Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 17 of 17 for “"van der Waals force"”.
-
Dynamic simulation of particulate and molecular systems
… Distinct Element Method (DEM). The dissipative forces including viscoelastic and frictional contact forces between the colliding particles cause the energy loss during the packing process, and finally the particles agglomerations is formed. When the particle diameter is less than 100 …
-
Interfacial Phenomena and Surface Forces of Hydrophobic Solids
… at the molecular level, it is not clear how this force scales up to objects with dimensions in the range 100 nm–1 m. This work sets out to measure the forces between particles with a radius of about 10 µm. Because we can only measure the total force, which includes the van der Waals force and the …
-
A study of recognition coating response for quartz crystal microbalances
… A linear relationship between calculated van der Waals force values and experimental dispersion force values may exist. BET isotherm plots indicate that heats of adsorption values for the interactions fall within the range of physical adsorption. At high analyte concentrations, PEI coated …
-
Theoretical and experimental investigation of particle interactions in pharmaceutical powder blending
… costs. Since particles are the basic unit of powder flow, a fundamental understanding of the crucial particle characteristics and particle interactions is essential for a good prediction and control of the blending process. In this work, inter-particle adhesion forces including van der Waals …
-
Effect of Non-Ionic Surfactants and Nano-Particles on the Stability of Foams
… by the classical DLVO theory, which considers contributions from the van der Waals-dispersion and double-layer forces to the disjoining pressure of the film. The discrepancy may be attributed to the presence of hydrophobic force, the magnitude of which has been estimated using the Reynolds …
-
Experimental study on enhanced oil recovery (EOR) mechanisms of nanogel combining with low salinity water for carbonate reservoirs
… measurements, the adsorption was driven by both van der Waals force and electrostatic attraction during nanogel transport through porous media. The limestone flooded with nanogel and low salinity water achieved a 62.4% ultimate oil recovery. These results suggest that the synergistic effect …
-
EXPERIMENTAL CHARACTERIZATION AND MODELING OF ASPECT-RATIO-DEPENDENT DIFFUSION OF NANOCRYSTALS IN NANOCHANNELS
… in rectangular nanochannels has been undertaken. The nanocrystals are terminated with hydrocarbon ligands and suspended in toluene, considered an aprotic solvent. Time-dependent concentration profiles are measured as a function of distance from the channel entrance by the calibrated …
-
Direct Force Measurement between Surfaces Coated with Hydrophobic Polymers in Aqueous Solutions and the Separation of Mixed Plastics by Flotation
… other. The separation process is based on rendering a selected mineral hydrophobic using an appropriate hydrophobizing reagent (collector), so that it can selectively attach onto the surfaces of a rising stream of air bubbles. Thus, controlling the hydrophobicity of the minerals to be …
-
Simulations of interfacial dynamics of complex fluids using diffuse interface method with adaptive meshing
… interface at modest computational costs. An advantage of this method is that topological changes such as interfacial rupture and coalescence happen naturally under a short-range force resembling the van der Waals force. There is no need for manual intervention as in sharp-interface model to …
-
Studies of Thin Liquid Films Confined between Hydrophobic Surfaces
Surface force measurements previously conducted with thiolated gold surfaces showed a decrease in excess film entropy (£GSf), suggesting that hydrophobic force originates from changes in the structure of the medium (water) confined between hydrophobic surfaces. As a follow-up to the previous study, …
-
Debonding in bi-layer material systems under moisture effect : a multiscale approach
… The intrinsic strength between epoxy and silica derived from the molecular level can be used to predict the structural behavior of epoxy-silica interface at the macroscopic length-scale by invoking a finite element approach using a cohesive zone model developed in this research. In order to …
-
Optoelectronics of graphene-based Van der Waals heterostructures
Research on van der Waals (vdW) materials (homo- or hetero-) is a rapidly emerging field in condensed matter physics. They are layered structures with strong chemical bonding within layers and relatively weak van der Waals force to combine layers together. This unique layer-bylayer nature makes it …
-
Experimental investigations of the role of proximity approximation in near-field radiative transfer
… at smaller gaps, however, wave effects such as evanescent wave tunneling, interference and diffraction render the classical theory invalid. The change in radiative transfer between two objects is most dramatic when they can support electromagnetic surface polaritons because of the high local …
-
Cantilever Dynamic Analysis in Tapping Mode Atomic Force Microscopy
Tapping mode atomic force microscopy (AFM) is becoming popular in the area of biology, as well as for polymer and semiconductor materials science. Unlike other AFM techniques, it only makes intermittent contact with the sample, which largely reduces any potential surface damage to soft materials, …
-
Application of the Coupled Dipole Method for Predicting Swelling and Exfoliation Behavior of Layered Inorganic Materials
… behavior of layered inorganic materials is the van der Waals (vdW) interaction. The vdW force, considered to be a weak interaction in many cases, has a strong influence on the structure and properties of colloidal and nano-materials, especially the swelling and exfoliation of nanometer-thick …
-
Development of Next-Generation Construction Materials with Graphene Additives
… cement (OPC) composites and alkali-activated binder composites have attracted significant attention in the past decade. Different technologies have been proposed to address current drawbacks of these construction materials (e.g. low tensile strength, flexural strength, and brittleness), reduce …