Magnetite (Fe3O4) nanoparticles becomes a new innovation that gets attention of biomedicine scientists. Magnetite can be applied to cancer treatment as a drug carrier because it’s good biocompatibility and very low toxicity. The purpose of this study was to determine the effect of temperature and stirring rate on the magnetite particle characteristics prepared by co-precipitation method. Firstly, FeCl3 and FeCl2 with 2:1 mole ratio were reacted with 10% NH4OH at 40 - 80°C temperatures and stirring speed of 300 - 500 rpm in a beaker glass. Subsequently, the precipitate was separated using filter paper and it dried into air oven at 100°C. The properties of obtained magnetite powder were determined using XRD and SEM. From XRD pattern indicates that magnetite formed at all temperatures with crystallite diameter in the range of 10-12 nm. The SEM results indicate the agglomeration of the magnetite particles with size in the range of 2.7 to 3.3 μm. In the other hand, the higher of temperature and stirring rate of agitation will make the agglomeration of the particles become more uniform. The increasing of temperature and the stirring rate will increase the magnetite crystallinity level.
Parking lots are one of the most important elements of transportation infrastructure. Parking lots with good design and the selection of suitable parking angles will provide optimal vehicle capacity. In this article, we will discuss the parking lot in the form of a Parallelogram with a broad concept of area, for parking a private car vehicle. In this paper, the land in the form of a jug is formed of two right and rectangular triangles. The method used is a linear program method that is formed from the broad concept of the area with the help of lindo software. The results obtained from this article are the forms of Parallelogram which are formed from two right triangles which are used divided into two parts, namely a right triangle with a base and a height of half a rectangle resulting in a total parking area of 873,600 square meters, with the number of car vehicles that can be parked on the inside of a parking lot with a 90 degree angle is as much as 520 car vehicles. So it can be concluded that the numbers formed from two right triangles and rectangles produce the optimal number of vehicles with a 90 degree parking angle.
Magnetite nanoparticles (Fe3O4) are a type of magnetic particle with huge potential for application as a drug carrier due to their excellent superparamagnetic, biocompatible, and easily modified surface properties. One characteristic of nanoparticles is that they can be controlled by studying the evolution of crystal growth. The purpose of this research is to study the evolution of magnetite-crystal growth and determine the crystal growth kinetics using the Ostwald ripening model. Magnetite nanoparticles were synthesized from FeCl3, citrate, urea, and polyethylene glycol using the hydrothermal method at 220 o C for times ranging from 1-12 hours. The characterizations using X-ray diffraction (XRD) indicated that the magnetite began to form after 3 hours synthesis. The crystallinity and crystal size of the magnetite increased with the reaction time. The diameter size of the magnetite crystals was in the range of 10-29 nm. The characterizations using a transmission electron microscope (TEM) showed that magnetite nanoparticles had a relatively uniform size and were not agglomerated. The core-shell nanoparticles were obtained after 3 hours synthesis and had a diameter of 60 nm, whereas the irregular-shaped nanoparticles were obtained in 12 hours and had a diameter of 50 nm. The characterizations using a vibrating sample magnetometer (VSM) revealed that magnetite nanoparticles have superparamagnetic properties. The magnetization saturation (Ms) value was proportional to the degree of crystallinity. The magnetite-crystal growth data can be fitted to an Ostwald ripening model with the growth controlled by the dissolution of the surface reaction (n≈4).
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