Journal articles: 'Random motion in random media'

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Bodineau, T., and A. Teixeira. "Interface Motion in Random Media." Communications in Mathematical Physics 334, no. 2 (September 6, 2014): 843–65. http://dx.doi.org/10.1007/s00220-014-2152-4.

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Mardoukhi, Yousof, Jae-Hyung Jeon, Aleksei V. Chechkin, and Ralf Metzler. "Fluctuations of random walks in critical random environments." Physical Chemistry Chemical Physics 20, no. 31 (2018): 20427–38. http://dx.doi.org/10.1039/c8cp03212b.

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Percolation networks have been widely used in the description of porous media but are now found to be relevant to understand the motion of particles in cellular membranes or the nucleus of biological cells. We here study the influence of the cluster size distribution on diffusion measurements in percolation networks.

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Chen, Lee-Wen, and M. Cristina Marchetti. "Interface motion in random media at finite temperature." Physical Review B 51, no. 10 (March 1, 1995): 6296–308. http://dx.doi.org/10.1103/physrevb.51.6296.

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Orsingher, E., and N. E. Ratanov. "Random motions in inhomogeneous media." Theory of Probability and Mathematical Statistics 76 (2008): 141–53. http://dx.doi.org/10.1090/s0094-9000-08-00738-2.

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Chen, Yuan, and Jie Li. "Ground Motion Analysis in Nonlinear Soil Site with Random Media." Advanced Materials Research 368-373 (October 2011): 920–25. http://dx.doi.org/10.4028/www.scientific.net/amr.368-373.920.

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In this article,by incorporating equivalent linearization method and the orthogonal expansion method into the wave finite element analysis of scattering problem, an analytical methodology for the evaluation of seismic response of nonlinear soil site with uncertain properties is proposed . Example is given to show the applicability of the methodology. The results show that the randomness of the site media has important effect on seismic site response , the randomness has greater influence on the variation of accelerations than on displacements. The coupling of the nonlinearity and the randomness of soil enhances the effect of randomness on the soil site.

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Luo, Qiaoen, Jason A. Newman, and Kevin J. Webb. "Motion-based coherent optical imaging in heavily scattering random media." Optics Letters 44, no. 11 (May 23, 2019): 2716. http://dx.doi.org/10.1364/ol.44.002716.

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Schneider, T., M. P. Soerensen, A. Politi, and M. Zannetti. "Relationship between Classical Motion in Random Media and Quantum Localization." Physical Review Letters 56, no. 22 (June 2, 1986): 2341–43. http://dx.doi.org/10.1103/physrevlett.56.2341.

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Cebiroglu, G., C. Weber, and L. Schimansky-Geier. "Rectification of motion in nonlinear media with asymmetric random drive." Chemical Physics 375, no. 2-3 (October 2010): 439–44. http://dx.doi.org/10.1016/j.chemphys.2010.02.015.

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Ruichong Zhang, Ray, and Menglin Lou. "Seismic wave motion modeling with layered 3D random heterogeneous media." Probabilistic Engineering Mechanics 16, no. 4 (October 2001): 381–97. http://dx.doi.org/10.1016/s0266-8920(01)00027-3.

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Mikheev, Lev V., Barbara Drossel, and Mehran Kardar. "Energy Barriers to Motion of Flux Lines in Random Media." Physical Review Letters 75, no. 6 (August 7, 1995): 1170–73. http://dx.doi.org/10.1103/physrevlett.75.1170.

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Lee, Y. G., and J. B. Ra. "Fast Motion Estimation Robust to Random Motions Based on a Distance Prediction." IEEE Transactions on Circuits and Systems for Video Technology 16, no. 7 (July 2006): 869–75. http://dx.doi.org/10.1109/tcsvt.2006.877149.

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Glatz, A., T. Nattermann, and V. Pokr vsky. "Domain walls in random media driven by AC fields." Journal de Physique IV 12, no. 9 (November 2002): 275. http://dx.doi.org/10.1051/jp4:20020414.

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The viscous motion of an interface driven by an ac external field of frequency $\omega_0$ in a random medium is considered here for the first time. The velocity exhibits a smeared depinning transition showing a double hysteresis which is absent in the adiabatic case $\omega_0 \rightarrow 0$. Using scaling arguments and an approximate renormalization group calculation we explain the main characteristics of the hysteresis loop. In the low frequency limit these can be expressed in terms of the depinning threshold and the critical exponents of the adiabatic case.

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Ratanov, N. "Reaction–advection random motions in inhomogeneous media." Physica D: Nonlinear Phenomena 189, no. 1-2 (February 2004): 130–40. http://dx.doi.org/10.1016/j.physd.2003.09.032.

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Lin, Yongbing, and Philipp Zhang. "A new bitstream random access scheme using multipicture motion-compensated prediction." IEEE Transactions on Consumer Electronics 55, no. 2 (May 2009): 670–76. http://dx.doi.org/10.1109/tce.2009.5174438.

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Koplik, J., and T. J. Lasseter. "Two-Phase Flow in Random Network Models of Porous Media." Society of Petroleum Engineers Journal 25, no. 01 (February 1, 1985): 89–100. http://dx.doi.org/10.2118/11014-pa.

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Abstract To explore how the microscopic geometry of a pore space affects the macroscopic characteristics of fluid flow in porous media, we have used approximate solutions of the porous media, we have used approximate solutions of the Navier-Stokes equations to calculate the flow of two fluids in random networks. The model pore space consists of an array of pores of variable radius connected to a random number of nearest neighbors by throats of variable length and radius. The various size and connectedness distributions may be arbitrarily assigned, as are the wetting characteristics of the two fluids in the pore space. The fluids are assumed to be incompressible, immiscible. Newtonian, and of equal viscosity. In the calculation, we use Stokes flow results for the motion of the individual fluids and incorporate microscopic capillary force by using the Washburn approximation. At any time, the problem is mathematically identical to a random electrical network of resistors, batteries, and diodes. From the numerical solution of the latter, we compute the fluid velocities and saturation rates of change and use a discrete timestepping procedure to follow the subsequent motion. The scale of the computation has restricted us so far to networks of hundreds of pores in two dimensions (2D). Within these limitations, we discuss the dependence of residual oil saturations and interface shapes on network geometry and flow conditions. Introduction A significant limitation to our understanding of the dynamics of multiphase fluids in porous media is the inability to connect the physics at the microscopic scale to the macroscopic phenomena observed in the laboratory and in the field. Within individual pores, the motion of fluids and menisci can be discussed, at least approximately, in terms of the microgeometry and the physical characteristics of the liquids. gases, and solids present. On the macroscopic scale, the multiphase Darcy equations involving several empirical parameters-relative permeabilities and average capillary pressures permeabilities and average capillary pressures conventionally are used. The connection between these two levels of description, if there is one, has never been elucidated despite years of effort (as reviewed by Scheidegger ). In consequence, it is difficult to predict the behavior of oil reservoirs in advance, and considerable waste of money, effort, and resources can ensue. Economic issues aside, this situation provides another example of a pervasive problem in physics: macroscopic averaging of a random problem in physics: macroscopic averaging of a random microscopically disordered medium to predict large-scale behavior from a knowledge of small-scale dynamics. In optimal circumstances, existing methods in the physics literature (i.e., Ziman ) can be used to carry out physics literature (i.e., Ziman ) can be used to carry out the averaging. For fluid problems, for example, percolation theory has been applied to the spatial distribution of percolation theory has been applied to the spatial distribution of fluids in a pore space, both in static situations and in quasistatic displacement. Another set of ideas, effective medium theories, has been applied to electrical conductivity and its fluid analog, absolute permeability. The general fluid displacement problem, when both permeability. The general fluid displacement problem, when both capillary and viscous forces are present, is related to a class of physics problems that are as yet unresolved, such as crystal growth, surface evolution, and dynamic percolation. In this situation, we are forced to resort to percolation. In this situation, we are forced to resort to brute-force numerical modeling, both as a means of obtaining statistical information and as a guide to approximations that may permit future analytical work. In this paper, we describe our initial efforts to calculate the motion of two fluids in porous media from the microscopic scale up, starting from the Stokes equations and boundary conditions in this pore space. As usual, we model the porous medium as a network of similarly shaped, but randomly sized, elements. The key to the calculation is the mathematical analogy between the fluid problem and an appropriate electrical network of random problem and an appropriate electrical network of random resistors, batteries, and diodes. The calculation is a very difficult one, numerically speaking, and to date we have been restricted to fairly small 2D networks of hundreds of pores. We expect, however, that with more sophisticated programming methods our approach can be applied to three-dimensional (3D) networks of thousands of pores. pores. After this work was in progress, we came across a paper of Singhal and Somerton where a similar calculational framework was used but with a different emphasis. Those authors considered a single realization of a small network of triangular channels of random sizes with flow regimes randomly assigned in each channel and compute the relative permeabilities and capillary pressure curves of the network. Our emphasis in this paper is on time-dependent phenomena and statistical averaging of flow quantities. We also note the somewhat related work by Payatakes et al., who considered a square lattice of Payatakes et al., who considered a square lattice of converging/diverging tubes meeting at point nodes and simulate the dislodgement of blobs of trapped oil. Subsequently, Dias and Payatakes used the same geometry and calculational rules similar to those employed here to study fluid displacement. SPEJ P. 89

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Wu, Chun-Hsien, and Jeen-Hwa Wang. "Vertical ground motion analysis for submerged pore-elastic media with random void ratios." Computers and Geotechnics 36, no. 6 (July 2009): 968–76. http://dx.doi.org/10.1016/j.compgeo.2009.03.004.

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Syaputra, Asep. "Implementasi Metode Random Sampling Pada Animasi Motion Grapich Herbisida Dan Fungisida." Jurnal Sisfokom (Sistem Informasi dan Komputer) 11, no. 2 (August 2, 2022): 142–47. http://dx.doi.org/10.32736/sisfokom.v11i2.1370.

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Promosi sangat penting untuk mendukung kegiatan pemasaran. Saat mempromosikan sebuah produk masih menggunakan brosur, berbicara langsung dengan konsumen di lapangan sehingga memiliki banyak biaya, energi, kebutuhan waktu dan konsumen dan kurangnya ketertarikan koonsumen untuk membeli produk, oleh karena itu dengan pemanfaatan dari teknologi multimedia maka permasalahan tersebut diharapkan dapat diatasi. Pada penelitian ini menggunakan pengembangan model ADDIE, yang terdiri dari 5 langkah yaitu analisis, desain, pengembangan, implementasi dan evaluasi. Animasi ini dibuat oleh Adobe oleh Effect CS6 dan dirancang untuk mengukur level valid dalam animasi Alpha Tester ini untuk mengukur validitas animasi dengan ulasan ahli, yaitu yaitu ahli design, ahli media, ahli bahasa, ahli materi. Untuk mengukur pemahaman dan minat konsumen, penulis menggunakan teknik sampling dalam penelitian ini dan penggunaan formula pengambilan sampel lambat untuk menentukan jumlah responden dari populasi. Dari hasil tes oleh para ahli yang diperoleh dengan hasil validitas, menyatakan bahwa ekstensi animasi ini sangat valid dengan memberikan rata-rata 4.15 dari hasil nilai validitas, dan merupakan rata-rata 4.31 dari responden.

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Yi-Jie, Zhou, and Di Chang-An. "Human motion recognition based on Kalman random Forest algorithm and 3D multimedia." Multimedia Tools and Applications 79, no. 15-16 (August 6, 2019): 9891–99. http://dx.doi.org/10.1007/s11042-019-08018-w.

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Li, Bo, Baoxing Bai, and Cheng Han. "Upper body motion recognition based on key frame and random forest regression." Multimedia Tools and Applications 79, no. 7-8 (July 7, 2018): 5197–212. http://dx.doi.org/10.1007/s11042-018-6357-y.

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Kung, Chieh, Te-Tan Liao, Kuo-Hwa Tseng, Kuo-Ying Chen, and Ming-Shuing Chuang. "THE INFLUENCES OF POWDER MIXING PROCESS ON THE QUALITY OF W-CU COMPOSITES." Transactions of the Canadian Society for Mechanical Engineering 33, no. 3 (September 2009): 361–75. http://dx.doi.org/10.1139/tcsme-2009-0026.

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The mixing homogeneity of powders has a significant influence on the quality of composites fabricated from a powder metallurgy process. The factors that influence the homogeneity include the powder mixer, the medium, and the ball-milling procedure. In this paper, the influences of powder mixers and mixing media on the quality of tungsten-particle reinforced copper matrix composites are studied. Apart from dry mixing, other media used in the wet mixing process include n-butyl alcohol, camphor oil, and paraffin oil. Comparisons on mixing feature are made to a TURBULA® mixer and a Random mixer. The TURBULA® mixer is commercially available, and the Random mixer is an in-house designed machine. Our results show that using paraffin oil as the mixing medium, one may obtain optimal homogeneity in the composites. The Random mixer is superior to the TUBULA® mixer due to the fact that the Random mixer offers an avalanching motion creating pure shear forces onto the powders.

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BÁRTEK, JAN, MARÍA J. GARRIDO-ATIENZA, and BOHDAN MASLOWSKI. "STOCHASTIC POROUS MEDIA EQUATION DRIVEN BY FRACTIONAL BROWNIAN MOTION." Stochastics and Dynamics 13, no. 04 (October 7, 2013): 1350010. http://dx.doi.org/10.1142/s021949371350010x.

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The present work deals with stochastic porous media equation with multiplicative noise, driven by fractional Brownian motion B(H) with Hurst index H > 1/2. The stochastic integral with integrator B(H) is defined pathwise following the theory developed by Zähle [24], based on the so-called fractional derivatives. It is shown that there is a one-to-one correspondence between solutions to the stochastic equation and solutions to its deterministic counterpart. By means of this correspondence and exploiting properties of the deterministic porous media equation, the existence, uniqueness, regularity and long-time properties of the solution is established. We also prove that the solution forms a random dynamical system in an appropriate function space.

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Tchawe, F. N., C. Gelis, L. F. BONILLA, and F. Lopez-Caballero. "Effects of 2-D random velocity perturbations on 2-D SH short-period ground motion simulations in the basin of Nice, France." Geophysical Journal International 226, no. 2 (April 12, 2021): 847–61. http://dx.doi.org/10.1093/gji/ggab141.

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SUMMARY Some geological configurations, like sedimentary basins, are prone to site effects. Basins are often composed of different geological layers whose properties are generally considered as spatially homogeneous or smoothly varying. In this study, we address the influence of small-scale velocity fluctuations on seismic response. For this purpose, we use the spectral element method to model the 2-D SH wave propagation on a basin of 1.1 km long and ≈ 60 m deep, representing a 2-D profile in the city of Nice, France. The velocity fluctuations are modelled statistically as a random process characterized by a Von Karman autocorrelation function and are superimposed to the deterministic model. We assess the influence of the amplitude and correlation length of the random velocities on the surface ground motion. We vary the autocorrelation function’s parameters and compute seismic wavefields in 10 random realizations of the stochastic models. The analyses of our results focus on the envelope and phase differences between the waveforms computed in the random and deterministic models; on the variability of ground motion intensity measures, such as the peak ground velocity, the pseudo-spectral acceleration response; and the 2-D basin response (transfer function). We find that the amplitude of fluctuations has a greater effect on the ground motion variability than the correlation length. Depending on the random medium realization, the ground motion in one stochastic model can be locally amplified or deamplified with respect to the reference model due to the presence of high or low velocity contrasts, respectively. When computing the mean amplification of different random realizations, the results may be smaller than those of the reference media due to the smoothing effect of the average. This study highlights the importance of knowing the site properties at different scales, particularly at small scales, for proper seismic hazard assessment.

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Chen, Yue-Meng, Ivan V. Bajic, and Parvaneh Saeedi. "Moving Region Segmentation From Compressed Video Using Global Motion Estimation and Markov Random Fields." IEEE Transactions on Multimedia 13, no. 3 (June 2011): 421–31. http://dx.doi.org/10.1109/tmm.2011.2127464.

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Bermana, Ary Leo. "PERANCANGAN MEDIA PROMOSI PARIWISATA KOTA BUKITTINGGI." Artchive: Indonesia Journal of Visual Art and Design 1, no. 1 (June 5, 2020): 10. http://dx.doi.org/10.53666/artchive.v1i1.1558.

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ABSTRACT Tourism is one of the mainstays in earning foreign exchange for national development. The city of Bukittinggi as one of the tourism cities in Indonesia, has enormous tourism potential, both in terms of nature, social and culture. However, the increase in the volume of tourists to the city of Bukittinggi has not matched what was expected when compared to the time and costs spent. When compared to other areas such as Bali, Bukittinggi is still behind in terms of tourism promotion efforts. For this reason, in the development of tourism promotion in the city of Bukittinggi, one of the solutions offered is through motion graphic animation media. Motion Graphic is a type of graphic animation that uses video recording or animation technology to create the illusion of motion or rotation, and is usually combined with the audio used in multimedia projects. In making this motion graphic, it uses visuals in the form of vector images of several tourist objects in the city of Bukittinggi and typography which is composed and still has a narrative so that the delivery of messages remains strong and informative.The design method used to create this motion graphic is the Random search method. This strategy is the most free strategy in its implementation, whether it is free in sorting the components of the design or the sequence of the exploration stages. Only the final goal of the design is decided at the beginning of the design process. This strategy starts from making briefs, collecting data, analyzing data, prototyping and evaluating. This is emphasized so that the final result can produce a solution in the form of motion graphics animation that can increase the reliability and effectiveness of the promotion and can create dynamic and interactive communication presentations. ABSTRAK Pariwisata merupakan salah satu andalan dalam perolehan devisa bagi pembangunan nasional. Kota Bukittinggi sebagai salah satu kota pariwisata di Indonesia, memiliki potensi pariwisata yang sangat besar, baik dilihat dari alam, sosial maupun budayanya. Namun peningkatan volume wisatawan ke kota Bukittinggi belum sesuai dengan apa yang diharapkan apabila dibandingkan dengan waktu dan biaya yang telah dikeluarkan. Jika dibandingkan dengan daerah lain seperti Bali, Bukittinggi masih ketinggalan dalam hal usaha promosi wisata. Untuk itu dalam pengembangan promosi pariwisata kota Bukittinggi, salah satu solusi yang ditawarkan adalah melalui media animasi motion graphic. Motion Graphic merupakan sejenis animasi grafis yang menggunakan rekaman video atau teknologi animasi untuk menciptakan ilusi gerak atau rotasi, dan biasanya dikombinasikan dengan audio yang digunakan dalam proyek multimedia. Dalam pembuatan motion graphic ini menggunakan visual berupa gambar vektor dari beberapa objek wisata yang ada di Kota Bukittinggi dan tipografi yang dikomposisikan serta tetap memiliki narasi sehingga penyampaian pesan tetap kuat dan informatif. Metode desain yang digunakan untuk menciptakan motion graphic ini adalah Metode Random search atau pencarian solusi secara acak. Strategi ini merupakan strategi yang paling bebas dalam pelaksanaannya, baik bebas dalam memilah komponen-komponen desain maupun urutan tahap eksplorasi. Yang diputuskan pada awal proses desain hanyalah sasaran akhir desain. Strategi ini di mulai dari pembuatan brief, pengumpulan data, analisis data, prototype serta evaluasi. Hal ini ditekankan agar hasil akhir yang di dapat bisa melahirkan solusi berupa animasi motion graphics yang dapat meningkatkan reabilitas dan keefektifan dari promosi tersebut serta dapat menciptakan presentasi komunikasi yang dinamis dan interaktif.

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Schneider, T., A. Politi, and R. Badii. "Relationship between classical diffusion, intermittency, and the motion of a quantum particle in modulated or random media." Physical Review A 34, no. 3 (September 1, 1986): 2505–8. http://dx.doi.org/10.1103/physreva.34.2505.

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Chatterjee, S. "Probability of arrival of rays of light for propagation through random media: Connection with rotational brownian motion." Optics Communications 74, no. 3-4 (December 1989): 149–51. http://dx.doi.org/10.1016/0030-4018(89)90338-6.

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He, Ying, Xu Liu, Zhongxian Liu, Xueling Chen, and Benchi Yin. "Effect of Randomness of Parameters on Amplification of Ground Motion in Saturated Sedimentary Valley." Applied Sciences 13, no. 2 (January 14, 2023): 1147. http://dx.doi.org/10.3390/app13021147.

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Based on Biot’s theory and the indirect boundary element method (IBEM), the Monte Carlo method is utilized to generate random samples to calculate the displacement response of a saturated sedimentary valley under SV wave incidence. The purpose of this paper is to explore the effects of randomness of porosity, permeability coefficient, and geometric shape on the seismic amplification effect of saturated complex sites. It is shown that the change of media porosity in the saturated site with defined boundary has relatively little influence on the ground motion, and the influence of the permeability coefficient is slightly larger. While in the site with a random boundary, the influence of both the porosity and permeability coefficient are significant, which cannot be ignored. The conclusion plays an important guiding role in earthquake disaster prevention and mitigation, such as seismic risk analysis and earthquake microzonation in saturated sedimentary valleys.

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Vitali, Silvia, Vittoria Sposini, Oleksii Sliusarenko, Paolo Paradisi, Gastone Castellani, and Gianni Pagnini. "Langevin equation in complex media and anomalous diffusion." Journal of The Royal Society Interface 15, no. 145 (August 2018): 20180282. http://dx.doi.org/10.1098/rsif.2018.0282.

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The problem of biological motion is a very intriguing and topical issue. Many efforts are being focused on the development of novel modelling approaches for the description of anomalous diffusion in biological systems, such as the very complex and heterogeneous cell environment. Nevertheless, many questions are still open, such as the joint manifestation of statistical features in agreement with different models that can also be somewhat alternative to each other, e.g. continuous time random walk and fractional Brownian motion. To overcome these limitations, we propose a stochastic diffusion model with additive noise and linear friction force (linear Langevin equation), thus involving the explicit modelling of velocity dynamics. The complexity of the medium is parametrized via a population of intensity parameters (relaxation time and diffusivity of velocity), thus introducing an additional randomness, in addition to white noise, in the particle's dynamics. We prove that, for proper distributions of these parameters, we can get both Gaussian anomalous diffusion, fractional diffusion and its generalizations.

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Amir, Shahizat, Mohamed Nor Sabirin, and Siti Aishah Hashim Ali. "Using Polymer Electrolyte Membranes as Media to Culture Fractals: A Simulation Study." Advanced Materials Research 93-94 (January 2010): 35–38. http://dx.doi.org/10.4028/www.scientific.net/amr.93-94.35.

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In the authors' laboratory, fern-like fractals have been cultured in polymer electrolyte membranes of polyethylene oxide (PEO) doped with ammonium iodide (NH4I). The simulation study was then carried out utilizing the Diffusion Limited Aggregation (DLA) based on random motion of aggregating particles modelling technique. The fractal dimension values and the forms of the simulated fractals are comparable to those observed in the PEO polymer membranes. These indicate that the simulation using the DLA model done in this study has resulted outputs that are in abidance with the original fractals cultured in the polymer membranes.

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Zhang, Qiang, Haijian Wang, and Tong Guo. "Fatigue Damage of V-Lock Chain Ring Under Random Load." Polish Maritime Research 23, s1 (October 1, 2016): 4–9. http://dx.doi.org/10.1515/pomr-2016-0039.

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Abstract To study the influence of the random load on the V-lock chain ring for mining, the numerical simulation technology is used. The dynamic tension is obtained by using the dynamic model of the plough. The life and damage nephograms are obtained by using ANSYS Workbench. The analysis results show that the short fatigue life region of the V-lock chain ring for mining is mainly concentrated on the transition region between the medial straight edge and arc, and the fatigue damage of the link chain on the side of the motion direction of the plow head is larger than that on the other side. This link chain has strong anti-fatigue performance.

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Adler, P. M., and J. F. Thovert. "Real Porous Media: Local Geometry and Macroscopic Properties." Applied Mechanics Reviews 51, no. 9 (September 1, 1998): 537–85. http://dx.doi.org/10.1115/1.3099022.

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The random geometry of real porous media is analyzed with the objective of reproducing it numerically; adequate algorithms are proposed for consolidated materials which may be statistically homogeneous or not, and may possess more than one solid phase; random packings of star-shape grains are built to mimic non-consolidated materials which are usually obtained by settling processes. The macroscopic properties of all these media can be deduced by solving the local partial differential equations which govern the phenomena; finite difference schemes are used most of the time. A number of physical situations have been already addressed. Elementary transport phenomena such as convection, diffusion and convection-diffusion provide the basic illustrations of our methodology. Multiphase flows is an exception in the sense that the resolution is achieved by means of a lattice-Boltzmann algorithm. The electrokinetic phenomena associated with the motion of an electrolyte through a charged medium are addressed close to equilibrium, in the limit of small dzeta potentials and thick double layers. Industrial processes may involve deposition and/or dissolution of a solute; first-order reactions of a single solute could be successfully analyzed and rationalized with the help of the Pe´clet and the Damko¨hler numbers. Similarly, the macroscopic mechanical properties of the solid matrix of a porous medium can be obtained by solving the elastostatic equations; macroscopic coefficients such as the equivalent Young’s modulus were derived for a number of structures. Some tentative remarks conclude this review. This article contains 289 references.

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Peñarrubia, Jorge. "Orbital scattering by random interactions with extended substructures." Monthly Notices of the Royal Astronomical Society 490, no. 1 (October 7, 2019): 1044–54. http://dx.doi.org/10.1093/mnras/stz2648.

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ABSTRACT This paper presents N-body and stochastic models that describe the motion of tracer particles in a potential that contains a large population of extended substructures. Fluctuations of the gravitational field induce a random walk of orbital velocities that is fully specified by drift and diffusion coefficients. In the impulse and local approximations, the coefficients are computed analytically from the number density, mass, size, and relative velocity of substructures without arbitrary cuts in forces or impact parameters. The resulting Coulomb logarithm attains a well-defined geometrical meaning, ln (Λ) = ln (D/c), where D/c is the ratio between the average separation and the individual size of substructures. Direct-force and Monte Carlo N-body experiments show excellent agreement with the theory if substructures are sufficiently extended (c/D ≳ 10−3) and not spatially overlapping (c/D ≲ 10−1). However, close encounters with point-like objects (c/D ≪ 10−3) induce a heavy-tailed, non-Gaussian distribution of high-energy impulses that cannot be described with Brownian statistics. In the point-mass limit (c/D ≈ 0), the median Coulomb logarithm measured from N-body models deviates from the theoretical relation, converging towards a maximum value 〈ln (Λ)〉 ≈ 8.2 independently of the mass and relative velocity of nearby substructures.

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Angraeni, Lia, and Henny Puspitasari. "PENGARUH MEDIA SIMULASI KOMPUTER TERHADAP HASIL BELAJAR MAHASISWA PADA MATERI KINEMATIKAGERAK." Jurnal Pendidikan Matematika dan IPA 10, no. 1 (January 11, 2019): 1. http://dx.doi.org/10.26418/jpmipa.v10i1.29659.

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AbstractThe purpose of this study was to determine the effect of using computer simulation media on learning outcomes of Physics in IKIP PGRI Pontianak ICT Education students. The population of this study is the 1st semester ICT Education students consisting of 2 classes totaling 79 students. Determination of the sample using Cluster Random Sampling technique, the sample used in this study is 1 class, namely class A Morning. The research method used is the experimental method. Learning outcomes data were taken using cognitive test instruments using multiple choice tests. The results showed that the average student learning outcomes before applied learning using simulation media amounted to 49.32 with a standard deviation of 14.45 and the average student learning outcomes after applied learning using simulation media amounted to 81.28 with a standard deviation of 14.63 . From the results of the analysis using the Wilcoxon Match Pairs test, Zhitung is 1,009 which is smaller than Zttable which is equal to 1,645. Then H0 is rejected and Ha is accepted, meaning that there are differences in student learning outcomes before and after being given learning using simulation media on the material of motion kinematics. Thus, the use of computer simulation media on the material of motion kinematics can improve student learning outcomes.Keywords: Computer simulation media, motion kinematics.

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Li, Jin, Xinggang Lin, and C. C. Jay Kuo. "Boundary-Control Vector (BCV) Motion Field Representation and Estimation by Using a Markov Random Field Model." Journal of Visual Communication and Image Representation 7, no. 3 (September 1996): 230–43. http://dx.doi.org/10.1006/jvci.1996.0021.

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Norris, A. N., and D. L. Johnson. "Nonlinear Elasticity of Granular Media." Journal of Applied Mechanics 64, no. 1 (March 1, 1997): 39–49. http://dx.doi.org/10.1115/1.2787292.

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The finite and incremental elasticity of a random packing of identical spheres is derived using energy methods. We consider different models for the contact forces between spheres, all of which are based upon or related to the fundamental Hertz theory; we consider only the special cases of perfect friction (no tangential slip) or no tangential friction. The existence of a strain energy function for the medium depends critically upon the type of contact. If the tangential contact stiffness is independent of the normal force, then the energy is well defined for all values of the macroscopic strain. Otherwise, the strain energy of the system is path dependent, in general. However, the concept of a quadratic strain energy function is always well defined for incremental motion superimposed on large confining stress and strain. For all models considered, we derive the changes in wave speeds due to incremental strains. For the models based upon an energy function we derive expressions for the third-order elastic constants as a function of confining pressure.

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Surowiak, Agnieszka, and Marian Brożek. "METHODOLOGY OF CALCULATION THE TERMINAL SETTLING VELOCITY DISTRIBUTION OF SPHERICAL PARTICLES FOR HIGH VALUES OF THE REYNOLD’S NUMBER." Archives of Mining Sciences 59, no. 1 (March 1, 2014): 269–82. http://dx.doi.org/10.2478/amsc-2014-0019.

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Abstract The particle settling velocity is the feature of separation in such processes as flowing classification and jigging. It characterizes material forwarded to the separation process and belongs to the so-called complex features because it is the function of particle density and size. i.e. the function of two simple features. The affiliation to a given subset is determined by the values of two properties and the distribution of such feature in a sample is the function of distributions of particle density and size. The knowledge about distribution of particle settling velocity in jigging process is as much important factor as knowledge about particle size distribution in screening or particle density distribution in dense media beneficiation. The paper will present a method of determining the distribution of settling velocity in the sample of spherical particles for the turbulent particle motion in which the settling velocity is expressed by the Newton formula. Because it depends on density and size of particle which are random variable of certain distributions, the settling velocity is a random variable. Applying theorems of probability, concerning distributions function of random variables, the authors present general formula of probability density function of settling velocity for the turbulent motion and particularly calculate probability density function for Weibull’s forms of frequency functions of particle size and density. Distribution of settling velocity will calculate numerically and perform in graphical form. The paper presents the simulation of calculation of settling velocity distribution on the basis of real distributions of density and projective diameter of particles assuming that particles are spherical.

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Rahadi, Ikman Nurhakim, Darwan Darwan, and Hendri Handoko. "The Use of Learning Media Motion Graphics Towards Students Mathematical Understanding." ITEJ (Information Technology Engineering Journals) 5, no. 2 (December 19, 2020): 97–104. http://dx.doi.org/10.24235/itej.v5i2.45.

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Learning about the concept and structure of a mathematical material and looking for relationships between them is real math learning. In many math learning materials, students often struggle to understand the concept of the material. The mathematical skills need to be stimulus and encouraged when learning. To practice such skills need innovations such as using motion graphics learning media. The purpose of this research is to know the student's response to the use of motion graphic media, to find out how much the mathematical skills of students after using motion graphic learning media, to know how much influence The media use of motion graphic learning to the students mathematical skills, to determine the effectiveness of the use of motion graphic learning media to the students mathematical skills. This method of research is experimental research with data collection techniques using poll and observation for variable X and test for variable Y. Population for this research is all students of grade IX SMP IT Umar Al Khattab Gunung Jati Kabupaten Cirebon, while the sample Taken by the cluster method of random sampling with the elected class IX B SMP IT Umar Al Khattab Gunung Jati Kabupaten Cirebon. Based on the results of the data processing, the student response questionnaire was obtained against the use of media in motion graphic media learning with an average of 85.23% with very strong criteria. Based on the hypothesis test result obtained tcount > ttable = 9,895 > 2.063, then H0 rejected or Ha is acceptable, the use of Motion graphics Learning Media is effective against the mathematical understanding of grade IX students SMP IT Umar Al Khattab. It is also supported through an N-Gain value of 65.40 as well as an indicator of the learning effectiveness of a KKM pass of 91.66% classifying, student response 85.23%, student activity of 77,,33%, as well as the ability of the teacher to manage the class that got the value 3.34.

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Chapman, Martin C. "A probabilistic approach to ground-motion selection for engineering design." Bulletin of the Seismological Society of America 85, no. 3 (June 1, 1995): 937–42. http://dx.doi.org/10.1785/bssa0850030937.

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Abstract The solutions of many earthquake engineering problems involve dynamic analyses using ground-motion time series. It is often desirable to base the selection of such motions on a probabilistic estimate of the seismic hazard. The hazard density function evaluated at a chosen hazard level provides the information necessary to determine objectively the most likely earthquake events, defined by magnitude and distance, that contribute to seismic hazard. For a wide range of hazard models it is possible to show that the difference between the median motion at a site, given the occurrence of the most likely event, and the motion value corresponding to a specified hazard level, is due entirely to the modeling of random error in the strong-motion data set. This points to a straightforward approach to selecting ground-motion recordings that represent the most likely time-domain realizations of the hazard model for a given motion parameter and hazard level. Ground-motion time series selection and/or synthesis based upon this approach, for various frequency bands of the response spectrum, can provide an optimum basis for seismic design.

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Kumar, Manish, Jeffrey S. Guasto, and Arezoo M. Ardekani. "Transport of complex and active fluids in porous media." Journal of Rheology 66, no. 2 (March 2022): 375–97. http://dx.doi.org/10.1122/8.0000389.

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Complex and active fluids find broad applications in flows through porous materials. Nontrivial rheology can couple to porous microstructure leading to surprising flow patterns and associated transport properties in geophysical, biological, and industrial systems. Viscoelastic instabilities are highly sensitive to pore geometry and can give rise to chaotic velocity fluctuations. A number of recent studies have begun to untangle how the pore-scale geometry influences the sample-scale flow topology and the resulting dispersive transport properties of these complex systems. Beyond classical rheological properties, active colloids and swimming cells exhibit a range of unique properties, including reduced effective viscosity, collective motion, and random walks, that present novel challenges to understanding their mechanics and transport in porous media flows. This review article aims to provide a brief overview of essential, fundamental concepts followed by an in-depth summary of recent developments in this rapidly evolving field. The chosen topics are motivated by applications, and new opportunities for discovery are highlighted.

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Rahmawati, Elin, Yustinus Ulung Anggraito, and Nugrahaningsih Wahyu Harini. "KEEFEKTIFAN MODEL PEMBELAJARAN PROJECT BASED LEARNING DENGAN MEDIA STOP MOTION VIDEO SISTEM KOORDINASI TERHADAP HASIL BELAJAR SISWA SMA." Bioma : Jurnal Ilmiah Biologi 8, no. 1 (October 10, 2019): 265–77. http://dx.doi.org/10.26877/bioma.v8i1.4683.

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Tujuan penelitian ini adalah untuk menganalisis keefektifan model pembelajaran Project Based Learning dengan media Stop Motion Video sistem koordinasi terhadap hasil belajar siswa SMA. Penelitian ini merupakan penelitian Quasy Experimental menggunakan Nonequivalent Control Group Design. Populasi penelitian ini adalah seluruh siswa kelas XI IPA SMA Negeri 1 Ngadirojo yang terdaftar pada Semester Genap Tahun Ajaran 2017/2018 yang terdiri dari empat kelas dengan teknik sampling yang digunakan adalah Simple Random Sampling, yaitu kelas XI IPA 3 sebagai kelas eksperimen dan kelas XI IPA 4 sebagai kelas kontrol. Pengumpulan data dilakukan dengan metode tes, observasi, dan angket. Hasil penelitian menunjukkan bahwa persentase ketuntasan klasikal pada kelas eksperimen 84,38% sedangkan kelas kontrol sebesar 53,12%. Hasil uji t menunjukkan rata-rata nilai posttest siswa kelas eksperimen berbeda dan lebih baik dibandingkan kelas kontrol. Uji N-Gain kelas eksperimen lebih baik (100%) dibandingkan dengan kelas kontrol (87,51%). Berdasarkan hasil penelitian di atas dapat disimpulkan bahwa penggunaan model pembelajaran Project Based Learning dengan media Stop Motion Video sistem koordinasi efektif diterapkan pada pembelajaran materi sistem koordinasi. Kata kunci: sistem koordinasi manusia, stop motion video, Project Based Learning, hasil belajar

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Liu, Xiao-Xiao, and Yuan-Sheng Wang. "A New Formulation on Seismic Risk Assessment for Reinforced Concrete Structures with Both Random and Bounded Uncertainties." Discrete Dynamics in Nature and Society 2018 (November 1, 2018): 1–15. http://dx.doi.org/10.1155/2018/5027958.

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A new formulation on seismic risk assessment for structures with both random and uncertain-but-bounded variables is investigated in this paper. Limit thresholds are regarded as random variables. The median of random variables is described through an improved multidimensional parallelepiped (IMP) convex model, in which the uncertain domain of the dependent bounded variables can be explicitly expressed. The corresponding Engineering Demand Parameters are taken to be dependent and follow a multidimensional lognormal distribution. Through matrix transformation, a given performance function is transformed into the regularized one. An effective method based on active learning Kriging model (ALK) is introduced to approximate the performance function in the region of interest rather than in the overall uncertain space. Based on ALK model, the failure probabilities for different limit states are calculated by using Monte Carlo Simulation (MCS). Further, the failure probabilities for different limit states in 50 years can be obtained through coupling the seismic failure probability with the ground motion hazard curve. A six-story reinforced concrete building subjected to ground motions is investigated to the efficiency and accuracy of the proposed method. The interstory drift and the acceleration as two responses of the case study are, respectively, obtained by utilizing Incremental Dynamic Analysis and nonlinear history analysis.

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Supriadi, Amir, Mesnan Mesnan, Imran Akhmad, Rahma Dewi, and Suprayitno Suprayitno. "The Effect of Learning Manipulative Skills Using Ball Thrower Learning Media on the Ability to Throw and Catch the Ball in Elementary School Students." International Journal of Education in Mathematics, Science and Technology 10, no. 3 (May 26, 2022): 590–603. http://dx.doi.org/10.46328/ijemst.2441.

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This study aims to improve the ability to catch in children using the ball thrower learning media. The method used in this study was experimental using a one-group pretest-posttest design. The research was conducted using manipulative motion learning to catch the ball using the throwing media. To measure and find out the results of the data obtained by researchers using the statistical package for the social sciences (SPSS) software. The sample in this study was upper-grade elementary school students. Twenty students were chosen with a random sampling technique. This study's data collection technique using the instrument is a ball catch test. The data analysis technique used a t-test with a significance level of 0.05. This study concluded that there was a significant effect of learning outcomes using the ball throwing learning media on the ability to catch the ball of elementary school students.

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Lorteije, Jeannette A. M., Nick E. Barraclough, Tjeerd Jellema, Mathijs Raemaekers, Jacob Duijnhouwer, Dengke Xiao, Mike W. Oram, Martin J. M. Lankheet, David I. Perrett, and Richard J. A. van Wezel. "Implied Motion Activation in Cortical Area MT Can Be Explained by Visual Low-level Features." Journal of Cognitive Neuroscience 23, no. 6 (June 2011): 1533–48. http://dx.doi.org/10.1162/jocn.2010.21533.

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To investigate form-related activity in motion-sensitive cortical areas, we recorded cell responses to animate implied motion in macaque middle temporal (MT) and medial superior temporal (MST) cortex and investigated these areas using fMRI in humans. In the single-cell studies, we compared responses with static images of human or monkey figures walking or running left or right with responses to the same human and monkey figures standing or sitting still. We also investigated whether the view of the animate figure (facing left or right) that elicited the highest response was correlated with the preferred direction for moving random dot patterns. First, figures were presented inside the cell's receptive field. Subsequently, figures were presented at the fovea while a dynamic noise pattern was presented at the cell's receptive field location. The results show that MT neurons did not discriminate between figures on the basis of the implied motion content. Instead, response preferences for implied motion correlated with preferences for low-level visual features such as orientation and size. No correlation was found between the preferred view of figures implying motion and the preferred direction for moving random dot patterns. Similar findings were obtained in a smaller population of MST cortical neurons. Testing human MT+ responses with fMRI further corroborated the notion that low-level stimulus features might explain implied motion activation in human MT+. Together, these results suggest that prior human imaging studies demonstrating animate implied motion processing in area MT+ can be best explained by sensitivity for low-level features rather than sensitivity for the motion implied by animate figures.

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Parinduri, Sri Handayani, and Melati Sukma Sitompul. "Peningkatan Hasil Belajar Fisika Siswa Menggunakan Model Pembelajaran Kooperatif Tipe Stad Dengan Media Powerpoint." Gravity Journal 1, no. 2 (December 30, 2022): 1–8. http://dx.doi.org/10.24952/gravity.v1i2.6708.

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This research aims to improve students' physics learning outcomes using the STAD-type cooperative learning model with powerpoint media on subject of elasticity and harmonic motion. The research population is all students of class XI IPA of SMA Swasta Kampus which amounts to 2 classes and the sample consists of two classes, namely control classes and experimental classes taken in random sampling clusters. The author applies the STAD-type cooperative learning model with powerpoint media in experimental classes and direct instruction model in control classes. The research instruments used are tests (multiple choice) and non-tests (observations). The average result of the experimental class postes was 79 and the average result of the control class postes was 72. The results showed that there was an increase in student physics learning outcomes using the STAD-type cooperative learning model with powerpoint media by 16.7% with a gain of 0.693 is a medium category.

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Goldshtein, Alexander, and Michael Shapiro. "Mechanics of collisional motion of granular materials. Part 1. General hydrodynamic equations." Journal of Fluid Mechanics 282 (January 10, 1995): 75–114. http://dx.doi.org/10.1017/s0022112095000048.

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Collisional motion of a granular material composed of rough inelastic spheres is analysed on the basis of the kinetic Boltzmann–Enskog equation. The Chapman–Enskog method for gas kinetic theory is modified to derive the Euler-like hydrodynamic equations for a system of moving spheres, possessing constant roughness and inelasticity. The solution is obtained by employing a general isotropic expression for the singlet distribution function, dependent upon the spatial gradients of averaged hydrodynamic properties. This solution form is shown to be appropriate for description of rapid shearless motions of granular materials, in particular vibrofluidized regimes induced by external vibrations.The existence of the hydrodynamic state of evolution of a granular medium, where the Euler-like equations are valid, is delineated in terms of the particle roughness, β, and restitution, e, coefficients. For perfectly elastic spheres this state is shown to exist for all values of particle roughness, i.e. − 1≤β≤1. However, for inelastically colliding granules the hydrodynamic state exists only when the particle restitution coefficient exceeds a certain value em(β)< 1.In contrast with the previous results obtained by approximate moment methods, the partition of the random-motion kinetic energy of inelastic rough particles between rotational and translational modes is shown to be strongly affected by the particle restitution coefficient. The effect of increasing inelasticity of particle collisions is to redistribute the kinetic energy of their random motion in favour of the rotational mode. This is shown to significantly affect the energy partition law, with respect to the one prevailing in a gas composed of perfectly elastic spheres of arbitrary roughness. In particular, the translational specific heat of a gas composed of inelastically colliding (e = 0.6) granules differs from its value for elastic particles by as much as 55 %.It is shown that the hydrodynamic Euler-like equation, describing the transport and evolution of the kinetic energy of particle random motion, contains energy sink terms of two types (both, however, stemming from the non-conservative nature of particle collisions) : (i) the term describing energy losses in incompressibly flowing gas; (ii) the terms accounting for kinetic energy loss (or gain) associated with the work of pressure forces, leading to gas compression (or expansion). The approximate moment methods are shown to yield the Euler-like energy equation with an incorrect energy sink term of type (ii), associated with the ‘dense gas effect’. Another sink term of the same type, but associated with the energy relaxation process occurring within compressed granular gases, was overlooked in all previous studies.The speed of sound waves propagating in a granular gas is analysed in the limits of low and high granular gas densities. It is shown that the particle collisional properties strongly affect the speed of sound in dense granular media. This dependence is manifested via the kinetic energy sink terms arising from gas compression. Omission of the latter terms in the evaluation of the speed of sound results in an error, which in the dense granular gas limit is shown to amount to a several-fold factor.

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CORWIN, IVAN. "THE KARDAR–PARISI–ZHANG EQUATION AND UNIVERSALITY CLASS." Random Matrices: Theory and Applications 01, no. 01 (January 2012): 1130001. http://dx.doi.org/10.1142/s2010326311300014.

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Brownian motion is a continuum scaling limit for a wide class of random processes, and there has been great success in developing a theory for its properties (such as distribution functions or regularity) and expanding the breadth of its universality class. Over the past 25 years a new universality class has emerged to describe a host of important physical and probabilistic models (including one-dimensional interface growth processes, interacting particle systems and polymers in random environments) which display characteristic, though unusual, scalings and new statistics. This class is called the Kardar–Parisi–Zhang (KPZ) universality class and underlying it is, again, a continuum object — a non-linear stochastic partial differential equation — known as the KPZ equation. The purpose of this survey is to explain the context for, as well as the content of a number of mathematical breakthroughs which have culminated in the derivation of the exact formula for the distribution function of the KPZ equation started with narrow wedge initial data. In particular we emphasize three topics: (1) The approximation of the KPZ equation through the weakly asymmetric simple exclusion process; (2) The derivation of the exact one-point distribution of the solution to the KPZ equation with narrow wedge initial data; (3) Connections with directed polymers in random media. As the purpose of this article is to survey and review, we make precise statements but provide only heuristic arguments with indications of the technical complexities necessary to make such arguments mathematically rigorous.

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Savran, W. H., and K. B. Olsen. "Ground motion simulation and validation of the 2008 Chino Hills earthquake in scattering media." Geophysical Journal International 219, no. 3 (September 10, 2019): 1836–50. http://dx.doi.org/10.1093/gji/ggz399.

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SUMMARY We simulate 0–2.5 Hz deterministic wave propagation in 3-D velocity models for the 2008 Chino Hills, CA, earthquake using a finite-fault source model and frequency-dependent anelastic attenuation. Small-scale heterogeneities are modeled as 3-D random fields defined using an elliptically anisotropic von Kármán autocorrelation function with its parameters constrained using Los Angeles basin borehole data. We superimpose the heterogeneity models on a leading deterministic community velocity model (CVM) of southern California. We find that models of velocity and density perturbations can have significant effects on the wavefield at frequencies as low as 0.5 Hz, with ensemble median values of various ground motion metrics varying up to ±50 per cent compared to those computed using the deterministic CVM only. In addition, we show that frequency-independent values of the shear-wave quality factor (Qs0) parametrized as Qs0 = 150Vs (Vs in km s–1) provides the best agreement with data when assuming the published moment magnitude (Mw) of 5.4 (M0 = 1.6 × 1017 Nm) for the finite-fault source model. This model for Qs0 trades off with Qs0 = 100Vs assuming Mw = 5.5 (M0 = 2.2 × 1017 Nm), which represents an upper bound of the Mw estimates for this event. We find the addition of small-scale heterogeneities provides limited overall improvement to the misfit between simulations and data for the considered ground motion metrics, because the primary sources of misfit originate from the deterministic CVM and/or the finite-fault source description.

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Latifah, Nur Khanifatul, Tomo Djudin, and Hamdani Hamdani. "Provision of Physics E-Comics to Improve Student Learning Outcomes on Straight-Motion Material at MTs Negeri 1 Kayong Utara." Jurnal Geliga Sains: Jurnal Pendidikan Fisika 10, no. 2 (December 30, 2022): 112. http://dx.doi.org/10.31258/jgs.10.2.112-119.

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The research was conducted to know the effectiveness of providing e-comics related to straight-motion material for improving student learning outcomes in class VIII MTsN 1 Kayong Utara. This type of research is experimental research that applies a non-equivalent control group design with an intact group random sampling technique. Based on the research data, the results were obtained, namely: 1) students who received e-comics and those who did not receive e-comics, their learning outcomes increased. The increase in learning outcomes in the experimental class was higher than that in the control class; 2) a significant difference was found in the learning outcomes of students who used e-comics and those who did not use e-comics with Sig. (2-tailed) < 0.05; 3) the provision of e-comics in learning is obtained with an effective level of 0.82 in the effective category. Therefore, e-comic media is effectively used in learning straight-motion material in class VIII MTsN 1 Kayong Utara.

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Liu, Bin, Chengwei Kang, and Fengzhou Fang. "Biometric Measurement of Anterior Segment: A Review." Sensors 20, no. 15 (July 31, 2020): 4285. http://dx.doi.org/10.3390/s20154285.

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Biometric measurement of the anterior segment is of great importance for the ophthalmology, human eye modeling, contact lens fitting, intraocular lens design, etc. This paper serves as a comprehensive review on the historical development and basic principles of the technologies for measuring the geometric profiles of the anterior segment. Both the advantages and drawbacks of the current technologies are illustrated. For in vivo measurement of the anterior segment, there are two main challenges that need to be addressed to achieve high speed, fine resolution, and large range imaging. One is the motion artefacts caused by the inevitable and random human eye movement. The other is the serious multiple scattering effects in intraocular turbid media. The future research perspectives are also outlined in this paper.

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Chang, AiLian, and HongGuang Sun. "Time-space fractional derivative models for CO2 transport in heterogeneous media." Fractional Calculus and Applied Analysis 21, no. 1 (February 23, 2018): 151–73. http://dx.doi.org/10.1515/fca-2018-0010.

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Abstract This study is mainly to explore gas transport process in heterogeneous media, which is to lay the foundation for oil-gas exploitation and development. Anomalous transport is observed to be ubiquitous in complex geological formations and has a paramount impact on petroleum engineering. Simultaneously, the random motion of particles usually exhibits obvious path- and history- dependent behaviors. This paper investigates the time-space fractional derivative models as a potential explanation for the time memory of long waiting time and the space non-locality of large regional-scale. A one-dimensional fractional advection-dispersion equation (FADE) based on fractional Fick’s law is firstly used to accurately describe the transport of Carbon dioxide (CO2) in complex media. The new fractional Darcy-advection-dispersion equation (FDADE) model has subsequently been proposed to make a comparison with FADE model and demonstrate its physical mechanism. Finally, the priori estimation of the parameters (fractional derivative index) in fractional derivative models and corresponding physical explanation are presented. Combined with experimental data, the numerical simulations show the fractional derivative models can well characterize the heavy-tailed and early breakthrough phenomenon of CO2 transport.

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Journal articles on the topic 'Random motion in random media'

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