Effect of PVP as a capping agent in single reaction synthesis of nanocomposite soft/hard ferrite nanoparticles

Nanocomposite magnets consist of soft and hard ferrite phases are known as an exchange spring magnet when they are sufficiently spin exchange coupled. Hard and soft ferrites offer high value of coercivity, Hc and saturation magnetization, Ms respectively. In order to obtain a better permanent magnet, both soft and hard ferrite phases need to be “exchange coupled”. The nanoparticles were prepared by a simple one-pot technique of 80% soft phase and 20% hard phase. This technique involves a single reaction mixture of metal nitrates and aqueous solution of varied amounts of polyvinylpyrrolidone (PVP). The heat treatment applied was at 800 °C for 3 h. The synthesized composites were characterized by Transmission Electron Microscope (TEM), Fourier Transform Infra-red (FT-IR), Energy Dispersive X-Ray (EDX), X-ray diffraction (XRD) and Vibrating sample magnetometer (VSM). The coexistence of two phases, Ni0.5Zn0.5Fe2O4 and SrFe12O19 were observed by XRD patterns. It also verified by the EDX that no impurities detected. The magnetic properties of nanocomposite ferrites for 0.06 g/ml PVP gives a better properties of Hc 932 G and Ms 39.0 emu/g with average particle size obtained from FESEM was 49.2 nm. The concentration of PVP used gives effect on the magnetic properties of the samples

Elastic constants and thermal properties of lead-bismuth borate glasses

Systematic series of lead-bismuth borate glasses, where PbO, Bi2O3 and B2O3 content change for every series based on their weight percentage have been prepared. The ultrasonic and glass transition temperature (Tg) of this glass system have been studied using the Matec MBS-8000 Digital Signal Processing and conventional Differential Thermal Analysis (DTA) method. Elastic properties of the glass have been calculated together with Poisson's ratio from the measured densities as well as longitudinal (VL) and shear (VS) ultrasonic velocities. The Tg determined from the change of the base line in the DTA chart. The result showed that both properties are much depends on the changes of their atomic arrangement behaviour with an addition of the modifiers. © 2006 Asian Network for Scientific Information

Ultrasonic and thermal properties of borate and phosphate glasses containing bismuth and lead

Systematic series of (B2O3,P2O5)‐Bi2O3‐PbO glasses have been successfully prepared by using the rapid quenching technique in which each oxide content changes for every series on the basis of its weight percentage. Their amorphous natures were confirmed earlier by the x‐ray diffraction technique. The experimental results show that the density of both glasses, determined by using the Archimedes principle, increases with the glass modifier content. This is due to the replacement of Bi2O3 and PbO in the borate and phosphate glassy networks. The molar volume for borate glass increases with the addition of bismuth and lead oxides, but a reverse trend occurs for the phosphate glass. The longitudinal and shear ultrasound velocities, determined by the MBS 8000 system, of both lead bismuth borate and phosphate glasses show a decreasing trend as more PbO and Bi2O3 are added to the glass system. The increase in PbO/Bi2O3 content was probably related to the progressive increase in the concentration of non‐bridging oxygen (NBOs). Thermal studies of the glass, using the Labsys DTA‐Setaram machine, show that the value of the glass transition temperature (Tg) is closely related to the chemical bond in the system. In lead bismuth borate glasses, the addition of more Pb2+ and Bi3+ results in a more dominant ionic bond character in the system and hence decreases Tg of the sample. However, in lead bismuth phosphate glasses, the addition of Pb2+ and Bi3+ not only failed to weaken the covalent character in P–O–P bonds, but strengthened it further, leading to an increment in the values of Tg

Study on acceptance of urban garden in bamboo seating structure in Ipoh, Perak

This project involves discovering does urban gardening interests the people that lives in an urbanized area and the perception they have on value added design of an ergonomic bamboo seating structure. The goal is to gives more awareness on urban gardening for the people that lives in an urbanized area and to propose ways on saving space by using bamboo which is sustainable as a seating structure when gardening. This project has been done by handing out questionnaires around Plan B area in Ipoh, Perak. Upon collecting data in the study area, it becomes clear that 59% of respondents do not have awareness on urban gardening. Next, regarding the design of bamboo seating structure proposed, Design 2 was the most selected by all of the respondents that is by 57.8%. Furthermore, it was respondents in early age that have the most interest in urban garden, so with this project done, it is hope that there will be more individual consider to practice urban gardening in the future while knowing how to use the limited space