Thermo-Decomposition Process of Preparation of Nanometer Cobalt Ferrite Oxides and their Doped into Peg-20000

2010 ◽  
Vol 148-149 ◽  
pp. 1254-1257
Author(s):  
Li Xiao ◽  
Guan Zhou Qiu ◽  
Le Xian Xia ◽  
Han Chen
Keyword(s):  
Magnetic Particles ◽  
Cobalt Ferrite ◽  
Sol Gel ◽  
Average Diameter ◽  
Decomposition Process ◽  
Effect Of Temperature ◽  
Decomposition Stage ◽  
Oxide Powders ◽  
The Difference ◽  
Xrd And Tem

The sol-gel method was used to prepare three kinds of nanometer magnetic particles, the nano-cobalt ferrite oxide powders and those doped by LaCl3.nH2O with different ratio. In the thermo-decomposition process of the precursors to get these magnetic particles, TG/DTG was applied for investigating their character. It has been showed that the difference of the activation energies of these particles in different thermo-decomposition stage, even not in the same stage for different sample. XRD was used to analysis the effect of temperature on precursor of CoFe2O4. It has been showed that the prepared magnetic particles with the average diameter less than 100nm were characterized by XRD and TEM. To study nano-magnetic particles and polymer electrolyte compounds, the three kinds of nanometer magnetic particles were doped into polyethylene glycol-20000 (peg-20000) with different rations respectively to obtain the compound substance with optimal conductivity, 0.686 S.m-1.

PREPARATION AND APPLICATION OF HOLLOW SILICA/MAGNETIC NANOCOMPOSITE PARTICLE

2012 ◽  
Vol 06 ◽  
pp. 601-609 ◽  
Author(s):  
CHENG-CHIEN WANG ◽  
JING-MO LIN ◽  
CHUN-RONG LIN ◽  
SHENG-CHANG WANG
Keyword(s):  
Electron Microscope ◽  
Cobalt Ferrite ◽  
Sol Gel ◽  
Average Diameter ◽  
Magnetic Microsphere ◽  
Buffer Solution ◽  
Spinel Type ◽  
Hollow Silica ◽  
Surface Areas ◽  
Co Precipitation

The hollow silica/cobalt ferrite ( CoFe 2 O 4) magnetic microsphere with amino-groups were successfully prepared via several steps, including preparing the chelating copolymer microparticles as template by soap-free emulsion polymerization, manufacturing the hollow cobalt ferrite magnetic microsphere by in-situ chemical co-precipitation following calcinations, and surface modifying of the hollow magnetic microsphere by 3-aminopropyltrime- thoxysilane via the sol-gel method. The average diameter of polymer microspheres was ca. 200 nm from transmission electron microscope (TEM) measurement. The structure of the hollow magnetic microsphere was characterized by using TEM and scanning electron microscope (SEM). The spinel-type lattice of CoFe 2 O 4 shell layer was identified by using XRD measurement. The diameter of CoFe 2 O 4 crystalline grains ranged from 54.1 nm to 8.5 nm which was estimated by Scherrer's equation. Additionally, the hollow silica/cobalt ferrite microsphere possesses superparamagnetic property after VSM measurement. The result of BET measurement reveals the hollow magnetic microsphere which has large surface areas (123.4m2/g). After glutaraldehyde modified, the maximum value of BSA immobilization capacity of the hollow magnetic microsphere was 33.8 mg/g at pH 5.0 buffer solution. For microwave absorption, when the hollow magnetic microsphere was compounded within epoxy resin, the maximum reflection loss of epoxy resins could reach -35dB at 5.4 GHz with 1.9 mm thickness.

Efficient Micromixing for Continuous Biodiesel Production from Jatropha Oil

2018 ◽  
Vol 9 (1) ◽  
pp. 133-139
Author(s):  
Waleed S. Mohammed ◽  
Ahmed H. El-Shazly ◽  
Marwa F. Elkady ◽  
Masahiro Ohshima
Keyword(s):  
Methyl Esters ◽  
Continuous Process ◽  
Sol Gel ◽  
Average Diameter ◽  
Biodiesel Production ◽  
High Mass ◽  
Molar Ratio ◽  
Jatropha Oil ◽  
Energy Deficiency ◽  
Gel Preparation

Introduction: The utilization of biodiesel as an alternative fuel is turning out to be progressively famous these days because of worldwide energy deficiency. The enthusiasm for utilizing Jatropha as a non-edible oil feedstock is quickly developing. The performance of the base catalyzed methanolysis reaction could be improved by a continuous process through a microreactor in view of the high mass transfer coefficient of this technique. Materials & Methods: Nanozirconium tungstovanadate, which was synthetized using sol-gel preparation method, was utilized in a complementary step for biodiesel production process. The prepared material has an average diameter of 0.066 &µm. Results: First, the NaOH catalyzed methanolysis of Jatropha oil was investigated in a continuous microreactor, and the efficient mixing over different mixers and its impact on the biodiesel yield were studied under varied conditions. Second, the effect of adding the nanocatalyst as a second stage was investigated. Conclusion: The maximum percentage of produced methyl esters from Jatropha oil was 98.1% using a methanol/Jatropha oil molar ratio of 11 within 94 s using 1% NaOH at 60 &°C. The same maximum conversion ratio was recorded with the nanocatalyst via only 0.3% NaOH.

scholarly journals The Respiration of some Planktonic copepods II. The Effect Of Temperature

1953 ◽  
Vol 31 (3) ◽  
pp. 447-460 ◽  
Author(s):  
D. T. Gauld ◽  
J. E. G. Raymont
Keyword(s):  
Respiratory Rate ◽  
The Body ◽  
The Other ◽  
Effect Of Temperature ◽  
Acartia Clausi ◽  
Temora Longicornis ◽  
Different Temperatures ◽  
Planktonic Copepods ◽  
The Difference ◽  
The Relationship

The respiratory rates of three species of planktonic copepods, Acartia clausi, Centropages hamatus and Temora longicornis, were measured at four different temperatures.The relationship between respiratory rate and temperature was found to be similar to that previously found for Calanus, although the slope of the curves differed in the different species.The observations on Centropages at 13 and 170 C. can be divided into two groups and it is suggested that the differences are due to the use of copepods from two different generations.The relationship between the respiratory rates and lengths of Acartia and Centropages agreed very well with that previously found for other species. That for Temora was rather different: the difference is probably due to the distinct difference in the shape of the body of Temora from those of the other species.The application of these measurements to estimates of the food requirements of the copepods is discussed.

Enhanced Skin Permeation of Punicalagin after Topical Application of Pluronic Micelles or Vesicles Loaded with Lafoensia pacari Extract

Planta Medica ◽  
2021 ◽  
Author(s):  
Sandra Alves de Sousa Garcia ◽  
Priscila Bianca Rodrigues da Rocha ◽  
Bruno dos Santos Souza ◽  
Andressa Tuane Santana Paz ◽  
Ana Luiza Caetano Negris ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Skin Permeation ◽  
Sol Gel ◽  
Extraction Procedure ◽  
Average Diameter ◽  
Skin Aging ◽  
Chemical Degradation ◽  
Vertical Diffusion ◽  
Flowing Liquid ◽  
Span 80

AbstractPunicalagin, the principal ellagitannin of Lafoensia pacari leaves, has proven antioxidant activity, and standardized extracts of L. pacari can be topically used for skin aging management. We hypothesized that Pluronic nanomicelles or vesicles could solubilize sufficiently large amounts of the standardized extracts of L. pacari and provide chemical stability to punicalagin. The standardized extracts of L. pacari were obtained with an optimized extraction procedure, and the antioxidant activity was characterized. Formulations containing Pluronic at 25% and 35% were obtained with or without Span 80. They were characterized by average diameter, polydispersity index, punicalagin content, physicochemical stability, and rheology. A release and skin permeation study was carried out in vertical diffusion cells. The extraction procedure allowed quantifying high punicalagin content (i.e., 141.61 ± 3.87 mg/g). The standardized extracts of L. pacari showed antioxidant activity for all evaluated methods. Pluronic at 25 and Pluronic at 35 with standardized extracts of L. pacari showed an average diameter of about 25 nm. The addition of Span 80 significantly increased the mean diameter by 15-fold (p < 0.05), indicating the spontaneous formation of vesicles. Pluronic formulations significantly protected punicalagin from chemical degradation (p < 0.05). Pluronic at 25 formulations presented as free-flowing liquid-like systems, while Pluronic at 35 resulted in an increase of about 44-fold in |ƞ*|. The addition of Span 80 significantly reduced the Pluronic sol-gel transition temperature (p < 0.05), indicating the formation of vesicles. Formulations with Span 80 significantly enhanced punicalagin skin permeation compared to formulations without Span 80 (p < 0.05). Formulations with Span 80 were demonstrated to be the most promising formulations, as they allowed significant permeation of punicalagin (about 80 to 315 µg/cm2), which has been shown to have antioxidant activity.

scholarly journals Photocrosslinking and photopatterning of magneto-optical nanocomposite sol–gel thin film under deep-UV irradiation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
C. Bidaud ◽  
D. Berling ◽  
D. Jamon ◽  
E. Gamet ◽  
S. Neveu ◽  
...  
Keyword(s):  
Uv Irradiation ◽  
Cobalt Ferrite ◽  
Sol Gel ◽  
Optical Devices ◽  
High Concentration ◽  
Nanocomposite Thin Films ◽  
Deep Uv ◽  
High Concentrations ◽  
193 Nm ◽  
The Impact

AbstractThis paper is aimed at investigating the process of photocrosslinking under Deep-UV irradiation of nanocomposite thin films doped with cobalt ferrite magnetic nanoparticles (MNPs). This material is composed of a hybrid sol–gel matrix in which MNP can be introduced with high concentrations up to 20 vol%. Deep-UV (193 nm) is not only interesting for high-resolution patterning but we also show an efficient photopolymerization pathway even in the presence of high concentration of MNPs. In this study, we demonstrate that the photocrosslinking is based on the free radical polymerization of the methacrylate functions of the hybrid precursor. This process is initiated by Titanium-oxo clusters. The impact of the nanoparticles on the photopolymerization kinetic and photopatterning is investigated. We finally show that the photosensitive nanocomposite is suitable to obtain micropatterns with sub-micron resolution, with a simple and versatile process, which opens many opportunities for fabrication of miniaturized magneto-optical devices for photonic applications.

Nanostructured TiO2-Based Composites for Light Absorption

2014 ◽  
Vol 975 ◽  
pp. 207-212
Author(s):  
Dayse I. dos Santos ◽  
Olayr Modesto Jr. ◽  
Luis Vicente A. Scalvi ◽  
Americo S. Tabata
Keyword(s):  
Metal Oxide ◽  
Light Absorption ◽  
Structural Characteristics ◽  
Sol Gel ◽  
Second Phase ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
Oxide Powders

Metal oxide nanocomposites were prepared by two different routes: polyol and sol-gel. Characterization by X ray diffraction showed that the first process produces directly a two-phase material, while the sol-gel powder never showed second phase below 600°C. Light spectroscopy of the treated powders indicated similarities for the processed materials. Although the overall material compositions are about the same, different structural characteristics are found for each processing. With the exception of Ti-Zn materials, all the double metal oxide powders showed higher absorbance than either TiO2 powder.

Direct Synthesis of 3,5-Dinitropyrazole Catalyzed by Newly Sulfated Nanosolid Superacid TiO2/ SO

2011 ◽  
Vol 391-392 ◽  
pp. 1296-1301
Author(s):  
Li Min Xi ◽  
Xin Xin Zhang
Keyword(s):  
Direct Synthesis ◽  
Sol Gel ◽  
Acid Base ◽  
Direct Transformation ◽  
Acid Base Titration ◽  
Optimal Reaction Condition ◽  
Superacid Catalyst ◽  
Average Size ◽  
Optimal Reaction ◽  
Xrd And Tem

The newly sulfated nanosolid superacid TiO2/SO4 prepared by sol-gel method was broadly characterized by acid base titration, XRD and TEM, which identified that the superfine solid TiO2/SO4 showing good dispersibility with average size of 27 nm belongs to kind of crystalline nanoparticles. With the help of the catalyst TiO2/SO4, the optimal reaction condition for direct transformation of pyrazole and nitrosonitric acid into 3, 5-Dinitropyrazole was n (pyrazol)=0.10 mol, m (TiO2/SO4 )＝1.5g, V(n-octannol)＝90mL, and V(nitrosonitric acid)＝50mL. Moreover, the optimal yield of the catalytic reaction reached up to 59.4% when the reaction time is 7 hours. The nanosolid superacid catalyst is still of high activity after regenerating eight times by calcination at 600。C.

Effect of pH Value on the Synthesis of NiO Nanoparticles and Microstructure of NiO Based Composite Anode

2021 ◽  
Vol 317 ◽  
pp. 447-453
Author(s):  
Noor Hidayah Aniza Zakaria ◽  
Nafisah Osman
Keyword(s):  
Ph Value ◽  
Sol Gel ◽  
Secondary Phase ◽  
Average Diameter ◽  
Morphological Observation ◽  
Nio Nanoparticles ◽  
Composite Anode ◽  
Ph Values ◽  
Particle Size Analyzer ◽  
Nio Nps

NiO nanoparticle was synthesized by a sol-gel method with three different pH values namely pH=1, 7 and 11, and then calcined at temperature of 450 ᵒC. The influence of different pH values on the physical properties of NiO nanoparticles were investigated by a particle size analyzer (PSA), field emission scanning electron microscope (FESEM) and X-ray diffractometer (XRD). Structural analysis confirmed that a cubic structure of NiO nanoparticle was obtained without any secondary phase for NiO powders prepared with pH=1, while the peak of secondary phase (Ni) appeared for NiO powders prepared with pH= 7 and 11. Morphological observation showed that the NiO nanoparticles prepared with pH=7 and 11 tend to form more agglomerates compared to one prepared with pH=1. The average diameter of NiO nanoparticles with pH 1, 7 and 11 were approximately in the range of 19-26 nm, 21-28 nm, and 24-30 nm, respectively. NiO powder that was synthesized with pH=1 was further used to prepare composite anode of NiO Nps-BaCe0.54Zr0.36Y0.1O2.95 (BCZY) powder. Unfortunately a composite of NiO Nps-BaCeO3-BaZrO3 was obtained instead of BCZY and governed by agglomerates with size in the range of 70-300 nm.

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