Adhesion of Partially and Fully Collapsed Nanotubes

2018 ◽  
Vol 86 (1) ◽  
Author(s):  
Ming Li ◽  
Hao Li ◽  
Fengwei Li ◽  
Zhan Kang
Keyword(s):  
Finite Deformation ◽  
Adhesion Energy ◽  
Van Der Waals Interactions ◽  
Critical Conditions ◽  
Nano Composites ◽  
Deformation Model ◽  
Analysis And Design ◽  
Structural Rigidity ◽  
Multiwall Nanotubes ◽  
The Stability

The competition between the structural rigidity and the van der Waals interactions may lead to collapsing of aligned nanotubes, and the resulting changes of both configurations and properties promise the applications of nanotubes in nano-composites and nano-electronics. In this paper, a finite-deformation model is applied to study the adhesion of parallel multiwall nanotubes with both partial and full collapsing, in which the noncontact adhesion energy is analytically determined. The analytical solutions of both configurations and energies of collapsed nanotubes are consistent with the molecular dynamics (MD) results, demonstrating the effectiveness of the finite-deformation model. To study the critical conditions of generating the partially and fully collapsed multiwall nanotubes, our analytical model gives the predictions for both the geometry- and energy-related critical diameters, which are helpful for the stability analysis and design of nanotube-based nano-devices.

ANALISIS KESTABILAN LERENG DINDING AKHIR DI PIT BARATLAUT PADA PENAMBANGAN BATUBARA DI PT. PUTERA BARA MITRA , KECAMATAN MENTEWE, KALIMANTAN SELATAN

KURVATEK ◽  
2018 ◽  
Vol 3 (1) ◽  
pp. 21-34
Author(s):  
Untung Wahyudi ◽  
Excelsior T P ◽  
Luthfi Wahyudi
Keyword(s):  
Slope Stability ◽  
Mining Operation ◽  
Subsurface Water ◽  
Mining System ◽  
Mine Site ◽  
Analysis And Design ◽  
The Stability ◽  
End Wall ◽  
Wall Slope ◽  
Mining Slope

PT. Putera Bara Mitra used open mining system for mining operation, Yet the completion of study on the end wall slope stability that  undertaken by geotechnical PT. Putera Bara Mitra in Northwest Pit and the occured a failure in the low wall on the 1st June 2012 led to the need for analysis and design the overall slope at the mine site. To analyze and design the overall slope, used value of the recommended minimum safety. The value was based on company for single slope SF ≥ 1.2 and SF ≥ 1.3 for overall slope. The calculation used Bichop method with the help of software slide v 5.0. Geometry improvements was done at the low slopes that originally single wall with a 30 m bench height and a slope 70° with SF = 0.781, into 4 levels with SF = 1.305. The analysis explained the factors that affect the stability of the low wall included the mining slope geometry, unfavorable drainase system, material stockpiles and seismicity factors. It was necessary to do prevention efforts to maintain the stability of the slope included the redesign to slope geometry, handling surface and subsurface water in a way to control slopes draining groundwater, vegetation stabilization using and monitoring slope using Total Station with Prism and Crackmeter to determine the movement of cracks visible on the surface. 

Impact of osmotic pressure on the stability of Taylor vortices

2022 ◽  
Vol 933 ◽  
Author(s):  
Rouae Ben Dhia ◽  
Nils Tilton ◽  
Denis Martinand
Keyword(s):  
Osmotic Pressure ◽  
Critical Conditions ◽  
Hydrodynamic Instabilities ◽  
Taylor Vortices ◽  
Dynamic Filtration ◽  
Analytical Criterion ◽  
Permeable Cylinders ◽  
Couette Cell ◽  
Taylor Couette ◽  
The Stability

We use linear stability analysis and direct numerical simulations to investigate the coupling between centrifugal instabilities, solute transport and osmotic pressure in a Taylor–Couette configuration that models rotating dynamic filtration devices. The geometry consists of a Taylor–Couette cell with a superimposed radial throughflow of solvent across two semi-permeable cylinders. Both cylinders totally reject the solute, inducing the build-up of a concentration boundary layer. The solute retroacts on the velocity field via the osmotic pressure associated with the concentration differences across the semi-permeable cylinders. Our results show that the presence of osmotic pressure strongly alters the dynamics of the centrifugal instabilities and substantially reduces the critical conditions above which Taylor vortices are observed. It is also found that this enhancement of the hydrodynamic instabilities eventually plateaus as the osmotic pressure is further increased. We propose a mechanism to explain how osmosis and instabilities cooperate and develop an analytical criterion to bound the parameter range for which osmosis fosters the hydrodynamic instabilities.

scholarly journals Energetics of carbohydrate binding by a 14 kDa S-type mammalian lectin

1995 ◽  
Vol 308 (1) ◽  
pp. 237-241 ◽  
Author(s):  
R Ramkumar ◽  
A Surolia ◽  
S K Podder
Keyword(s):  
Binding Constants ◽  
Van Der Waals Interactions ◽  
Titration Calorimetry ◽  
Carbohydrate Binding ◽  
Glucose Binding ◽  
The Stability ◽  
L 14 ◽  
Derivatives Of ◽  
Binding Lectin ◽  
Site Binding

The thermodynamics of the binding of derivatives of galactose and lactose to a 14 kDa beta-galactoside-binding lectin (L-14) from sheep spleen has been studied in 10 nM phosphate/150 mM NaCl/10 mM beta-mercaptoethanol buffer, pH 7.4, and in the temperature range 285-300 K using titration calorimetry. The single-site binding constants of various sugars for the lectin were in the following order: N-acetyl-lactosamine thiodigalactoside > 4-methylumbelliferyl lactoside > lactose > 4-methylumbelliferyl alpha-D-galactoside > methyl-alpha-galactose > methyl-beta-galactose. Reactions were essentially enthalpically driven with the binding enthalpies ranging from -53.8 kJ/mol for thiodigalactoside at 301 K to -2.2 kJ/mol for galactose at 300 K, indicating that hydrogen-bonding and van der Waals interactions provide the major stabilization for these reactions. However, the binding of 4-methylumbelliferyl-alpha-D-galactose displays relatively favourable entropic contributions, indicating the existence of a non-polar site adjacent to the galactose-binding subsite. From the increments in the enthalpies for the binding of lactose, N-acetyl-lactosamine and thiodigalactoside relative to methyl-beta-galactose, the contribution of glucose binding in the subsite adjacent to that for galactose shows that glucose makes a major contribution to the stability of L-14 disaccharide complexes. Observation of enthalpy-entropy compensation for the recognition of saccharides such as lactose by L-14 and the absence of it for monosaccharides such as galactose, together with the lack of appreciable changes in the heat capacity (delta Cp), indicate that reorganization of water plays an important role in these reactions.

Predictive estimates of subsidence of the earth’s surface during the development of the Yamburgskoye oil and gas condensate field

2021 ◽  
pp. 9-22
Author(s):  
Yu. V. Vasiliev ◽  
M. S. Mimeev ◽  
D. A. Misyurev
Keyword(s):  
Oil And Gas ◽  
Active Faults ◽  
Physical And Mechanical Properties ◽  
Deformation Model ◽  
Reservoir Pressure ◽  
Gas Reservoirs ◽  
Field Development ◽  
Geodynamic Processes ◽  
Deformation Processes ◽  
The Stability

The production of hydrocarbons is associated with a change in the physical and mechanical properties of oil and gas reservoirs under the influence of rock and reservoir pressures. Deformation of the reservoir due to a drop in reservoir pressure leads to the formation of various natural and man-made geodynamic and geomechanical phenomena, one of which is the formation of a subsidence trough of the earth's surface, which leads to a violation of the stability of field technological objects.In order to ensure geodynamic safety, a set of works is used, which includes analysis of geological and field indicators and geological and tectonic models of the field, interpretation of aerospace photographs, identification of active faults, construction of a predictive model of subsidence of the earth's surface of the field with identification of zones of geodynamic risk.This work was carried out to assess the predicted parameters of rock displacement processes during field development; even insignificant disturbances in the operation of technological equipment caused by deformation processes can cause significant damage.Prediction of rock displacements is possible only on the basis of a reservoir deformation model that adequately reflects the geomechanical and geodynamic processes occurring in the subsoil. The article presents a model of reservoir deformation with a drop in reservoir pressure, describes its numerical implementation, and performs calculations of schemes for typical development conditions.

Laminar Swirling Pipe Flow

1954 ◽  
Vol 21 (1) ◽  
pp. 1-7
Author(s):  
L. Talbot
Keyword(s):  
Swirling Flow ◽  
Nonlinear Effects ◽  
Critical Conditions ◽  
Flow Conditions ◽  
Rotationally Symmetric ◽  
Rate Of Decay ◽  
Linearized Theory ◽  
The Stability ◽  
Experimental Values ◽  
Rates Of Decay

Abstract The problem of the decay of a rotationally symmetric steady swirl superimposed on Poiseuille flow in a round pipe was investigated theoretically and experimentally. The object was to determine the degree to which the rate of decay of the swirl as predicted by a linearized theory agreed with measured rates of decay at flow conditions near the critical conditions for swirl instability. The solution to the linearized equation of motion for the swirl was obtained. Swirling flow was produced experimentally by rotating a section of the test pipe. Swirl velocities were determined from motion-picture studies of colored oil droplets introduced in the flow. The stability of the swirl was investigated through visualization of a dye filament, and a critical curve for swirl instability was determined experimentally relating the angular velocity of the rotating section to the Reynolds number. The theoretical and experimental values for the decay parameter were found to agree closely, even at conditions of flow near the critical conditions for instability. It was concluded that in the problem under consideration the nonlinear effects are not appreciable for stable decay of the swirl.

scholarly journals On the stability of the generalized, finite deformation correspondence model of peridynamics

2020 ◽  
Vol 182-183 ◽  
pp. 64-76 ◽  
Author(s):  
Masoud Behzadinasab ◽  
John T. Foster
Keyword(s):  
Finite Deformation ◽  
The Stability

First-principles study on the stability and magnetoelectric properties of multiferroic materials XTiO3 (X = Mn, Fe, Co, Ni)

2018 ◽  
Vol 32 (09) ◽  
pp. 1850105 ◽  
Author(s):  
Xing-Yuan Chen ◽  
Guo-Xia Lai ◽  
Di Gu ◽  
Wei-Ling Zhu ◽  
Tian-Shu Lai ◽  
...  
Keyword(s):  
Magnetic Property ◽  
First Principles ◽  
Phonon Dispersion ◽  
Critical Conditions ◽  
First Principles Calculations ◽  
Multiferroic Materials ◽  
Equilibrium Conditions ◽  
Magnetoelectric Properties ◽  
Strong Hybridization ◽  
The Stability

The XTiO3 (X = Mn, Fe, Co and Ni) materials with R3c structure could be grown under critical conditions based on first-principles calculations and thermodynamic stability analysis. FeTiO3 and MnTiO3 could be synthesized relatively easily under metal-rich and O-poor conditions, while NiTiO3 could be stable under Ni-rich, O-rich and Ti-poor conditions. The predicted R3c CoTiO3 under thermodynamic equilibrium conditions is suggested to be synthesized under Co-rich, O-rich and Ti-poor conditions, but the calculated phonon dispersion indicates R3c CoTiO3 becomes unstable under the dynamical conditions. The ferroelectric behavior in the XTiO3 (X = Mn, Fe, Co and Ni) system could be dominated by the Ti ion with d0 state and the strong hybridization between Ti and O, while the magnetic property is mainly caused by the contribution of 3d transition metal.

Surveillance Ship with Fuel Cell Performance Analysis and Design

2014 ◽  
Vol 496-500 ◽  
pp. 728-732
Author(s):  
Yean Der Kuan ◽  
Jing Yi Chang ◽  
Min Shiang Huang ◽  
Yen Yao Chu ◽  
Yan Ci Chen ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Clean Energy ◽  
Proton Exchange ◽  
Fuel Cell Performance ◽  
Analysis And Design ◽  
The Stability ◽  
Performance Analysis And Design ◽  
Exchange Membrane ◽  
Command Center

The main content of this paper is to design and fabricate a type of surveillance ship with a proton exchange membrane fuel cell (PEMFC), which adopts hydrogen as fuel cell to generate electricity to drive the surveillance ship. This ship has devices of reconnaissance, lighting, shooting. The reconnaissance device could return real-time images to the command center via cloud technique which could understand the current situation of the reconnaissance location. A buoyancy device is designed into the hull to enhance the stability of running. This paper starts from the functional design and system evaluation, then conducts the fabrication and assembly of the surveillance ship, and finally makes the electric integration and the tests of the PEMFC, surveillance ship running, and hydrogen consumption. The results of the research shows the developed surveillance ship has the advantages of low pollution, clean energy, no effect of day and night, and could be driven via only a small amount of hydrogen, which meets the trend of environmental protection and has the potential of applications in the future.

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