High Coercivity of Oleic Acid Capped CoFe2O4Nanoparticles at Room Temperature

2009 ◽  
Vol 113 (27) ◽  
pp. 9070-9076 ◽  
Author(s):  
Mukta V. Limaye ◽  
Shashi B. Singh ◽  
Sadgopal K. Date ◽  
Deepti Kothari ◽  
V. Raghavendra Reddy ◽  
...  
2019 ◽  
Vol 1 (1) ◽  
pp. 46
Author(s):  
F R Rangganita ◽  
L Hermida ◽  
A Angraeni ◽  
D Khoirunnisa

Sulfated zirconia functionalized SBA-15 catalsyt (SZr-SBA-15) was prepared byreacting SBA-15 with Zirkoniumoxychloride and urea at 90oC to form ZrO2-SBA-15. Then, ZrO2-SBA-15 was reacted with H2SO4 at room temperature to produceSZr-SBA-15 catalsyt.. The catalyst was characterized in terms of adsorptiondesorption nitrogen analysis, SEM-EDX and FTIR. Based on SEM-EDX andadsorption-desorption nitrogen analysis results, it was found that Zr had beenincorporated in SBA-15. By using the SZr-SBA-15 catalyst, esterification reactionof oleic acid with TMP to produce biolubricant oil of Trimethylolpropanetrioleatachieved 85% oleic acid conversion and selectivity of 63,7%. Reusability study ofSZr-SBA-15 catalyst was carried out for 3 rounds of reaction. It was found that thecatalyst could be used up to 3 rounds without significant decrease in activityKeywords: biolubricant oil, catalyst reusability, sba-15, sulfated zirconia.


2021 ◽  
Vol 73 ◽  
pp. 105541
Author(s):  
J.L. Silva Junior ◽  
F.X. Nobre ◽  
F.A. de Freitas ◽  
T.A.F. de Carvalho ◽  
S.S. de Barros ◽  
...  

2006 ◽  
Vol 6 (3) ◽  
pp. 852-856 ◽  
Author(s):  
X. R. Ye ◽  
C. Daraio ◽  
C. Wang ◽  
J. B. Talbot ◽  
S. Jin

We have successfully demonstrated a facile, solvent-free synthesis of highly crystalline and monodisperse Fe3O4 nanocrystallites at ambient temperature avoiding any heating. Solid state reaction of inorganic Fe(II) and Fe(III) salts with NaOH was found to produce highly crystalline Fe3O4 nanoparticles. The reaction, if carried out in the presence of surfactant such as oleic acid–oleylamine adduct, generated monodisperse Fe3O4 nanocrystals extractable directly from the reaction mixture. The extracted nanoparticles were capable of forming self-assembled, two-dimensional and uniform periodic array. The new process utilizes inexpensive and nontoxic starting materials, and does not require a use of high boiling point and toxic solvents, thus is amenable to an environmentally desirable, large-scale synthesis of nanocrystals.


2021 ◽  
Vol 317 ◽  
pp. 119-124
Author(s):  
Sabiu Said Abdullahi ◽  
Garba Shehu Musa Galadanci ◽  
Norlaily Mohd Saiden ◽  
Josephine Ying Chyi Liew

The emergence of Dilute Magnetic Semiconductors (DMS) with a potentials for spintronic application have attracted much researches attention, special consideration has been given to ZnO semiconductor material due to its wide band gap of 3.37 eV, large exciting binding energy of 60 meV, moreover, its ferromagnetic behavior at room temperature when doped with transition metals. MxZn1-xO (M = Fe or Ni) nanoparticles were synthesized by microwave assisted synthesis method calcined at 600°C. The structural, morphological and magnetic properties of these nanoparticles were studied using X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Vibrating Sample Magnetometer (VSM) respectively. Single phase Wurtzite hexagonal crystal structure was observed for the undoped and Fe doped ZnO nanoparticles with no any impurity, whereas Ni doped ZnO nanoparticles shows the formation of NiO impurities. The magnetic measurement reveals a diamagnetic behavior for the undoped ZnO meanwhile a clear room temperature ferromagnetism was observed for both Fe and Ni doped ZnO. Fe doped ZnO present a high saturation magnetization compared to Ni doped ZnO. However, Ni doped ZnO present high coercivity. The research was confirmed that Fe doped ZnO material will be good material combination for spintronic applications.


2012 ◽  
Vol 48 (11) ◽  
pp. 3641-3643 ◽  
Author(s):  
Chins Chinnasamy ◽  
Melania M. Jasinski ◽  
Aaron Ulmer ◽  
Wanfeng Li ◽  
George Hadjipanayis ◽  
...  

IUCrJ ◽  
2016 ◽  
Vol 3 (2) ◽  
pp. 115-126 ◽  
Author(s):  
E. I. Howard ◽  
B. Guillot ◽  
M. P. Blakeley ◽  
M. Haertlein ◽  
M. Moulin ◽  
...  

Crystal diffraction data of heart fatty acid binding protein (H-FABP) in complex with oleic acid were measured at room temperature with high-resolution X-ray and neutron protein crystallography (0.98 and 1.90 Å resolution, respectively). These data provided very detailed information about the cluster of water molecules and the bound oleic acid in the H-FABP large internal cavity. The jointly refined X-ray/neutron structure of H-FABP was complemented by a transferred multipolar electron-density distribution using the parameters of the ELMAMII library. The resulting electron density allowed a precise determination of the electrostatic potential in the fatty acid (FA) binding pocket. Bader's quantum theory of atoms in molecules was then used to study interactions involving the internal water molecules, the FA and the protein. This approach showed H...H contacts of the FA with highly conserved hydrophobic residues known to play a role in the stabilization of long-chain FAs in the binding cavity. The determination of water hydrogen (deuterium) positions allowed the analysis of the orientation and electrostatic properties of the water molecules in the very ordered cluster. As a result, a significant alignment of the permanent dipoles of the water molecules with the protein electrostatic field was observed. This can be related to the dielectric properties of hydration layers around proteins, where the shielding of electrostatic interactions depends directly on the rotational degrees of freedom of the water molecules in the interface.


2015 ◽  
Vol 33 (1) ◽  
pp. 100-106 ◽  
Author(s):  
Atieh Aliakbari ◽  
Majid Seifi ◽  
Sharareh Mirzaee ◽  
Hoda Hekmatara

AbstractIn the present paper, iron oxide nanoparticles coated by oleic acid have been synthesized in different conditions by coprecipitation method. For investigating the effect of time spent on adding the oleic acid to the precursor solution, two different processes have been considered. The as synthesized samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FT-IR). Magnetic measurement was carried out at room temperature using a vibrating sample magnetometer (VSM). The results show that the magnetic nanoparticles decorated with oleic acid decreased the saturation of magnetization. From the data, it can also be concluded that the magnetization of Fe3O4/oleic acid nanoparticles depends on synthesis conditions.


2019 ◽  
Vol 17 (1) ◽  
pp. 357-364
Author(s):  
Xiao Wu ◽  
Zhenpeng Wang ◽  
Zhenwen Zhao ◽  
Lei Chen ◽  
Fengyun Tao ◽  
...  

AbstractIn this study, we introduce a method to formulate Ginkgolide B lipid microemulsion (GB-LM). We have assessed its general characteristics and pharmacokinetics in animals. Soybean oil (10.0%) and oleic acid (2.4%) were chosen as the oil phase, refined egg yolk lecithin (PC98T) (1.8%) as the surfactant, and glycerol (2.25%) as the co-surfactant. The optimized formulation process resulted in particles with average diameter of 185.9 ± 52.5 nm and the zeta potential of −19.8 ± 1.3 mV. The GB-LM remained steady for three months at room temperature. Giving each dose of 4 mg/kg to rats through the vein, a clearance rate of CL (L/h): 2.594 and C max (ng/mL) was achieved: 353.8 through pharmacokinetic analysis and statistical analysis. The AUC of GB-LM was about 1.57-fold higher than that of the products available in the market. In addition, brain tissue distribution studies show that after 0.5 h administration of GB, the concentration of GB in brain tissue can reach its maximum, and then significantly decrease after 2 hours. Therefore, the improved formulation of GB-LM shows encouraging results compared with present products in several features.


1976 ◽  
Vol 59 (3) ◽  
pp. 658-661
Author(s):  
William Horwitz

Abstract Numerous variations exist for determining the acidity of fats and oils by titration. A Youden ruggedness test was performed, using extreme conditions existing in the methods, endorsed by various international organizations: aqueous and alcoholic standard alkali, 5 or 56 g sample, 50 or 150 ml alcohol or alcohol-ether solvent, titration at room temperature or 60°C with 2 ml or 8 drops of phenolphthalein indicator, to the first color change or to a pink persisting for 60 sec. The titration method was found to be extremely rugged at the 1 % oleic acid level with none of the variables influencing the result. At the 0.15% level, only the sample size affected the result.


2006 ◽  
Vol 6 (1) ◽  
pp. 221-226 ◽  
Author(s):  
Yonghua Leng ◽  
Huaiyu Shao ◽  
Yuntao Wang ◽  
Masaaki Suzuki ◽  
Xingguo Li

Pure nickel carbide (Ni3C) nanoparticles with particle diameters of 40 nm have been prepared by thermal decomposition of nickel formate in the presence of oleic acid and oleyl amine. The co-existence of active nickel and active carbon plays an important role in the formation of metastable Ni3C. Ni3C powder decomposes at 770 K in an N2 atmosphere to yield nickel and carbon. While in an H2 atmosphere, Ni3C powder is converted into Ni at 627 K. In addition, Ni3C nanoparticles exhibit superparamagnetism and are easier to magnetize at room temperature due to their good crystallinity and few defects.


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