scholarly journals Systematic preparation and physical property characterization of a novel stable BiOIO3 nanofluids

2021 ◽  
pp. 337-337
Author(s):  
Ruihao Zhang ◽  
Hao Zhang ◽  
Shan Qing ◽  
Zhang Xiaohui ◽  
Zhumei Luo ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Average Particle Size ◽  
Physical Property ◽  
Average Particle ◽  
Step Method ◽  
Heat Transfer Fluids ◽  
New Type ◽  
Near Future ◽  
To Receive

Nanofluids due to their good thermal conductivity and stability, have been proposed as a way to surpass the performance of currently available heat transfer fluids in the near future. In this work?we focuses on the preparation of nanofluids with excellent stability and thermal conductivity, which a new type of stable BiOIO3 (one type of infrared nonlinear optical crystal) nanofluids is successfully prepared by using the two-step method. After the initial physical characterization of BiOIO3 particles, five different dispersants are used to disperse the BiOIO3 nanoparticles, and the best performing nanofluids with a zeta potential value of 144.45 and an average particle size of 22.90nm could be prepared with PVP dispersant. Furthermore, the addition of PVP dispersant in UV-Visible experiments smooth the light absorption curve of the nanofluids, reach a peak of 1.1 at around 350 nm. In the most important thermal conductivity test, the value of thermal conductivity of BiOIO3 nanofluid becomes larger with increasing concentration at 50?C, reaching a maximum value of 1.52 at 0.134vol%, which increases by 0.72 over the same volume concentration of TiO2, indicating the importance of the laminar structure. In view of the excellent properties, new laminar structured nanofluids with light-absorbing properties are expected to receive more attention and exploration in the future

Suspension Stability and Thermal Conductivity of Oxide Based Nanofluids with Low Volume Concentration

2010 ◽  
Vol 160-162 ◽  
pp. 802-808 ◽  
Author(s):  
Wei Lin Zhao ◽  
Bao Jie Zhu ◽  
Jin Kai Li ◽  
Yan Xiang Guan ◽  
Dong Dong Li
Keyword(s):  
Thermal Conductivity ◽  
Volume Concentration ◽  
Average Particle Size ◽  
Sio2 Nanoparticles ◽  
Heat Transfer Fluid ◽  
Suspension Stability ◽  
Average Particle ◽  
Step Method ◽  
Low Volume ◽  
Thermal Conductivities

Nanofluid is a new class of heat transfer fluid which contains suspended metallic or nonmetallic nanoparticles in traditional fluid. In this paper, nanofluids containing low volume concentrations (0.1-0.5vol.%) of Al2O3 and SiO2 nanoparticles were produced using a two-step method with ultrasonication and without any surfactant. Suspension stability of nanofluid was characterized and analyzed using zeta potential, average particle size and absorbancy method. The KD2-pro thermal property meter was used to measure the thermal conductivities of Al2O3(40nm)-water and SiO2(30nm)-water nanofluids at different volume concentrations (0.1-0.5vol.%) and temperature(25-50°C). The results show that adding nanoparticles into base fluid can enhance the thermal conductivity greatly. Furthermore, it is also show that the thermal conductivities increase nearly linearly with the nanoparticle volume concentration increasing, and increase significantly with the temperature increasing. A model of thermal conductivity of nanofluid, which has a much better precision, was proposed. But the values of the model are lower than the measured thermal conductivities.

Microstructural and Thermal Characterization of Diamond Nanofluids

2018 ◽  
Author(s):  
Farzin Mashali ◽  
Ethan M. Languri ◽  
Gholamreza Mirshekari ◽  
Jim Davidson ◽  
David Kerns
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Particle Size ◽  
Base Fluid ◽  
Average Particle Size ◽  
Thermal Characterization ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Heat Transfer Fluids ◽  
Transmission Electron

Conventional heat transfer fluids such as water, ethylene glycol, and mineral oil, that are used widely in industry suffer from low thermal conductivity. On the other hand, diamond has shown exceptional thermal properties with a thermal conductivity higher than five times of copper and about zero electrical conductivity. To investigate the effectiveness of nanodiamond particles in traditional heat transfer fluids, we study deaggregated ultra-dispersed diamonds (UDD) using X-ray diffraction analysis (XRD) and transmission electron microscopy (TEM). Furthermore, nanodiamond nanofluids were prepared at different concentrations in deionized (DI) water as the base fluid. Particle size distribution was investigated using TEM and the average particle size have been reported around 6 nm. The thermal conductivity of nanofluids was measured at different concentrations and temperatures. The results indicate up to 15% enhancement in thermal conductivity compared with the base fluid and thermal conductivity increases with temperature and particle loading. The viscosity raise in the samples have been negligible.

Synthesis and Characterization of Water-Soluble Monolayer-Protected Gold Nanoparticles

2011 ◽  
Vol 415-417 ◽  
pp. 617-620 ◽  
Author(s):  
Yan Su ◽  
Ying Yun Lin ◽  
Yu Li Fu ◽  
Fan Qian ◽  
Xiu Pei Yang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Gold Nanoparticles ◽  
Average Particle Size ◽  
Water Soluble ◽  
Synthesis And Characterization ◽  
Average Particle ◽  
Transmission Electron

Water-soluble gold nanoparticles (AuNPs) were prepared using 2-mercapto-4-methyl-5- thiazoleacetic acid (MMTA) as a stabilizing agent and sodium borohydride (NaBH4) as a reducing agent. The AuNPs product was analyzed by transmission electron microscopy (TEM), UV-vis absorption spectroscopy and Fourier transform infrared spectroscopy (FTIR). The TEM image shows that the particles were well-dispersed and their average particle size is about 5 nm. The UV-vis absorption and FTIR spectra confirm that the MMTA-AuNPs was stabilized by the carboxylate ions present on the surface of the AuNPs.

scholarly journals Preparation and characterization of domperidone nanoparticles for dissolution improvement

2018 ◽  
Vol 27 (1) ◽  
pp. 39-52
Author(s):  
Mohammed Sabar Al-lami ◽  
Malath H. Oudah ◽  
Firas A. Rahi
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
In Vitro Release ◽  
Methyl Cellulose ◽  
Precipitation Method ◽  
Average Particle ◽  
Antisolvent Precipitation ◽  
Stirring Time

This study was carried out to prepare and characterize domperidone nanoparticles to enhance solubility and the release rate. Domperidone is practically insoluble in water and has low and an erratic bioavailability range from 13%-17%. The domperidone nanoparticles were prepared by solvent/antisolvent precipitation method at different polymer:drug ratios of 1:1 and 2:1 using different polymers and grades of poly vinyl pyrolidone, hydroxy propyl methyl cellulose and sodium carboxymethyl cellulose as stabilizers. The effect of polymer type, ratio of polymer:drug, solvent:antisolvent ratio, stirring rate and stirring time on the particle size, were investigated and found to have a significant (p? 0.05) effect on particle size. The best formula was obtained with lowest average particle size of 84.05. This formula was studied for compatibility by FTIR and DSC, surface morphology by FESEM and crystalline state by XRPD. Then domperidone nanoparticles were formulated into a simple capsule dosage form in order to study of the in vitro release of drug from nanoparticles in comparison raw drug and mixture of polymer:drug ratios of 2:1. The release of domperidone from best formula was highly improved with a significant (p? 0.05) increase.

CONTROLLED SYNTHESIS AND CHARACTERIZATION OF CERIUM-DOPED ZnS NANOPARTICLES IN HMTA MATRIX

2011 ◽  
Vol 10 (03) ◽  
pp. 487-493 ◽  
Author(s):  
K. VIJAI ANAND ◽  
R. MOHAN ◽  
R. MOHAN KUMAR ◽  
M. KARL CHINNU ◽  
R. JAYAVEL
Keyword(s):  
Quantum Confinement Effect ◽  
Average Particle Size ◽  
Surface States ◽  
Deep Trap ◽  
Average Particle ◽  
Zns Nanoparticles ◽  
Selected Area Electron Diffraction ◽  
Luminescence Process ◽  
Photoluminescence Studies

Cerium-doped ZnS nanoparticles have been synthesized through hydrothermal method. The nanoparticles were stabilized using hexamethylenetetramine (HMTA) as surfactant in aqueous solution. The average particle size of the prepared samples is about 2 nm. The structure of the as-prepared ZnS nanoparticles is cubic (zinc blende) as demonstrated by X-ray powder diffraction (XRD) and selected area electron diffraction (SAED) analysis. TEM results showed that the synthesized nanoparticles were uniformly dispersed in the HMTA matrix without aggregation. The UV–Vis absorption spectra of the prepared ZnS nanoparticles show a considerable blueshift in the absorption band edge compared to bulk ZnS indicating a strong quantum confinement effect. Formation of HMTA-capped ZnS nanoparticles was confirmed by FTIR studies. Photoluminescence studies showed that the relative emission intensity of Ce3+ -doped ZnS nanoparticles is higher than that of undoped ZnS nanoparticles, which is due to the enhancement of radiative recombination in the luminescence process. The PL spectra showed two emission peaks at around 420 nm and 442 nm, which may be attributed to deep-trap emission or defect-related emission of ZnS and presence of various surface states.

Experimental Study of Heat Conduction in Aqueous Suspensions of Aluminum Oxide Nanoparticles

2008 ◽  
Vol 130 (9) ◽  
Author(s):  
Y. Sungtaek Ju ◽  
Jichul Kim ◽  
Ming-Tsung Hung
Keyword(s):  
Thermal Conductivity ◽  
Aluminum Oxide ◽  
Average Particle Size ◽  
Oxide Nanoparticles ◽  
Average Particle ◽  
Aluminum Oxide Nanoparticles ◽  
Aqueous Suspensions ◽  
Effective Medium Model ◽  
Transient Hot Wire Technique ◽  
Different Temperatures

We report measurements of the thermal conductivity of aqueous suspensions of aluminum oxide nanoparticles with nominal diameters of 20nm, 30nm, and 45nm and at volume concentrations up to 10%. Potential complications in the pulsed transient hot-wire technique for characterizing nanofluids are examined, which motivate the development of a microhot strip setup with a small thermal time constant. The average particle size is monitored for samples subjected to different durations of sonication and the thermal conductivity is determined at two different temperatures for each of the samples. The present data do not reveal any anomalous enhancement in the thermal conductivity previously reported for comparable nanofluids. The concentration dependence of the thermal conductivity can be explained using the conventional effective medium model with a physically reasonable set of parameters.

The Aggregation Study and Characterization of Silver Nanoparticles

2017 ◽  
Vol 263 ◽  
pp. 165-169
Author(s):  
Silvia Chowdhury ◽  
Faridah Yusof ◽  
Nadzril Sulaiman ◽  
Mohammad Omer Faruck
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Silver Nanoparticles ◽  
Absorption Spectrum ◽  
Average Particle Size ◽  
Average Particle ◽  
Transmission Electron ◽  
Vis Spectroscopy

In this article, we have studied the process of silver nanoparticles (AgNPs) aggregation and to stop aggregation 0.3% Polyvinylpyrrolidone (PVP) was used. Aggregation study carried out via UV-vis spectroscopy and it is reported that the absorption spectrum of spherical silver nanoparticles were found a maximum peak at 420 nm wavelength. Furthermore, Transmission Electron Microscopy (TEM) were used to characterized the size and shape of AgNPs, where the average particle size is around 10 to 25 nm in diameter and the AgNPs shape is spherical. Next, Dynamic Light Scattering (DLS) were used, owing to observed size distribution and self-correlation of AgNPs.

scholarly journals Synthesis and characterization of the aluminium phosphates modified with ammonium, calcium and molybdenum by hydrothermal method

2016 ◽  
Vol 18 (2) ◽  
pp. 131-139
Author(s):  
Kinga Łuczka ◽  
Barbara Grzmil ◽  
Bogumił Kic ◽  
Krzysztof Kowalczyk
Keyword(s):  
Particle Size ◽  
Physicochemical Parameters ◽  
Average Particle Size ◽  
Synthesis And Characterization ◽  
Average Particle ◽  
Influence Of Process Parameters ◽  
Molar Ratios ◽  
Aluminum Phosphates ◽  
The Individual

Abstract Synthesis and characterization of the aluminum phosphates modified with ammonium, calcium and molybdenum were conducted. The influence of process parameters (reactive pressure and molar ratios) in the reaction mixture were studied. The contents of the individual components in the products were in the range of: 10.97–17.31 wt% Al, 2.65–13.32 wt% Ca, 0.70–3.11 wt% Mo, 4.36–8.38 wt% NH3, and 35.12–50.54 wt% P2O5. The materials obtained in the experiments were characterized by various physicochemical parameters. The absorption oil number was in the range from 67 to 89 of oil/100 g of product, the surface area was within the range of 4–76 m2/g, whereas the average particle size of products reached 282–370 nm. The Tafel tests revealed comparable anticorrosive properties of aluminum phosphates modified with ammonium, calcium, molybdenum in comparison with commercial phosphate.

Preparation and Characterization of Folate-Decorated Chitosan Microspheres as a Sustained-Release Drugs Carrier

2013 ◽  
Vol 684 ◽  
pp. 57-62 ◽  
Author(s):  
Zhi Hua Xing
Keyword(s):  
Encapsulation Efficiency ◽  
Average Particle Size ◽  
Morphological Characteristics ◽  
Average Particle ◽  
Loading Capacity ◽  
Chitosan Microspheres ◽  
Ionic Crosslinking ◽  
Artificial Gastric Juice

Folic acid-chitosan (FA-CTS) and 10-hydroxycamptothecin (HCPT)-loaded folate-conjugated chitosan (FA-CTS/HCPT) microspheres were prepared by the ionic crosslinking method.The morphological characteristics of microspheres were examined using a scanning electron microscope (SEM). The average particle size and size distribution were determined by dynamic light scattering. The drug encapsulation efficiency (EE) , loading capacity (LC)and release characteristics in vitro were determined using ultraviolet spectrophotometer.The results shown that the microspheres are uniform spherical and regular with a size between 19.79 and81.40μm.Optimized preparation parameters lead to the successful preparation of hydroxycamptothecin-loaded folate-conjugated chitosan microspheres characterized with encapsulation efficiency and loading capacity up to (86.8±0.1)% and 20.6±0.3 % respectively. More then 90% of 10-hydroxycamptothecin was released from microspheres in 4 h at artificial gastric juice, 8h at artificial small intestinal fluid with a good delayed release effect.

Rheological, Structural and Mechanical Characterization of Monolithic Zircon-Alumina Bodies

2014 ◽  
Vol 793 ◽  
pp. 151-158 ◽  
Author(s):  
M. León-Carriedo ◽  
C.A. Gutiérrez Chavarría ◽  
J.L. Rodríguez Galicia ◽  
Jorge López-Cuevas ◽  
M.I. Pech Canul
Keyword(s):  
Particle Size ◽  
Raw Materials ◽  
Mechanical Test ◽  
Average Particle Size ◽  
Young Modulus ◽  
Particle Morphology ◽  
Ceramic Materials ◽  
Transgranular Fracture ◽  
Average Particle

In the present work, the characterization of monolithic materials formulated at different weight concentrations was conducted; employing two of the ceramic materials most used in the refractory industry, zircon and alumina. These monolithic materials were fabricated using colloidal techniques, specifically plaster casting mold, in order to obtain pieces with a higher particle consolidation and density, reducing porosity to lower values than the obtained using traditional shaping process of these materials. The monoliths were obtained employing two ceramic powders with different average particle size and morphology to achieve better packing in the green body. This characterization was carried out, firstly, determining the particle size of the raw materials by laser diffraction and the evaluation of particle morphology by scanning electron microscopy. Aqueous suspensions were formulated by containing both ceramic materials, which were dispersed with Tamol 963, and analyzed by rheometric techniques. Subsequently, bars were manufactured having the following dimensions; 4 mm wide, 3 mm thick and 45 mm in length, according to ASTM C1161-02cc, to be characterized microstructural and mechanically, also was observed the fracture habit after the mechanical test. As a final result, the materials formulated at higher alumina content showed higher density values, reaching 94.95% of the theoretical density, also showed a higher thermal expansion coefficient and high rupture modulus, reaching up to 600 MPa and Young modulus of 230 GPa. From the microstructure characterization it was observed that alumina matrix shows a transgranular fracture across the grains and zircon particles exhibited intergranular fracture among the grain boundaries.

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