Read by QxMD icon Read

discrete element method

Adam J Brown, David C James
Promoter functionality is highly context dependent, as exemplified by gene-specific expression profiles across different tissues and cell types. Cell type-specific promoter regulation is a function of each cell's unique complement of transcriptional machinery components. Accordingly, to achieve high levels of transcriptional activity within a particular cell type, synthetic promoters must be specifically designed to harness those cells discrete repertoire of available transcription factors . Here, we describe a method for constructing very strong cell type-specific synthetic promoters for use in any given mammalian host cell...
2017: Methods in Molecular Biology
Meng-Shan Wu, Hui-Li Han, Cui Yao, Xiao-Rong He, Jun-Yi Zhang, Ting-Yun Shi
We calculate the rovibrational bound levels with total angular momentum J = 0, 1 of (40)Ar2(84)Kr trimer using the slow variable discretization method combined with the finite-element method-discrete variable representation basis. The statistical distributions of the rovibrational levels for J(Π)=0(e), 1(e), and 1(o) symmetries are presented and the effects of the Axilrod-Teller potential term are considered. For the 0(e) and 1(e) symmetries, the Axilrod-Teller term makes the spectra become fully chaotic. However, for the 1(o) symmetry, statistical properties depend mainly on the coupling between K = 0 and K = 1 and the Axilrod-Teller term has a small effect...
August 7, 2017: Journal of Chemical Physics
Ning Zhu, Dennj De Meo, Erkan Oterkus
An ordinary state-based peridynamic formulation is developed to analyse cubic polycrystalline materials for the first time in the literature. This new approach has the advantage that no constraint condition is imposed on material constants as opposed to bond-based peridynamic theory. The formulation is validated by first considering static analyses and comparing the displacement fields obtained from the finite element method and ordinary state-based peridynamics. Then, dynamic analysis is performed to investigate the effect of grain boundary strength, crystal size, and discretization size on fracture behaviour and fracture morphology...
December 2, 2016: Materials
Zixin Yin, Yuxing Peng, Zhencai Zhu, Zhangfa Yu, Tongqing Li
The impact behavior between the charge and lifter has significant effect to address the mill processing, and is affected by various factors including mill speed, mill filling, lifter height and media shape. To investigate the multi-body impact load behavior, a series of experiments and Discrete Element Method (DEM) simulations were performed on a laboratory-scale mill, in order to improve the grinding efficiency and prolong the life of the lifter. DEM simulation hitherto has been extensively applied as a leading tool to describe diverse issues in granular processes...
July 31, 2017: Materials
Daisuke Nishiura, Hide Sakaguchi, Akira Aikawa
Simulation of a large number of deformable bodies is often difficult because complex high-level modeling is required to address both multi-body contact and viscoelastic deformation. This necessitates the combined use of a discrete element method (DEM) and a finite element method (FEM). In this study, a quadruple discrete element method (QDEM) was developed for dynamic analysis of viscoelastic materials using a simpler algorithm compared to the standard FEM. QDEM easily incorporates the contact algorithm used in DEM...
June 3, 2017: Materials
Tongqing Li, Yuxing Peng, Zhencai Zhu, Shengyong Zou, Zixin Yin
Aiming at predicting what happens in reality inside mills, the contact parameters of iron ore particles for discrete element method (DEM) simulations should be determined accurately. To allow the irregular shape to be accurately determined, the sphere clump method was employed in modelling the particle shape. The inter-particle contact parameters were systematically altered whilst the contact parameters between the particle and wall were arbitrarily assumed, in order to purely assess its impact on the angle of repose for the mono-sized iron ore particles...
May 11, 2017: Materials
Erkai Watson, Martin O Steinhauser
In this paper, we introduce a computational model for the simulation of hypervelocity impact (HVI) phenomena which is based on the Discrete Element Method (DEM). Our paper constitutes the first application of DEM to the modeling and simulating of impact events for velocities beyond 5 kms(-1). We present here the results of a systematic numerical study on HVI of solids. For modeling the solids, we use discrete spherical particles that interact with each other via potentials. In our numerical investigations we are particularly interested in the dynamics of material fragmentation upon impact...
April 2, 2017: Materials
Amin Yaghoobi, Mi G Chorzepa, S Sonny Kim, Stephan A
Concrete is a complex heterogeneous material, and thus, it is important to develop numerical modeling methods to enhance the prediction accuracy of the fracture mechanism. In this study, a two-dimensional mesoscale model is developed using a non-ordinary state-based peridynamic (NOSBPD) method. Fracture in a concrete cube specimen subjected to pure tension is studied. The presence of heterogeneous materials consisting of coarse aggregates, interfacial transition zones, air voids and cementitious matrix is characterized as particle points in a two-dimensional mesoscale model...
February 10, 2017: Materials
Xiaolin Huang, Qi Zhao, Shengwen Qi, Kaiwen Xia, Giovanni Grasselli, Xuguang Chen
This paper numerically investigates the seismic response of the filled joint under high amplitude stress waves using the combined finite-discrete element method (FDEM). A thin layer of independent polygonal particles are used to simulate the joint fillings. Each particle is meshed using the Delaunay triangulation scheme and can be crushed when the load exceeds its strength. The propagation of the 1D longitude wave through a single filled joint is studied, considering the influences of the joint thickness and the characteristics of the incident wave, such as the amplitude and frequency...
December 27, 2016: Materials
Yanpeng Guan, Enzhi Wang, Xiaoli Liu, Sijing Wang, Hebing Luan
We have attempted a multiscale and quantified characterization method of the contact in three-dimensional granular material made of spherical particles, particularly in cemented granular material. Particle contact is defined as a type of surface contact with voids in its surroundings, rather than a point contact. Macro contact is a particle contact set satisfying the restrictive condition of a two-dimensional manifold with a boundary. On the basis of graph theory, two dual geometrical systems are abstracted from the granular pack...
August 3, 2017: Materials
Jin-Zhong Gu, Xiao-Xiao Liang, Yan Cai, Jiang Wu, Zi-Fa Shi, Alexander M Kirillov
In this work, a trifunctional N,O-building block, 5-(4-carboxyphenoxy)nicotinic acid (H2cpna), that combines three distinct types of functional groups (COOH, N-pyridyl, and O-ether) was used for the hydrothermal assembly of thirteen new coordination compounds: [Co(μ3-Hcpna)2]n (1), [Mn(μ4-cpna)(H2O)]n (2), [Mn(μ4-cpna)(H2O)2]n (3), [Mn(μ-cpna)(2,2'-bipy)(H2O)2]n (4), {[Ni(μ3-cpna)(2,2'-bipy)(H2O)]2·H2O}n (5), {[Cd(μ3-cpna)(2,2'-bipy)]·2H2O}n (6), [Zn2(μ-cpna)2(2,2'-bipy)2] (7), [Cu(μ-cpna)(2,2'-bipy)(H2O)]n (8), {[Mn(μ-cpna)(phen)2]·6H2O}n (9), {[Ni(μ3-cpna)(phen)(H2O)]·H2O}n (10), [Zn2(μ-cpna)2(phen)2] (11), {[Pb(μ3-cpna)(phen)]·H2O}n (12), and [Ni(μ3-cpna)(4,4'-bipy)0...
August 2, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Ignacio Peralta, Víctor D Fachinotti
In this work, we present a new method for the design of heat flux manipulating devices, with emphasis on their fabricability. The design is obtained as solution of a nonlinear optimization problem where the objective function represents the given heat flux manipulation task, and the design variables define the material distribution in the device. In order to facilitate the fabrication of the device, the material at a given point is chosen from a set of predefined metamaterials. Each candidate material is assumed to be a laminate of materials with high conductivity contrast, so it is a metamaterial with a highly anisotropic effective conductivity...
July 24, 2017: Scientific Reports
Ned C Rouze, Yufeng Deng, Mark L Palmeri, Kathryn R Nightingale
Recent measurements of shear wave propagation in viscoelastic materials have been analyzed by constructing the 2-D Fourier transform (2DFT) of the shear wave signal and measuring the phase velocity c(ω) and attenuation α(ω) from the peak location and full width at half-maximum (FWHM) of the 2DFT signal at discrete frequencies. However, when the shear wave is observed over a finite spatial range, the 2DFT signal is a convolution of the true signal and the observation window, and measurements using the FWHM can yield biased results...
July 18, 2017: Ultrasound in Medicine & Biology
Zilong Zou, Wilkins Aquino, Isaac Harari
In this work, we use Nitsche's formulation to weakly enforce kinematic constraints at an embedded interface in Helmholtz problems. Allowing embedded interfaces in a mesh provides significant ease for discretization, especially when material interfaces have complex geometries. We provide analytical results that establish the well-posedness of Helmholtz variational problems and convergence of the corresponding finite element discretizations when Nitsche's method is used to enforce kinematic constraints. As in the analysis of conventional Helmholtz problems, we show that the inf-sup constant remains positive provided that the Nitsche's stabilization parameter is judiciously chosen...
May 18, 2017: International Journal for Numerical Methods in Engineering
Kim-Sarah Kleij, Ulla Tangermann, Volker E Amelung, Christian Krauth
BACKGROUND: Primary care is a key element of health care systems and addresses the main health problems of the population. Due to the demographic change, primary care even gains in importance. The knowledge of the patients' preferences can help policy makers as well as physicians to set priorities in their effort to make health care delivery more responsive to patients' needs. Our objective was to describe which aspects of primary care were included in preference studies and which of them were the most preferred aspects...
July 11, 2017: BMC Health Services Research
Peizhen Wang, Liying Jiang, Shaochun Chen
In this paper, we construct a semi-discrete scheme and a fully discrete scheme using the Wilson nonconforming element for the parabolic integro-differential equation arising in modeling the non-Fickian flow in porous media by the interior penalty method. Without using the conventional elliptic projection, which was an indispensable tool in the convergence analysis of finite element methods in previous literature, we get an optimal error estimate which is only determined by the interpolation error. Finally, we give some numerical experiments to show the efficiency of the method...
2017: Journal of Inequalities and Applications
Wendelin Schramm, Johannes Rickmann, Fabian Sailer
Disease Modelling of chronic diseases such as diabetes or asthma plays an important role in medical decision making. State transition models are the most frequently used method. The objective is to illustrate the elements and the most important underlying procedures for designing a decision analytic Markov model with only three-states. METHOD: Being "healthy" can be interpreted as a norm state, being "sick" as a temporary state and "dead" as an absorbing state. Transitions with accompanying transition probabilities that allow a cohort of model objects "to flow" between the cumulative exhaustive and mutually exclusive states complete the model structure...
2017: Studies in Health Technology and Informatics
Aleksander Sesek, Andrej Zemva, Janez Trontelj
BACKGROUND: The THz sensors using microbolometers as a sensing element are reported as one of the most sensitive room-temperature THz detectors suitable for THz imaging and spectroscopic applications. Microbolometer detectors are usually fabricated using different types of the MEMS technology. The patent for the detection system presented in this paper describes a method for microbolometer fabrication using a standard CMOS technology with advanced micromachining techniques. The measured sensitivity of the sensors fabricated by the patented method is 1000 V/W at an optimal frequency and is determined by the performance of a double-dipole antenna and quarter-wavelength resonant cavity...
July 4, 2017: Recent Patents on Nanotechnology
Mark R Schure, Joe M Davis
Orthogonality metrics (OMs) for three and higher dimensional separations are proposed as extensions of previously developed OMs, which were used to evaluate the zone utilization of two-dimensional (2D) separations. These OMs include correlation coefficients, dimensionality, information theory metrics and convex-hull metrics. In a number of these cases, lower dimensional subspace metrics exist and can be readily calculated. The metrics are used to interpret previously generated experimental data. The experimental datasets are derived from Gilar's peptide data, now modified to be three dimensional (3D), and a comprehensive 3D chromatogram from Moore and Jorgenson...
June 13, 2017: Journal of Chromatography. A
Andrea Simoni, Alexandra Viel, Jean-Michel Launay
We apply the spectral element method to the determination of scattering and bound states of the multichannel Schrödinger equation. In our approach, the reaction coordinate is discretized on a grid of points whereas the internal coordinates are described by either purely diabatic or locally diabatic (diabatic-by-sector) bases. Bound levels and scattering matrix elements are determined with spectral accuracy using relatively small number of points. The scattering problem is cast as a linear system solved using state-of-the-art sparse matrix non-iterative packages...
June 28, 2017: Journal of Chemical Physics
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"