Chemistry Research Papers/Topics

Magnetoelectric, dielectric, and magnetic investigations of multiferroic NixCo1-xFe2O4-SryBa1-yNb2O6 composites

Magnetoelectric (NixCo1-xFe2O4)0.3-(SryBa1-yNb2O6)0.7 composites with a 0–3 connectivity and different cation stoichiometries were synthesized via a classical mixed-oxide method. XRD patterns of all ceramics show reflections of the target phases SryBa1-yNb2O6 and NixCo1-xFe2O4. The influence of stoichiometry of the ferrimagnetic and ferroelectric phase on the magnetoelectric behavior was studied on composites with composition of (NixCo1-xFe2O4)0.3-(Sr0.5Ba0.5Nb2O6)0.7 and (NiFe2O4)0.3-(SryB...

Unusual adsorption-induced phase transitions in a pillared-layered copper ethylenediphosphonate with ultrasmall channels

In this work, we thoroughly assess the CO2 adsorption behaviour of a recently reported, pillared-layered CuII ethylenediphosphonate of formula Cu2(H2O)1.7(O3P–C2H4–PO3)1.5H2O (Cu-EtP), that features narrow channel-like pores (diameter o 5 Å). Once the metal coordinated H2O molecules are removed, Cu-EtP features a very high density of open metal sites (0.0188 sites Å-3) and can adsorb a significant amount of CO2 at saturation (2.9 mmol g-1, 6.9 mmol cm-3). Most interesting, it displays a...

Improvement of the magnetoelectric response in NiFe2O4-Sr0.5Ba0.5Nb2O6 composites using LiNbO3 as sintering additive

Magnetoelectric (NiFe2O4)0.3-(Sr0.5Ba0.5Nb2O6)0.7 composites with addition of LiNbO3 as sintering additive were prepared by a classical mixed-oxide method. XRD patterns of ceramics sintered between 1000 and 1200 ◦C show the desired Sr0.5Ba0.5Nb2O6 and NiFe2O4 phases. SEM investigations confirm the 0–3 connectivity of the composite ceramics. The addition of 10 and 20 mol% LiNbO3 improves the densification of the composite ceramics and leads to an increase of the size of the Sr0.5Ba0.5Nb2O6...

Determination of Melting Point of Vegetable Oils and Fats by Differential Scanning Calorimetry (DSC) Technique

SUMMARY Determination of melting point of vegetable oils and fats by differential scanning calorimetry (DSC) technique. Melting point of fats is used to characterize oils and fats and is related to their physical properties, such as hardness and thermal behaviour. The present work shows the utilization of DSC technique on the determination of melting point of fats. In a comparison with softening point (AOCS method Cc 3-25), DSC values were higher than those obtained by AOCS method. It has occ...

Quality evaluation and antimicrobial activities of Adzuki bean seed oil (vigina Angularis)

ABSTRACT The crude oil extracted from Adzuki bean oil (Vigna Angularis), purchased from Owo in Oba market in Owo local government area of Ondo state Nigeria. The extraction of the oil from the seed was carried out by soxhlet method using hexane as the extractant. The physicochemical properties of the oil were determined using gas chromatography (GC) and other standard methods. The antimicrobial activities were carried out using five species of bacterial. The results of the investigation is a...

HISTORY & PHILOSOPHY OF SCIENCE/HEALTH, ENVIRONMENT & SUSTAINABLE DEVELOPMENT

I-DEFINITIONS & CLASSIFICATION OF SCIENCE Deinition On the simplest level, deined as the knowledge of the world of nature. Human investigative endeavour (HIE) whose object is the natural world and natural phenomena A tool developed and employed to interrogate the natural world However, science generally is viewed in three main ways as; i. A method for acquiring knowledge or studying and understanding the world. o The steps of that method includes; observation, problem deinition, hypothesis fo...

GST 104: Human Reproduction Infertility and Abortions

For a human being to be formed there must surely be a man and a woman. The man will produce sperm and the woman will produce eggs. 

Vibrational Circular Dichorism and Non Linear optics of Azobenzene Derivatives; A Theoretical Study

The present work reports a theoretical study on vibrational spectra and nonlinear optical properties of azobenzene derivatives. The theoretical geometrical parameters in the ground state have been investigated by density functional method using B3LYP functional and 6-311G++ (d, p) basis set. The analysis of calculated IR and VCD indicates that the binaphthyl and alkoxy side chain of azobenzenes derivatives contribute differently to spectral line shape. The out-of-phase bending and twisting of...

Antimicrobial activity assessment of certain anilide derivatives

Several physiochemical, structural and quantum-mechanics based descriptors were derived for a set of anilide derivatives, using DFT-B3LYP/6-311G (d, p) level of theory. The aim of this study was to develop QSAR model using multiple linear regression to predict the antimicrobial activity of anilides towards E. Coli in terms of several electronic and molecular descriptors. The best-fit model involved electrophilicity index (w) in conjunction with molecular weight (W) and logarithm of the octano...

Effect of sintering additives on the densification and dielectric properties of Sr0.5Ba0.5Nb2O6 ceramics synthesized by a soft-chemistry method

https://doi.org/10.1016/j.jssc.2022.123564._ Nano-crystalline Sr0.5Ba0.5Nb2O6 powders with addition of LiNbO3 or LiF as sintering additives were prepared by a soft-chemistry synthesis using polyethylene glycol. Calcination at 600 C results in nanocrystalline powders (dcryst. 30 nm) which were sintered between 1000 and 1300 C to ceramic bodies. By addition of 10 and 20 mol % LiNbO3, the sintering temperature was reduced by about 200 K and the activation energy of the initial stage of sintering...

Fine-grained Magnetoelectric Sr0.5Ba0.5Nb2O6–CoFe2O4 Composites Synthesized by a Straightforward One-pot Method

https://doi.org/10.1016/j.matchemphys.2021.125616._ Magnetoelectric (Sr0.5Ba0.5Nb2O6)1-x(CoFe2O4)x (x = 0.2–0.6) composites were prepared by a one-pot softchemistry synthesis using PEG400. Calcining at 700 ◦C resulted in nanocrystalline composite powders (dcryst. = 24–30 nm) which were sintered between 1050 and 1200 ◦C to ceramic bodies with relative densities up to 98%. SEM investigations confirm the formation of composite ceramics with a 0–3 connectivity and variable grain sizes f...

Investigations of Nano-crystalline Sr0.5Ba0.5Nb2O6 and Bulk Ceramics Synthesized by a Polymerization Method using PEG400

Abstract. J. Eur. Ceram. Soc. 39 (2019) 1156–1163. (DOI: 10.1016/j.jeurceramsoc.2018.11.043). Nano-crystalline Sr0.5Ba0.5Nb2O6 was synthesized by a one-pot method using PEG400 and citric acid. Calcination of the (Sr,Ba,Nb)-gel at 600 °C leads to Sr0.5Ba0.5Nb2O6 with a crystallite size of 24(2) nm and a specific surface area of 38.5(10) m2 g-1. Sintering upto 1325 °C leads to ceramics with globular or irregular-shaped grains and average grain sizes between 1.3 and 2.4 μm, whereas higher ...

Preparation and Characterization of Nano-sized Magnesium Ferrite Powders by a Starch-gel Process and Corresponding Ceramics

Abstract: J. Mater. Sci. 48 (2013) 6509–6518. (DOI: 10.1007/s10853-013-7447-x).The synthesis and characterization of nano-sized MgFe2O4 by a starch-gel method is described herein. A phase-pure nano-sized MgFe2O4 powder (1a) was obtained after calcining a (MgFe)-starch gel at 550 °C. The powder has a specific surface area of 60.6 m2/g and a crystallite size of 9 nm. TEM investigations reveal particles in the range of 7 to 15 nm. The activation energy of the crystallite growth process w...

BaGeO3 as Sintering Additive for BaTiO3-MgFe2O4 Composite Ceramics.

Abstract: RSC Adv. 5 (2015) 71491 (Open Access, DOI: 10.1039/c5ra12312g).BaTiO3-MgFe2O4 composites (30 wt.% MgFe2O4) with a small addition of BaGeO3 as a sintering additive were synthesized by a one-pot Pechini-like sol-gel process. Nano-crystalline composite powders with a crystallite size of about 10 nm were obtained after reaction at 700 °C for 1 h. Magnetic investigations suggest that the nano-powder is in its superparamagnetic state at room temperature. The addition of BaGeO3 leads to a...

Thermoanalytical, Optical, and Magnetic Investigations on Nanocrystalline Li0.5Fe2.5O4 and Resulting Ceramics Prepared by a Starch-based Soft-chemistry Synthesis.

Abstract. J. Solid State Chem. 287 (2020) 121380. (DOI: 10.1016/j.jssc.2020.121380). Nanocrystalline Li0.5Fe2.5O4 was prepared by a starch-based soft-chemistry synthesis. Calcining of the (LiFe)-gel between 350 and 1000 °C results in Li0.5Fe2.5O4 powders with crystallite sizes from 13 to 141 nm and specific surface areas between 35 and 7.1 m2 g-1. XRD investigations reveal the formation of ordered Li0.5Fe2.5O4. Sintering between 1050 and 1250 °C leads to ceramics with relative densities of ...


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