Effect Of Curvature Research Articles

The effect of path curvature on the stability of reversing truck–semitrailer in the presence of feedback delay

Stability analysis of the low-speed reverse motion along clothoid curve is presented for the truck–semitrailer combination. The single-track kinematic model supplemented with the steering system and the lower-level controller is applied. A higher-level controller is designed to stabilise the reverse motion of the vehicle. Linear state feedback with time delay is used with feedforward term to force the vehicle to the desired path. The linear stability analysis is done by semi-discretization and D-subdivision methods to determine the optimal control gain setup. The effects of path curvature and time delay on the stability are investigated and verified via numerical simulations. Results are validated via experiments using a small-scale test rig.

Transverse flow under oscillating stimulation in helical square ducts with cochlea-like geometrical curvature and torsion

The cochlea, situated within the inner ear, is a spiral-shaped, liquid-filled organ responsible for hearing. The physiological significance of its shape remains uncertain. Previous research has scarcely addressed the occurrence of transverse flow within the cochlea, particularly in relation to its unique shape. This study aims to investigate the impact of the geometric features of the cochlea on fluid dynamics by characterizing transverse flow induced by harmonically oscillating axial flow in square ducts with curvature and torsion resembling human cochlear anatomy. We examined four geometries to investigate curvature and torsion effects on axial and transverse flow components. Twelve frequencies from 0.125 Hz to 256 Hz were studied, covering infrasound and low-frequency hearing, with mean inlet velocity amplitudes representing levels expected for normal conversation or louder situations. Our simulations show that torsion contributes significantly to transverse flow in unsteady conditions, and that its contribution increases with increasing oscillation frequency. Curvature alone has a small effect on transverse flow strength, which decreases rapidly with increasing frequency. Strikingly, the combined effect of curvature and torsion on transverse flow is greater than expected from a simple superposition of the two effects, especially when the relative contribution of curvature alone becomes negligible. These findings may be relevant to understanding physiological processes in the cochlea, including metabolite transport and wall shear stress. Further studies are needed to investigate possible implications for cochlear mechanics.

Correspondence of Concept of Circular Orbits in Schwarzschild Metric and Kerr Metric to those in Tidally Evolving Binaries in Weak Gravitational Regime and its Application in Determination of Spin of Supermassive Black Hole

This paper rederives diameters of the Innermost Stable Circular Orbits (ISCO) in Schwarzschild Metric (RDISCO = 6RSch for non-rotating BH with a =0) and in Kerr metric with particular reference to recently studied Super Massive Black Hole in NGC1365 (RDISCO = 9RSch for retrograde orbits and RDISCO = 1RSch for prograde orbits around maximally spinning BH of a=1). Next the same derivations are made in tidally evolving binaries based on kinematic model. Kinematic Model derivation corresponds to the derivations made in Kerr Metric for Circular Orbits in all its details at weak gravitation regime. At strong gravitation regime in Kerr metric, the two orbits converge to Innermost Stable Circular Orbit due to the Space-Time Curvature and Frame-Dragging Effect in the vicinity of SMBH. Kinematic model fails to arrive at ISCO since it has not included the relativistic mechanics.

Energies of Fröhlich surface optical phonon in Q1D nanostructures: Curvature and dielectric effects

Energy of Fröhlich surface optical (SO) phonon in quasi-one-dimensional (Q1D) nanostructures remains doubtful in terms of Raman and photoluminescence experimental data. Based on a notion of the curvature proposed, the confusion is clearly clarified. It is found that the energy interval of SO modes previously accepted in the quantum system could be further divided into two sub-intervals based on the positive and negative curvature of nanowire (NW) and nanohole (NH). Furthermore, the cutoff energy and width of energy sub-intervals in NW and NH can be modulated by altering the dielectric constant of the surrounding medium. Moreover, the physical mechanism of curvature and dielectric effects on the energies of SO phonon in NW and NH are comprehended reasonably from a perspective of electrostatic potential distribution. The calculated energies of SO modes in low-energy sub-interval are fully consistent with the Raman and PL experimental results for AlN, GaN, and InN NWs. It is predicted that SO modes of high-energy sub-interval could be observed in the NH structure. The current theoretical scheme and numerical results not only extend and deepen the knowledge of the energy of the SO phonon but also can be used in the design and development of optical and optoelectronic devices based on SO modes of Q1D nanostructures.

Nonlinear gyrokinetic modelling of high confinement negative triangularity plasmas

Nonlinear gyrokinetic simulations correctly predict particle as well as ion and electron energy fluxes of high confinement plasmas with a negative triangularity cross sectional shape, showing that core transport in these plasmas is well described by standard gyrokinetic models. Experimentally inferred power balance fluxes are mostly reproduced within one standard deviation across a wide portion of the minor radius. Experimental conditions are reproduced by ion scale simulations, without the need to include density and temperature profile curvature effects. The experimental case is used as baseline to predict that the non-dimensional confinement scaling in negative triangularity plasmas increases strongly with plasma current while slightly degrading at increasing normalized pressure and decreasing collisionality. Recent experiments showed that low toroidal rotation negatively impacts confinement; consistent with the experiment, simulations predict that low rotational shear significantly affects confinement unless the plasma effective charge is maintained above a minimum level. Core confinement is predicted to significantly degrade in low aspect ratio devices.

Holographic description for correlation functions

We study general correlation functions of various quantum field theories in the holographic setup. Following the holographic proposal, we investigate correlation functions via a geodesic length connecting boundary operators. We show that this holographic description can reproduce the known two- and three-point functions of conformal field theory. Using this holographic method, we further study general two-point functions of a two-dimensional thermal conformal field theory (CFT) and of a scalar field theory living in a de Sitter or anti–de Sitter space. Due to the nontrivial thermal or curvature effect, the two-point functions in an IR limit show different scaling behaviors from those of the UV CFT. We study such nontrivial IR scaling behaviors by applying the holographic method. Published by the American Physical Society 2024

Charged Black-Hole-Like Electronic Structure Driven by Geometric Potential of 2D Semiconductors.

One of the exotic expectations in the 2D curved spacetime is the geometric potential from the curvature of the 2D space, still possessing unsolved fundamental questions through Dirac quantization. The atomically thin 2D materials are promising for the realization of the geometric potential, but the geometric potential in 2D materials is not identified experimentally. Here, the curvature-induced ring-patterned bound states are observed in structurally deformed 2D semiconductors and formulated the modified geometric potential for the curvature effect, which demonstrates the ring-shape bound states with angular momentum. The formulated modified geometric potential is analogous to the effective potential of a rotating charged black hole. Density functional theory and tight-binding calculations are performed, which quantitatively agree well with the results of the modified geometric potential. The modified geometric potential is described by modified Gaussian and mean curvatures, corresponding to the curvature-induced changes in spin-orbit interaction and band gap, respectively. Even for complex structural deformation, the geometric potential solves the complexity, which aligns well with experimental results. The understanding of the modified geometric potential provides us with an intuitive clue for quantum transport and a key factor for new quantum applications such as valleytronics, spintronics, and straintronics in 2D semiconductors.

Structures of Laminar Lean Premixed H2/CH4/Air Polyhedral Flames: Effects of Flow Velocity, H2 Content and Equivalence Ratio

AbstractPolyhedral Bunsen flames, induced by hydrodynamic and thermo-diffusive instabilities, are characterized by periodic trough and cusp cellular structures along the conical flame front. In this study, the effects of flow velocity, hydrogen content, and equivalence ratio on the internal cellular structure of premixed fuel-lean hydrogen/methane/air polyhedral flames are experimentally investigated. A high-spatial-resolution one-dimensional Raman/Rayleigh scattering system is employed to measure the internal scalar structures of polyhedral flames in troughs and cusps. Planar laser-induced fluorescence of hydroxyl radicals and chemiluminescence imaging measurements are used to quantify the flame front morphology. In the experiments, stationary polyhedral flames with varying flow velocities from 1.65 to 2.50 m/s, hydrogen contents from 50 to 83%, and equivalence ratios from 0.53 to 0.64 are selected and measured. The results indicate that the positively curved troughs exhibit significantly higher hydrogen mole fractions and local equivalence ratios compared to the negatively curved cusps, due to the respective focusing/defocusing effect of trough/cusp structure on highly diffusive hydrogen. The hydrogen mole fraction and local equivalence ratio differences between troughs and cusps are first increased and then decreased with increasing measurement height from 5 to 13 mm, due to the three-dimensional effect of the flame front. With increasing flow velocity from 1.65 to 2.50 m/s, the hydrogen mole fraction and local equivalence ratio differences between troughs and cusps decrease, which is attributed to the overall decreasing curvatures in troughs and cusps due to the decreased residence time and increased velocity-induced strain. With increasing hydrogen content from 50 to 83%, the hydrogen mole fraction and local equivalence ratio differences between troughs and cusps are amplified, due to the enhanced effects of the flame front curvature and the differential diffusion of hydrogen. With increasing equivalence ratio from 0.53 to 0.64, a clear increasing trend in hydrogen mole fraction and equivalence ratio differences between troughs and cusps is observed at constant flow velocity condition, which is a trade-off result between increasing effective Lewis number and increasing curvatures in troughs and cusps.

A semi-analytical spectral element model for guided wave propagation in composite laminated conical shells

The conical shell is a typical non-uniform waveguide with its circumferential radius varies linearly. This work aims to provide physical insights for the composite laminated conical shell in terms of waves. A semi-analytical spectral element model is presented, which adopts the Fourier series in the circumferential direction and the higher-order shape functions in the axial direction. The first-order shear deformation theory and Hamilton principle are employed to derive the energy functions of the conical shell, and they are discretized using the spectral elements to achieve a weak-form variational problem. The dispersion equation and the group velocity expression are derived via the piecewise approximation concept and Bloch's periodic theorem. The accuracy of the developed spectral element is verified by comparison with published results. The deformation evolution mechanisms of the composite conical shell are revealed, and the wave propagation characteristics of uniform and ply drop-off composite conical shells are investigated. The results demonstrated that wavenumber distribution at 0–5 kHz is spatially dependent, and wavenumber becomes cut off and bifurcate near the cone vertex. When the frequency exceeds 2 kHz, the deformation of conical shell changes from rigid to flexible, and the structure tends to be a uniform waveguide. Compared to the geometric curvature effect, the asymmetric lay-up leads to more significant mode coupling.

Evaluating fingerprint-like patterns in the healthy Henle fiber layer using enface OCT imaging

PurposeEnface OCT may disclose a distinct “fingerprint-like' pattern within the HFL in various macular disorders. This study aims to investigate the frequency and characteristics of this pattern in healthy eyes and identify potential factors influencing its visibility. MethodsTwo, independent masked reading center graders evaluated for the presence and prominence of a fingerprint pattern in the Henle fiber layer (HFL) on enface OCT images from 33 healthy subjects (66 eyes). The prominence of the pattern was rated qualitatively using a 0–3 scale, with 3 indicating the strongest prominence. Tilt angles (relative to the normal/perpendicular at the center) of the retina were measured on horizontal and vertical B-scans, and the retinal curvature was assessed using ImageJ, in order to determine the impact of the incident light angle on the visibility and prominence of the fingerprint pattern. Inter-grader agreement using Cohen's kappa and the frequency and percentage of patterns in the entire enface image and in each quadrant were calculated and compared using the Friedman test with Dunn's post-test. A generalized estimating equation (GEE) was used to analyze the association between these metrics and fingerprint prominence. ResultsSubstantial inter-grader agreement was observed (Cohen's kappa = 0.71) for assessing the prominence of the fingerprint pattern. Over 70% of eyes exhibited some evidence of the pattern (score ≥1). Significant difference in pattern prominence across quadrants was detected (p < 0.05), with lowest prominence in the temporal quadrant (p < 0.001 for pairwise comparisons against all other quadrants). The GEE analysis to account for the extent of the effect of scan tilt angle and RPE curvature was not able to predict the prominence of the fingerprint pattern, highlighting that angle of incidence (of the scanning laser light) alone could not explain the pattern. ConclusionsThis study confirms that a fingerprint-like pattern within the HFL can also be observed in healthy eyes, challenging the notion that this finding is only manifest in the setting of disease. In addition, the lack of correlation with angle of incident light suggests that the pattern may be related to other intrinsic characteristics of the HFL.

A computational study of artery curvature and endograft oversize influence on seal zone behavior in endovascular aortic repair

Thoracic endovascular aortic repair (TEVAR) is a minimally invasive procedure involving the placement of an endograft inside the dissection or an aneurysm to direct blood flow and prevent rupture. A significant challenge in endovascular surgery is the geometrical mismatch between the endograft and the artery, which can lead to endoleak formation, a condition where blood leaks between the endograft and the vessel wall. This study uses computational modeling to investigate the effects of artery curvature and endograft oversizing, the selection of an endograft with a larger diameter than the artery, on endoleak creation. Finite element analysis is employed to simulate the deployment of endografts in arteries with varying curvature and diameter. Numerical simulations are conducted to assess the seal zone and to quantify the potential endoleak volume as a function of curvature and oversizing. A theoretical framework is developed to explain the mechanisms of endoleak formation along with proof-of-concept experiments. Two main mechanisms of endoleak creation are identified: local buckling due to diameter mismatch and global buckling due to centerline curvature mismatch. Local buckling, characterized by excess graft material buckling and wrinkle formation, increases with higher levels of oversizing, leading to a larger potential endoleak volume. Global buckling, where the endograft bends or deforms to conform to the centerline curvature of the artery, is observed to require a certain degree of oversizing to bridge the curvature mismatch. This study highlights the importance of considering both curvature and diameter mismatch in the design and clinical use of endografts. Understanding the mechanisms of endoleak formation can provide valuable insights for optimizing endograft design and surgical planning, leading to improved clinical outcomes in endovascular aortic procedures.

1D analytic and numerical analysis of thin film heat transfer gauges and infra-red cameras in non-planar applications

The impulse response method is widely used for heat transfer analysis in turbomachinery applications. Traditionally, the 1D method assumes a: linear time invariant, isotropic, semi-infinite block with planar surfaces and does not accurately model the true geometric behaviour. This paper evaluates the error introduced by the planar assumption and outlines the required modifications for accurate freeform surface analysis. Adapted cylindrical basis functions are defined for the impulse response method and used to evaluate the impact of the 1D planar assumption. The analytic solutions for both convex and concave surfaces are presented. A penta-diagonal algorithm, for a modified numerical Crank-Nicolson scheme, is also evaluated for fast stable implementation of curved geometry simulation. The scheme shows comparable performance to the impulse response, whilst removing the requirement for linear time invariance. The new methods are demonstrated in the case of aerothermal analysis for heat transfer in a turbine nozzle guide vane. A 3D ANSYS simulation is used as a benchmark and further highlights the importance of the curvature effects. The methods are extended using curvature mapping for infra-red camera data, enabling direct 3D thermal simulation or the fast calculation of freeform curvature. This paper defines the methodology to analyse heat transfer measurements on non-planar geometry.

Design of High-Performance Triple-axis Cross Pivots

Abstract Cross-axis flexural pivots are increasingly implemented in mechanical systems due to their high precision and wide range of motion. However, designing high-performance pivots in terms of low axis drift, low rotational stiffness, and low values of maximum stress remains a challenging task. In fact, these features often behave antagonistically to each other. In this paper, the design of a novel family of high-performance cross-axis pivots is presented. The compliant joints are obtained by the composition of two crossing flexible elements with initially curved axis, and of one auxiliary flexure with straight axis. Two different arrangements, that depend on the constraints layout, are proposed. Chained beam constraint model and non-linear finite element analysis are implemented for the analysis of the kinetostatic response of the pivots. The effects of initial curvature and orientation of the flexures on axis drift, stiffness, and maximum stress, are investigated and reported in the form of design maps. A global performance index, that embodies the above-mentioned features and captures the overall kinetostatic behavior of the pivot is introduced. The design maps and the global index serve as key tools for the design procedure, giving insight into the antagonistic issue and leading to the determination of the best trade-off solutions that meet the application requirements. An experimental campaign is conducted to compare the performance improvement of triple-axis pivots with respect to a benchmark double-axis joint, and to validate the design method.

Impact of interfacial curvature on molecular properties of aqueous interfaces.

The curvature of soft interfaces plays a crucial role in determining their mechanical and thermodynamic properties, both at macroscopic and microscopic scales. In the case of air/water interfaces, particular attention has recently focused on water microdroplets, due to their distinctive chemical reactivity. However, the specific impact of curvature on the molecular properties of interfacial water and interfacial reactivity has so far remained elusive. Here, we use molecular dynamics simulations to determine the effect of curvature on a broad range of structural, dynamical, and thermodynamical properties of the interface. For a droplet, a flat interface, and a cavity, we successively examine the structure of the hydrogen-bond network and its relation to vibrational spectroscopy, the dynamics of water translation, rotation, and hydrogen-bond exchanges, and the thermodynamics of ion solvation and ion-pair dissociation. Our simulations show that curvature predominantly impacts the hydrogen-bond structure through the fraction of dangling OH groups and the dynamics of interfacial water molecules. In contrast, curvature has a limited effect on solvation and ion-pair dissociation thermodynamics. For water microdroplets, this suggests that the curvature alone cannot fully account for the distinctive reactivity measured in these systems, which are of great importance for catalysis and atmospheric chemistry.

Experimental Evidence for a Berry Curvature Quadrupole in an Antiferromagnet

Berry curvature multipoles appearing in topological quantum materials have recently attracted much attention. Their presence can manifest in novel phenomena, such as nonlinear anomalous Hall effects (NLAHE). The notion of Berry curvature multipoles extends our understanding of Berry curvature effects on the material properties. Hence, research on this subject is of fundamental importance and may also enable future applications in energy harvesting and high-frequency technology. It was shown that a Berry curvature dipole can give rise to a second-order NLAHE in materials of low crystalline symmetry. Here, we demonstrate a fundamentally new mechanism for Berry curvature multipoles in antiferromagnets that are supported by the underlying magnetic symmetries. Carrying out electric transport measurements on the kagome antiferromagnet FeSn, we observe a third-order NLAHE, which appears as a transverse voltage response at the third harmonic frequency when a longitudinal ac drive is applied. Interestingly, this NLAHE is strongest at and above room temperature. We combine these measurements with a scaling law analysis, a symmetry analysis, model calculations, first-principle calculations, and magnetic Monte Carlo simulations to show that the observed NLAHE is induced by a Berry curvature quadrupole appearing in the spin-canted state of FeSn. At a practical level, our study establishes NLAHE as a sensitive probe of antiferromagnetic phase transitions in other materials—such as moiré superlattices, two-dimensional van der Waal magnets, and quantum spin liquid candidates, which remain poorly understood to date. More broadly, Berry curvature multipole effects are predicted to exist for 90 magnetic point groups. Hence, our work opens a new research area to study a variety of topological magnetic materials through nonlinear measurement protocols. Published by the American Physical Society 2024

Limosilactobacillus fermentum-derived silver nanoparticles: biosynthesis, optimization, and biological activities

AbstractProbiotic bacteria represent valuable sources of bioactive metabolites with diverse biological functions. This study focused on isolation and identification of promising probiotic isolates obtained from fermented dairy products, aiming to employ their capability for biosynthesizing silver nanoparticles (AgNPs) and to assess their biological activities. Among six probiotic examined isolates, isolate HwOs-2 exhibited the most promising characteristics, synthesizing spherical AgNPs ranging from 6 to 23 nm in size, as visualized by high-resolution transmission electron microscopy (HR-TEM). These nanoparticles displayed a negative zeta potential (−7.11 millivolts), effectively preventing aggregation. X-ray diffraction (XRD) analysis confirmed the crystalline nature of the AgNPs, revealing distinct diffraction peaks at specific 2θ angles (38.2°, 44.3°, 64.5°, and 77.4°) corresponding to the (111), (200), (220), and (311) planes of a face-centered cubic lattice. Fourier Transform Infrared Spectroscopy (FTIR) indicated the presence of organic coatings on the AgNPs, including proteins, amino acids, and carboxylic acids, potentially contributing to diverse biological activities. Isolate HwOs-2 was identified as Limosilactobacillus fermentum through Vitek2 automated system and 16 S rDNA partial sequence analysis. Furthermore, optimization of AgNP biosynthesis using response surface methodology (RSM) revealed the significant influence of silver nitrate solution volume, while pH and filtrate volume exhibit negligible effects and incubation time displays a curvature effect on AgNP production. Antibacterial assays against seven bacterial strains, encompassing both gram-positive and gram-negative species, demonstrated substantial antibacterial efficacy, with inhibition zones ranging from 20.3 to 27.6 mm against S. typhi and MRSA, respectively. Additionally, the AgNPs exhibited antitumor activity against Caco-2 and Huh-7 cell lines, with IC50 values of 350.08 and 388.35 µg/mL, respectively, while displaying lower cytotoxicity against normal (VERO) cells (IC50 value = 622.17 µg/mL). These findings underscore the biomedical potential of AgNPs produced by Limosilactobacillus fermentum across a spectrum of applications.

Gravitational Wormholes

Spacetime wormholes are evidently an essential component of the construction of a time machine. Within the context of general relativity, such objects require, for their formation, exotic matter—matter that violates at least one of the standard energy conditions. Here, we explore the possibility that higher-curvature gravity theories might permit the construction of a wormhole without any matter at all. In particular, we consider the simplest form of a generalized quasi topological theory in four spacetime dimensions, known as Einsteinian Cubic Gravity. This theory has a number of promising features that make it an interesting phenomenological competitor to general relativity, including having non-hairy generalizations of the Schwarzschild black hole and linearized equations of second order around maximally symmetric backgrounds. By matching series solutions near the horizon and at large distances, we find evidence that strong asymptotically AdS wormhole solutions can be constructed, with strong curvature effects ensuring that the wormhole throat can exist.

Determining the difference between local acceleration and local gravity: Applications of the equivalence principle to relativistic trajectories

We show by direct calculation that the common equivalence principle explanation for why gravity must deflect light is quantitatively incorrect by a factor of three in Schwarzschild geometry. It is, therefore, possible, at least as a matter of principle, to tell the difference between local acceleration and a true gravitational field by measuring the local deflection of light. We calculate as well the deflection of test particles of arbitrary energy and construct a leading-order coordinate transformation from Schwarzschild to local inertial coordinates, which shows explicitly how the effects of spatial curvature manifest locally for relativistic trajectories of both finite and vanishing rest mass particles.

Tailoring Versatile Cathodes and Induced Anodes for Zn-Se Batteries: Anisotropic Orientation of Tin-Based Materials within Bowl-In-Ball Carbon.

The advancement of Zn-Se batteries has been hindered by significant challenges, such as the sluggish kinetics of Se cathodes, limited Se loading, and uncontrollable formation of Zn dendrites. In this study, a bidirectional optimization strategy is devised for both cathode and anode to bolster the performance of Zn-Se batteries. A novel bowl-in-ball structured carbon (BIBCs) material is synthesized to serve as a nanoreactor, in which tin-based materials are grown and derived in situ to construct cathodes and anodes. Within the cathode, the multifunctional host material (SnSe@BIBCs) exhibits large adsorption capacity for selenium, and demonstrates supreme catalytic properties and spatially confined characteristics toward the selenium reduction reaction (SeRR). On the anode, Sn@BIBCs displays triple-induced properties, including the zincophilic of the internal metallic Sn, the homogenized spatial electric field from the 3D spatial structure, and the curvature effect of the bowl-shaped carbon. Collectively, these factors induce preferential nucleation of Zn, ensuring its uniform deposition. As a result, the integrated Zn-Se battery system achieves a remarkable specific capacity of up to 603 mAh g-1 and an impressive energy density of 581W kg-1, highlighting its tremendous potential for practical applications.

Examining stagnation-point flow impinging on a deforming cylinder in Reiner-Rivlin fluid with integrated heat and mass transfer

Here the Reiner-Rivlin model is applied to explore non-Newtonian flow in stagnation-point region around a stretching cylinder. Under the influence of viscous heating and thermos-diffusion, the phenomena of combined heat and mass transport are investigated. To explore the intrinsic irreversible nature of transport phenomena, the current work incorporates an analysis of entropy generation. Additionally, prescribed wall temperature and concentration are taken into consideration when developing the computational framework, and it will be shown later that these assumptions are essential to achieving self-similar analysis. Numerical computations are developed by the MATLAB tool “bvp4c” while analytical solutions are found by the optimal homotopy approach embedded in the routine “BVPh 2.0” of MATHEMATICA. For a reasonable choice of embedded parameters, both techniques produce the same numerical results. For various regulating parameters, the importance of curvature effects on the boundary layers is explained. Flow visualization utilizing streamlines and isotherms reveals interesting patterns for both Newtonian and non-Newtonian flows. The force required by the stretching cylinder is analyzed by evaluating skin friction coefficient, in the case of Reiner-Rivlin fluid. Furthermore, surface cooling rate and mass flux are scrutinized graphically and in tabular form. The cooling rate of the cylindrical boundary is higher than that of the flat plate boundary. Furthermore, a noticeable reduction in surface cooling rate is found for increasing values of Reiner-Rivlin fluid parameter.