of view. Also the developed aluminium matrix composites have potential applications in many industries such as pressure vessels, pipe fittings, boat hulls, gears and pistons.
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Ishii, Eiji, i Taisuke Sugii. "Surface Tension Model for Particle Method Using Inter-Particle Force Derived From Potential Energy". W ASME 2012 Fluids Engineering Division Summer Meeting collocated with the ASME 2012 Heat Transfer Summer Conference and the ASME 2012 10th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/fedsm2012-72030.
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Fluid-flow simulation within micro/nano spaces is essential for designing micro/nano devices, such as those in micro-electro-mechanical systems and nanoimprint processes. Surface tension is a dominant force in the fluid flow within micro/nano spaces. Surface-tension models can be classified into two groups: models based on continuous surface force in immiscible phases, and models based on inter-particle force in miscible phases. The surface-tension model based on inter-particle force for modeling interactions between materials would fit fluid-flow simulation within micro/nano spaces better than the surface-tension model based on continuous surface force. We developed a surface tension model using inter-particle force for use with a particle method in a past study. However, workings of inter-particle forces in miscible phases were not verified. Furthermore, accuracy in three-dimensional simulation needed to be verified. These subjects were verified in this study using simple benchmark tests. First, cohesion based on potential energy was validated to qualitatively check the workings of inter-particle force. The phase separation from the mixed two-phase flow due to inter-particle force was simulated. Next, the inter-particle force at the gas-liquid interface was quantitatively verified using the theory of the Young-Laplace equation; the pressure in a droplet was compared in two- and three-dimensional simulations, and the predicted pressures in a droplet agreed well with this theory. The inter-particle force at the gas-liquid-solid interface for the wall adhesion of a droplet was also verified; the results for wall adhesion in three-dimensional space agreed much better than that in two-dimensional space. We found that our surface tension model was useful for simulating the fluid flow within micro/nano spaces.
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Baah, David, Julaunica Tigner, Bernard Britton i Tamara Floyd-Smith. "Microfluidics for Controlled Production of Thin Films and Particles". W ASME 2012 Third International Conference on Micro/Nanoscale Heat and Mass Transfer. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/mnhmt2012-75108.
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Tailored materials with nano to micron dimensions are becoming increasingly important for niche applications in optics, personnel protection and biomedicine. Microfluidics is a robust platform for producing these tailored materials because of the spatial control that can be realized in microfluidic systems due to laminar flow profiles and small dimensions. For this work, a pre-polymer solution, consisting of water, polyethylene glycol diacrylate (PEGDA) and a photo-initiator, flows through a microfluidic channel. For the general scheme, the pre-polymer is exposed to UV light in the microfluidic channel to crosslink the polymer. Depending on the application, the model pre-polymer, PEGDA, may need to be substituted with a different photo-polymerizable pre-polymer to address issues such as chemical compatibility and moisture stability prior to commercialization. Nonetheless, proof-of-concept is demonstrated using PEGDA with results that are transferrable to other photo-polymerizable pre-polymers. For this work, two distinct applications will be presented. In one application, the pre-polymer has a graded profile of nanoparticles. The nanoparticles modify the refractive index of the heterogeneous material and allow light to be directed through the material according to Snell’s Law. When the pre-polymer solution is polymerized, a thin film with a controlled refractive index profile is produced with potential for waveguiding applications. In a second application, the light is masked during UV exposure to produce particles instead of thin films. The particles can be of any two-dimensional extruded shape. If the pre-polymer solution is loaded with ceramic nanoparticles and sintered, ceramic particles that retain the shape of the original composite particle are produced. To date, numerous particle cross sections of polymeric particles and limited ceramic particles have been demonstrated with applications in liquid body armor, abrasives and drug delivery.
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Zhu, Dongsheng, Xianju Wang i Xinfang Li. "Influence of SDBS on Dispersive Stability of Al2O3 Nano-Suspenions". W ASME 2008 First International Conference on Micro/Nanoscale Heat Transfer. ASMEDC, 2008. http://dx.doi.org/10.1115/mnht2008-52288.
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In this paper, the influence of sodium dodecylbenzenesulfonate (SDBS) on the dispersive behavior of Al2O3 nanoparticles in water are investigated by measuring zeta potential and hydrodynamic sizes of the nanoparticles in suspension at different pHs and different concentration of SDBS. The experimental results show that at different pHs the magnitude of zeta potential has very homologous relation with particle size, the higher magnitude of zeta potential values are, the smaller of the hydrodynamic sizes are, and the better dispersive stability of the nano-suspension is, and that an optimizing pH value of the nano-suspension can induce the highest magnitude zeta potential, then result in the best dispersion stability of the nano-suspension. It is also found that concentrations of SDBS can significantly affect the values of zeta potential and hydrodynamic sizes of the nanoparticles by electrostatic repulsions. Similarity, optimizing concentrations of SDBS can also lead to the highest enhancement of the dispersive stability of the Al2O3 suspension and the optimizing concentration for SDBS is 0.09% in 0.1% Al2O3 nano-suspensions, which have the best disperse results.
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Wen, Dongsheng, i Yulong Ding. "Effect on Heat Transfer of Particle Migration in Suspensions of Nanoparticles Flowing Through Minichannels". W ASME 2004 2nd International Conference on Microchannels and Minichannels. ASMEDC, 2004. http://dx.doi.org/10.1115/icmm2004-2434.
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Thermal management is one of the greatest challenges in maintaining the functionality and reliability of high-speed micro-electronic systems such as MEMS and NEMS. This requires development of high performance heat transfer media, which can not only flow through micro- and nano-channels under local operating conditions, but also carry as more heat as possible out of the system. Recent work has shown that suspensions of nanoparticles with a size considerably smaller that 100nm but with thermal conductivity orders of magnitudes higher that the base liquids have a greater potential as a high energy carrier for the micro- and nano-systems. However, it is also known that particles in a suspension undergoing a shearing action may migrate, hence lead to non-uniformity. This indicates that the efficiency of heat transfer in the micro- and nano-channels may not be as superior as expected, which bears significance to the system design and operation. This work aims at addressing this issue by examine the effect of particle migration on heat transfer in small channels. This involves development of both flow and heat transfer models, and numerical solution to the models. The flow model takes into account the effects of the shear-induced and viscosity gradient-induced particle migrations, as well as self-diffusion due to the Brownian motion, which is coupled with an energy equation. The results show that particle migration leads to concentration of particles in the wall region can be much lower than that in the core region. Particle migration is also shown to increase the Nusselt number under both constant temperature and constant heat flux conditions.
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Deng, Zhong-Shan, Jing Liu i Ji-Ren Zhang. "Conformal RF Ablation to Reduce “Dead Region” With Adjuvant Injection of Magnetic Micro/Nano Particles: Feasibility Study". W 2007 First International Conference on Integration and Commercialization of Micro and Nanosystems. ASMEDC, 2007. http://dx.doi.org/10.1115/mnc2007-21267.
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Radiofrequency (RF) ablation is a minimally invasive technique for tumor treatment. Intended benefits of oncological RF ablation include the availability of tumor treatment in nonsurgical candidate, minimal risk to patient, reduced morbidity and shorter recovery period compared with those after conventional surgery, and the potential for treatment on an outpatient basis. RF ablation, by producing heat energy that raises the temperature of the target tissue to a degree sufficient to cause thermally mediated coagulation necrosis, has been shown to be remarkably effective for thermal ablation of small tumors. Although RF hyperthermia has been successful in ablating small tumors, further optimization of the ablation technique is required to induce the larger volumes of coagulation that are necessary to treat larger tumors. In addition, due to the extremely irregular shape of tumor in clinics, the conventional RF ablation technique is hard to produce a conformal lesion to exactly enwrap the tumor as could as possible. This may lead to “dead region” within the area between RF probes and thus a failed treatment. To obtain a conformal treatment of complex tumor, strategies to flexibly control the size and shape of the ablated zone are desired.
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Li, Xinfang, Dongsheng Zhu, Gang Chen i Xianju Wang. "Influence of SDBS on Stability of Copper Nano-Suspensions". W 2007 First International Conference on Integration and Commercialization of Micro and Nanosystems. ASMEDC, 2007. http://dx.doi.org/10.1115/mnc2007-21091.
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Dispersion and stability of Cu nano-suspensions with dispersant is the important base for the study of rheology and heat transfer enhancement of the suspensions. This paper presented a procedure for preparing a nanofluid which was a suspension consisting of nanophase powders and a base liquids. By means of the procedure, Cu-H2O nanofluids with and without dispersant were prepared, whose sedimentation photographs were given to illustrate the stability and evenness of suspension with dispersant. Dispersion and stability of Cu nanoparticles in water were studied under different pH values and the concentration of sodium dodecylbenzenesulfonate (SDBS) dispersant by the method of zeta potential, absorbency and sedimentation photographs. The results show that zeta potential has very corresponding relation with absorbency, and the higher absolute value of zeta potential and absorbency are, the better dispersion and stability in system is. The absolute value of zeta potential and absorbency are higher at pH 9.5. SDBS can significantly increase the absolute value of the zeta potential of the particle surfaces by electrostatic repulsions, which leads to the enhancement of the stability of the Cu suspensions. The optimizing concentration for SDBS in the 0.1% copper nano-suspensions is 0.07%, which has the best disperse results.
Raporty organizacyjne na temat "Potential of nano and micro particles"
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Pinet, N., O. H. Ardakani, J. Cesar, D. C. Petts, C. Debuhr i P J Sack. Exploring the link between organic matter and Carlin-type gold mineralization: new insights from Yukon deposits. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/330086.
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The link between organic matter and gold in sediment-hosted Carlin-type deposits is controversial. This study aims to tackle this potential link by documenting the occurrence of organic matter in a single borehole from a Carlin-type gold deposit in Yukon and by considering, in a preliminary way, the spatial and/or temporal relationship between organic matter and gold mineralization. The sedimentary succession hosting the Conrad deposit was relatively rich in organic matter, possibly related to Archea. Despite the high maturation of samples, the total organic carbon (TOC) content of the limestone unit averages 1.31 wt. % (maximum = 3.18 wt. %). Petrographic observations indicate that pore and fracture filling pyrobitumen is the dominant organic matter maceral in the studied samples. This type of pyrobitumen was matured after its emplacement, indicating that hydrocarbon fluids cannot have served as an agent for gold transport. Pyrobitumen disseminated in the rock or associated with stylolites are also documented. The correlation between TOC and Tl (the best proxy for Au) for selected samples and the high As content of pyrobitumen filling pores may suggest a link between organic matter content and gold deposition, but this was not demonstrated by LA-ICP-MS micro-scale mapping. This study also highlights the challenges of establishing a direct spatial relationship between 'invisible' gold and very small (&lt; 10 µm) pyrobitumen particles.
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Litaor, Iggy, James Ippolito, Iris Zohar i Michael Massey. Phosphorus capture recycling and utilization for sustainable agriculture using Al/organic composite water treatment residuals. United States Department of Agriculture, styczeń 2015. http://dx.doi.org/10.32747/2015.7600037.bard.
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Objectives: 1) develop a thorough understanding of the sorption mechanisms of Pi and Po onto the Al/O- WTR; 2) determine the breakthrough range of the composite Al/O-WTR during P capturing from agro- wastewaters; and 3) critically evaluate the performance of the composite Al/O-WTR as a fertilizer using selected plants grown in lysimeters and test-field studies. Instead of lysimeters we used pots (Israel) and one- liter cone-tainers (USA). We conducted one field study but in spite of major pretreatments the soils still exhibited high enough P from previous experiments so no differences between control and P additions were noticeable. Due to time constrains the field study was discontinued. Background: Phosphorous, a non-renewable resource, has been applied extensively in fields to increase crop yield, yet consequently has increased the potential of waterway eutrophication. Our proposal impetus is the need to develop an innovative method of P capturing, recycling and reuse that will sustain agricultural productivity while concurrently reducing the level of P discharge from and to agricultural settings. Major Conclusions & Achievements: An innovative approach was developed for P removal from soil leachate, dairy wastewater (Israel), and swine effluents (USA) using Al-based water treatment residuals (Al- WTR) to create an organic-Al-WTR composite (Al/O-WTR), potentially capable of serving as a P fertilizer source. The Al-WTR removed 95% inorganic-P, 80% to 99.9% organic P, and over 60% dissolved organic carbon from the agro-industrial waste streams. Organic C accumulation on particles surfaces possibly enhanced weak P bonding and facilitated P desorption. Analysis by scanning electron microscope (SEM- EDS), indicated that P was sparsely sorbed on both calcic and Al (hydr)oxide surfaces. Sorption of P onto WW-Al/O-WTR was reversible due to weak Ca-P and Al-P bonds induced by the slight alkaline nature and in the presence of organic moieties. Synchrotron-based microfocused X-ray fluorescence (micro-XRF) spectrometry, bulk P K-edge X-ray absorption near edge structure spectroscopy (XANES), and P K-edge micro-XANES spectroscopy indicated that adsorption was the primary P retention mechanism in the Al- WTR materials. However, distinct apatite- or octocalciumphosphatelike P grains were also observed. Synchrotron micro-XRF mapping further suggested that exposure of the aggregate exteriors to wastewater caused P to diffuse into the porous Al-WTR aggregates. Organic P species were not explicitly identified via P K-edge XANES despite high organic matter content, suggesting that organic P may have been predominantly associated with mineral surfaces. In screen houses experiments (Israel) we showed that the highest additions of Al/O-WTR (5 and 7 g kg⁻¹) produced the highest lettuce (Lactuca sativa L. var. longifolial) yield. Lettuce yield and P concentration were similar across treatments, indicating that Al/O- WTR can provide sufficient P to perform similarly to common fertilizers. A greenhouse study (USA) was utilized to compare increasing rates of swine wastewater derived Al/O-WTR and inorganic P fertilizer (both applied at 33.6, 67.3, and 134.5 kg P₂O₅ ha⁻¹) to supply plant-available P to spring wheat (TriticumaestivumL.) in either sandy loam or sandy clay loam soil. Spring wheat straw and grain P uptake were comparable across all treatments in the sandy loam, while Al/O-WTR application to the sandy clay loam reduced straw and grain P uptake. The Al/O-WTR did not affect soil organic P concentrations, but did increase phosphatase activity in both soils; this suggests that Al/O-WTR application stimulated microorganisms and enhance the extent to which microbial communities can mineralize Al/O-WTR-bound organic P. Implications: Overall, results suggest that creating a new P fertilizer from Al-WTR and agro-industrial waste sources may be a feasible alternative to mining inorganic P fertilizer sources, while protecting the environment from unnecessary waste disposal.
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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.