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We use molecular dynamics (MD) simulations in conjunction with the probe rheology technique to investigate the linear viscoelasticity of nanocolloidal suspensions. A particulate model of the solvent is used in which the hydrodynamics is governed by interparticle interactions. Active and passive probe rheology molecular simulations are performed on the colloidal suspensions of different volume fractions ranging from 0.30 to 0.45 to determine the linear viscoelastic properties of these systems. The viscoelastic modulus of the suspensions is obtained by analyzing the probe motion using continuum mechanics. In active rheology, the distribution of colloid particles around the probe is observed to be symmetric indicating that the system is in the linear regime at all conditions investigated. In passive rheology, the mean-squared displacement of the probe covers the range of motion from ballistic to diffusive regimes. The dynamic modulus and the reduced complex viscosity values obtained from probe rheology simulations are in good agreement with the results from the oscillatory nonequilibrium MD (NEMD) simulations and the literature theoretical predictions. At low frequency values, accounting for artificial hydrodynamic interactions between the probe and its periodic images improves the quantitative accuracy of the modulus values obtained from simulations. Simulations carried out using probes of different sizes indicate that only the probes that are larger than the colloids yield viscoelastic modulus values that are in good agreement with the NEMD values at all volume fractions investigated. [ABSTRACT FROM AUTHOR]

In single-particle microrheology, the viscoelastic properties of a complex fluid can be extracted using the generalized Stokes–Einstein (GSE) relation by embedding a micrometer-sized particle and tracking its motion through the fluid. Applying the same analysis to molecular dynamics simulations can result in overestimated G ∗ values because of the hydrodynamic interaction between the probe bead and its periodic images. We derive a simple correction to the GSE equation by implementing an analytical solution for Stokes drag on a periodic array of spheres, which allows smaller box sizes to be simulated while still retaining accuracy. Fluid and particle inertia are neglected, although the approach used here might be generalized to include them. The correction is applied to molecular dynamics simulations of a coarse-grained polymer melt. For several bead-to-box-size ratios R / L and two probe sizes, we measure the mean squared displacement and calculate G ∗ using both the original GSE and the corrected hydrodynamic Stokes–Einstein (HSE) equations. These results are compared to small amplitude oscillatory non-equilibrium molecular dynamics (NEMD) simulations, which show that the HSE analysis correctly predicts the G ∗ values at low frequencies but breaks down when either fluid inertia is important or the bead size is too small to "see" a continuum. For small R / L , the GSE and HSE results are similar, although a small correction is still required for the finite box size and computational cost is significantly larger. The HSE equation allows the use of smaller box sizes, reducing computational costs by more than an order of magnitude. [ABSTRACT FROM AUTHOR]

Effect of chain architecture on the chain size, shape, and intrinsic viscosity was investigated by performing molecular dynamics simulations of polymer solutions in a good solvent. Four types of chains - linear, comb shaped, H-shaped, and star - were studied for this purpose using a model in which the solvent particles were considered explicitly. Results indicated that the chain length (N) dependence of the mean squared radius of gyration of the chains followed a power-law behavior (Rg²)1/2 ~ Nv with scaling exponents of u = 0.605, 0.642, 0.602, and 0.608, for the linear, comb shaped, H-shaped, and star shaped chains, respectively. The simulation results for the geometrical shrinking factor were higher than the prior theoretical predictions for comb shaped chains. Analysis of chain shape demonstrated that the star chains were significantly smaller and more spherical than the others, while the comb and H-shaped polymer chains showed a more cylindrical shape. It is shown that the intrinsic viscosity of the chains can be calculated by plotting the specific viscosity determined from simulations against the solution concentration. The intrinsic viscosity exhibited linear behavior with the reciprocal of the overlap concentration for all chain architectures studied. The molecular weight dependence of the intrinsic viscosity followed the Mark-Houwink relation, [n] = KMa, for all chain architectures. When comparing the calculated values of exponent a with the literature experimental values, agreement was found only for the H and star chains, and a disagreement for the linear and comb chains. The viscosity shrinking factor of the branched chains was compared with the available experimental data and the theoretical predictions and a general agreement was found. [ABSTRACT FROM AUTHOR]

Although bead microrheology experiments are routinely used to characterize the viscoelasticity of complex matter, their simulation analog—probe rheology molecular simulations—has been scarcely used since the system characteristics required for its robust implementation are not established in the literature. We address this issue by analyzing an active probe rheology simulation setup consisting of a probe particle that is subjected to an external oscillatory force and a harmonic trapping force. We identify a set of eight conditions of the system properties that must be satisfied for the successful implementation of the probe rheology technique in molecular simulations. Among these criteria, the two most important are as follows: (1) The spring force constant for the trapping force should be sufficiently large such that the peak in the Fourier transform of the probe displacement occurs at the same frequency as that of the applied force. (2) System parameters should be chosen such that the magnitude of the external force used to drive the probe motion should be comparable to the magnitude of the hydrodynamic friction force experienced by the probe particle in the viscoelastic medium. Furthermore, a scaling relation that can be used to determine the frequency at which inertial effects set in for a given probe size is also established. The validity of our procedure is demonstrated by applying it to determine the viscoelastic properties of a weakly entangled polymer melt system. [ABSTRACT FROM AUTHOR]

A particulate molecular model in which the solvent particles are considered explicitly is developed for studying the linear viscoelasticity of nanocolloidal suspensions using molecular dynamics simulations. Nanocolloidal systems of volume fractions ranging from 0.10 to 0.49 are studied. The hydrodynamics in these model systems are governed by interparticle interactions. The volume fraction dependence of the relative zero shear viscosity exhibited by this molecular model is consistent with that reported in the literature experiments and simulations. Over the range of frequencies studied, the relative dynamic viscosity values follow the same qualitative trend as that seen in the literature experiments. The time-concentration superposition (TCS) principle is successfully applied to construct the viscoelastic master curves that span nine decades of frequency in the case of the elastic modulus and more than four decades of frequency in the case of the loss modulus. The TCS principle was observed to fail at high volume fractions that are near the glass transition concentration; this finding is consistent with the literature experimental and simulation observations. The volume fraction dependence of the shift factors used in the construction of the viscoelastic master curves is in good quantitative agreement with that of the viscosity of the nanocolloidal systems. Our results demonstrate that molecular simulations in conjunction with an explicit solvent model can be used to quantitatively represent the viscosity and the viscoelastic properties of nanocolloidal suspensions. Such particulate models will be useful for studying the rheology of systems whose properties are governed by specific chemical interactions. [ABSTRACT FROM AUTHOR]

We have studied the effect of chain topology on the structural properties and diffusion of polymers in a dilute solution in a good solvent. Specifically, we have used three different simulation techniques to compare the chain size and diffusion coefficient of linear and ring polymers in solution. The polymer chain is modeled using a bead-spring representation. The solvent is modeled using three different techniques: molecular dynamics (MD) simulations with a particulate solvent in which hydrodynamic interactions are accounted through the intermolecular interactions, multiparticle collision dynamics (MPCD) with a point particle solvent which has stochastic interactions with the polymer, and the lattice Boltzmann method in which the polymer chains are coupled to the lattice fluid through friction. Our results show that the three methods give quantitatively similar results for the effect of chain topology on the conformation and diffusion behavior of the polymer chain in a good solvent. The ratio of diffusivities of ring and linear polymers is observed to be close to that predicted by perturbation calculations based on the Kirkwood hydrodynamic theory. [ABSTRACT FROM AUTHOR]

Recent developments in techniques of micro- and nanofluidics have led to an increased interest in nanoscale hydrodynamics in confined geometries. In our previous study [S. C. Kohale and R. Khare, J. Chem. Phys. 129, 164706 (2008)], we analyzed the friction force experienced by a smooth spherical particle that is translating in a fluid confined between parallel plates. The magnitude of three effects—velocity slip at particle surface, the presence of confining surfaces, and the cooperative hydrodynamic interactions between periodic images of the moving particle—that determine the friction force was quantified in that work using molecular dynamics simulations. In this work, we have studied the motion of a rough spherical particle in a confined geometry. Specifically, the friction force experienced by a translating particle and the torque experienced by a rotating particle are studied using molecular dynamics simulations. Our results demonstrate that the surface roughness of the particle significantly reduces the slip at the particle surface, thus leading to higher values of the friction force and hence a better agreement with the continuum predictions. The particle size dependence of the friction force and the torque values is shown to be consistent with the expectations from the continuum theory. As was observed for the smooth sphere, the cooperative hydrodynamic interactions between the images of the sphere have a significant effect on the value of the friction force experienced by the translating sphere. On the other hand, the torque experienced by a spherical particle that is rotating at the channel center is insensitive to this effect. [ABSTRACT FROM AUTHOR]

We use molecular dynamics simulations to study the shear flow of a polymer solution in a nanochannel by using an explicit, atomistic model of the solvent. The length scales representing the chain size, channel size, and the molecular scale structure in these nanochannels are comparable. The diffusion and hydrodynamic interactions in the system are governed by the intermolecular interactions in the explicit solvent model that is used in the simulations. We study the cross stream migration of flexible polymer chains in a solution that is subjected to a planar Couette flow in a nanochannel. We present a detailed study of the effects of chain length, channel size, and solution concentration on the cross stream chain migration process. Our results show that when a dilute solution containing a longer and a shorter chain is subjected to shear flow, the longer chains that are stretched by the flow migrate away from the channel walls, while the shorter chains that do not stretch also do not exhibit this migration behavior. The thickness of the chain depletion layer at the channel surface resulting from cross stream migration is found to increase with an increase in the channel height. On the other hand, this degree of migration away from the channel walls is found to decrease with an increase in the solution concentration. In solutions with concentrations comparable to or greater than the overlap concentration, the depletion layer thickness in shear flow is found to be comparable or slightly smaller than that observed in the absence of flow. [ABSTRACT FROM AUTHOR]

We use molecular dynamics simulations to investigate the cooperative hydrodynamic interactions involved in the collective translation of a periodic array of spheres in a fluid which is confined between two atomistic surfaces. In particular, we study a spherical particle that is moving with a constant velocity parallel to the two confining surfaces. This central sphere along with its periodic images forms the translating two dimensional periodic grid. The cooperative hydrodynamic effects between neighboring spheres in the grid are determined by monitoring the friction force experienced by the spheres that are moving through an atomistic solvent. The dependence of the hydrodynamic cooperativity on the grid spacing is quantified by running simulations in systems with different sizes of the periodic box. Our results show a clear evidence of hydrodynamic cooperation between the spherical particles for grid spacing of 90σ and larger, where σ is the solvent molecular diameter. These cooperative interactions lead to a reduced value of the friction force experienced by these spheres as opposed to the case for a single sphere moving in an infinite quiescent fluid. The simulated friction force values are compared with the recent continuum mechanics predictions [Bhattacharya, J. Chem. Phys. 128, 074709 (2008)] for the same problem of the motion of a periodic grid of particles through a confined fluid. The simulated values of friction force were found to follow the same qualitative trend as the continuum results but the continuum predictions were consistently larger than the simulation results by approximately 22%. We attribute this difference to the fluid slip at the surface of the spherical particle, as measured in the simulations. [ABSTRACT FROM AUTHOR]

A new set of united-atom force field parameters is proposed for simulating the phase equilibria of branched alkanes. These parameters complement the already existing set of Nath, Escobedo, and de Pablo revised (NERD) [Nath et al., J. Chem. Phys. 105, 4391 (1998); Nath and de Pablo, Mol. Phys. 98, 231 (2000)] force field parameters. The proposed force field is used to study vapor–liquid equilibria for various isomers of alkanes up to C[sub 8]. Results of simulations are found to be in good agreement with available experimental data. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The details of the molecular model, including the procedure used for developing the force field parameters for alcohol alcohol s are presented. These details are discussed with the results from the Gibbs ensemble simulation procedures.

Glycohydrogels containing 2′‐acrylamidoethyl‐β‐d‐galactopyranoside and varying levels of N,N′ methylene bisacrylamide and 3‐acrylamidopropyltris(trimethylsiloxy)silane were synthesized to determine the effects of crosslinker and amphipathic balance on equilibrium water content (EWC), bound water population, and hydrogen bonding dynamics at the water–polymer interface. Analogous dimethylacrylamide hydrogels were synthesized for comparison with a system containing lower hydrogen bonding propensity. An approach combining experiment (proton nuclear magnetic resonance, thermogravimetric analysis, differential scanning calorimetry, and dynamic vapor sorption analysis) and molecular dynamics simulations was employed to examine the relationship between bulk hydrogel properties, molecular water mobility, and hydrogen bonding characteristics. It was found that copolymer composition (hydrophobic content) and crosslink concentration in high water content glycohydrogels affect EWC, and by extension, structural water population. The organization of water at the polymer interface is greatly impacted by the surrounding environment, where hindered molecular water mobility promotes water–polymer binding and decreases water–water clustering. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 584–597 [ABSTRACT FROM AUTHOR]

We reexamine the theoretical framework of electrolyte nonrandom two‐liquid model and formulate the binary interaction parameters as functions of species diameter (σ), effective interaction strength (ɛ), the domain radius around the center species (R), and the nonrandomness factor (α). We show that these quantities can be directly obtained from molecular simulations using aqueous NaCl as the model system. The binary interaction parameters determined from the simulations are consistent with those obtained from regression of experimental data. Our work provides a molecular interpretation of the classical thermodynamic model and shows a way to predict from molecular simulations the binary interaction parameters for use in process industries. © 2019 American Institute of Chemical Engineers AIChE J, 65: 1315–1324, 2019 [ABSTRACT FROM AUTHOR]

Investigates the rheological, thermodynamic and structural behavior of linear and branched alkanes in simple shear using nonequilibrium-dynamics simulation of united atom model fluids. Results for the zero-shear viscosity of linear alkanes; Simulation results for intermediate molecular weight linear alkanes.

Investigates the behavior of simple fluids under shear using molecular dynamics simulations. Background on the simulated system consisting of a fluid confined between atomistic walls moved in opposite directions; Comparison of approaches for shear flow simulations.

Pitzer and electrolyte nonrandom two‐liquid (eNRTL) models are the two most widely used electrolyte thermodynamic models. For aqueous sodium chloride (NaCl) solution, both models correlate the experimental mean ionic activity coefficient (γ±) data satisfactorily up to salt saturation concentration, that is, ionic strength around 6 m. However, beyond 6 m, the model extrapolations deviate significantly and diverge from each other. We examine this divergence by calculating the mean ionic activity coefficient over a wide range of concentration based on molecular simulations and Kirkwood–Buff theory. The asymptotic behavior of the activity coefficient predicted by the eNRTL model is consistent with the molecular simulation results and supersaturation experimental data. © 2018 American Institute of Chemical Engineers AIChE J, 64: 3728–3734, 2018 [ABSTRACT FROM AUTHOR]

We show that the several decades gap between the time scales of experiments and atomistic simulations can be significantly reduced by applying time-temperature superposition (TTS) to the simulation results for various rheological properties of asphalt. Molecular dynamics simulations with atomistically detailed models were performed to characterize the temperature dependence of shear viscosity, dynamic modulus, and tensile creep compliance of AAM–1 asphalt. The TTS principle was successfully applied to the data to construct master curves of these rheological properties, and a comparison of simulation data with experiments showed good agreement. Application of TTS resulted in a six decade increase in the frequency range available for moduli determination and a two decade increase in both the shear rate range available for viscosity determination and the time scale available for characterization of creep compliance. The horizontal shift factors (aT) used in the construction of the master curves for the different rheological properties were quantitatively consistent with each other. The corresponding temperature dependence of the scaled relaxation times was compared with the expectations from three literature models, namely, the Vogel–Fulcher–Tammann, double exponential, and parabolic–Arrhenius models. A distinct change from super-Arrhenius to Arrhenius behavior was observed for the scaled relaxation times below the glass transition temperature (Tg). Only the parabolic-Arrhenius model was able to capture the temperature dependence of the data over the entire temperature range that covers both the glassy and the rubbery states. [ABSTRACT FROM AUTHOR]

A predictive approach for calculating the binary interaction parameters ( τ i j) of the nonrandom two liquid (NRTL) local composition model is developed, combining molecular simulations with the two‐fluid theory. The binary interaction parameters are determined for the following three sets of model binary mixtures: water + methanol, methanol + methyl acrylate, and water + methyl acrylate. For each binary mixture, the interaction parameters are expressed in terms of molecular size and strength of interactions, which are in turn, calculated from molecular simulations. We show that the binary interaction parameters determined from simulations are in qualitative agreement with those estimated from regressing experimental data. The major factors that determine the binary interaction parameters are outlined based on simple thermodynamic arguments for each mixture. © 2018 American Institute of Chemical Engineers AIChE J, 64: 2758–2769, 2018 [ABSTRACT FROM AUTHOR]

Layered polymeric systems are widely used in membrane separation applications; chain mobility in these layered systems is a key consideration in the design of the membranes. The transport properties of membrane polymers can be significantly altered by the perturbations in chain dynamics induced by the presence of an interface and also by the topological properties of the polymers constituting the layered systems. In this work, we use molecular dynamics (MD) simulations to determine the effects of polymer backbone flexibility and interlayer interactions on the glass transition and chain dynamics of polymer layers in the layered systems. We observed that the onset of glass transition of the entire layered system is governed by the stiffer polymer layer and is independent of the type of interactions between the layers. However, the interlayer interactions govern the strength of the glass transition of the entire layered system. Polymer mobility, on the other hand, exhibits a strong dependence on both the chain flexibility and the interlayer interactions. In systems with attractive interactions between the layers, the fully flexible polymer chains at the interface have a lower mobility than those in the bulk region of the layer; the behavior differs from that of rigid polymers, which have a higher mobility at the interface compared to that in the bulk. On the other hand, when the interactions between the layers are repulsive, each layer acts as a free-standing film with chains in both the layers exhibiting higher mobility at the interface. [ABSTRACT FROM AUTHOR]

A Stokesian dynamics simulation of the effect of surface Couette flow on the microstructure of particles irreversibly adsorbed to an interface is presented. Rather than modeling both bulk phases, the interface, and particles in a full 3D simulation, known interfacial interactions between adsorbed particles are used to create a 2D model from a top down perspective. This novel methodology is easy to implement and computationally inexpensive, which makes it favorable to simulate behavior of particles under applied flow at fluid-fluid interfaces. The methodology is used to examine microstructure deformation of monodisperse, rigid spherical colloids with repulsive interactions when a surface Couette flow is imposed. Simulation results compare favorably to experimental results taken from literature, showing that interparticle forces must be 1 order of magnitude greater than viscous drag for microstructure to transition from aligned particle strings to rotation of local hexagonal domains. Additionally, it is demonstrated that hydrodynamic interactions between particles play a significant role in the magnitude of these microstructure deformations. [ABSTRACT FROM AUTHOR]

Background:Hemorrhage occurs when there is excessive external or internal blood loss. Shock occurs when there is hypoperfusion of vital organs. The present study was conducted in the department of general medicine. Materials & Methods: The present study was conducted in the department of general medicine on 520 patients of both genders. An estimated blood loss more than 40% (more than 2000 ml for a 70 kg man) of blood volume and a SBP <90 mmHg was considered. Results: Out of 520 patients, males were 280 and females were 240. The difference was non- significant (P- 0.1).Out of 280 males, 198 survived and 82 died. Out of 240 females, 170 survived and 70 died. Common cause of shock was road traffic accident in males (120) and females (110), fall in males (100) and females (80) and assault in males (60) and females (50). The difference was significant (P< 0.05).SBP (mean± S.D) in males was 124± 16 and in females was 110± 12. Pulse (mean± S.D) in males was 108.2± 10 and in females was 106.4± 14. Conclusion: Hemorrhagic shock is the leading cause of deaths worldwide. Males had higher number as compared to females. The deaths were more in males. [ABSTRACT FROM AUTHOR]

Here we demonstrate through experiment and simulation the polymer-assisted dispersion of inorganic 2D layered nanomaterials such as boron nitride nanosheets (BNNSs), molybdenum disulfide nanosheets (MoS2), and tungsten disulfide nanosheets (WS2), and we show that spray drying can be used to alter such nanosheets into a crumpled morphology. Our data indicate that polyvinylpyrrolidone (PVP) can act as a dispersant for the inorganic 2D layered nanomaterials in water and a range of organic solvents; the effectiveness of our dispersion process was characterized by UV-vis spectroscopy, microscopy and dynamic light scattering. Molecular dynamics simulations confirm that PVP readily physisorbs to BNNS surfaces. Collectively, these results indicate that PVP acts as a general dispersant for nanosheets. Finally, a rapid spray drying technique was utilized to convert these 2D dispersed nanosheets into 3D crumpled nanosheets; this is the first report of 3D crumpled inorganic nanosheets of any kind. Electron microscopy images confirm that the crumpled nanosheets (1–2 μm in diameter) show a distinctive morphology with dimples on the surface as opposed to a wrinkled, compressed surface, which matches earlier simulation results. These results demonstrate the possibility of scalable production of inorganic nanosheets with tailored morphology. [ABSTRACT FROM AUTHOR]

We have used atomistic molecularsimulations to study the effectof nanofiller dispersion on the glass transition behavior of cross-linkedepoxy–carbon nanotube (CNT) nanocomposites. Specific chemicalinteractions at the interface of CNTs and cross-linked epoxy createan interphase region, whose impact on the properties of their nanocompositesincreases with an increasing extent of dispersion. To investigatethis aspect, we have compared the volumetric, structural, and dynamicalproperties of three systems: neat cross-linked epoxy, cross-linkedepoxy nanocomposite containing dispersed CNTs, and cross-linked epoxynanocomposite containing aggregated CNTs. We find that the nanocompositecontaining dispersed CNTs shows a depression in the glass transitiontemperature (Tg) by ∼66 K as comparedto the neat cross-linked epoxy, whereas such a large depression isabsent in the nanocomposite containing aggregated CNTs. Our resultssuggest that the poor interfacial interactions between the CNTs andthe cross-linked epoxy matrix lead to a more compressible interphaseregion between the CNTs and the bulk matrix. An analysis of the resultingdynamic heterogeneity shows that the probability of percolation ofimmobile domains becomes unity near the Tgcalculated from volumetric properties. Our observations also lendsupport to the conceptual analogy between polymer nanocomposites andthe nanoconfinement of polymer thin films. [ABSTRACT FROM AUTHOR]

A directed diffusion approach is used to create atomistic models of crosslinked epoxy. In polymerization-based approaches for preparing epoxy model structures, conversions higher than 95% are difficult to achieve due to very slow diffusion of unreacted monomers and crosslinkers in the partially formed network. This problem is overcome by creating very long bonds in the polymerization stage, and then relaxing these to equilibrium values by using a directed-diffusion-based relaxation strategy. The method minimizes the use of custom code by relying on the in-built functionality in LAMMPS package (S. Plimpton, J. Comput. Phys. 1995, 117, 1). The approach allows for near-complete conversion (≈99%) and the thermal and volumetric properties of the structures so prepared show good agreement with experimental data. [ABSTRACT FROM AUTHOR]

We have used molecular simulations to study the properties of nanocomposites formed by the chemical incorporation of polyhedral oligomeric silsesquioxane (POSS) particles in the cross-linked epoxy network. The particular POSS molecule chosen-glycidyloxypropyl-heptaphenyl POSS-can form only one bond with the cross-linker and thus was present as a dangling unit in the network. Four epoxy-POSS nanocomposites containing different fractions (up to 30 mass/%) of POSS particles were studied in this work. Well-relaxed atomistic model structures of the nanocomposites were created and then molecular dynamics simulations were used to characterize the density, glass transition temperature ( T), and the coefficient of volume thermal expansion (CVTE) of the systems. In addition to the effect of nanoparticle loading, the effect of nanoparticle chemistry on the nanocomposite properties was also characterized by comparing these results with our previous results (Lin and Khare, Macromolecules 42:4319-4327, 2009) on neat cross-linked epoxy and a nanocomposite containing a POSS nanoparticle that formed eight bonds with the cross-linked network. Our results showed that incorporation of these monofunctional POSS particles into cross-linked epoxy does not cause a measurable change in its density, glass transition temperature, or the CVTE. Furthermore, simulation results were used to characterize the aggregation of POSS particles in the system. The nanofiller particles in systems containing 11, 20, and 30 mass/% POSS were found to form small clusters. The cluster-size distribution of nanoparticles was also characterized for these systems. [ABSTRACT FROM AUTHOR]

Abstract: The thermal resistance of a model solid–liquid interface in the presence of laminar shear flow is investigated using molecular dynamics simulations. Two model liquids – a monoatomic liquid and a polymeric liquid composed of 20 repeat units – are confined between walls which are modeled as idealized lattice surfaces composed of atoms identical to the monomers. We find that in the absence of a velocity slip (discontinuity) at the solid–fluid interface, the mass flow does not affect the thermal interfacial resistance, but the presence of velocity slip results in an increase in the interfacial thermal resistance by about a factor of two. [Copyright &y& Elsevier]