arXiv subjects

Sparisoma Viridi

Publications and source records attributed to Sparisoma Viridi.

42 records · Page 3Linked to original sources

arXiv2011

How to produce discreet Gaussian sequences: Algorithm and code

Algorithm and code to produce sequences whose members obey Gaussian distribution function is reported. Discreet and limited number of groups are defined in the distribution function, where each group is represented only with one value instead of a range of value. The produced sequences are also checked back whether they still fit the discreet distribution function. Increasing of number of particles N increases the value of correlation coefficient R^2, but increasing number of groups M reduces it. Value R^2 = 1 can be found for N = 1000000 at least with M = 5000$ and for M = 10 at least with N = 1000.

physics.data-an↗

arXiv2011

Self-Siphon Simulation Using Molecular Dynamics Method

A self activated siphon, which is also known as self-siphon or self-priming siphon, is simulated using molecular dynamics (MD) method in order to study its behavior, especially why it has a critical height that prevents fluid from flowing through it. The trajectory of the fluid interface with air in front of the flow or the head is also fitted the trajectory modeled by parametric equations, which is derived from geometry construction of the self-siphon. Numerical equations solved using MD method is derived from equations of motion of the head which is obtained by introducing all considered forces influencing the movement of it. Time duration needed for fluid to pass the entire tube of the self-siphon, τ, obtained from the simulation is compared quantitatively to the observation data from the previous work and it shows inverse behavior. Length of the three vertical segments are varied independently using a parameter for each segment, which are N_5, N_3, and N_1. Room parameters of N_5, N_3, and N_1 are constructed and the dependency of τ to these parameters are discussed.

physics.flu-dyn↗

arXiv2011

Rise or sink: spherical intruder in density frequency dependence static granular fluid

A simple model for intruder in vibrating granular bed is constructed by introducing a term that governs frequency dependent granular bed density. Varying the vibrating frequency will drive the buoyant force acting on the intruder by the granular bed. Swapped regions of rising and sinking intruder compared to other reported result have bee found.

cond-mat.soft↗

arXiv2011

Ab initio calculation of UV-Vis absorption spectra of a single molecule chlorophyll a: Comparison study between RHF/CIS, TDDFT, and semi-empirical methods

Chlorophyll a is one the most abundant pigment on Earth that responsible for trapping the light energy to perform photosynthesis in green plants. This molecule is a metal-complex that consists of a porphyrin ring with high symmetry that acts as ligands with magnesium as the central ion. Chlorophyll a has been studied for many years from different point of views for both experimental and theoretical interests. In this study, the restricted Hartree-Fock configuration interaction single (RHF/CIS), time-dependent density functional theory (TDDFT) and some semi-empirical methods (CNDO/s and ZINDO) calculations were carried out and compared to reconstruct the UV-Vis absorption spectra of chlorophyll a. In some extend, the calculation results based on a single molecule calculation were succeeded to reconstruct the absorption spectra but required to be scaling to match the experimental one. Different computational methods (ab initio and semi-empirical) exhibit the differences in the energy correction factor and the presence of transition states, however, still conserve the main spectral features. In general, the semi-empirical methods provide a better energy scaling factor, which means closer to the experimental one. However, they lack of fine features or vertical transitions with respect to the experimental spectra. The ab initio calculations result more complete features than the semi-empirical methods, especially the TDDFT with high level of basis sets that provides a good accuracy in transition energies. The contribution of ground states and excited states orbitals in the main vertical transitions is discussed based on orbital structure. This might gives a new perspective to explain the energy transfer phenomena in the absorption processes that related to the function of chlorophyll a as a light-harvesting antenna.

physics.chem-ph↗

arXiv2011

Steady energy transfer dependence granular temperature on single bouncing granular particle

Simulation of a system consisted of free particle bouncing on a vertically vibrated based is performed. Two different states, which are steady and unsteady energy transfer state are found. The vibrating based is hold at constant vibration frequency $f = 0.1$ as the vibration amplitude $A$ varied. Sinusoidal form is used. Granular temperature $T_g$ as function of based velocity and coefficient of restitution is used but shown no role in determining energy transfer state of the system. Peak of free particle trajectory $x_m$ around value 20 seperate region of the two states.

cond-mat.soft↗

arXiv2011

Rise time of spherical intruder in granular fluid

A model is developed to explain rise time of a spherical intruder placed in a granular bed, which is considered as fluid. Phenomenon of rising intruder in a granular bed is well known as Brazil nut effect. Radius of the intruder is varied with $R_n = R_0 n, n = 1 .. 10$. An approximation for $t << τ$ is chosen in order to simplify the solution of second order differential equation of intruder vertical position to obtain the rise time T. A non-physical parameter $α$ and also transformation from $T$ to $T'$ are needed to be introduced in order to control the results to mimic reported experiment qualitatively. Several forms of rise time $T_n$ and also transformed rise time $T_n'$ against $n$ are presented and discussed.

cond-mat.soft↗