DLA Model Research Articles

Study on hydrophobic floc structure of coal particles based on fractal simulation

Utilizing the Matlab platform, two-dimensional diffusion-limited aggregation and three-dimensional diffusion-limited cluster aggregation models were established to simulate the hydrophobic flocculation of coal particles. The formation process of flocs aggregated by monomer particles and small groups was simulated from both plane and space perspectives. The gyration radius fractal dimension increased from 1.401 to 1.539 in the DLA model and from 1.623 to 1.729 in the DLCA model, indicating that the floc morphology gradually stabilized and the structure became increasingly regular during the hydrophobic flocculation process. The porosity of DLA increased from 0.762 to 0.851, indicating that the dendritic structure of flocs formed a spatial shielding effect on the planar structure, which prevented the particles from entering the flocs. In contrast, the porosity of DLCA first increased from 0.506 to 0.611 and then decreased, stabilizing at approximately 0.53, indicating that small groups filled the internal voids of flocs in the spatial structure, leading to a gradual increase in floc density. The surface fractal dimension and density of flocs were calculated using the surface fractal and hydrostatic sedimentation-terminal velocity theories, respectively, confirming the conclusions drawn from the simulation analysis.

Application of the Iot Network and the Deep Learning Concept in Music Teaching

In order to realize students’ in-depth understanding of music teaching content, it is necessary to reasonably allocate teaching materials according to the teaching content. Therefore, this paper puts forward the application of the concept of the Iot network and deep learning in music teaching. After the teaching resources are vectorized, the distinguishing local registration method of the DLA model is used to extract their features. Based on the dimension of the teaching content, the features of the teaching content are output in the DLA model, the music teaching resources are allocated according to the minimum matching error criterion, the hyperbolic tangent function is taken as the activation function, and the feature error is filtered by maximum aggregation. The experimental results show that the design method can, according to the music teaching content, have more than 80% accuracy in the shallow distribution and deep distribution of teaching materials, and play a positive role in promoting students’ in-depth learning.

Study on the fractal structure of carbon nanomaterials’ smokescreen

In the diffusion of carbon nanomaterials’ smokescreen, the condensates generated by the collision of particles have fractal structures. In order to research this process, this paper is based on DLA condensation model programmed by MATLAB. Using DLA model, the geometrical structure of agglomerate formed by spherical nanoparticles is simulated and the fractal dimensions of agglomerates were computed by using the cyclotron radius method. Large numbers of simulations indicated the fractal dimension of agglomerates on two-dimensional plane distributed between 1.4 and 1.7. And with the increasing number of the particles, the fractal dimension displayed in intensive range. The research in this paper has laid a foundation for the study of the aerodynamic characteristics of condensed particles in the next stage.

Innovative deep learning artificial intelligence applications for predicting relationships between individual tree height and diameter at breast height

BackgroundDeep Learning Algorithms (DLA) have become prominent as an application of Artificial Intelligence (AI) Techniques since 2010. This paper introduces the DLA to predict the relationships between individual tree height (ITH) and the diameter at breast height (DBH).MethodsA set of 2024 pairs of individual height and diameter at breast height measurements, originating from 150 sample plots located in stands of even aged and pure Anatolian Crimean Pine (Pinus nigra J.F. Arnold ssp. pallasiana (Lamb.) Holmboe) in Konya Forest Enterprise. The present study primarily investigated the capability and usability of DLA models for predicting the relationships between the ITH and the DBH sampled from some stands with different growth structures. The 80 different DLA models, which involve different the alternatives for the numbers of hidden layers and neuron, have been trained and compared to determine optimum and best predictive DLAs network structure.ResultsIt was determined that the DLA model with 9 layers and 100 neurons has been the best predictive network model compared as those by other different DLA, Artificial Neural Network, Nonlinear Regression and Nonlinear Mixed Effect models. The alternative of 100 # neurons and 9 # hidden layers in deep learning algorithms resulted in best predictive ITH values with root mean squared error (RMSE, 0.5575), percent of the root mean squared error (RMSE%, 4.9504%), Akaike information criterion (AIC, − 998.9540), Bayesian information criterion (BIC, 884.6591), fit index (FI, 0.9436), average absolute error (AAE, 0.4077), maximum absolute error (max. AE, 2.5106), Bias (0.0057) and percent Bias (Bias%, 0.0502%). In addition, these predictive results with DLAs were further validated by the Equivalence tests that showed the DLA models successfully predicted the tree height in the independent dataset.ConclusionThis study has emphasized the capability of the DLA models, novel artificial intelligence technique, for predicting the relationships between individual tree height and the diameter at breast height that can be required information for the management of forests.

FRACTIONAL DIFFUSION-LIMITED AGGREGATION: ANISOTROPY ORIGINATING FROM MEMORY

This paper introduces a modified DLA model, based on a fractional diffusion mechanism, as a novel approach to modeling fractal growth. The specific memory performance of fractional operators can be reflected macroscopically in aggregated patterns eventually. The influence of the model’s order on the structure and behavior of its pattern is further quantitatively described by anisotropy index and fractal dimension. Some simulations are provided to illustrate the correctness and effectiveness of the main results.

Graph-analytical model of the electrical conductivity of a semiconductor island plumbum telluride nanofilm

This article presents the results of experimental studies on obtaining and measuring the electronically conductive properties of island semiconductor plumbum telluride nanofilms, as well as modeling their conductive properties within the hopping conductivity model and the classical model taking into account the structure within the DLA model using graph theory methods.

In-silico design and synthesis of N9-substituted β-Carbolines as PLK-1 inhibitors and their in-vitro/in-vivo tumor suppressing evaluation

A new series of β-Carboline/Schiff bases was designed, synthesized, characterised and biologically evaluated as inhibitors of PLK-1. The synthesized compounds exhibited strong to moderate cytotoxic activities against NCI-60 panel cell assay. Compound SB-2 was the most potent, particularly against colon with GI50 of 3–45 µM on NCI-60 panel cell lines. SB-2 selectively inhibited PLK-1 at 15 µM on KinomeScan screening. It also showed a dose-dependent cell cycle arrest at S/G2 phase on HCT-116 and induced apoptosis by the activation of procaspase-3 and cleaved PARP. Further, the antitumor studies on DLA and EAC model revealed that SB-2, at 100 mg/kg/bd.wt significantly increased their average lifespan. Further, a decrease in the body weight of the tumor-bearing mice was also observed when compared to the tumor controlled mice. SB-2 thus shows good potential as antitumor agent.

Fractal simulation of thin film nucleation growth process using a diffusion-limited aggregation model

In order to study the initial nucleation and growth process of the films, a two-dimensional (2D) DLA model was established, and fractal dimension was calculated by sandbox method. Compared with the experimental results, the model can well characterize the morphology of nucleation and growth in the initial stage of film growth. In addition to the number of particles and deposition probability involved in other studies, the size of substrate and the location of central particles are also considered in this work. The growth morphology, fractal dimension and the number of simulated steps are presented in this paper.

Oil and water: A two-type internal aggregation model

We introduce a two-type internal DLA model which is an example of a nonunary abelian network. Starting with $n$ “oil” and $n$ “water” particles at the origin, the particles diffuse in $\mathbb{Z}$ according to the following rule: whenever some site $x\in\mathbb{Z}$ has at least $1$ oil and at least $1$ water particle present, it fires by sending $1$ oil particle and $1$ water particle each to an independent random neighbor $x\pm1$. Firing continues until every site has at most one type of particles. We establish the correct order for several statistics of this model and identify the scaling limit under assumption of existence.

Using Modified DLA Model Simulation of the Form of Copolymer Flower-Like Aggregation

In this papper, based on the study of basic algorithm of fractal DLA model, the standard DLA model was modified by setting the parameters, and the PS-b-PAA block copolymer representating a kind of flower-like aggregation was taken as the research object. Through observating the growth characteristics of this kind of flower-like aggregations formed in different external conditions, their fractal characteristics were determined by box-counting method. Then the modified DLA model combined with the image processing technology was used to simulate this kind of flower-like aggregations. Finally, the simulated results were evaluated through visual observation and fractal dimension.

Phase Field Method Simulation of Dendrite Crystal Growth of Metal Nickel Based on Fractal Theory

Using fractal theory simulation of dendrite crystal DLA growth model of pure substance, the undercooling during solidification process of crystal nucleation is simulated; and then in the crystal nuclei are formed on the basis of a pure substance, the phase field model and combined with the finite difference method further differentiation simulation of dendrite crystal growth. According to MATLAB programming, the simulation results obtained by field and temperature field can be seen in the DLA growth, growth model with random premise, for the same kind of material simulated dendrite crystal have both similarities and differences exist. Then, we can get the conclusion, through fractal growth of DLA model with phase field model of dendrite nucleation, growth process is carried out the simulation results, a simple by phase field model is more accord with the dendrite crystal in the experiment.

Fractal growth in the presence of a surface force field

We numerically simulate the dynamics of atomic clusters aggregation deposited on a surface interacting with the growing island. We make use of the well-known DLA model but replace the underlying diffusion equation by the Smoluchowski equation which results in a drifted DLA model and anisotropic jump probabilities. The shape of the structures resulting from their aggregation-limited random walk is affected by the presence of a Laplacian potential due to, for instance, the surface stress field. We characterize the morphologies we obtain by their Hausdorff fractal dimension as well as the so-called external fractal dimension. We compare our results to previously published experimental results for antimony and silver clusters deposited onto graphite surface.

The research on Virtual Plants Growth Based on DLA Model

Abstract This article summarizes the separated Evolutionary Algorithm in fractal algorithm of Diffusion Limited Aggregation model (i.e. DLA model) and put forward the virtual plant growth realization in computer based on DLA model. The method is carried out in the VB6.0 environment to achieve and verify the plant growth based on DLA model.

Fractal Growth of Minerals: a Modified DLA Model

A modified fractal growth model of minerals was considered in the square lattice 300 × 300. One seed is placed at the center of the square lattice as a growth focus and the attraction domain is set to diamond. Three main parameters are considered in this model which probability of the surface adhesion is Pg with the range of 0 to 99% to eliminate the noise impact and adsorption distance d varies from 0 to 9 units on behalf of the gravitational field strength between particles and fill gaps s varied from 0.00 to 5.00 units distance to perform the influence of environmental temperature on the minerals growth system. Three model sets are carried out with two fixed parameters and the other changed parameter. The results show the fractal dimension of DLA group increase with the decrease of Pg and the increases of d and s, as well as the structure of minerals from disseminated, star or radial gradual transition to agglomerate. The model is a two-dimensional simulation for three-dimensional fractal growth and can not fully reflect the complex growth dynamics of mineral aggregate in three-dimensional confined space.

Plasma screening effects on the atomic structure and radiative opacity of dense carbon plasmas based on the DLA model

A study of plasma screening effects using a Debye-Hückel model is presented. The effects on the energy levels, oscillator strengths, ionization potential and photoionization cross sections of different ionization stages of carbon and on the radiative opacity of hot dense carbon plasmas are presented. The treatment of the atomic structure and radiative opacity is based on the detailed fine-structure level accounting formalism. For the basic atomic data, we compare our calculated energy levels and oscillator strengths with other theoretical results available in the literature and good agreement is found. The calculated ionization potential depressions of helium-like carbon, C V, are compared with the experimental and other theoretical results for a variety of plasma condition. Since the Saha–Boltzmann equation, which determines the ion stage populations, is dependent on the energy levels and ionization potentials of all ionization stages of carbon, the plasma screening effects on these quantities were included to obtain the population distribution. The screening effects play an important role on the spectrally resolved opacity by affecting the position and intensity of the absorption peaks and the K-shell ionization thresholds. With the decrease of Debye screening length, the number and intensity of the absorption peaks are reduced. In particular, the continuum opacity near the K-edge will be so sufficiently affected by the screening effects as to be experimentally observed. Finally, the plasma screening effects on the Rosseland and Planck mean opacities are investigated.

DIFFUSION-LIMITED AGGREGATION DRIVEN BY OPTIMAL TRANSPORTATION

In this article, we combine the DLA model of Witten and Sander with ideas from ramified optimal transportation. We propose a modification of the DLA model in which the probability of sticking is inversely proportional to the additional transport cost from the point to the root. We used a family of cost functions parameterized by a parameter α as studied in ramified optimal transportation. α < 0 promotes growth near the root whereas α > 0 promotes growth at the tips of the cluster. α = 0 is a phase transition point and corresponds to standard DLA. What makes this model interesting is that when α is negative enough (e.g. α < -2) the final cluster is an one-dimensional curve. On the other hand, when α is positive enough (e.g. α > 2) we get a nearly two dimensional disk. Thus our model encompasses the full range of fractal dimension from 1 to 2.

On Flows in Porous Media with Moving Boundaries Arising as Scaling Limits of Discrete Aggregation Models

We study porous medium (or, equivalently, Hele-Shaw) flows with a moving boundary which arise as scaling (i.e., continuous) limits of certain discrete aggregation models. Specifically, we study the scaling limit of the internal DLA model with a killing and a one-way passing condition for particles on the negative semi-axis. These models were recently studied by L. Levine and Y. Peres. We give an exact self-similar solution for the corresponding porous medium flow in the first case (which matches perfectly the numerical data obtained by L. Levine and Y. Peres), and derive moment properties of such solution in the second case.

Modeling the Variability of Shapes of a Human Placenta

Background Placentas are generally round/oval in shape, but “irregular” shapes are common. In the Collaborative Perinatal Project data, irregular shapes were associated with lower birth weight for placental weight, suggesting variably shaped placentas have altered function. Methods (I) Using a 3D one-parameter model of placental vascular growth based on Diffusion Limited Aggregation (an accepted model for generating highly branched fractals), models were run with a branching density growth parameter either fixed or perturbed at either 5–7% or 50% of model growth. (II) In a data set with detailed measures of 1207 placental perimeters, radial standard deviations of placental shapes were calculated from the umbilical cord insertion, and from the centroid of the shape (a biologically arbitrary point). These two were compared to the difference between the observed scaling exponent and the Kleiber scaling exponent (0.75), considered optimal for vascular fractal transport systems. Spearman's rank correlation considered p < 0.05 significant. Results (I) Unperturbed, random values of the growth parameter created round/oval fractal shapes. Perturbation at 5–7% of model growth created multilobate shapes, while perturbation at 50% of model growth created “star-shaped” fractals. (II) The radial standard deviation of the perimeter from the umbilical cord (but not from the centroid) was associated with differences from the Kleiber exponent ( p = 0.006). Conclusions A dynamical DLA model recapitulates multilobate and “star” placental shapes via changing fractal branching density. We suggest that (1) irregular placental outlines reflect deformation of the underlying placental fractal vascular network, (2) such irregularities in placental outline indicate sub-optimal branching structure of the vascular tree, and (3) this accounts for the lower birth weight observed in non-round/oval placentas in the Collaborative Perinatal Project.

Exponential Clogging Time for a One Dimensional DLA

In this paper a simple DLA type model is analyzed. In (Benjamini and Yadin in Commun. Math. Phys. 279:187–223, [2008]) the standard DLA model from (Witten and Sander in Phys. Rev. B 27:5686–5697, [1983]) was considered on a cylinder and the arm growing phenomena was established, provided that the section of the cylinder has sufficiently fast mixing rate. When considering DLA on a cylinder it is natural to ask how many particles it takes to clog the cylinder, e.g. modeling clogging of arteries. In this note we formulate a very simple DLA clogging model and establish an exponential lower bound on the number of particles arriving before clogging appears. In particular we possibly shed some light on why it takes so long to reach the bypass operation.

Microscopy investigation of Ag-TCNQ micro/nanostructures synthesized via two solution routes

The micro/nanostructures of metal–organic complex Ag-TCNQ were successfully synthesized by the reaction between Ag film and TCNQ dissolved in acetonitrile via two solution routes, i.e. immerging and dipping reaction. X-ray diffraction confirmed that the obtained Ag-TCNQ micro/nanostructures were crystalline. The morphology of the as-grown structures varied from straight nanowires and microtubes to complex fractals and dendrites. The growth mechanism of the mainly dendrites may be considered within the framework of DLA model.