scholarly journals Silo discharge of mixtures of soft and rigid grains

Soft Matter ◽  
2021 ◽  
Author(s):  
Jing Wang ◽  
Bo Fan ◽  
Tivadar Pongo ◽  
Kirsten Harth ◽  
Torsten Trittel ◽  
...  
Keyword(s):  
Two Dimensional ◽  
Low Friction ◽  
Silo Discharge ◽  
Spherical Grains

We study the outflow dynamics and clogging phenomena of mixtures of soft, elastic low-friction spherical grains and hard frictional spheres of similar size in a quasi-two-dimensional (2D) silo with narrow...

Role of Alkaline Fusion in the Growth of Sodium Titanite Nanostructures from Rutile Mineral

2012 ◽  
Vol 21 ◽  
pp. 77-82
Author(s):  
Yusoff M.S. Meor ◽  
E.M. Mahdi ◽  
Muslimin Masliana ◽  
Paulus Wilfred
Keyword(s):  
Hydrothermal Process ◽  
Sodium Titanate ◽  
Average Diameter ◽  
Fusion Process ◽  
Dissolution Time ◽  
Two Dimensional ◽  
Alkaline Fusion ◽  
Spherical Structure ◽  
Spherical Grains

The paper presents a study on the use of alkaline fusion to produce nanostructured sodium titanate from rutile mineral. The spherical structure of the micron-sized starting material changed and transformed to a two-dimensional nanostructure after the alkaline fusion process. After 7 hours dissolution with 30% NaOH, the growth of sodium titanate nanorod is observed, and after undergoing prolonged dissolution, nanowires, with an average diameter of 20-40 nm and a length of 1-4 µm are formed. The study also showed that using 0.1M HCl to wash the titanate complex results in a sodium titanate that is free from NaOH residue, although at higher molarities, the nanostructure will collapse, and spherical grains formed. The important role of alkaline fusion in this hydrothermal process is that it will reduce dissolution time, while NaOH concentration is required for the growth of nanostructured sodium titanate.

Ultra-low Friction and Patterning on Atomically Thin MoS2 via Electronic Tightly Binding

Nanoscale ◽  
2021 ◽  
Author(s):  
Bin Shi ◽  
Xuehui Gan ◽  
Yitian Peng ◽  
Haojie Lang ◽  
kun zou ◽  
...  
Keyword(s):  
Molybdenum Disulfide ◽  
Solid Lubricant ◽  
Electromechanical System ◽  
Two Dimensional ◽  
Low Friction ◽  
Nano Electromechanical System

Atomically thin two-dimensional molybdenum disulfide (MoS2) is well known for its excellent lubricating characteristics and is usually used as a solid lubricant in diverse micro/nano electromechanical system (MEMS/NEMS). The friction...

scholarly journals The Unusual Tribological Properties of Graphene/Antimonene Heterojunctions: A First-Principles Investigation

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1201
Author(s):  
Xian Jiang ◽  
Zhibin Lu ◽  
Renhui Zhang
Keyword(s):  
Tribological Properties ◽  
First Principles ◽  
2D Materials ◽  
Two Dimensional ◽  
Lateral Interactions ◽  
Low Friction ◽  
Friction Coefficients ◽  
Work Of Separation ◽  
First Principles Method

The extremely low friction between incommensurate two-dimensional (2D) materials has drawn more attention in the recent years. Structural superlubricity is a fascinating tribological phenomenon that is achieved in 2D heterojunctions despite the aligned or misaligned contacts that occur due to the disappearance of the lateral interactions between two incommensurate contacting surfaces. In this study, using the first-principles method, we report the computational realization of structural superlubricity for graphene/antimonene heterojunctions at the nanoscale. The calculated results clearly demonstrate that structural superlubricity between graphene and antimonene monolayers could be achieved under the misaligned contacts. The structural superlubricity is mainly attributed to lower work of separation, which maintains superlow friction coefficients.

scholarly journals The performance of the µ(I)-rheology model on flat bottom silos discharge

2021 ◽  
Vol 249 ◽  
pp. 03032
Author(s):  
César Venier ◽  
Leonardo Binda ◽  
Damián Ramajo ◽  
Santiago Márquez Damián ◽  
Irene Ippolito ◽  
...  
Keyword(s):  
Discharge Rate ◽  
General Structure ◽  
Computational Simulation ◽  
Numerical Implementation ◽  
Two Dimensional ◽  
Flat Bottom ◽  
Silo Discharge ◽  
Real Scale ◽  
Rheology Model ◽  
Do So

The aim of this work is to explore the capability of the µ(I)-rheology model and its numerical implementation in addressing a silo discharge problem by computational simulation. In order to do so, the model was implemented in the general structure of an Eulerian multiphase solver based on the Volume-Of-Fluid (VOF) method of the OpenFOAM(R) suite. First, the implementation is validated against the results of another Lagrangian and Eulerian codes in a two-dimensional discharge problem. After that, the model is tested against the experimental results of a lab-scale and industrial-scale discharge problem. While the results of the first one were satisfactory in terms of discharge rate, for the latter one, the model exhibits disagreements in the flow patterns inside the silo. The study shows the limits of applicability of the standard formulation of the model for real scale silos and sets the ground for further discussion and improvements.

scholarly journals Non-negative depth reconstruction for a two-dimensional partial inertial inundation model

2014 ◽  
Vol 16 (5) ◽  
pp. 1158-1177 ◽  
Author(s):  
Hongbin Zhang ◽  
Yueling Wang ◽  
Qiuhua Liang ◽  
Luke S. Smith ◽  
Chris G. Kilsby
Keyword(s):  
Momentum Equation ◽  
Steep Slope ◽  
Test Cases ◽  
Reconstruction Method ◽  
Two Dimensional ◽  
Low Friction ◽  
Depth Reconstruction ◽  
Practical Challenge ◽  
Numerical Performance ◽  
Flood Simulations

This paper proposes a non-negative depth reconstruction method for improving the numerical performance of a partial inertial model (PIM) for applications involving steep-slope and low-friction conditions. The PIM solves the continuity equation of two-dimensional (2D) shallow water equations (SWEs) with the interface fluxes evaluated by a simplified momentum equation that partially restores the inertial terms. In applying the PIM to flood simulations, a practical challenge is to represent complex topography and to track the moving wet–dry interface without resulting in negative water depths. Another challenge is to avoid the numerical issue caused by the lack of physical diffusive terms when it is applied to low-friction cases. To cope with these difficulties, the PIM is improved by introducing a non-negative depth reconstruction method, featuring two different ways for calculating the interface fluxes. The performance of the improved PIMs is investigated through applications to several theoretical and practical benchmark test cases. The comparison of the numerical results against analytical solutions or predictions from the original PIM and a full 2D finite-volume hydrodynamic model shows that the proposed reconstruction method can avoid non-negative water depth predictions, and improve the numerical performance of the original PIM when applied to steep-slope and low-friction conditions.

Spectrophotometric measurements of objective-prism spectra

1966 ◽  
Vol 24 ◽  
pp. 118-119
Author(s):  
Th. Schmidt-Kaler
Keyword(s):  
Progress Report ◽  
Two Dimensional ◽  
Objective Prism ◽  
Made In

I should like to give you a very condensed progress report on some spectrophotometric measurements of objective-prism spectra made in collaboration with H. Leicher at Bonn. The procedure used is almost completely automatic. The measurements are made with the help of a semi-automatic fully digitized registering microphotometer constructed by Hög-Hamburg. The reductions are carried out with the aid of a number of interconnected programmes written for the computer IBM 7090, beginning with the output of the photometer in the form of punched cards and ending with the printing-out of the final two-dimensional classifications.

Introductory paper

1966 ◽  
Vol 24 ◽  
pp. 3-5
Author(s):  
W. W. Morgan
Keyword(s):  
Line Intensity ◽  
Classification Scheme ◽  
Two Dimensional ◽  
Spectral Classification ◽  
Dimensional Array ◽  
Rr Lyrae ◽  
Metallic Line ◽  
Introductory Paper ◽  
Parameter Varying ◽  
Definition Of

1. The definition of “normal” stars in spectral classification changes with time; at the time of the publication of theYerkes Spectral Atlasthe term “normal” was applied to stars whose spectra could be fitted smoothly into a two-dimensional array. Thus, at that time, weak-lined spectra (RR Lyrae and HD 140283) would have been considered peculiar. At the present time we would tend to classify such spectra as “normal”—in a more complicated classification scheme which would have a parameter varying with metallic-line intensity within a specific spectral subdivision.

A one-dimensional self-gravitating stellar gas

1966 ◽  
Vol 25 ◽  
pp. 46-48 ◽  
Author(s):  
M. Lecar
Keyword(s):  
Gravitational Field ◽  
Phase Space ◽  
Motion Picture ◽  
Space Distribution ◽  
Two Dimensional ◽  
One Dimensional ◽  
Phase Space Distribution ◽  
Dimensional Phase Space ◽  
The Mean

“Dynamical mixing”, i.e. relaxation of a stellar phase space distribution through interaction with the mean gravitational field, is numerically investigated for a one-dimensional self-gravitating stellar gas. Qualitative results are presented in the form of a motion picture of the flow of phase points (representing homogeneous slabs of stars) in two-dimensional phase space.

Analysis of the 9th November 1990 flare

2000 ◽  
Vol 179 ◽  
pp. 229-232
Author(s):  
Anita Joshi ◽  
Wahab Uddin
Keyword(s):  
Image Processing ◽  
Two Dimensional ◽  
Temporal Behaviour ◽  
Contour Maps ◽  
Dimensional Measurements ◽  
Processing Software ◽  
Image Processing Software

AbstractIn this paper we present complete two-dimensional measurements of the observed brightness of the 9th November 1990Hαflare, using a PDS microdensitometer scanner and image processing software MIDAS. The resulting isophotal contour maps, were used to describe morphological-cum-temporal behaviour of the flare and also the kernels of the flare. Correlation of theHαflare with SXR and MW radiations were also studied.

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