scholarly journals Computational Study on Surface Bonding Based on Nanocone Arrays

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1369
Author(s):  
Xiaohui Song ◽  
Shunli Wu ◽  
Rui Zhang
Keyword(s):  
Bonding Strength ◽  
Computational Study ◽  
Cone Angle ◽  
Separation Distance ◽  
Contact Length ◽  
Van Der Waals Interactions ◽  
Main Role ◽  
Atom Diffusion ◽  
Surface Bonding ◽  
Cold Bonding

Surface bonding is an essential step in device manufacturing and assembly, providing mechanical support, heat transfer, and electrical integration. Molecular dynamics simulations of surface bonding and debonding failure of copper nanocones are conducted to investigate the underlying adhesive mechanism of nanocones and the effects of separation distance, contact length, temperature, and size of the cones. It is found that van der Waals interactions and surface atom diffusion simultaneously contribute to bonding strength, and different adhesive mechanisms play a main role in different regimes. The results reveal that increasing contact length and decreasing separation distance can simultaneously contribute to increasing bonding strength. Furthermore, our simulations indicate that a higher temperature promotes diffusion across the interface so that subsequent cooling results in better adhesion when compared with cold bonding at the same lower temperature. It also reveals that maximum bonding strength was obtained when the cone angle was around 53°. These findings are useful in designing advanced metallic bonding processes at low temperatures and pressure with tenable performance.

scholarly journals Development and Application of a New Flame-Retardant Adhesive

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2007 ◽  
Author(s):  
Xianqing Xiong ◽  
Yiting Niu ◽  
Zhuorong Zhou ◽  
Jie Ren
Keyword(s):  
Research And Development ◽  
Flame Retardant ◽  
Flame Retardancy ◽  
Bonding Strength ◽  
Formaldehyde Emission ◽  
National Standard ◽  
Data Support ◽  
Surface Bonding ◽  
Flame Retardant Properties

A new design adhesive mixed with flame retardant was developed by an optimized and modified dedicated flame retardant and selected at a suitable proportion between the adhesive and flame retardant as well as the coating amount of the adhesive. The new design adhesive was applied to ecological board production, and the flame-retardant properties of products were examined. The dipping and peeling properties, surface bonding strength, and formaldehyde emission reached the national standard GB/T 34722-2017, the flame retardancy meets the requirements of GB/T 8626-2017, GB/T 20284-2006, GB/T20285-2006, and it also reaches the B1-C level (the nonflammable level in the flame retardant level). This study not only has theoretical guidance but also has strong practical value to provide a basis and data support for the research and development of flame-retardant ecological boards.

Comparison Between a Center-Mounted and a Side-Mounted Injector for Gasoline Applications: A Computational Study

2020 ◽  
Author(s):  
Lorenzo Nocivelli ◽  
Anqi Zhang ◽  
Brandon A. Sforzo ◽  
Aniket Tekawade ◽  
Alexander K. Voice ◽  
...  
Keyword(s):  
Best Practice ◽  
Computational Study ◽  
Ambient Pressure ◽  
Near Field ◽  
Cone Angle ◽  
Injection Pressure ◽  
Operating Conditions ◽  
Gasoline Direct Injection ◽  
X Ray ◽  
Fuel Density

Abstract The differences between a center-mounted and a side-mounted injector for gasoline direct injection (GDI) applications are analyzed through computational fluid dynamics (CFD). The Engine Combustion Network’s (ECN) axisymmetric 8-hole Spray G injector is compared to a 6-hole injector designed to be side-mounted in an engine. Nozzle-flow simulations are carried out with the commercial CFD software CONVERGE, injecting Euro 5 certification gasoline into a constant volume chamber. Low-load operating conditions are targeted, setting the injection pressure at 50 bar and the ambient pressure to be representative of very early pilot injections. The phase change is handled with the Homogeneous Relaxation Model (HRM), which is assessed and adapted to gasoline flash-boiling conditions. The simulation domains are generated leveraging real injector internal geometries obtained by micron-resolution X-ray tomographic measurements, which introduce manufacturing tolerances and surface roughness in the computational study. Steady needle lift conditions are analyzed. The near-field fuel density distributions and plume morphologies are evaluated, validated and compared to X-ray radiography measurements. A computational best practice is defined and single plume characteristics and variability trends are highlighted as functions of the geometry of the orifices. The plume-plume interaction dynamics are identified and assessed, underlining differences from center- to side-mounted injectors at strong flashing conditions. The obtained numerical framework allows the identification of near-nozzle injection characteristics such as single plume direction, cone angle, spray initial velocity and spatial fuel density distribution. The presented results represent a unique dataset for the initialization of more-affordable Lagrangian spray models, which differentiate the behavior of side-mounted and center-mounted injectors.

Aerodynamic Interactions Between Parachute Canopies

2003 ◽  
Vol 70 (1) ◽  
pp. 50-57 ◽  
Author(s):  
K. Stein ◽  
T. Tezduyar ◽  
V. Kumar ◽  
S. Sathe ◽  
R. Benney ◽  
...  
Keyword(s):  
Computational Study ◽  
Separation Distance ◽  
Fluid Structure Interactions ◽  
Fluid Structure

Aerodynamic interactions between parachute canopies can occur when two separate parachutes come close to each other or in a cluster of parachutes. For the case of two separate parachutes, our computational study focuses on the effect of the separation distance on the aerodynamic interactions, and also focuses on the fluid-structure interactions with given initial relative positions. For the aerodynamic interactions between the canopies of a cluster of parachutes, we focus on the effect of varying the number and arrangement of the canopies.

scholarly journals The Performance Optimization of Oriented Strand Board Veneer Technology

Coatings ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 511 ◽  
Author(s):  
Xianqing Xiong ◽  
Qingru Ma ◽  
Jie Ren
Keyword(s):  
Performance Optimization ◽  
Hot Pressing ◽  
Bonding Strength ◽  
Oriented Strand Board ◽  
Penetration Rate ◽  
Pressing Temperature ◽  
Processing Technologies ◽  
Pressing Time ◽  
Surface Bonding ◽  
Unit Pressure

Oriented strand board (OSB) veneer technology and its performance have been widely studied in order to expand the range of OSB substrates. In this paper, OSB was a modified composite with boards as substrates, Myanmar old mahogany bark as the veneer material, and a cornstarch adhesive. Under such conditions, the optimal veneer technology was studied, and the index of the surface bonding strength and the veneer penetration rate were utilized in order to determine the performance. Two different processing technologies, cold pressing and hot pressing, were experimentally compared and hot pressing showed better performance. Subsequently, experiments were performed on the surface bonding strength and veneer penetration rate. The results show that the veneer performance of OSB is best when the unit pressure is 1.0 MPa, the hot-pressing temperature is 90 °C, and the hot-pressing time is 240 s. Furthermore, the magnitude of influence of the factors affecting the bonding strength is as follows: unit pressure > hot-pressing temperature > hot-pressing time. The research results have prospective significance for the performance optimization of OSB veneer technology.

A Computational Study of Gas-solid Flow in an Enhanced Solid Entrainment (ESE) Nozzle System

2005 ◽  
Vol 3 (1) ◽  
Author(s):  
Maopei Cui ◽  
Anthony G Straatman ◽  
Chao Zhang
Keyword(s):  
Draft Tube ◽  
Numerical Study ◽  
Computational Study ◽  
Full Range ◽  
Three Dimensional ◽  
Separation Distance ◽  
Solid Particles ◽  
Eulerian Model ◽  
Flow Parameters ◽  
Multi Phase

A numerical study has been undertaken to explore the influence of geometry and flow parameters on the entrainment of solid in an ESE nozzle system immersed in a fluidized riser. A fully three-dimensional computational model of the nozzle system has been developed and all appropriate approximations and simplifications are described. A multi-phase Eulerian-Eulerian model incorporating the kinetic theory for solid particles is used. Numerical results are obtained using the commercial Computational Fluid Dynamics software FLUENT. The results indicate that solid entrainment in the ESE system is a strong function of both geometry and flow. The optimal entrainment is seen to occur when the ratio of the draft tube diameter D to separation distance I is approximately unity. At this value, the jet of injected gas is seen to spread fully into the opening of the draft tube causing the highest transport of solid particles through the tube. The entrainment is shown to increase with increasing jet velocity across the full range of flows considered. The results are consistent with similar experimental results. The results of this study should find immediate application in the design and implementation of ESE nozzle systems.

Carbon monoxide adsorption on a nickel iron surface: bonding and electronic structure computational study

2012 ◽  
Vol 110 (2) ◽  
pp. 113-120 ◽  
Author(s):  
G. Canto ◽  
L. Dzib ◽  
C. Lanz ◽  
A. Juan ◽  
G. Brizuela ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Electronic Structure ◽  
Computational Study ◽  
Iron Surface ◽  
Carbon Monoxide Adsorption ◽  
Nickel Iron ◽  
Surface Bonding
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