Smartphone sensors have been widely researched and published in literature by experts to be used in physics learning. This paper presents the use of smartphone sensors and applications as a measuring instrument in the...
Smartphone sensors have been widely researched and published in literature by experts to be used in physics learning. This paper presents the use of smartphone sensors and applications as a measuring instrument in the classical sound wave experiment adapted from physics textbooks at school or university. Tone generator, sound meter, and audio autocorrelation were used in the experiment to visualize sound as a propagating vibration, sound waves as mechanical waves, characteristics of sound waves (loud and soft or high-pitched or low-pitched), sound range, and sound power. The experimental results presented are expected to help students understand the concept of sound waves.
Simulation of cell asexual reproduction is performed through two different mechanisms in this work. The first is budding and the second is binary fission. These two mechanisms have different steps in producing the off...
Simulation of cell asexual reproduction is performed through two different mechanisms in this work. The first is budding and the second is binary fission. These two mechanisms have different steps in producing the offspring. Budding will produce smaller size of offspring, while binary fission will produce offspring with the same size as its parent. Cell requires to grow until it reaches its mature state and then it can reproduce an offspring through one of the two mechanisms. There is also reproduction period after a cell is mature, which is the time it repeats the reproduction process. There are only two force types are considered, which are normal force as the repulsive force and a gravitational-like force as the attractive force. The former force holds for rij < Ri + Rj, while the later force holds rij ≥ Ri + Rj, where rij is distance between center of two spherical cells and Ri is radius of cell i. Cell form is simplified as spherical granular particle. As initial condition at time t = 0 three different number of cell N0 = 1, 2, 4 are used for both asexual reproduction mechanisms. It is observed for N0 > 1 that two or more clusters of cells are collapsing to produce single cluster. Number of cells N as function of time t for binary fission shows a smooth curve compared to budding which produce a step-like curve. It is due to mature time of the offspring, which is different in the two mechanisms. Average colony radius R as function of time t for both mechanisms do not show a distinct feature
Barium M-hexaferrite were synthesized with Co-Ni doping ions (BaFe12-2xCoNixO19) using the co-precipitation method, based on the natural iron sand of the Loang Balok beach, Sekarbela District, Mataram, Indonesia. The ...
Barium M-hexaferrite were synthesized with Co-Ni doping ions (BaFe12-2xCoNixO19) using the co-precipitation method, based on the natural iron sand of the Loang Balok beach, Sekarbela District, Mataram, Indonesia. The synthesis was carried out with variations in the concentration of doping ions (x = 0.0, 0.6, and 1.0). The characterization of the sample was completed using XRD, SEM-EDX, TEM. The XRD results showed that the sample had a hexagonal structure because it had a c / value of 2.3 to 2.6. In contrast, SEM-EDX showed that the sample size of BaFe12CoNiO19 had reached the range of nanoparticles from 41 nm to 151 nm which was evenly distributed, with a composition of Ba = 12.22%; Fe = 49.1%; Co = 8.78%; Ni = 4.76%; and O = 21.37%, and slight impurities Cl = 3.77%.
Binding force in the form of spring force binds two adjacent spherical grains and based on this interaction various structures of composite particles can be constructed. In this work only composite particles up to N =...
Binding force in the form of spring force binds two adjacent spherical grains and based on this interaction various structures of composite particles can be constructed. In this work only composite particles up to N = 4 are discussed, where N is number of spherical grains in a composite particle, and the forms are limited to the two-dimensional cases only. There is only one structure of composite particle for each value of N for 1 < N ≤ 2. For N = 3 there are five structures and for N = 4 there are fifteen structures. Between spherical grains from different composite particles only two types of force are considered. The first is a long-range attractive force in the form of gravitation force and the last is a short-range repulsion force in the form of normal force. The first type of force will help the aggregation process, while the second will prevent two spherical grains to collapse into a single grain due to the first. It is observed that the time required to produce the compact aggregate or T is dependent on N, where larger N makes larger T.
Brazil-Nut Effect (BNE) is a granular material phenomenon, where larger grains (usually known as intruder) rise to the top when the granular system vibrated. We observe a single intruder rise time of BNE phenomenon in...
Brazil-Nut Effect (BNE) is a granular material phenomenon, where larger grains (usually known as intruder) rise to the top when the granular system vibrated. We observe a single intruder rise time of BNE phenomenon in a two-dimensional molecular dynamics simulation of hard spheres collision scheme. Some experiments have shown that some granular properties, such as size and density ratio, play an important role to determine the rise time. However, other property, such as coefficients of restitution, is considered not to have a measurable impact. We explore the intruder inelasticity dependence of the rise time by varying its coefficient of restitution. We found that the intruder rise time tends to be flat for relatively high coefficient of restitution and increases exponentially below a certain deflecting point for low coefficient of restitution. This holds for specific mass ratio.
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