scholarly journals Synthesis and thermal conductivity of functionalized biocarbon-Fe3O4 nanocomposite-based green nanofluid for heat transfer applications

2021 ◽  
Vol 321 ◽  
pp. 01003
Author(s):  
Divya Barai ◽  
Sohan Parbat ◽  
Bharat Bhanvase
Keyword(s):  
Heat Transfer ◽  
Electron Microscopy ◽  
Thermal Conductivity ◽  
Nanocomposite Particles ◽  
X Ray ◽  
Conductivity Enhancement ◽  
Water Based ◽  
One Step ◽  
Ultrasound Assisted ◽  
Scanning Electron

Bio-based graphitic carbon was synthesized in this work by one-step carbonization of bamboo waste at low temperature. This bio-based carbon was then functionalized in order to decorated it with Fe3O4 nanoparticles. The functionalized biocarbon-Fe3O4 (f-biocarbon-Fe3O4) nanocomposite was synthesized using ultrasound-assisted coprecipitation method which was then confirmed by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffractometry. Water-based nanofluid was prepared using the synthesized f-biocarbon-Fe3O4 nanocomposite particles. Thermal conductivity of this nanofluid was analyzed at different concentrations and temperatures. A thermal conductivity enhancement of almost 80% was recorded at 35°C for nanofluid containing 0.1 vol.% of f-biocarbon-Fe3O4 nanocomposite particles compared to water. Also, empirical model is developed for prediction of thermal conductivity as a function of concentration and temperature of bamboo waste-derived f-biocarbon-Fe3O4 nanocomposite-based green nanofluid.

scholarly journals Structural and thermoelectric properties of the Pr2Zr2O7 compound

2019 ◽  
pp. 4-9
Author(s):  
Adolfo Quiroz-Rodríguez ◽  
Cesia Guarneros-Aguilar ◽  
Ricardo Agustin-Serrano
Keyword(s):  
Electron Microscopy ◽  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Crystal Size ◽  
Ambient Pressure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Increasing Temperature ◽  
Thermal Stability Of ◽  
Scanning Electron

In this research, it is presented a detailed study of the structural and thermoelectric properties of the pyrochlore zirconium Pr2Zr2O7 compound prepared by solid-state reaction (SSR) in air at ambient pressure. The synthesized sample was characterized using powder X-ray diffraction. The thermal stability of the thermoelectric compound (TE) Pr2Zr2O7 was tested by thermogravimetric analysis (TGA) and differential thermal analysis (DTA). Scanning electron microscopy shows that the crystal size varies between 0.69 and 2.81μm. Electrical conductivity (\sigma) of the sample calcined at 1400 °C presented values increase irregularly with the increasing temperature from 0.001 to 0.018 S cm-1 as expected in a semiconductor material. The thermal conductivity is lower than 0.44 - 775 W m-1 K-1 which is quite anomalous in comparison with the thermal conductivity of other oxides.

scholarly journals Fabrication of a Thick Crystalline Al2O3 Coating with Insulation and High Thermal Conductivity via Anodic Oxidation and Subsequent Mic Arc Discharge Treatment

Coatings ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 38
Author(s):  
Wei Song ◽  
Bailing Jiang ◽  
Dongdong Ji
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Thermal Conductivity ◽  
Anodic Oxidation ◽  
Arc Discharge ◽  
Al2o3 Coating ◽  
Compact Structure ◽  
X Ray ◽  
Amorphous Al2o3 ◽  
Scanning Electron

Amorphous Al2O3 coating with a thickness of 143 μm was firstly prepared by anodic oxidation, then the amorphous Al2O3 was transformed into crystalline Al2O3 through applying micro arc discharge. The crystal structure of the Al2O3 coatings was analyzed with an X-ray diffractometer. Results indicated that the coating consisted of amorphous and crystalline Al2O3. The microstructure of the coating was characterized by scanning electron microscopy, which showed that the coating had a compact structure. The thermal conductivity of the coating was 23.7 W/m·K, which is significantly higher than that of amorphous Al2O3 coating. The total and specific breakdown voltages of the coating were 3.85 kV and 26.92 kV/mm, which is suitable to apply for high power LED heat sink substrate.

Solvothermal Synthesis and Electrochemical Properties of Hairball-Like Bismuth Trisulphide Microcrystallines

2011 ◽  
Vol 233-235 ◽  
pp. 2289-2293
Author(s):  
Pin Jiang Li ◽  
Wen Jun Fa ◽  
Yan Ge Zhang ◽  
Bao Jun Huang ◽  
Yi Dong Zhang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Solvothermal Synthesis ◽  
Growth Process ◽  
Solvothermal Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
One Step ◽  
Scanning Electron

Hairball-like bismuth trisulphide microcrystallines has been successfully prepared via one step solvothermal process and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM) techniques. The morphologies of the Bi2S3 microcrystallines were influenced by reaction time, temperature, the mole ratio of the reactants and concentration of starting materials, and the growth process has been proposed. The electrochemical behavior of Bi2S3 was investigated using the cyclic voltammetry.

Effects of Reductive Conditions on the Electrochemical Properties of LiFePO4/C Derived by Fe3+ Sources

2014 ◽  
Vol 1081 ◽  
pp. 313-317
Author(s):  
Yan Wen Lu ◽  
Yu Ge ◽  
Yue Feng Tang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Raw Materials ◽  
Thermal Method ◽  
X Ray Diffraction ◽  
Sintering Atmosphere ◽  
X Ray ◽  
Electrochemical Capacity ◽  
One Step ◽  
Scanning Electron

A one-step carbon thermal method was used to prepare LiFePO4/C particles by using normal Fe2O3, LiH2PO4and sucrose as raw materials. The effect of H2content in the sintering atmosphere of N2on the morphology and the electrochemical performance were investigated. LiFePO4/C materials were characterized by X-ray diffraction, scanning electron microscopy and the elemental analyzer. The results show that the precursor sintering under the atmosphere of 8%H2+N2exhibits the highest electrochemical capacity (162.3 mAh/g at 0.1C) .

scholarly journals The Influence of the Preparation and Stability of Nanofluids for Heat Transfer

2019 ◽  
Vol 25 (4) ◽  
pp. 45-54 ◽  
Author(s):  
Noor Sabih Majeed ◽  
Basma A. Abdulmajeed ◽  
Anwar Khudhur Yaseen
Keyword(s):  
Heat Transfer ◽  
Electron Microscopy ◽  
Base Fluid ◽  
X Ray Diffraction ◽  
Step Method ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
The Stability ◽  
Scanning Electron

Recently the use of nanofluids represents very important materials. They are used in different branches like medicine, engineering, power, heat transfer, etc. The stability of nanofluids is an important factor to improve the performance of nanofluids with good results. In this research two types of nanoparticles, TiO2 (titanium oxide) and γ-Al2O3 (gamma aluminum oxide) were used with base fluid water. Two-step method were used to prepare the nanofluids. One concentration 0.003 vol. %, the nanoparticles were examined. Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and X-ray diffraction (XRD) were used to accomplish these tests. The stability of the two types of nanofluids is measured by zeta potential and UV-vis spectrophotometer. The results showed that γ-Al2O3/water has more stable than TiO2/ water for the same period of time.  

scholarly journals Graphene oxide-loaded shortening as an environmentally friendly heat transfer fluid with high thermal conductivity

2017 ◽  
Vol 21 (5) ◽  
pp. 2247-2254
Author(s):  
Thammasit Vongsetskul ◽  
Peeranut Prakulpawong ◽  
Panmanas Sirisomboon ◽  
Jonggol Tantirungrotechai ◽  
Chanasuk Surasit ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Electron Microscopy ◽  
Thermal Conductivity ◽  
Graphene Oxide ◽  
Environmentally Friendly ◽  
High Thermal Conductivity ◽  
Chemical Degradation ◽  
Heat Transfer Fluid ◽  
Increasing Temperature ◽  
Scanning Electron

Graphene oxide-loaded shortening (GOS), an environmentally friendly heat transfer fluid with high thermal conductivity, was successfully prepared by mixing graphene oxide (GO) with a shortening. Scanning electron microscopy revealed that GO particles, prepared by the modified Hummer?s method, dispersed well in the shortening. In addition, the latent heat of GOS decreased while their viscosity and thermal conductivity increased with increasing the amount of loaded GO. The thermal conductivity of the GOS with 4% GO was higher than that of pure shortening of ca. three times, from 0.1751 to 0.6022 W/mK, and increased with increasing temperature. The GOS started to be degraded at ca. 360?C. After being heated and cooled at 100?C for 100 cycles, its viscosity slightly decreased and no chemical degradation was observed. Therefore, the prepared GOS is potentially used as environmentally friendly heat transfer fluid at high temperature.

Facile and green synthesis of amino-functionalized carbon nanodots for biomedical applications

2019 ◽  
Vol 12 (04) ◽  
pp. 1950062
Author(s):  
Zhongyan Gao ◽  
Qiang Ding ◽  
Qizhi Diao ◽  
Zhongying Guan ◽  
Biqiong Liu
Keyword(s):  
Electron Microscopy ◽  
Biomedical Applications ◽  
Carbon Nanodots ◽  
Excitation Wavelength ◽  
Pine Needle ◽  
Step Method ◽  
X Ray ◽  
Transmission Electron ◽  
One Step ◽  
Scanning Electron

Considering the high interests and concerns in regards to quantum dots (QDs), their properties and applications, this paper presents highly photoluminescent amino-functionalized carbon QDs which were prepared via a simple one-step method developed directly from pine needle. They were characterized by X-ray powder diffraction, photoluminescence (PL), UV-Vis diffused reflectance spectra, transmission electron microscope and scanning electron microscopy. These carbon QDs show strong and stable PL, which is dependent on excitation wavelength. The intense PL under longer excitation wavelength and excellent bioactivities suggest they can be used for biomedical applications due to its high photostability and biocompatibility.

scholarly journals The ultrasound effect on the morphological properties of hydroxyapatite

2018 ◽  
Vol 243 ◽  
pp. 00012 ◽  
Author(s):  
Konstantin Chuprunov ◽  
Eugenii Kolesnikov ◽  
Igor Ilinykh ◽  
Andrey Yudin ◽  
Denis Leybo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Ultrasonic Treatment ◽  
Nitrogen Adsorption ◽  
Morphological Properties ◽  
Pressure Treatment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ultrasound Assisted ◽  
Ultrasound Effect ◽  
Scanning Electron

The present study considers the morphological and dispersity characteristics of hydroxyapatite (HAp) samples synthesised through the ultrasound-assisted hydrothermal method with additional pressure treatment. The samples were analyzed by the X – Ray diffraction, scanning electron microscopy, low-temperature nitrogen adsorption. The ultrasound effect on the HAp morphologiy and dispersity was studied. The pressure assisted ultrasonic treatment made possible obtaining HAp samples with different morphology from rods and flakes to particles with irregular shape close to spherical. Also pressure assisted ultrasonic treatment able to increase the porosity of HAp materials.

scholarly journals Surface Modification of Aluminum Nitride to Fabricate Thermally Conductive poly(Butylene Succinate) Nanocomposite

Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 148 ◽  
Author(s):  
Zelalem Lule ◽  
Jooheon Kim
Keyword(s):  
Electron Microscopy ◽  
Thermal Conductivity ◽  
Aluminum Nitride ◽  
Thermomechanical Properties ◽  
Butylene Succinate ◽  
Conductivity Enhancement ◽  
Thermally Conductive ◽  
Surface Modified ◽  
Surface Modified Nanoparticles ◽  
Scanning Electron

Biodegradable polymers and their composites are considered promising materials for replacing conventional polymer plastics in various engineering fields. In this study, poly(butylene succinate) (PBS) composites filled with 5% aluminum nitride nanoparticles were successfully fabricated. The aluminum nitride nanoparticles were surface-modified to improve their interaction with the PBS matrix. Field-emission scanning electron microscopy revealed that the nanocomposites with surface-modified nanoparticles had better interface interaction and dispersion in the polymer matrix than those with untreated nanoparticles. The PBS/modified AlN nanocomposites exhibited maximal thermal conductivity enhancement, 63.7%, compared to the neat PBS. In addition, other thermomechanical properties of the PBS nanocomposites were investigated in this study. The nanocomposites also showed a superior storage modulus compared to the neat PBS matrix. In this work, a PBS nanocomposite with suitable thermal conductivity that can be used in various electronic fields was fabricated.

Effect of Preparation on Standard Dry Density and Strength of Foamed Cement by Orthogonal Test

2014 ◽  
Vol 577 ◽  
pp. 1119-1122
Author(s):  
Na Li ◽  
Qi Wang ◽  
Peng Song
Keyword(s):  
Electron Microscopy ◽  
Thermal Conductivity ◽  
High Strength ◽  
Xrd Analysis ◽  
Orthogonal Test ◽  
Dry Density ◽  
Light Weight ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

In this paper, we studied the effect of preparation on standard dry density and strength of foamed cement by orthogonal test. The results indicate that the more excellent combination is A1B1C1, namely G1, the standard dry density is 376 kg/m3, the flexural and compressive strengths are 0.43 MPa and 0.8 MPa respectively, and the thermal conductivity is 0.074 W/(m·K), which conforms to the characteristics of light weight and high strength. Fewer Ca (OH)2 crystals and more C-S-H gel generated in G1 through scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis is the reason for its high strength.

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