Synthesis of Electrospun Titania Nanofibers for Thermal Lens Study in Heat Transport Applications

2018 ◽  
Vol 936 ◽  
pp. 58-62
Author(s):  
José Alfredo Pescador-Rojas ◽  
José Luis Jiménez-Pérez ◽  
José Francisco Sánchez-Ramírez ◽  
Rubén Gutiérrez-Fuentes ◽  
Zormy Nacary Correa-Pacheco ◽  
...  
Keyword(s):  
Thermal Diffusivity ◽  
Thermal Lens ◽  
Fiber Diameter ◽  
Sol Gel ◽  
Average Diameter ◽  
Thermal Lens Spectrometry ◽  
X Ray ◽  
Complementary Techniques ◽  
Thermal Diffusivities ◽  
Titania Nanofibers

Thermal lens spectrometry (TLS) technique was used to obtain the thermal diffusivity of electrospun Titania nanofibers (TiO2), with average diameter size of 50-80 nm, in water. TiO2nanofibers have been successfully prepared by sol-gel and electrospining techniques. TLS provides reliable alternative to measure the thermal diffusivities of semitransparent materials and low thermal diffusivities. The results show that the nanofluid thermal diffusivity increases with the presence of nanofibers. Complementary techniques: scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDS) were employed to characterize the nanofibers morphology, average fiber diameter and chemical composition, respectively.

scholarly journals Physical Characteristics of Titania Nanofibers Synthesized by Sol-Gel and Electrospinning Techniques

2010 ◽  
Vol 5 (1) ◽  
pp. 155892501000500 ◽  
Author(s):  
Soo-Jin Park ◽  
Yong C. Kang ◽  
Ju Y. Park ◽  
Ed A. Evans ◽  
Rex D. Ramsier ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Average Diameter ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Ceramic Nanofibers ◽  
Titania Nanofibers

Titania nanofibers were successfully synthesized by sol-gel coating of electrospun polymer nanofibers followed by calcining to form either the pure anatase or rutile phases. Characterization of these materials was carried out using scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV-vis spectroscopy techniques. The average diameter of these ceramic nanofibers was observed to be around 200 nm for both the rutile and anatase forms. The valence band structure and optical absorption thresholds differ, however, indicating that nanofibrous mats of titania can be selectively developed for different applications in catalysis and photochemistry.

Preparation and Photocatalytic Properties of Rod-Shaped TiO2 Based on Salix Fiber

2014 ◽  
Vol 609-610 ◽  
pp. 250-254
Author(s):  
Ya Bin Li ◽  
Jin Tian Huang ◽  
Yan Fei Pan
Keyword(s):  
Photocatalytic Performance ◽  
Sol Gel ◽  
Average Diameter ◽  
X Ray Diffraction ◽  
Nanocomposite Structure ◽  
X Ray ◽  
Infrared Spectrometer ◽  
Ft Ir ◽  
Degradation Of Methyl Orange ◽  
Scanning Electron

In the paper, the TiO2nanomaterials adopted the microcrystalline cellulose as the template by the template method and sol-gel method was prepared. Through the infrared spectrometer (FT-IR), scanning electron microscope (SEM), X-ray diffraction (XRD), the surface morphology, composition and the type of the samples were characterized respectively. The influence of the macro morphology of TiO2photocatalytic performance to use the reaction of decolorization and degradation of methyl orange as model was analyzed. The results showed that TiO2which was produced by the template of sallix fiber was Rod-shaped and the average diameter size of nanocomposite structure was 20.592 nm, which can provide a new method of producing other morphology of TiO2.

Thermal Diffusivity of Multi-Walled Carbon Nanotubes Dispersed in Oleic Acid

2012 ◽  
Vol 21 ◽  
pp. 125-130 ◽  
Author(s):  
Alex Junior de Freitas Cabral ◽  
Clascídia Aparecida Furtado ◽  
Cristiano Fantini ◽  
Petrus Alcantara Jr.
Keyword(s):  
Carbon Nanotubes ◽  
Oleic Acid ◽  
Thermal Diffusivity ◽  
Thermal Lens ◽  
Theoretical Expression ◽  
Thermal Lens Spectrometry ◽  
Multi Walled Carbon Nanotubes ◽  
Spectrometry Technique ◽  
Transient Thermal ◽  
Walled Carbon Nanotubes

Suspensions of oleic acid with carbon nanotubes were prepared. Using a thermal lens experimental setup, the thermal diffusivity of oleic acid in presence of multi-walled carbon nanoparticles with different concentrations was measured. The results show that, the thermal diffusivity increases with the increase of nanotubes concentration, enhancing the thermal diffusivity in the solution. Modification in the thermal diffusivity as function of quantity of carbon nanotubes was investigated, for a constant volume of oleic acid 10 mL. The diffusivities were obtained by using the thermal lens spectrometry technique. The characteristic time constant of the transient thermal lens was obtained by fitting the theoretical expression to the experimental data.

Synthesis and Thermal Stability of Nontransformable Tetragonal (ZrO2)0.96(REO1.5)0.04 (Re=Sc3+, Y3+) Nanocrystals

2013 ◽  
Vol 334-335 ◽  
pp. 60-64 ◽  
Author(s):  
Mohammad Reza Loghman-Estark ◽  
Reza Shoja Razavi ◽  
Hossein Edris
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Scanning Electron Microscopy ◽  
Sol Gel ◽  
Average Diameter ◽  
X Ray ◽  
Transmission Electron ◽  
20 Nm ◽  
Thermal Stability Of ◽  
Scanning Electron

Scandia, yttria doped zirconia ((ZrO2)0.96(REO1.5)0.04(RE=Sc3+, Y3+)) nanoparticles were prepared by the modified sol-gel method. The microstructure of the products was characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. Thermal stabillity of SYSZ nanocrystals were also investigated. The SYSZ nanocrystals synthesized with EGM:Zr+4mole ratio 4:1, calcined at 700°C, have average diameter of ~20 nm.

Evaluation of the thermal diffusivity of vegetable oils during frying by Thermal Lens Spectrometry

2008 ◽  
Vol 153 (1) ◽  
pp. 531-534 ◽  
Author(s):  
S. M. Lima ◽  
E. S. Bannwart ◽  
R. G. Oliveira ◽  
L. H.C. Andrade ◽  
P. V. Del Ré ◽  
...  
Keyword(s):  
Thermal Diffusivity ◽  
Vegetable Oils ◽  
Thermal Lens ◽  
Thermal Lens Spectrometry

Anomaly of Thermal Properties in Thin Films of La1-xSrxCoO3 Series Synthesized with a Combinatorial Processing

2001 ◽  
Vol 700 ◽  
Author(s):  
Yoshiaki Takata ◽  
Yutaka Adachi ◽  
Hajime Haneda ◽  
Yoshiki Wada ◽  
Makoto Ohtani ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
High Precision ◽  
Distribution Profile ◽  
Excitation Light ◽  
X Ray ◽  
Fundamental Wavelength ◽  
Thermal Diffusivities ◽  
Grating Spacing

AbstractThe thermal diffusivities throughout a composition-spread film comprising La1- xSrxCoO3 series were determined by Transient Reflecting Grating (TRG) measurements. Thermal diffusivities of transparent SrCoO3 film and SrTiO3 substrate were determined by using third harmonics having wavelength of 266 nm as an excitation light with only a certain length of grating spacing. The thermal diffusivities of them were 0.02 and 0.05 cm2/s, respectively. With regard to untransparent thin films, the experiment was performed by setting three kinds of grating spacing for the excitation light having the fundamental wavelength, 800 nm in order to obtain high precision. The distribution profile of obtained values of the thermal diffusivity throughout the sample was traced as 0.06 - 0.18 - 0.01 cm2/s corresponding to the variation of in La1-xSrxCoO3, thus showing a convex profile, however, this anomalous profile was verified by comparing with the data obtained by the X-ray diffractometer.

Effect of Mixed-Phase TiO2/PVA Nanofibers on the Degradation on Methyl Orange

2015 ◽  
Vol 1107 ◽  
pp. 353-358
Author(s):  
Norizan Mohammed Lot ◽  
S. Nafisah Md. Rashid ◽  
Umi Sarah Jais ◽  
M. Kamil Abd Rahman
Keyword(s):  
Methyl Orange ◽  
Reaction Rate ◽  
Sol Gel ◽  
Average Diameter ◽  
Mixed Phase ◽  
Electrospinning Technique ◽  
X Ray ◽  
First Order ◽  
Reaction Rate Constants ◽  
Sol Gel Process

We report on the synthesis of nanostructured TiO2for various structural phases and observed the rate of degradation of methyl orange (MO) upon UV irradiation. Mixed phase nanocrystalline TiO2at temperature of 800°C shows higher rate of degradation of MO with the rate of 0.0203/min compared to other phases. This rate corresponds to the percentage of MO degradation of 58.85%, 71.69%, 86.25% and 91.82% for duration of 30, 60, 90 and 120 min of UV irradiations, respectively. The TiO2powder was prepared using titanium (IV) butoxide as the precursor via sol gel process. The samples were characterized using X-ray diffractometer (XRD) and field emission scanning electron microscopy (FESEM). The rate of degradation of MO after UV exposure was measured using UV-Vis spectrophotometer. The first order reaction rate constants (kapp) of anatase; mixed-phase; and rutile phases were 0.0130, 0.0203 and 0.0029, respectively, which shows that mixed-phase TiO2has higherkappvalue indicating higher rate of degradation. The PVA/TiO2nanofibers were produced via electrospinning technique and similar tests on the nanofibers were conducted.Energy dispersive X-ray spectroscopy (EDX) indicates significant presence of TiO2is in nanofibers and the average diameter of the nanofibers was 600 nm.

Effect of Morphology of MgO on the CO2 Adsorption Capacity for Low Temperature Applications

2017 ◽  
Vol 888 ◽  
pp. 503-507
Author(s):  
Ramarao Poliah ◽  
Srimala Sreekantan
Keyword(s):  
Low Temperature ◽  
Crystallite Size ◽  
Adsorption Capacity ◽  
Hydrothermal Method ◽  
Sol Gel ◽  
Average Diameter ◽  
X Ray Diffraction ◽  
Mgo Nanoparticles ◽  
X Ray ◽  
Adsorption Temperature

MgO nanoparticles, nanoflakes and nanorods were synthesized by sol-gel or hydrothermal method. X-ray diffraction confirmed the formation of cubic MgO in entire samples after calcination. The round particles diameter was in the range of 200-500 nm while the flakes structure were with thickness 100-200 nm. The rods were in average diameter of 150-500 nm. CO2 adsorption capacity was measured by using TGA. MgO flakes with smaller crystallite size demonstrated high CO2 adsorption capacity of 1.738 mmol/g at low adsorption temperature of 50°C.

Preparation of SiO2 Encapsulated ZnO Nanopowders by Sol-Gel Method

2011 ◽  
Vol 412 ◽  
pp. 13-16
Author(s):  
Yan Xiang Wang ◽  
Jian Sun ◽  
Xiao Yan Li
Keyword(s):  
Liquid Phase ◽  
Sol Gel ◽  
Average Diameter ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zno Nanocrystals ◽  
Zno Particles ◽  
Low Temperature Crystallization ◽  
Temperature Crystallization

The shell-core structures of SiO2/ZnO nanopowders were obtained by simple two-step technique based on low-temperature crystallization from liquid phase. The influence of molar ratio of SiO2/ZnO in the reaction mixture on the morphology of obtained SiO2/ZnO nanopowders was studied. Crystalline structure of SiO2/ZnO nanocrystals obtained was proofed by the X-ray diffraction data. The average diameter of SiO2/ZnO nanocrystals was about 80~100nm according to FSEM and TEM data. It is shown that SiO2 components on the surface prevent the thermal interfusion of ZnO particles. Morphology and diameter of raw ZnO, SiO2/ZnO nanopowders prepared with molar ratio of SiO2/ZnO 0.1, 0.2, and 0.5 were almost same. When molar ratio of SiO2/ZnO was 0.5, ZnO core was coated with SiO2, and the thickness of shell was about 10nm. At the same time, SiO2 nanocrystals also formed the islands structure.

Magnetic Properties of Mg0.4Ca0.6Fe2O4 Nanoparticles Synthesized by Sol-Gel Method for Hyperthermia Treatment

2014 ◽  
Vol 631 ◽  
pp. 193-197
Author(s):  
A.M. Escamilla-Pérez ◽  
D.A. Cortés-Hernández ◽  
J.M. Almanza-Robles ◽  
D. Mantovani ◽  
P. Chevallier
Keyword(s):  
Magnetic Properties ◽  
Sol Gel ◽  
Average Diameter ◽  
X Ray Diffraction ◽  
Hyperthermia Treatment ◽  
X Ray ◽  
Transmission Electron ◽  
Heat Treated ◽  
Different Temperatures ◽  
Xrd Patterns

Powders of Mg0.4Ca0.6Fe2O4were prepared by sol-gel using ethylene glycol and Mg, Ca and Fe nitrates as starting materials. Those powders were heat treated at different temperatures (300, 400, 500 and 600 °C) for 30 min. The materials obtained were characterized by X-ray diffraction (XRD) and vibrating sample magnetometry (VSM). The Ca-Mg ferrite with the most appropriate magnetic properties was further analyzed by transmission electron microscopy (TEM). The heating capability of the nanoferrites was also tested via magnetic induction. The XRD patterns of these Ca-Mg ferrites showed a cubic inverse spinel structure. Furthermore, neither traces of hematite nor orthorhombic Ca ferrite phases were detected. Moreover, all the Ca-Mg ferrites are superparamagnetic and the particle size distribution of these Ca-Mg magnetic nanoparticles exhibits an average diameter within the range of 10-14 nm. The needed temperature for hyperthermia treatment was achieved at around 12 min.

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