Letteratura scientifica selezionata sul tema "Micro-sized particles of iron oxide"
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Articoli di riviste sul tema "Micro-sized particles of iron oxide"
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Muska, M., A. Naeem, M. Hamayun, S. L. Badshah, M. Farooq, M. Fida, A. Mahmood, K. H. Shah e Y. N. Mabkhot. "Comparative sorption studies of chromate by nano-and-micro sized Fe2O3 particles". Open Chemistry 15, n. 1 (14 giugno 2017): 147–55. http://dx.doi.org/10.1515/chem-2017-0016.
Testo completoAbstract (sommario):
AbstractThe comparative adsorption studies of Cr (VI) on nano and micro-powder Fe2O3 were investigated using kinetics and batch adsorption techniques. The uptake of chromate onto both the oxides of iron was observed to be dependent on the pH, contact time, temperature, media dosage and concentration of chromate anions. The values of sorption maxima were higher in the case of Fe2O3 nanopowder than the micro-powder which can be ascribed to the high surface area and point of zero charge (PZC) of the former oxide. The Dubinin-Radushkivech and Langmuir models were found well fitted for the description of the batch adsorption data. The FTIR studies confirmed that the hexavalent chromium was adsorbed onto both the iron oxides in the form of the Cr2O72−.
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Kong, Yuan Yuan, e Hao Zhou. "Formation and Magnetic Characterization of Magnesium Oxide / Iron Nano Composite Particles". Advanced Materials Research 236-238 (maggio 2011): 1927–30. http://dx.doi.org/10.4028/www.scientific.net/amr.236-238.1927.
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Nano-sized composite magnetic particles MgO /Fe were in-situ combustion synthesized at 620°Cfor the Mg-70.9wt%Fe3O4 system. In this paper, we discussed the reactant ratio on the influence of micro-morphology and the magnetic properties of nanoparticles. It was indentified that: Mg(29.1wt%) was the suitable reactant ratio, the sintered composite spherical particles with mean diameter 40nm distributed evenly, particles had good soft magnetic properties, and it was the future drug carriers materials.
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Khushnood, Rao Arsalan, Siraj ud din, Nafeesa Shaheen, Sajjad Ahmad e Filza Zarrar. "Bio-inspired self-healing cementitious mortar using Bacillus subtilis immobilized on nano-/micro-additives". Journal of Intelligent Material Systems and Structures 30, n. 1 (3 novembre 2018): 3–15. http://dx.doi.org/10.1177/1045389x18806401.
Testo completoAbstract (sommario):
Bio-inspired self-healing strategies are much innovative and potentially viable for the production of healable cement mortar matrix. The present research explores the feasibility of gram-positive “Bacillus subtilis” microorganisms in the effective healing of nano-/micro-scale-induced structural and non-structural cracks. The main concern related to the survival of such microorganisms in cementitious environment has been successfully addressed by devising proficient immobilization scheme coherently. The investigated immobilizing media includes iron oxide nano-sized particles, micro-sized limestone particles, and milli-sized siliceous sand. The effect of induced B. subtilis microorganisms immobilized on nano-micro-additives was analyzed by the quantification of average compressive resistance of specimens (ASTM C109) and healing evaluation. The healing process was mechanically gauged by compressive strength regain of pre-cracked specimens after the healing period of 28 days. The pre-cracking load was affixed at 80% of ultimate compressive stress “[Formula: see text]” while the age of pre-cracking was kept variable as 3, 7, 14, and 28 days to precisely correlate healing effectiveness as the function of cracking period. The healing mechanism was further explored by examining the healed micro-crack using field emission scanning electron micrographs, energy dispersive x-ray spectrographs, and thermogravimetry. The results revealed that B. subtilis microorganisms contribute extremely well in the improvement of compressive strength and efficient healing process of pre-cracked cement mortar formulations. The iron oxide nano-sized particles were found to be the most effective immobilizer for preserving B. subtilis microbes till the generation of cracks followed by siliceous sand and limestone particles. The micro-graphical and chemical investigations endorsed the mechanical measurements by evidencing calcite precipitation in the induced nano-/micro-cracks as a result of microbial activity.
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Cuong, Le Viet, Pham Duc Thang e Nguyen The Hien. "A Simple Process to Fabricate Micro Flux Sources with High Magnetic Field Gradient". Communications in Physics 24, n. 3S1 (7 novembre 2014): 85–89. http://dx.doi.org/10.15625/0868-3166/24/3s1/5225.
Testo completoAbstract (sommario):
In this paper, we present a fabrication process to produce the micro-sized magnetic structures based on the hard magnetic powders. Under the magnetic field originated from a micro patterned hard magnetic film, these magnetic powders are magnetically aligned to form arrays of the micro magnets on a polydimethysiloxane (PDMS) substrate. The high magnetic field gradient and stable magnetic flux can be obtained at certain micro-sized area on the surface of the micro magnets. The fabricated structures have been used for trapping iron oxide particles. Generally this fabrication process is simple, low cost and the micro magnets can be used for further applications in biology, medicine and beyond.
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Yogo, Toshinobu, Tomoyuki Nakamura, Wataru Sakamoto e Shin-ichi Hirano. "Synthesis of magnetic particle/organic hybrid from metalorganic compounds". Journal of Materials Research 14, n. 7 (luglio 1999): 2855–60. http://dx.doi.org/10.1557/jmr.1999.0381.
Testo completoAbstract (sommario):
A nanocrystalline magnetic particle/oligomer hybrid was successfully synthesized by polymerization of iron(III) 3-allylacetylacetonate (IAA) followed by in situ hydrolysis. An iron oxide particle/oligomer hybrid was synthesized by hydrolysis of the IAA oligomer under alkaline and reducing conditions by the addition of hydrazine or methylhydrazine. Crystalline particles of approximately 10 nm were found to be dispersed in the oligomeric matrix. The nanocrystalline particles were identified to be iron oxide spinel by x-ray diffraction analysis and electron diffraction. The nanometer-sized ferrimagnetic iron oxide particle/oligomer hybrid showed a typical superparamagnetic behavior.
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Siddhartha, O. Sai, e S. V. Satyanarayana. "Iron Oxides' Influence on the Thermal Decomposition of Pure Ammonium Perchlorate: A Comprehensive Review". Scholars International Journal of Chemistry and Material Sciences 7, n. 04 (9 aprile 2024): 35–44. http://dx.doi.org/10.36348/sijcms.2024.v07i04.001.
Testo completoAbstract (sommario):
The combustion of ammonium perchlorate (AP) has long been a focal point in the development of solid rocket propellants, with particular attention paid to the catalytic effects of iron oxides. Beginning in the 1950s, researchers have diligently studied the kinetics and mechanisms underlying AP combustion, with a focus on both micron-sized and nano-sized iron oxide catalysts due to their widespread application in rocket formulations worldwide. This research effort specifically excludes investigations involving alternative iron oxide-based catalysts, such as doped or mixed oxides, or supported iron oxides, as they are not commonly utilized in major rocket propellant formulations. Despite variations in specific parameters like activation energy and heat of dissociation, the fundamental understanding of AP decomposition with iron oxides remains consistent with earlier findings. Notably, micron-sized catalysts have minimal impact on the low-temperature decomposition (LTD) of AP but can influence high-temperature decomposition (HTD) by altering decomposition temperatures and reducing activation energy. In contrast, nano-sized catalysts tend to accelerate the reaction to such an extent that the LTD phase is often bypassed altogether due to the rapid consumption of NH3, a crucial component in the process. However, the transition to nano-sized particles presents a new challenge: the propensity for particle agglomeration. Current research endeavours are therefore dedicated to devising effective strategies to mitigate this issue and harness the full potential of nano-sized iron oxide catalysts in rocket propellant formulations.
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Chandrasekharan, Prashant, Renesmee Kuo, K. L. Barry Fung, Chinmoy Saayujya, Jacob Bryan, Mariam Yousuf, Benjamin Fellows et al. "Magnetic Particle Imaging in Vascular Imaging, Immunotherapy, Cell Tracking, and Noninvasive Diagnosis". Molecular Imaging 2023 (15 marzo 2023): 1–22. http://dx.doi.org/10.1155/2023/4131117.
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Magnetic particle imaging (MPI) is a new tracer-based imaging modality that is useful in diagnosing various pathophysiology related to the vascular system and for sensitive tracking of cytotherapies. MPI uses nonradioactive and easily assimilated nanometer-sized iron oxide particles as tracers. MPI images the nonlinear Langevin behavior of the iron oxide particles and has allowed for the sensitive detection of iron oxide-labeled therapeutic cells in the body. This review will provide an overview of MPI technology, the tracer, and its use in vascular imaging and cytotherapies using molecular targets.
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Huang, Yuan Ming, Bao Gai Zhai, Qing Lan Ma e Ming Meng. "Magnetic Properties of Ferrous Ferric Oxide Confined in Porous Silicon". Materials Science Forum 663-665 (novembre 2010): 1142–45. http://dx.doi.org/10.4028/www.scientific.net/msf.663-665.1142.
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During the chemical synthesis nanometer-sized particles of ferrous iron oxide were in situ infiltrated into the mesopores in a porous silicon film. The microstructures of porous silicon and the magnetic properties of the nanometer-sized particles of the ferrous iron oxide were characterized with scanning electron microscopy, X-ray diffractometry, and the hysteresis loop measurement, respectively. Our results have demonstrated that the magnetic properties of the nanometer-sized Fe3O4 particles can be dramatically modified when they are confined into the mesopores of the porous silicon film.
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Leybo, Denis, Marat Tagirov, Elizaveta Permyakova, Anton Konopatsky, Konstantin Firestein, Feruza Tuyakova, Dmitry Arkhipov e Denis Kuznetsov. "Ascorbic Acid-Assisted Polyol Synthesis of Iron and Fe/GO, Fe/h-BN Composites for Pb2+ Removal from Wastewaters". Nanomaterials 10, n. 1 (22 dicembre 2019): 37. http://dx.doi.org/10.3390/nano10010037.
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Iron powders and Fe/graphene oxide and Fe/boron nitride composites were synthesized by means of a polyol synthesis method. The effect of NaOH/Fe and ascorbic acid/Fe ratios on the characteristics of synthesized products were evaluated. The samples were characterized by X-ray diffraction, scanning and transmission electron microscopy, low-temperature nitrogen adsorption and Raman-spectroscopy. Ascorbic acid-assisted polyol synthesis resulted in the 10-fold decrease of the iron particles’ size and almost 2-fold increase of lead removal efficiency. The deposition of iron on the surface of graphene oxide lead to the formation of small 20–30 nm sized particles as well as bigger 200–300 nm sized particles, while the reduction in presence of boron nitride resulted in the 100–200 nm sized particles. The difference is attributed to the surface state of graphene oxide and boron nitride. Adsorption properties of the obtained materials were studied in the process of Pb2+ ion removal from wastewater.
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Mehdikhani, Behzad, e Gholam Borhani. "Optical spectroscopy of sodium silicate glasses prepared with nano- and micro-sized iron oxide particles". Processing and Application of Ceramics 7, n. 3 (2013): 117–21. http://dx.doi.org/10.2298/pac1303117m.
Testo completoTesi sul tema "Micro-sized particles of iron oxide"
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Yang, Yidong. "Monitoring cell infiltration into the myocardial infarction site using micrometer-sized iron oxide particles-enhanced magnetic resonance imaging". Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/41151.
Testo completoAbstract (sommario):
The cell infiltration into the myocardial infarction (MI) site was studied using magnetic resonance imaging (MRI) with micrometer-sized iron oxide particles (MPIO) as cell labeling probes. MI is a leading cause of global death and disability. However, the roles of inflammatory cells and stem cells during the post-MI remodeling and repair processes are yet to be discovered. This study was to develop noninvasive MRI techniques to monitor and quantify the cellular infiltration into the MI site. MPIO can produce pronounced signal attenuation at regions of interest in MRI. Therefore, cells labeled with these particles can be detected after they are activated and home to the MI site. In the first project, MPIO of various doses were injected into the mouse blood stream 7 days before the MI surgery. Serial MRI was performed at various time points post-MI to monitor the inflammatory cell infiltration into the MI site. Significant signal attenuation caused by labeled cells, in particular macrophages, was observed at the MI site. The study suggests an optimal imaging window should be from 7 to 14 days post-MI, during which the MR signal was inversely proportional to the MPIO dose. The study also suggests an optimal MPIO dose should be between 9.1 and 14.5 µg Fe/g body weight. In the second project, mesenchymal stem cells labeled with MPIO were transplanted into the mouse bone marrow 14 days before the MI surgery. Serial MRI was performed at various time points post-MI to monitor the labeled cells, which mobilized from the bone marrow and homed to the MI site. All the MRI findings were further confirmed by histology. In addition to revealing the characteristics of cell infiltration during MI, this study also provides noninvasive MRI techniques to monitor and potentially quantify labeled cells at the pathological site. The technique can also be used to investigate the function of cells engaged in MI and to test the effect on cell infiltration caused by any treatment strategies.
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Pedron, Swannie. "Ιmagerie mοléculaire utilisant des micrοparticules d'οxyde de fer pοur la détectiοn de l'inflammatiοn cardiaque (par Ιmagerie par Résοnance Μagnétique) et de l'inflammatiοn pulmοnaire (par Ιmagerie à Ρarticules Μagnétiques - ΙΡΜ οu ΜΡΙ)". Electronic Thesis or Diss., Normandie, 2024. http://www.theses.fr/2024NORMC419.
Testo completoAbstract (sommario):
Les méthodes d'imagerie classiques comme l'IRM cardiaque et le scanner thoracique sont couramment utilisées pour le diagnostic des maladies cardiovasculaires et pulmonaires. Cependant, elles ne permettent que l’identification des retentissements fonctionnels et anatomiques, et la détection de la composante inflammatoire impliquée dans ces pathologies reste perfectible. Dans ces travaux de thèse, nous développons une nouvelle approche d’imagerie moléculaire appelée « immuno-IRM », qui cible les molécules d'adhésion endothéliales impliquées dans le recrutement des leucocytes vers les sites inflammatoires. En utilisant des microparticules d’oxyde de fer conjuguées à un anticorps VCAM-1 (MPIO@αVCAM-1), nous avons évalué la capacité de l’immuno-IRM à détecter in vivo et de manière spécifique l’inflammation cardiaque dans des modèles animaux de dysfonction cardiaque septique et de myocardite auto-immune expérimentale (EAM). Nous comparons notamment l’efficacité de l’immuno-IRM pour révéler l’inflammation cardiaque par rapport au rehaussement tardif au gadolinium, utilisé en clinique et considéré comme la méthode de référence (« gold standard ») pour le diagnostic de la myocardite. Dans la deuxième partie de cette thèse, nous avons développé l’utilisation d’un nouvel appareil d’imagerie appelé « Imagerie à Particules Magnétiques » (IPM), qui repose sur la détection de particules d’oxyde de fer pour créer des images corps entier, sans utiliser de rayonnements ionisants. À travers des modèles de sepsis et de maladie respiratoire infectieuse, nous avons montré que l’IPM couplée à l’utilisation de MPIO@αVCAM-1 était un outil rapide, sensible et non invasif permettant la détection de l’inflammation pulmonaire. Nos données apportent les premiers éléments permettant d’envisager, à terme, l’application de l’immuno-IRM et de l’IPM pour le diagnostic de pathologies inflammatoires cardiaques et pulmonairesConventional imaging methods such as cardiac MRI and thoracic CT scans are commonly used for diagnosing cardiovascular and pulmonary diseases. However, they only identify functional and anatomical abnormalities, and detecting the inflammatory component involved in these pathologies remains challenging. In this thesis, we develop a new molecular imaging approach called "immunoMRI," which targets endothelial adhesion molecules involved in recruiting leukocytes to inflammatory sites. Using iron oxide microparticles conjugated with a VCAM-1 antibody (MPIO@αVCAM-1), we assessed the ability of immuno-MRI to specifically detect cardiac inflammation in vivo in animal models of septic cardiac dysfunction and experimental autoimmune myocarditis (EAM). We also compared the effectiveness of immuno-MRI in detecting cardiac inflammation to late gadolinium enhancement, which is used in clinical practice and considered the gold standard for myocarditis diagnosis. In the second part of this work, we developed the use of a new imaging device called "Magnetic Particle Imaging" (MPI), which detects iron oxide particles to create whole-body images without using ionizing radiation. Through models of sepsis and infectious respiratory disease, we demonstrated that MPI coupled with MPIO@αVCAM-1 is a rapid, sensitive, and non-invasive tool for detecting pulmonary inflammation. Our data provide the first evidence suggesting the potential future application of immuno-MRI and MPI for diagnosing inflammatory cardiac and pulmonary conditions
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Liu, Lixiang. "Nickel-Iron Oxide-based Nanomembranes as Anodes for Micro-Lithium-Ion Batteries". 2020. https://monarch.qucosa.de/id/qucosa%3A72231.
Testo completoAbstract (sommario):
Development of microsized batteries plays an important role in the design of in-situ electrochemical investigation systems and portable/wearable electronics. This emerging field intimately correlates with the topics of rechargeable batteries, nanomaterials, on-chip microfabrication, flexibility with reliable mechanical properties etc. Among the various energy materials, conversion-type materials have been proposed as high-energy-density alternatives to traditional intercalation-based materials. However, these materials usually show complex reaction processes accompanied by multi-reaction intermediates, which poses a great challenge to understand the chemical mechanisms. Benefiting from the merits of microsized battery devices, we develop a novel strategy to investigate and then optimize the electrochemical performance of a specific conversion-type material: nickel-iron oxide (NFO). Subsequently, this kind of materials are employed for flexible minimized energy storage systems.
Unlike traditional characterization methods based on slurry-coated electrodes, micro-platforms directly probe the intrinsic electrochemical properties of a single active material in real-time due to the elimination of other additives. In this thesis, we firstly design a micro-lithium batteries (MLBs), based on a single “Swiss-roll” microtubular nanomembrane electrode. This platform enables us to investigate the electrochemical mechanisms of electrode materials in lithium batteries by in-situ Raman spectroscopy, electrical conductivity measurements, and electrochemistry characterization. With this designed MLBs, we systematically studied NFO nanomembranes. Using in-situ Raman spectroscopy during the delithiation/lithiation process, we monitored the transition of the chemical component directly. Guided by our investigations of micro-batteries, composite NFO nanomembrane electrodes were fabricated and tested in coin cells, which showed an excellent rate performance: 440 mAh g-1 at a high rate of 20 A g-1 and a long-term stable cycling performance over 1600 cycles. One step further, a flexible energy storage micro-device is achieved using such optimized materials. We demonstrate a thin, lightweight, and flexible micro-full lithium-ion battery based on nickel-iron oxide with a high-rate performance and energy density that can be repeatedly bent to 180° without structural failure and performance loss. It delivers a stable output capacity of 140 mAh g-1 over 1000 charge/discharge cycles. Meanwhile, the excellent rate performance guarantees high energy output up to 255 W h kg-1 at a high power density of 12000 W kg-1 at the microscale.
Capitoli di libri sul tema "Micro-sized particles of iron oxide"
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Anthony, Daniel C., Nicola R. Sibson, Martina A. McAteer, Ben Davis e Robin P. Choudhury. "Detection of Brain Pathology by Magnetic Resonance Imaging of Iron Oxide Micro-particles". In Methods in Molecular Biology, 213–27. Totowa, NJ: Humana Press, 2010. http://dx.doi.org/10.1007/978-1-60761-938-3_9.
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Margel, Shlomo, Tammy Lublin‐Tennenbaum, Sigalit Gura, Merav Tsubery, Udi Akiva, Nava Shpaisman, Anna Galperin et al. "Synthesis and characterization of nano‐ and micron‐sized iron oxide and iron particles for biomedical applications". In Laboratory Techniques in Biochemistry and Molecular Biology, 119–62. Elsevier, 2007. http://dx.doi.org/10.1016/s0075-7535(06)32006-2.
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A. Awe, Samuel. "Root Cause Failure Analysis of Castings: A Case Study of a Brake Rotor". In Failure Analysis [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.107950.
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A premature failure of a vehicle brake rotor was investigated and reported. The brake rotor was manufactured from a grey cast iron material and had covered about 10 670 miles before it failed. The failure-generated tremendous concern for the autoparts manufacturer due to the warranty claims from the Original Equipment Manufacturer (OEM). This chapter, however, intends to describe the methodical approach used to identify the failure’s main cause using a root cause failure analysis technique and offer suggestions to prevent a similar failure from re-occurring. The results of this investigation showed that the disc’s early failure was caused by oxide inclusions that were accidentally entrapped into the disc’s neck region. The eventual disc failure was initiated by micro-cracks developed within the inclusion particles and propagated through the weakest interface between flaky graphite and the pearlitic matrix. To ensure that nonmetallic inclusions are kept out of cast components, several solutions for improving casting quality were proposed.
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Sarkar Shathi, Tonmoye, e Abdur Rahman. "Functionalized ferrites for therapeutics and environmental pollution management". In Applications of Ferrites [Working Title]. IntechOpen, 2024. http://dx.doi.org/10.5772/intechopen.1002336.
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Surface-functionalized ferrite materials are the ultimate products obtained from micro/nanofabrication of one or more metal containing magnetic iron-based oxides and their surface fine-tuning with suitable molecules for desired applications. Appropriate functionalization of ferrite surface often implants a wide range of application-specific physicochemical characteristics. Herein, we have discussed surface functionalization of ferrites with different organic molecules, inorganic oxides, metals, and polymeric materials. Impacts of surface functionalization on the dispersibility, biocompatibility, conductivity, photocatalytic activity, and pH responsiveness of ferrite particles and their therapeutic and environmental potentials are also highlighted. Then, some widely used and important functionalization routes like coupling, ligand exchange, polymer encapsulation, and sol-gel techniques are illustrated. Finally, a brief overview of biomedical and environmental pollutant mitigation efficacies of the functionalized ferrite compounds is emphasized.
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Ananth, M. Prem, e J. Sivaramapandian. "EVALUATION OF THE MECHANICAL CHARACTERISTICS OF B4C AND ALUMINIUM OXIDE REINFORCED HYBRID ALUMINIUM COMPOSITES FOR THE AUTOMOBILE, AEROSPACE APPLICATION IN FUTURE". In Futuristic Trends in Mechanical Engineering Volume 3 Book 6, 224–35. Iterative International Publisher, Selfypage Developers Pvt Ltd, 2024. http://dx.doi.org/10.58532/v3bgme6p4ch3.
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In this century we are in a position to think about alternate material for all the application. Based on this ideology, we started to work on the ‘Aluminum Metal Matrix Composites(AMMC) because of its many good and essential characteristics. AMMC are widely favored in industries like marine, aerospace and automotive due to its exceptional properties, including strength-to-weight ratio is high and excellent resistance to wear. Furthermore, the incorporation of nano-sized particles is gaining momentum as it improves the strength of the Metal Matrix Composites (MMC) while. These studies focuses on the production and assess the characteristics of mechanical of an Aluminium Matrix composites (AMC) reinforced with ‘micro-sized Boron Carbide (B4C) and nano-sized aluminum oxide’ using stir casting technique.
Atti di convegni sul tema "Micro-sized particles of iron oxide"
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Dutta, Abhishek, Sakya Mohapatra, Atanu Sen e Sudarshan Mukherjee. "Alternative for by-pass surgery using iron-oxide nano-particles". In 2006 Bio Micro and Nanosystems Conference. IEEE, 2006. http://dx.doi.org/10.1109/bmn.2006.330890.
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Kurtoglu, Evrim, Alihan Kaya, Devrim Gözüaçık, Havva Funda Yağcı Acar e Ali Kosar. "Heat Transfer Enhancement With Iron Oxide Nanoparticle Based Ferrofluids". In ASME 2013 11th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/icnmm2013-73146.
Testo completoAbstract (sommario):
Nanofluids are colloidal compounds, where the solid phase material is composed of nano sized particles, and the liquid phase can potentially be any fluid but aqueous media are common. As a common nanofluid type, ferrofluids are formed by holding solid nanoparticles in suspension by weak intermolecular forces and may be produced from materials with different magnetic properties. Heat transfer performance of ferrofluids is one of the crucial properties among many others that should be analyzed and considered for their wide range of applications. For this purpose, experiments were conducted in order to characterize heat transfer properties of ironoxide based ferrofluids flowing through a microchannel. In this study, convective heat transfer experiments were conducted in order to characterize convective heat transfer enhancements with Lauric acid coated ironoxide (Fe3O4) nanoparticle based ferrofluids, which have volumetric fractions between 0%–∼5% and average particle diameter of 25 nm, in a 2.5 cm long hypodermic stainless steel microtube with an inner diameter of 514 μm and an outer diameter of 819 μm. Heat fluxes up to 184 W/cm2 were applied to the system at three different flow rates (1ml/s, 0.62ml/s and 0.36 ml/s). Promising results were obtained from this study, which are suggesting the use of ferrofluids for heat transfer applications can be advantageous.
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Dormer, Kenneth, Sunny Po, Kejian Chen, Benjamin Scherlag, Isaac Rutel, Kytai Nguyen, Satish Kyriyavar et al. "Magnetic Targeting of Therapeutics". In ASME 2010 First Global Congress on NanoEngineering for Medicine and Biology. ASMEDC, 2010. http://dx.doi.org/10.1115/nemb2010-13022.
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Multiple formulations of nano-sized particles, capsules, dendrimers, lipids, ceramics and genetic materials are being investigated in multiple labs for delivery of therapeutic moieties to targeted tissues. Interest is driven by reducing health care costs while increasing therapeutic efficacy and cost of treatment. One technology, magnetic targeting, incorporates iron oxide nanoparticles, to target nanomedicine payloads, down the gradients of external magnetic fields. When iron oxide crystal domains are less than ∼20–40 nm, particles become superparamagnetic (SPION), that is exhibit no remanent induction but very high magnetic susceptibility in the presence of an external magnetic field. Thus, targeting can be vectored by magnetic lines of flux. Particles can be pulled out of the microcirculation and across membranes into tissues. Two target organs that can employ magnetic targeting are the heart (epicardium) and inner ear (cochlea).
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Kurtoglu, Evrim, Alihan Kaya, Havva Funda Yagci Acar e Ali Kosar. "An Experimental Study on Heat Transfer Performance of Iron Oxide Based Ferrofluids". In ASME 2012 10th International Conference on Nanochannels, Microchannels, and Minichannels collocated with the ASME 2012 Heat Transfer Summer Conference and the ASME 2012 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/icnmm2012-73126.
Testo completoAbstract (sommario):
Nanofluids are colloidal compounds, where the solid phase material is composed of nano sized particles, and the liquid phase can potentially be any fluid but aqueous media are common. As a common nanofluid type, ferrofluids are formed by holding solid nanoparticles in suspension by weak intermolecular forces and may be produced from materials with different magnetic properties. Magnetite is one of the materials used for its natural ferromagnetic properties. Heat transfer performance of ferrofluids is one of the crucial properties among many others that should be analyzed and considered for their wide range of applications. For this purpose, experiments were conducted in order to characterize heat transfer properties of ironoxide based ferrofluids flowing through a microchannel. Promising results were obtained from this study, which are suggesting the use of ferrofluids for heat transfer applications can be advantageous.
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Han, Zenghu, Bao Yang, S. H. Kim e M. R. Zachariah. "Nanofluids Containing Hybrid Sphere/Carbon Nanotube Particles". In 2007 First International Conference on Integration and Commercialization of Micro and Nanosystems. ASMEDC, 2007. http://dx.doi.org/10.1115/mnc2007-21331.
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Previous studies on nanofluids have focused on spherical or long-fiber particles. In this work, a new type of complex nanoparticles—hybrid sphere/carbon nanotube (CNT) particle, consisting of numerous CNTs attached to an alumina/iron oxide sphere—is proposed for applications in nanofluids. In such hybrid nanoparticles, heat is expected to transport rapidly from one CNT to another through the center sphere and thus leading to less thermal-contact-resistance between CNTs when compared to simple CNTs dispersed in fluids. CNTs have an extremely high thermal conductivity, but thermal resistance between the CNTs and the fluid has limited their performance in the nanofluids. The proposed hybrid sphere/CNT particles are synthesized by a spray pyrolysis followed by catalytic growth of CNTs. The spheres are about 70 nm in diameter in average, and the attached CNTs have a length up to 2μm. These hybrid nanoparticles are dispersed to poly-alpha-olefin with sonication and a small amount of surfactants to form stable nanofluids. The thermal conductivity of the fluids has been measured by a 3ω-wire method over a temperature range 10–90°C. The results indicate that the effective thermal conductivity of the fluids is increased by about 21% at room temperature for particle volume fractions of 0.2%.
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Khanolkar, Ratnesh U., e A. K. Suresh. "Effect of Material of Nanoparticle on Mass Transfer Enhancement and a Convective Diffusion Model to Predict the Enhancement". In ASME 2013 4th International Conference on Micro/Nanoscale Heat and Mass Transfer. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/mnhmt2013-22178.
Testo completoAbstract (sommario):
While particles smaller than the thickness of the diffusion film have been known to enhance rates of interfacial mass transfer [1], a relatively new result is the discovery that nanoparticles in suspension show enhancements that far exceed the earlier reported enhancements, and without any apparent adsorptive or reactive effects[2]. Different mechanisms for the enhancements have been speculated upon, but there is a paucity of data on different nanoparticulate materials, collected in a systematic way on model contactors so that rational comparisons may be made. In this work, enhancement in Carbon dioxide absorption in water has been studied using SiO2 and TiO2 nanoparticles using the same capillary tube apparatus for which previous results of Fe3O4 were reported. For 0.4% silica particles and 0.0118% TiO2 nanoparticles, 165% and 155% enhancement was observed respectively. A phenomenological convective diffusion model has been proposed to explain the observed effects of particle size, holdup and material density. The model accounts for the overall effect of the Brownian (and any diffusiophoretic) motion of the nanoparticles on the surrounding fluid in terms of an ‘effective’ convective velocity, which is determined from the experimental data and correlated to the modified Sherwood Number proposed earlier [2], volume fraction of Nanoparticles and a solid Reynolds number Rp. This model provides a good fit to the data from wetted wall column and capillary tube experiment for iron oxide from the previous literature, as well as for the data on silica and Titanium dioxide nanoparticles from this work, the average error being 8.3%.
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Su, Di, Ronghui Ma e Liang Zhu. "Numerical Study of Nanofluid Transport in Tumors During Nanofluid Infusion for Magnetic Nanoparticle Hyperthermia Treatment". In ASME 2012 Third International Conference on Micro/Nanoscale Heat and Mass Transfer. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/mnhmt2012-75101.
Testo completoAbstract (sommario):
The application of nanostructures in hyperthermia treatment of cancer has attracted growing research interest due to the fact that magnetic nanoparticles are able to generate impressive levels of heat when excited by an external magnetic field [1–3]. Various types of nanoparticles such as magnetite and superparamagentic iron oxide nanoparticles have demonstrated great potentials in hyperthermia treatment; however many challenges need to be addressed for future applications of this method in clinical studies. One leading issue is the limited knowledge of nanoparticle distribution in tumors. Since the temperature elevation is induced as the result of the heat generation by the nanoparticles, the concentration distributions of the particles in a tumor play a critical role in determining the efficacy of the treatment. The lack of control of the nanoparticle distribution may lead to inadequacy in killing tumor cells and/or damage to the healthy tissue.
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Goto, Y., S. Kawanishi, S. Natsui, J. Takahashi e H. Nogami. "Direct observation of the fayalite slag formation behaviour from large SiO2 grains". In 12th International Conference of Molten Slags, Fluxes and Salts (MOLTEN 2024) Proceedings, 653–62. Australasian Institute of Mining and Metallurgy (AusIMM), 2024. http://dx.doi.org/10.62053/jhaw7732.
Testo completoAbstract (sommario):
The demand for copper increases yearly, and further improvements in copper smelting efficiency using flash furnaces are required. This study was conducted to understand and promote the interfacial reaction associated with the collision of silica flux and iron oxide particles, ie the formation reaction of fayalite slag, in the reaction shaft of the flash furnace. High-temperature microscopy was used to observe the reaction behaviour of a 2 mm granular SiO2 reagent in contact with micrometre-order-sized FeO reagents in situ. When the amount of FeO was lower than the stoichiometric amount with SiO2, the molten slag formed at the interface between FeO and SiO2 diffused into the SiO2 particle before dissolving the remaining FeO particles. It did not contribute to the subsequent reaction, and despite having the lowest amount of FeO among the samples in this study, many unreacted FeO particles remained on the surface of the samples after testing. On the other hand, under conditions with high FeO content and close to the eutectic composition of the FeO-SiO2 system, a liquid phase formed from low temperatures, gradually increasing in volume and eventually completely dissolving the 2 mm SiO2 grain. These results indicate that the early-stage slag is essential in increasing the interfacial area between FeO and SiO2 and facilitating the supply of FeO to SiO2. In other words, the FeO/SiO2 determines the amount of liquid phase and significantly influences the subsequent interfacial reaction rate between FeO and SiO2. Therefore, the local FeO/SiO2 of the particles falling down the reaction shaft should also be optimised to ensure early slag formation. Meanwhile, the time required for 2 mm SiO2 to complete the reaction for the temperature history employed in this study was significantly longer than the particle residence time in the reaction shaft. Further detailed investigation of the effects of silica flux particle size, composition, and reaction temperature on the reaction time will help find the conditions under which the reaction of silica flux can be completed in the reaction shaft. These kinetic approaches could contribute to future innovations in the copper smelting process using flash furnaces.
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Manzo, Maurizio, e Megha Bakaraju. "Fabrication and Testing of Asymmetric Magnetic-Polymer Flexible Sheets for Biomedical Actuated Devices". In ASME 2022 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/imece2022-95020.
Testo completoAbstract (sommario):
Abstract Flexible actuated sheets are currently being used in different devices in the biomedical field for a variety of different applications. Examples of biomedical devices that use flexible actuated sheets are neural probes, microneedles, micropumps for insulin, intraocular and inner ear drug delivery systems. Among them, micropumps are one of the most flexible and popular devices. In fact, micropumps are being extensively studied for multiple biomedical applications — controlled drug delivery systems, artificial sphincter prosthesis, cell culturing, micro-fluidic analyses. One of the most important applications for actuated membranes is in drug delivery systems, but there are multiple challenges that exist including maintaining controlled flow rate, reaching delicate tissues, and preventing complex side effects. In this paper, the effect of an inhomogeneous distribution of magnetic particles in the membrane used for actuation is studied for the first time. The fabrication and testing of asymmetric thin flexible sheets magnetic actuators are presented. Focus of this research is to fabricate thin polymeric sheets with thickness range of 120–125μm, with asymmetric distribution of magnetic nano/micro particles. Iron oxide (Fe3O4) particles are embedded into polymeric membranes made of Polydimethylsiloxane (PDMS). From the perspective of biomedical application, PDMS is chosen for its excellent biocompatibility and Fe3O4 for its non-toxic nature. The particles are mixed with the PDMS polymeric solution and micromagnets are used to localize the magnetic particles during the curing process at selected locations to create asymmetry into the particles’ distribution. Fe3O4 – PDMS membranes are fabricated and mounted to a fixture to observe deflection by using a camera. An external magnetic field is applied for the actuation of the membrane and two measurement types are made: static and dynamic. A permanent magnet is used for generating the external magnetic field, which is attached to a piezoelectric actuator. The effect of the distribution of magnetic particles are investigated in terms of the deflection of membranes for both static and dynamic behavior. A comparative study of membranes with inhomogeneous and randomly distributed particles is carried out. This work shows that the inhomogeneous distribution of particles has a positive effect on the deflection of the membranes, making them favorable for a wide range of applications involving localized and targeted treatments and precision medicine. Since magnetic actuation does not require onboard batteries or other power systems, it is very convenient to use. Magnetically actuated sheets can be used in Hyperthermia to have enhanced results due to asymmetric distribution of magnetic particles.
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Sandri, Monica, Michele Iafisco, Silvia Panseri, Elisa Savini e Anna Tampieri. "Fully Biodegradable Magnetic Micro-Nanoparticles: A New Platform for Tissue Regeneration and Theranostic". In ASME 2013 2nd Global Congress on NanoEngineering for Medicine and Biology. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/nemb2013-93223.
Testo completoAbstract (sommario):
Nowadays, magnetic materials are receiving special attention due to their potential applications in different fields and in particular in medicine. Magnetic micro-nano-particles have been progressively employed as support materials for enzyme immobilization, and have been used as drug-delivery vehicles, contrast agents for magnetic resonance imaging as well as heat mediators for hyperthermia-based anti-cancer treatments and many other exciting biomedical applications. Magnetic materials have also attracted a big interest in the field of bone tissue regeneration because it has been demonstrated that magnetic nanoparticles have effect of osteoinduction even without external magnetic force. Therefore, one of the most big challenge in this field is the production of magnetic materials with good biocompatibility and biodegradability. In fact, the long-term effects in the human body of iron oxide (maghemite or magnetite), the most popular magnetic phase used in medicine and biotechnology, are not yet completely assessed. To this aim, in this work we developed an innovative biocompatible and bioresorbable superparamagnetic-like phase by doping nano-hydroxyapatite with Fe2+/Fe3+ ions (FeHA). Moreover the same magnetic nanoparticles were used as nano-particulate emulsifier for the preparation of hollow hybrid Fe-HA-poly(L-lactic) acid (PLLA) micro-nano-spheres. PLLA has been used because poly(α-hydroxy-esters) are the most frequently used synthetic polymers for biomedical applications owing to their biocompatibility, hydrolytic degradation process and proper mechanical properties. These micro-nanospheres could be used as new type of scaffold for hard tissue regeneration. In fact, spherical scaffold display several advantages respect to the monolithic counterpart e.g., (i) improving control over sustained delivery of therapeutic agents, signalling biomolecules and even pluripotent stem cells, (ii) serving as stimulus-sensitive delivery vehicles for triggered release, (iii) introducing porosity and/or improve the mechanical properties of bulk scaffolds by acting as porogen or reinforcement phase, (iv) supplying compartmentalized micro-reactors for dedicated biochemical processes, (v) functioning as cell delivery vehicle, and, finally, (vi) giving possibility of preparing injectable and/or mouldable formulations to be applied by using minimally invasive surgery. Moreover, the same magnetic materials could find applications in nanomedicine as a multifunctional carrier. Their magnetic functionality could be utilized to move them into the body towards target organs by an external magnetic field. Furthermore, the superparamagnetic feature of the nanoparticles could allow to tailor the release of the therapeutic agent by switching (on-off) the external magnetic field and/or to treat cancer cells by hyperthermia.