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This study examines the impact of the transfer of mass and heat characteristics on the magnetohydrodynamic natural convection travel over a slanted surface in an impermeable, electrically conductive fluid. The equations that govern can be transformed into standard differential equations through the use of nondimensional quantities, which can subsequently be solved through the ordinary perturbation method. Equations for temperature, concentration, and velocity were produced by using this method. Furthermore, MATLAB-generated graphics were used to analyse and illustrate the effects of several parameters on acceleration, concentration and temperature, including the Schmidt number, thermal Grashof, singular Grashof number and angle of inclination. [ABSTRACT FROM AUTHOR]

Multi-phase flows, encountered in nature or in industry, exhibit non-trivial rheological properties, which we attempt to better understand thanks to model materials and appropriate rheometers. Unsaturated wet granular flows down a rough inclined plane turn out to be steady and uniform for a wide range of parameters, despite the cohesion and the grain aggregates. The cohesive Mohr–Coulomb yield criterion extended to inertial granular flows, with a cohesion stress dependent on the liquid content and an internal friction coefficient dependent on the inertial number, allows for predictions in good agreement with our experimental measurements, when one introduces a grain aggregate size, which defines the appropriate length and relaxation time scales in the inertial number. We found that the grain aggregate size depends not monotonically on the liquid content and does not scale with the cohesion length induced by the cohesion stress, due to the non-trivial distribution of the liquid within the granular material. [ABSTRACT FROM AUTHOR]

An analysis is presented for the stability of a viscous liquid film flowing down an inclined plane with respect to three-dimensional disturbances under the action of gravity and surface tension. Using momentum-integral method, the nonlinear free surface evolution equation is derived by introducing the self-similar semiparabolic velocity profiles along the flow (x - and y -axis) directions. A normal mode technique and the method of multiple scales are used to obtain the theoretical (linear and nonlinear stability) results of this flow problem, which conceive the physical parameters: Reynolds number R e , Weber number W e , angle of inclination of the plane θ and the angle of propagation of the interfacial disturbances ϕ. The temporal growth rate ω i + and second Landau constant J 2 , based on which various (explosive, supercritical, unconditional, subcritical) stability zones of this flow problem are categorized, contain the shape factors B and β owing to the non-zero steady basic flow along the y -axis direction. A novel result which emerges from the linear stability analysis is that for any given value of R e , W e and θ , any stability that arises in two-dimensional disturbances (ϕ = 0) must also be present in three-dimensional disturbances. For ϕ = 0, there exists a second explosive unstable zone (instead of unconditional stable zone) after a certain value of R e (or θ) due to the involvement of B and β in the expression of J 2. This explosive unstable zone vanishes after a certain value of ϕ depending upon the values of R e , W e and θ , which confirms the stabilizing influence of ϕ on the thin film flow dynamics irrespective of the values of R e , W e and θ. • Steady basic solution. • Three-dimensional waves. • Linear stability. • Weakly nonlinear tability. [ABSTRACT FROM AUTHOR]

In physics, several problems are solved by considering the extended object as being a particle with all the mass concentrated in the center of mass and neglected dimensions, however for rotating and rolling objects this approximation will result in a serious disagreement between theory and experimentation. In this work we present an experimental assembly of a sliding body on an inclined plane, which can measure its position as a function of time and thus predict its velocity and acceleration. In addition to basic kinematics, the moment of inertia of rotating bodies will be considered. We will use bodies with different shapes and moments of inertia, experimentally identifying their contribution along the displacement. We propose the construction and use of an experimental apparatus using Arduino, collecting a large number of points, in which it is possible to analyze the temporal displacement of the center of mass of the object along the inclined plane with different angles, cylindrical and spherical objects, identifying the discrepancy when disregarding the moment of inertia of the rotating bodies. [ABSTRACT FROM AUTHOR]

[Display omitted] The shape of the "freezing tip" formed by the crystallization of water droplets demonstrated remarkable universality - no dependence on the cooling rate and physico-chemical properties of the substrate has been observed. At the same time, the spatial orientation of the freezing cone may be varied. We hypothesized that the orientation of the freezing tip is determined by the direction of heat flux at the base of the sessile droplet. This direction is expected to be changed when the substrate with a low thermal diffusivity is not cooled uniformly. We studied the freezing of water droplets placed on the inclined surface of wedges made from a variety of materials (polymers: Polymethylmethacrylate, Polytetrafluoroethylene, Polyurethane and metal: Titanium), which were cooled from below. The shape of the frozen droplets was controlled in situ. The computational model was suggested for the transient temperature field in the polymer wedge to determine a time variation of the local heat flux under the droplets. A comparison of numerical results and the measurements enabled us to confirm the aforementioned hypothesis relating the orientation of the freezing tips to the direction of the heat flux. It was established that the orientation of the freezing cone axis depends on the location of the frozen droplet on the inclined surface of the wedge. Calculations of the transient temperature field of the wedge confirmed our hypothesis about the physical reason of the various spatial orientations of the freezing cones. [ABSTRACT FROM AUTHOR]

This work presents an alternative method of teaching undergraduate introductory physics laboratory. Students are presented with an experimental scenario "Rolling object on an inclined plane" and guided to develop their own laboratory activities in a studio-style setting. The overall goal of this alternative approach is to shift part of the learning responsibility to students. Through guided self-developed activities, students establish the connections between different physics concepts. Such a shift makes students active participants in the classroom, allows them to explore ideas independently, and discover through doing the exploring. Furthermore, the pedagogy is aimed at (i) motivating and actively engaging students in the learning process, (ii) helping students learn how to think independently, (iii) developing scientific ideas, and (iv) taking ownership of the learning process. Assessment of data from a 3-year pilot study showed improvement in students' technical writing skills (30%), creative lab and research skills (6%), as well as critical thinking and quantitative skills (6%). In addition, students who participated in the study scored higher (6%) than their control group counterparts on the final exam. Other benefits are improvement in understanding of the research process and laboratory technical skills. [ABSTRACT FROM AUTHOR]

Analogous to the Amonton–Coulomb relation, which states the linear dependency between the dynamic sliding friction and the normal reaction, the rolling friction moment is commonly accepted as proportional to the normal reaction in a concentrated point contact. This hypothesis persists since it gives simple dynamic models and also due to difficulties met in experimental estimations of the rolling friction torques. Recent theoretical studies proved that this dependency is nonlinear even for elastic materials. A special rotor is designed, with an adjustable position for the center of mass but with constant mass and constant axial inertia moment. The pure rolling motion of the rotor on an inclined controlled small slope is studied. The angular acceleration of motion is theoretically deduced, assuming that the rolling friction torque is proportional to the normal force raised at a certain power. The deduced theoretical dynamic model evidences the influence of the eccentricity of the rotor upon the acceleration. For the particular case of linear dependency—the exponent of the power equal to one, the law of motion is independent of the configuration of the rotor. Experimental tests were made using the rotor constructed according to the theoretical model. For two positions of the center of mass, the experimental law of motion on the inclined plane is established by a non-contact method and the two different laws obtained to validate the nonlinear dependence rolling friction torque-normal force. The paper validates in an experimental manner the considered nonlinear assumption. The experimental tests concerning the microtopography of the contacting surfaces reveal that the hypothesis required by Hertzian theory, namely smooth contacting surfaces, is not satisfied. Thus, the distribution of pressure on the contact area does not obey the Hertzian semi-ellipsoidal distribution and further experimental tests are required for quantitative findings on the rolling friction torque-normal force relationship. [ABSTRACT FROM AUTHOR]

In an increasingly data-oriented science, the use of automatic computational methods is progressively indispensable. In this context, it becomes important to expose undergraduate physics students to artificial intelligence and machine learning methodologies. In this work we propose a way to use such methods in physics, solving the didactic problem of rolling on an inclined plane. We introduce the main concepts of machine learning techiniques and measure the travel time of different objects (rim, disk and sphere) for an initial height and tilt angle. Based on these data, we used classification models capable of predicting the object that was dropped with an accuracy of 83%, and regression models which were able to predict the average speed of the object that was rolled with mean absolute error of 1.4 cms-1. We also show that this didactic model is instructive because it allows a direct comparison with physical models and serves as a discussion of the meaning of teaching physics to the computer. [ABSTRACT FROM AUTHOR]

The major focus of this research is to discuss the precise results of the unstable, indirect and natural free convection flow of radiating fluid with heat and the analysis of its collective transmission along with an inclined plane. The subsequent liquid is optically thick, sticky and is unable to be compressed and further it is prone to electrical conducting. Analytical solutions are developed by applying the method of Laplace transform for the governing differential equations. The obtained results are discussed minutely for some special cases and further the effects of the related parameters are considered in detail. Rosseland radiational flux model is employed in order to model the impacts of the thermal radiation. For this purpose, graphical and numerical results are derived for the appropriate parameters in flow regime and these parameters exert significant impact on the obtained results. [ABSTRACT FROM AUTHOR]

The paper focuses on the evaluation of the shear strength in conditions of low normal stress of various geosynthetic-geosynthetic interfaces, which are typical of landfill cover systems, by means of the inclined plane test, with the aim of studying the friction mobilisation in relation to various kinematic behaviours. The results of three different methods to evaluate the angle of friction were analysed, together with the sensitivity of the interfaces in relation to the wear effect and the influence of the state of hydration. The results showed very different responses of the interfaces to the shear stress, which involved three main types of sliding mechanisms, referred to as sudden, gradual and uneven sliding. Another outcome observed was that the shear strength of geosynthetic-geosynthetic interfaces cannot always be properly characterised following the procedure proposed by the European standard for soil-geosynthetic interfaces (EN ISO 12957–2), since the actual mobilised kinematic behaviour should be taken into consideration. In this regard, the paper provides some hints on the choice of the more representative parameter of friction for each type of sliding. A particular focus was given to the case of gradual sliding interfaces, for which the static friction is difficult to detect due to the very slow movements; for practical purposes, the design friction of these interfaces should be evaluated by using an adequate safety factor with respect to the friction evaluated at 1 mm of displacement. • The paper offers a comparison of the results of three different methods to evaluate the angle of interface friction at low normal stress by means of the inclined plane test for various interfaces, considering alsowearing and hydration state. • The research highlights the response of the interfaces to the shear stress may be very different, involving various sliding mechanisms. • These kinematics cannot be revealed by the common direct shear test, in which the speed is imposed by the apparatus. From this point of view, the inclined plane device allows increasing stress state rather than imposed strain rate. • The results show that the shear strength of geosynthetic-geosynthetic interfaces cannot be correctly characterised if the real sliding kinematics is not taken into consideration. • The paper provides some hints on the choice of the more representative parameter of friction, for design purposes, according to the various interface behaviours. [ABSTRACT FROM AUTHOR]

This study investigates how the shear rate can affect the geomembrane – protective geotextile friction angle. Four types of geomembranes (GMB) were considered (EPDM, HPDE, PP, and PVC) and a single nonwoven needle-punched geotextile (GTX nw) was used to make the interfaces with the geomembrane. Three shear devices were used: a large-scale inclined plane (IP), a shear box (SB), and a small-scale shear device (ssSD). The ssSD allows two shear modes to be compared: one mode involves incrementally increasing the shear stress, and the other involves imposing a constant tangential velocity at the interface. Only the PP GMB- GTX nw was tested with the SB and the ssSD. Inclined plane standardised tests show that for the three interfaces that undergoes gradual sliding (EPDM, PP and PVC GMB- GTX nw), it is shown that a step-by-step experimental procedure gives significantly lower interface friction angle than that given by the procedure from the current international standard, which is explained by the increase of interface shear stress with sliding speed. These observations are confirmed by shear box tests. One major practical result is that, following the nature of geosynthetics, the shear rate applied in large-scale shear box tests should be adapted to assess a safety value of a geosynthetic - geosynthetic interface friction angle. [ABSTRACT FROM AUTHOR]

The flow of fractional Jeffrey fluid due to time-dependent motion of plate has been investigated. An inclined plate is considered, and thermal effects with mass diffusivity in flow are also taken into account. The set of governing equations is operated by integral transform namely Laplace transform technique. Caputo–Fabrizio time-fractional derivative is considered in energy and diffusion equations. Moreover, exact analytical solutions are achieved. In the limiting cases, the general solutions for accelerating and oscillating motion of Jeffrey fluid are obtained. Effects of involved physical parameters, fractional parameter α , inclination of plate θ , Prandtl number Pr and Schmidt number Sc on the flow, are graphically detected. [ABSTRACT FROM AUTHOR]

The paper is concerned with the dynamics of advancing liquid blobs of fluid on curved and flat solid surfaces, such as cycloids and inclined planes. We investigate the kinematics of such blobs on hydrophobic surfaces with emphasis on the shape of the interface as the fluid advances. A theoretical model is proposed that captures the shape of the interface at early times. Also, the trajectory of the fluid, as it detaches from the cycloid, is investigated and compared with theoretical predictions. We find a good qualitative agreement between predictions and experimental data. As an extension of the present findings, we also investigate the shape and the dynamics of advancing drops on cycloids, placed in a viscous outer immiscible liquid. We find both similarities, in terms of kinematics, and specific differences in the shape of the advancing drop. [ABSTRACT FROM AUTHOR]

Fillet end milling is widely used in mould, aerospace, shipping manufacture and other fields. As one of the important parameter in milling machining, milling force is related to machining efficiency and quality, as well as tool wear, but it is difficult to predict. Aiming at fillet end milling under a pre-determined inclination angle, considering cutter run-out, this paper presents a cutting force coefficients identification model related to chip thickness and axial position angle, and then achieve milling force prediction. A parametric relationship among feed direction, cutter axis and to-be-machined surface are established, and then, the analytic expression of previous swept surface, to-be-machined surface and cutter envelope surface is derived. Boundary curves of cutter workpiece engagement (CWE) are established based on spatial surface intersection analytically. The criterion of the cutter edge element involved in cutting is proposed. Judging element along the cutter edge one by one, whereafter the algorithm of in-cut-cutting edge (ICCE) is proposed. Combining mechanical force model with chip thickness considering feed direction and cutter run-out, a milling force prediction model is established. Based on the method of undetermined coefficients, combining average instantaneous measured force, coefficients corresponding to axial position angle and chip thickness are solved. Further instantaneous peak measured force is used to obtain cutter run-out parameters. Simulation and experiments show that CWE agrees well with that of experiment and ICCE is consistent well with that of simulation. Milling force experiments of different machining parameters show the milling force coefficients and run-out parameters can be applied to fillet end milling under pre-determined inclination angle well. [ABSTRACT FROM AUTHOR]

Key points: It is known that interception of targets accelerated by gravity involves internal models coupled with visual signals.Non‐visual signals related to head and body orientation relative to gravity may also contribute, although their role is poorly understood.In a novel experiment, we asked pitched observers to hit a virtual target approaching with an acceleration that was either coherent or incoherent with their pitch‐tilt.Initially, the timing errors were large and independent of the coherence between target acceleration and observer's pitch. With practice, however, the timing errors became substantially smaller in the coherent conditions.The results show that information about head and body orientation can contribute to modelling the effects of gravity on a moving target. Orientation cues from vestibular and somatosensory signals might be integrated with visual signals in the vestibular cortex, where the internal model of gravity is assumed to be encoded. Interception of moving targets relies on visual signals and internal models. Less is known about the additional contribution of non‐visual cues about head and body orientation relative to gravity. We took advantage of Galileo's law of motion along an incline to demonstrate the effects of vestibular and somatosensory cues about head and body orientation on interception timing. Participants were asked to hit a ball rolling in a gutter towards the eyes, resulting in image expansion. The scene was presented in a head‐mounted display, without any visual information about gravity direction. In separate blocks of trials participants were pitched backwards by 20° or 60°, whereas ball acceleration was randomized across trials so as to be compatible with rolling down a slope of 20° or 60°. Initially, the timing errors were large, independently of the coherence between ball acceleration and pitch angle, consistent with responses based exclusively on visual information because visual stimuli were identical at both tilts. At the end of the experiment, however, the timing errors were systematically smaller in the coherent conditions than the incoherent ones. Moreover, the responses were significantly (P = 0.007) earlier when participants were pitched by 60° than when they were pitched by 20°. Therefore, practice with the task led to incorporation of information about head and body orientation relative to gravity for response timing. Instead, posture did not affect response timing in a control experiment in which participants hit a static target in synchrony with the last of a predictable series of stationary audiovisual stimuli. Key points: It is known that interception of targets accelerated by gravity involves internal models coupled with visual signals.Non‐visual signals related to head and body orientation relative to gravity may also contribute, although their role is poorly understood.In a novel experiment, we asked pitched observers to hit a virtual target approaching with an acceleration that was either coherent or incoherent with their pitch‐tilt.Initially, the timing errors were large and independent of the coherence between target acceleration and observer's pitch. With practice, however, the timing errors became substantially smaller in the coherent conditions.The results show that information about head and body orientation can contribute to modelling the effects of gravity on a moving target. Orientation cues from vestibular and somatosensory signals might be integrated with visual signals in the vestibular cortex, where the internal model of gravity is assumed to be encoded. [ABSTRACT FROM AUTHOR]

Abstract The influence of transverse mechanical vibrations on dense flows of granular material down inclines with a rough bed is analyzed using 3D DEM simulations and compared with experimental results. The vibrations make appear two distinct behaviors: a gravity-driven regime and a vibration-driven regime. In the gravity-driven regime, our results are consistent with previous studies from the literature. The vibrations induce particles velocity fluctuations in the vibration-driven regime, which generate a granular temperature profile along the depth of the packing related to the velocity profile. The velocity profile is consistent with a creeping flow which makes appear a critical length scale related to a nonlocal rheology. Our results suggest that this length scale emerges from the characteristic damping length of transverse vibration waves which propagate in the bulk of the granular material. These results could be of interest for the optimization of powders conveying. Graphical ABSTRACT Unlabelled Image Highlights • Vibrations allow the transport of granular materials to be tuned. • Vibrations allow possible flows below the angle of avalanche. • Vibrations induce a nonlocal rheology related to a characteristic length. • This characteristic length depends on the acceleration of the vibrations. [ABSTRACT FROM AUTHOR]

Abstract The stability of shear-thinning fluid down an inclined plane is investigated theoretically with application to process engineering (coating process) and natural hazards as well (debris flow impact). The power-law model is used to describe the fluid rheological behavior. A linear stability analysis is brought out for building a generalized Orr-Sommerfeld model with appropriate definition of non-dimensional numbers in order to overcome the inconsistency of the existing shallow-water models. The solution to the secular equation showed that at zeroth order, there is no instability with respect to the long wave perturbations considered. Waves propagate without dispersion, at the same dimensional speed for any wavenumber. Moreover, the interface and the stream function are in phase, while the components of the perturbation velocities are respectively in phase and in quadrature of phase. Finally, the perturbation celerity decreases for increasing power law index, with a value of 2 as minimum for the Newtonian fluid. At first order, the effect of the different forces acting on the flow has been pointed out. It was particularly shown that pressure and surface tension have a stabilizing effect, while inertia and rheofluidification have a destabilizing effect. Moreover, the relative variation of critical Reynolds number increases with increasing reduced wavenumber for all values of slope tested while it decreases with increasing power-law index for all values of reduced wavenumber tested. Highlights • A generalized Orr-Sommerfeld equation was built and solved by a perturbation method. • Order zero: waves propagate without dispersion at the same speed for any wavenumber. • Perturbation celerity decreases for increasing power law index, with 2 as minimum. • Order one: the celerity correction only affects its growth rate but not its value. • Effects of all forces acting on flow stability have been respectively characterized. [ABSTRACT FROM AUTHOR]

Finding the coefficient of rolling friction (CRF) by the inclined plane method is similar to the manner used in establishing the coefficient of sliding friction. For the rolling case, the difficulty arises from the fact that the usual devices employed in angular measurements present errors greater than the effective angle. This paper surmounts this inconvenience by restricting the body to roll along a well controlled direction different from the steepest line of the plane. The experimental values found out for the coefficient of rolling friction are in good agreement with the ones from literature. [ABSTRACT FROM AUTHOR]

The motion of a two‐body limbless crawler along a line of maximum slope on an inclined plane is considered. Dry friction (anisotropic in the general case) acts between the system's bodies and the underlying plane. The motion is excited and controlled by a periodic change in the distance between the bodies. Of most interest is the periodic upward motion of the system, when the velocity of the system's center of mass changes periodically with a period coinciding with that of the excitation. A mathematical model of the crawler is presented. An upper bound for the inclination angles of the plane at which the system can move upward is estimated. This estimate is based on the averaged model, which implies smallness of the coefficient of friction. Numerical and physical simulation is performed to verify the theoretical results and define an applicability area for them. The motion of a two‐body limbless crawler along a line of maximum slope on an inclined plane is considered. Dry friction (anisotropic in the general case) acts between the system's bodies and the underlying plane. The motion is excited and controlled by a periodic change in the distance between the bodies. Of most interest is the periodic upward motion of the system, when the velocity of the system's center of mass changes periodically with a period coinciding with that of the excitation. A mathematical model of the crawler is presented. An upper bound for the inclination angles of the plane at which the system can move upward is estimated. This estimate is based on the averaged model, which implies smallness of the coefficient of friction. Numerical and physical simulation is performed to verify the theoretical results and define an applicability area for them. [ABSTRACT FROM AUTHOR]

Winter brings snow and ice to Northern Europe and with it the need to move safely over ice. It has been customary to select an appropriate material surface for movement over ice, but another way to influence the interaction with ice is to appropriately prepare the ice surface. The objective of the research is to investigate the influence of ice texture on initiating movement over ice and on sliding velocity over ice in the laboratory and field conditions. The ice has been prepared smooth, scratched and glazed similar to the one found in real life situations. The static coefficient of friction and the sliding speed have been measured at the laboratory, but the sliding speed quantified on a skeleton - at the skeleton push-start facility. The scratched ice surface has increased the resistance to movement, thus resulting in the lowest sliding speed under laboratory conditions. Sliding is better on the smooth ice and glazed ice. The contact surfaces have been measured to determine the effect of contact area on sliding properties. Field experiments with heavier loads have flattened the ice surface irregularities for more constant sliding conditions over time. This outcome provides a useful indicator for pedestrians and road traffic related to the safety of movement over different ice surfaces as well as a reference for those involved in winter sports. [ABSTRACT FROM AUTHOR]

Attenuation of sunlight in wastewater treatment ponds reduces the depth of the water exposed to disinfecting irradiances. Shallow pond depth with paddlewheel rotation increases exposure of pathogens to sunlight in high rate algal ponds. Generation of thin films, using pond walls as inclined planes, may increase inactivation of pathogens by increasing sunlight exposure. The performance of a laboratory based model system incorporating an inclined plane (IP) was evaluated. F-RNA bacteriophage, in tap water or wastewater, was exposed to sunlight only on the IP with the bulk water incubated in the dark. MS2 inactivation was significantly higher when the IP was present (P<0.05) with a 63% increase observed. Prolonged exposure increased MS2 die-off irrespective of IP presence. Versatility of the IP was also demonstrated with faster inactivation observed in both optically clear tap water and wastewaters. IPs of different surface areas produced similar inactivation rates when operated at similar hydraulic loading rates regardless of slope length. [ABSTRACT FROM AUTHOR]

We investigated interfacial instability of a thin liquid film flowing down an inclined plane, considering the linear variation of fluid properties such as density, dynamical viscosity, surface tension and thermal diffusivity, for the small variation of temperature. Using long wave expansion method and considering order analysis specially for very small Biot number ( B i ) we obtained a single surface equation in terms of the free surface h ( x , t ) . Considering sinusoidal perturbation method we carried out linear stability analysis and obtained the critical Reynolds number ( R e c ) and linear phase speed ( c r ) , both of which depend on K μ , K ρ but independent of K σ , K κ . Using the method of multiple scales, weakly nonlinear stability analysis is carried out. We demarcated subcritical, supercritical, unconditional and explosive zones and their variations for the variation of K μ , K ρ and K σ . Also we discussed the variations of threshold amplitude in the subcritical as well as in the supercritical zones for the variation of K μ , K ρ and K σ . Finally we discussed the variation of nonlinear wave speed N c r for the variation of K μ , K ρ and K σ . [ABSTRACT FROM AUTHOR]

The droplet evaporation on inclined surfaces is common in engineering applications. Hence, it is necessary to understand and enhance the droplet evaporation characteristics on inclined surface. The existing studies have confirmed that electric field can enhance the droplet evaporation rate on horizontal surfaces and the droplet evaporation characteristics on inclined surfaces is different from that on horizontal surface. Therefore, in order to explore the effect of electric field on the droplet evaporation characteristics at inclined plane, the droplet evaporation at different inclination plane and various electric field conditions is investigated by experiment. It is found that the electric field can greatly enhance the droplet evaporation rate on inclined surface, and the enhancement effect is better than that of applying electric field to the droplet on horizontal surfaces. Different direction switching frequencies of electric field have different effects on evaporation rate, and increasing the electric field strength can enhance the evaporation rate continuously. Moreover, the droplet evaporation pattern on inclined surfaces is not affected by the electric field, but the internal vortex flow and heat transfer efficiency are enhanced. Particularly, the droplet oscillation basically disappears after the inclination angle larger than 10°. [Display omitted] • Electric field has better effect for droplet on tilt plane than on horizon. • The curve of evaporation time with tilt angle varies at different electric field. • The droplet oscillation disappears when plane is tilted. [ABSTRACT FROM AUTHOR]

The ability to slide on ice has previously focused on the measurement of friction coefficient rather than the actual sliding velocity that is affected by it. The performance can only be directly measured by the sliding velocity, and therefore the objective was to design and setup a facility to measure velocity, and determine how experimental conditions affect it. Optical sensors were placed on an angled ice track to provide sliding velocity measurements along three sections and the velocity for the total sliding distance. Experimental conditions included the surface roughness, ambient temperature and load. The effect of roughness was best reported with a Criterion of Contact that showed a similar sliding velocity for metal blocks abraded with sand paper smoother than 600 grit. Searching for the effect of temperature, the highest sliding velocity coincided with the previously reported lowest coefficient of ice friction. Load showed the greatest velocity increase at temperatures closer to the ice melting point suggesting that in such conditions metal block overcame friction forces more easily than in solid friction. Further research needs to be conducted on a longer ice track, with larger metal surfaces, heavier loads and higher velocities to determine how laboratory experiments can predict real-life situations. [ABSTRACT FROM AUTHOR]

We consider a two-dimensional motion of a thin film flowing down an inclined plane under the influence of the gravity and the surface tension. In order to investigate the stability of such flow, we often use a thin film approximation, which is an approximation obtained by the perturbation expansion with respect to the aspect ratio of the film. The famous examples of the approximate equations are the Burgers equation, Kuramoto–Sivashinsky equation, KdV–Burgers equation, KdV–Kuramoto–Sivashinsky equation, and so on. In this paper, we give a mathematically rigorous justification of a thin film approximation by establishing an error estimate between the solution of the Navier–Stokes equations and those of approximate equations. [ABSTRACT FROM AUTHOR]

The study explored whether laypersons correctly tacitly know Galileo's law of the inclined plane and what the basis of such knowledge could be. Participants predicted the time a ball would take to roll down a slope with factorial combination of ball travel distance and slope angle. The resulting pattern of factorial curves relating the square of predicted time to travel distance for each slope angle was identical to that implied by Galileo's law, indicating a correct cognitive representation of this law. Intuitive physics research suggests that this cognitive representation may result from memories of past perceptions of objects rolling down a slope. Such a basis and the correct cognitive representation of Galileo's law led to the hypothesis that Galileo's law is also perceptually represented correctly. To test this hypothesis, participants were asked to judge the perceived travel time of a ball actually rolling down a slope, with perceived travel distance and perceived slope angle varied in a factorial design. The obtained pattern of factorial curves was equal to that implied by Galileo's law, indicating that the functional relationships defined in this law were perceptually represented correctly. The results foster the idea that laypersons may tacitly know both linear and nonlinear multiplicative physical laws of the everyday world. As a practical implication, the awareness of this conclusion may help develop more effective methods for teaching physics and for improving human performance in the physical environment. [ABSTRACT FROM AUTHOR]

The use of didactical laboratories is a common necessity both for distance and traditional universities. If in the first case institutions have to invest money not only in the creation but also in the maintenance of the structures, for distance learning there is an always under discussion problem related to how laboratory activities can be offered to students. In this context, smartphone applications can help both cases offering simple, low cost and didactical effective laboratories. In this paper, a review of the state of art is presented together with a case study realized during the annual internships organized by INFN-Frascati for secondary school students. [ABSTRACT FROM AUTHOR]

The onset of motion of a drop with an initially non-circular three phase contact line was studied experimentally and numerically. Two drops of volume 10 μl were made to coalesce and form a composite 20 μl drop. The contact line of this drop was approximately elliptical and the local contact angle along the contact line was not a constant (as would have been the case with a circular contact line). The orientation of the drop to the impending direction of motion was varied. Inclined plate experiments were performed and the moving and sliding angles were noted in each case. It was observed that the moving and sliding angles of the drop were strongly dependent on this orientation. Specifically, the local conditions on the contact line at the front and back edges of the drop as well as the drop profile width were found to be the determining parameters. Surface evolver simulations were performed to understand the results of the experiments. It was found that the evolution of the contact line for non-circular drops was rather counter-intuitive when compared to the results from a drop with a circular contact line and resulted from a competition between gravity and the local contact angle hysteresis forces. [ABSTRACT FROM AUTHOR]

Diabetic peripheral neuropathy (DPN) is widely considered as a degenerative complication of diabetic patients. The clinical effectiveness of folic acid (FA) on DPN is uncertain. The objective of the present study was to determine the effect of FA in DPN using electromyography (EMG), histopathological examination, immunohistochemistry, inclined plane test, and malondialdehyde (MDA) levels as a marker for lipid peroxidation in experimental diabetic rats. A total of 21 Sprague Dawley rats were randomly divided into 3 groups: control group, diabetes group, and FA-treated group. In EMG, compound muscle action potential (CMAP) amplitude in the sciatic nerve was lower in the diabetes group compared with the control group. CMAP amplitude in the sciatic nerve was higher in the FA-treated group when compared with the diabetes group. Distal latency and CMAP duration in the sciatic nerve were lower in the FA-treated group when compared with the diabetes group. In histopathological examination of the sciatic nerve, peripheral fibrosis was present in the diabetic group; the fibrosis was lower in the FA-treated group. In comparison with the diabetes group, the expression of nerve growth factor (NGF) was higher in the FA-treated group. The scores for the inclined plane test were lower in the diabetes group and higher in the FA-treated group than the control group. The MDA levels were significantly lower in the FA-treated group when compared with the diabetes group.The study suggests that FA can protect diabetic rats against DPN and that the underlying mechanism for this may be related to improvement of the expression of NGF and lower MDA levels. [ABSTRACT FROM AUTHOR]

We consider a two-dimensional motion of a thin film flowing down an inclined plane under the influence of the gravity and the surface tension. In order to investigate the stability of such flow, it is hard to treat the Navier–Stokes equations directly, so that a thin film approximation is often used. It is an approximation obtained by the perturbation expansion with respect to the aspect ratio δ of the film under the thin film regime δ ≪ 1 . Our purpose is to give a mathematically rigorous justification of the thin film approximation by establishing an error estimate between the solution of the Navier–Stokes equations and those of approximate equations. To this end, in this paper we derive a uniform estimate for the solution of the Navier–Stokes equations with respect to δ under appropriate assumptions. [ABSTRACT FROM AUTHOR]

Given the advancement of tangible technology within human-computer interaction and that the equipment in Physics laboratories of higher education institutions are expensive to be afforded and upgraded, this paper presents the feasibility of using a remote control of video game called Wiimote as a tangible device in an inclined plane practice. The results were satisfactory and the students said that the design of the implanted experience contributed to the conceptual and procedural learning related to the inclined plane. The results seem to demonstrate the usefulness of tangible technology in building closer models of science representations and helping students to form mental images that can be used by them on new challenges. In the future, the development of a pedagogical design with this practice is expected. [ABSTRACT FROM AUTHOR]

In this work we have examined the motion of a body that rolls on an inclined plane, without the assumption of a rigid body. Under these conditions, the body may suffer small deformations. From the equations of motion we obtain an analytical expression for the acceleration of the center of mass. We show that some cases reported in the literature can be obtained as special cases of our expression. In addition, we obtain an expression for the friction coe?cient of rolling, which can be calculated from experimental measurements performed on an inclined plane. These results can be used for students of physics to do a deeper analysis of the friction phenomenon associated with rolling bodies. [ABSTRACT FROM AUTHOR]

Inclined plane test is widely used, especially in Europe, for the friction characterization of geosynthetics liner systems, for example in landfill applications. However, interpretation of the test is more complex and less consensual than for the direct shear test. In this paper, a comprehensive analysis of interface behaviour at the Inclined Plane device is presented for a non-woven geotextile on a geomembrane in dry condition. New test procedure are proposed, and the related parameters of friction are defined in order to properly characterise friction behaviour. For the Inclined Plane, the shear strength of a geosynthetic interface cannot be characterised by a single parameter, as the interface behaviour is sensitive to the different kinematic conditions. To this purpose, a comparison is shown with the results of complementary tests carried out using the Shaking Table test. For both test procedures, particular attention was paid to the influence of the relative sliding velocity. Finally, the sensitivity of the interface to mechanical damage caused by large relative displacements was quantified. [ABSTRACT FROM AUTHOR]

The flow of a thin film down a vertical cold thick wall with finite thermal conductivity is investigated under the lubrication approximation. It is shown that, despite the cooling from the wall, it is possible to find a new flow instability. That is, the free surface response to the wall deformation increases its amplitude with the negative Marangoni number. This amplitude growth is independent from the evolution of the time-dependent perturbations imposed on the free surface which, in contrast, are stabilized by cooling from the wall. However it is demonstrated that, even in this case, spatial resonance (see Dávalos-Orozco, 2007, 2008) is more effective to stabilize the time-dependent perturbations. From the results it is evident that these effects are possible only when the magnitudes of the thicknesses ratio and the thermal conductivities ratio are small. [ABSTRACT FROM AUTHOR]

The stability of a thin layer of viscoelastic fluid flowing through a porous medium down a non-uniformly heated inclined plane with a constant temperature gradient along the plane is considered. The film flow system is influenced by gravity, mean surface tension, thermocapillary forces, viscoelastic forces, porosity, and permeability of porous medium. We seek a solution of the stability problem in a series in small wave numbers, and the obtained results, when the plane is heated in the downstream direction, show that the Marangoni, Galileo, and Biot numbers, porosity, and permeability of the porous medium have dual roles in the stability of the flow system, while the viscoelastic parameter and angle of inclination have stabilizing effects, and the Prandtl number has a destabilizing effect. The effects of these physical parameters are also discussed in the case when the plane is cooled in the downstream direction, and we found that their effects are opposite to those of the previous case. © 2013 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (). DOI 10.1002/htj.21105 [ABSTRACT FROM AUTHOR]

We have studied the gravity driven flow of spherical shaped, millimetric sized granular material coated with aspherical, micron-sized, near frictionless lubricant particles. Experiments were performed on an inclined plane using two different sized particles for varying concentrations of the lubricant. The particle volumetric flow rate exhibits a non-monotonic behavior with increasing lubricant concentration. It shows an increase at lower lubricant concentration followed by a decrease at higher lubricant concentration. The lubricant particles adhere to the granular particle surface thereby reducing the inter-particle friction. However, presence of lubricant particles at higher concentration damps out inter-particle collision thereby reducing the inter-particle momentum transfer. Non-monotonicity in the observed behavior is then conjectured to arise due to competing effects of inter-particle friction and inter-particle collision. The present work and the overall observed behavior therein provides a simple experimental system to characterize the effects of added lubricant material in pharmaceutical and other relevant industrial applications. [Display omitted] • Coating of granular material with a solid lubricant induces flow variability. • Flow rate of coated granular material improves due to reduced inter-particle friction. • Excessive coating of lubricant slows the flow due to increased inter-particle collisional damping. • Inclined plane geometry is a good experimental system to characterize lubricant coated granular material. [ABSTRACT FROM AUTHOR]

Familiarity with the visual environment affects our expectations about the objects in a scene, aiding in recognition and interaction. Here we tested whether the familiarity with the specific trajectory followed by a moving target facilitates the interpretation of the effects of underlying physical forces. Participants intercepted a target sliding down either an inclined plane or a tautochrone. Gravity accelerated the target by the same amount in both cases, but the inclined plane represented a familiar trajectory whereas the tautochrone was unfamiliar to the participants. In separate sessions, the gravity field was consistent with either natural gravity or artificial reversed gravity. Target motion was occluded from view over the last segment. We found that the responses in the session with unnatural forces were systematically delayed relative to those with natural forces, but only for the inclined plane. The time shift is consistent with a bias for natural gravity, in so far as it reflects an a priori expectation that a target not affected by natural forces will arrive later than one accelerated downwards by gravity. Instead, we did not find any significant time shift with unnatural forces in the case of the tautochrone. We argue that interception of a moving target relies on the integration of the high-level cue of trajectory familiarity with low-level cues related to target kinematics. [ABSTRACT FROM AUTHOR]

A 2D incompressible smoothed particle hydrodynamics (SPH) method is implemented to simulate the impact flows associated with complex free surface. In the incompressible SPH framework, pressure Poisson equation (PPE) based on the projection method is solved using a semi-implicit scheme to evaluate the correct pressure distribution. In this procedure, the PPE comprises the divergence-free velocity condition and density-invariance condition with a relaxation parameter. To test the accuracy and efficiency of the proposed incompressible SPH method, it was applied to several sample problems with largely distorted free surface, including 2D dam-break over horizontal and inclined planes with different inclination angles, as well as the water entry of a circular cylinder into a tank. We mainly focused on the time history of impact pressure on various positions of the solid boundary and temporal evolution of free surface profiles. The results showed reasonably good agreement with experimental data. However, further improvement is needed for extremely high impact flow. [ABSTRACT FROM AUTHOR]

Highlights: [•] ADSA-P modification for bubbles adhering to an inclined solid surface. [•] Contact angles on lower and upper bubble parts are described separately. [•] Very good agreement of calculated and experimental data was obtained. [•] The method could improve description of TPC line expansion. [ABSTRACT FROM AUTHOR]

This paper investigates the drainage of an Oldroyd eight constant fluid down an inclined plane. Analytical expressions for the velocity field are developed by using the variational iteration method (VIM) and the Adomian decomposition method (ADM). Comparison between these two methods shows that the VIM is more efficient than the ADM from a computational viewpoint; also it solves the nonlinear problems without using the Adomian polynomials. Further, the series solution obtained by the VIM shows a faster rate of convergence than with the ADM with easily computable components. The conclusion is that the VIM may be considered as an alternative and powerful method for solving nonlinear problems arising in non-Newtonian fluid mechanics. [ABSTRACT FROM AUTHOR]

Abstract: The problem of hydrodynamic instability of a very thin UCM liquid film flowing down on the outer surface of an inclined plane is investigated. In order to improve the accuracy of numerical results, the viscoelastic parameters and van der Waals forces have been included into the governing equations. Also, the analytical solutions are obtained by utilizing the long-wave perturbation method. The influence of some physical parameters is discussed in both linear and non-linear steps of the problem. It has been revealed that the instability of the film flow is weakened when Reynolds number, viscoelastic property and attractive van der Waals force are reduced. Further, the thin film flow can be stabilized by short-range Born repulsion. The results show that both supercritical stability and subcritical instability may take place within the film flow system. Moreover, the presence of non-linear terms leads to an obvious difference in the behavior of some physical parameters. [Copyright &y& Elsevier]

Abstract: The therapeutic effects of UDP-glucose (UDPG), an endogenous agonist of GPR17 that may promote the self-repair of white matter, glial cell line-derived neurotrophic factor (GDNF), a neurotrophic factor correlated with the growth and survival of nerve cells, and memantine, an antagonist of NMDA receptors, were evaluated for functional improvement of neonatal rats with experimental periventricular leukomalacia (PVL). Five day-old neonatal rat pups were subjected to an ischemia-induced model of PVL. The pups were then randomly divided into sham, PVL, PVL plus UDPG, PVL plus GDNF, and PVL plus memantine groups. All pups were weighed and the age at first eye opening recorded. Pathological changes and myelin sheath formation in the white matter were assessed under both light and electron microscopy on day 7 and 21 after induction of PVL. Values of escape latency (EL) and swimming distance (SD) in Morris water maze test, and the modified inclined plane scores in Rivlin inclined plane test were recorded for rats on day 26. Pups in the PVL group were found to be significantly lower in weight (p<0.05), delayed in age at first eye opening (p<0.01), and impaired in their inclined plane (p<0.01) and Morris water maze (p<0.01) performance compared with those in the sham, UDPG, GDNF and memantine groups. Histopathological grading of the white matter classified all pups in the PVL group with significantly more severe injury (p<0.01), and the number and thickness of their myelin sheaths were significantly less (p<0.01), compared to the UDPG, GDNF, memantine, or sham groups. These results indicate that treatment with UDPG, GDNF, and memantine may significantly improve long-term prognosis in neonatal rats with cerebral white matter injury, characteristic of PVL. [Copyright &y& Elsevier]

The two-legged humanoid structure has advantages for an assistive robot in the human living and working environment. However, the control of bipedal walk is a challenge. Walking performance on solely even floor is not satisfactory. This paper presents a study on bipedal walk on inclined planes with changing slopes. A Zero Moment Point (ZMP) based gait synthesis technique is employed. The pitch angle reference for the foot sole plane-as expressed in a coordinate frame attached at the robot body-is adjusted online by a fuzzy logic system to adapt to different walking surface slopes. Ankle pitch torques and the average value of the body pitch angle, computed over a history of a predetermined number of sampling instants, are used as the inputs to this system. The proposed control method is tested via walking experiments with the 29 degrees-of-freedom human-sized full-body humanoid robot SURALP (Sabanci University Robotics Research Laboratory Platform) on even floor and inclined planes with different slopes. The results indicate that the approach presented is successful in enabling the robot to stably enter, ascend and leave inclined planes with 15 % (8.5°) grade. This, to the best knowledge of the authors, constitutes the steepest ascend reported to date, with a transition from even floor, by a blind walking biped robot. [ABSTRACT FROM AUTHOR]

Liquid food products stick to solid surfaces. This problem occurs in all supply chain steps from production to recycling. Although the basic problem has been known for a long time, the parameters influencing the interfacial adhesion have not been clarified yet. Here, two methods (product depletion test and tack test) to evaluate the adhesion of highly viscous liquids to solid surfaces have been developed. The product depletion test allows the assessment of the residue amounts and covered surface areas during the gravity-driven flow on an inclined plane. The tack test is conducted by filling the gap between two parallelly mounted, horizontally oriented plates with a liquid product and measuring the normal force while separating the plates by pulling off the upper plate under defined conditions. The influence of the experimental parameters on the maximum normal force (Fmax) could be shown. While the correlation between the pull off velocity of the upper plate and Fmax follows a power law, the dependency between the gap size and Fmax follows an exponential function. Although no significant correlation between Fm&ldquor; or the work of adhesion (Wa) and the solid's properties could be identified, a correlation between Fmax and Wa was observed. As shown by product depletion with ketchup, although the surface coverage is only slightly influenced by the packaging material, the opposite is the case for the covered surface area which, therefore, determines the residue amounts. For some coated samples a large residue reduction was observed. [ABSTRACT FROM AUTHOR]

The aim of this paper is to investigate the influence of the time of rest on the change of maximal and average power as a function of time during training on an inclined plane. The values of power, developed during 7 series of 10 bounces with a 0.5 and 1 minute break, were analyzed. The research was conducted on 10 female students from the second year of master studies with a major of physical education. Taking into account the results obtained, which were compared to data from other sources, it is possible to conclude that the value of maximal power for the whole group examined during the training with a 0.5 minute break decreased by 22%, and for the training with a 1 minute break by 12%. One can assume that the training with a 0.5 minute break was more tiring, and for that reason students were not able to regenerate fully so as to bounce in the subsequent series. That is why one should say that the second method of training is more efficient for the evaluation of the maximal power of the contestant. [ABSTRACT FROM AUTHOR]

Abstract: The paper deals with modeling of a power-law fluid film flowing down an inclined plane for small to moderate Reynolds numbers. A model, accurate up to second order [first order] for dilatant [pseudoplastic] fluids is proposed to describe the nonlinear behavior of the flow. The modeling procedure consists of a combination of the lubrication theory and the weighted residual approach using an appropriate projection basis. A suitable choice of weighting functions allows a significant reduction of the dimension of the problem. The resulting model is naturally unique, i.e., independent of the particular form of the trial functions. Reduced models are proposed for the evolution of the local film thickness and flow rate; their linear spectra are compared to that obtained from the full Orr–Sommerfeld numerical solution. To obtain the latter, a new formulation of the eigenvalue problem is proposed to overcome the classical divergence of the apparent viscosity at the free surface. The full model and its reduced forms all have the advantage of the Benney like model close to criticality. Far from the instability threshold the full model continues to follow the Orr–Sommerfeld solution up to sufficiently large Reynolds numbers and gives better predictions than the depth averaging model. An incomplete regularization procedure is performed to cure the rapid divergence of the reduced two-equation model. Due to its relative simplicity the latter might be preferred in practice to the full model, at least at the initial stage of the nonlinear regime. It is also shown that the convective nature of the instability is not affected by the variation of the power law index. [Copyright &y& Elsevier]

Abstract: The nonlinear thermal instability of a thin liquid film falling down a heated wall is investigated. In particular, the heat conductivity and the thickness of the wall are taken into account. It is found that these two effects are represented by only one parameter which is the ratio of the nondimensional thickness of the wall and the nondimensional heat conductivity of the wall, that is . The longwave linear stability is described in a general form with respect to a wide range of values of this parameter in order to understand the behavior of the thin film. In the nonlinear case, the thin film instability is investigated in space and time for two examples of time dependent perturbations. The first one is at a perturbation frequency of 0.5 and the second one is at 2.5. The Reynolds numbers corresponding to the isothermal maximum growth rate are used and it is shown that they are located at important places of the k vs. R plane, where k is the wave number and R is the Reynolds number. It is found the important result that, for any fixed Marangoni number Ma, the increase of the parameter stabilizes the flow and at the same time decreases the nonlinear amplitude of the perturbations. [Copyright &y& Elsevier]

The effect of base dissipation on the granular flow down an inclined plane is examined by altering the coefficient of restitution between the moving and base particles in discrete element (DE) simulations. The interaction laws between two moving particles are kept fixed, and the coefficient of restitution (damping constant in the DE simulations) between the base and moving particles are altered to reduce dissipation, and inject energy from the base. The energy injection does result in an increase in the strain rate by up to an order of magnitude, and the temperature by up to two orders of magnitude at the base. However, the volume fraction, strain rate and temperature profiles in the bulk (above about 15 particle diameters from the base) are altered very little by the energy injection at the base. We also examine the variation of h, the minimum height at the cessation of flow, with energy injection from the base. It is found that at a fixed angle of inclination, h decreases as the energy dissipation at the base decreases. [ABSTRACT FROM AUTHOR]

An exact solution for the thin film flow of a third-grade fluid on an inclined plane is presented. This is a corrected version of the solution obtained by Hayat et al. (Chaos Solitons Fractals 38:1336-1341, ). An alternative parametric form for the solution is also derived. The variation of the dimensionless velocity and average velocity is given for a wide range of parameter values. An asymptotic solution for large parameter values is obtained giving rise to a boundary-layer structure at the free surface. [ABSTRACT FROM AUTHOR]

We study theoretically the unsteady gravity-driven thermal convection flow of a viscous incompressible absorbing-emitting gray gas along an inclined plane in the presence of a pressure gradient and significant thermal radiation effects. The Rosseland diffusion flux model is employed to simulate thermal radiation effects. The momentum and energy conservation equations are nondimensionalized and solved exactly using the Laplace transform technique. Expressions are derived for the frictional shearing stress at the inclined plane surface and also the critical Grashof number. The effects of time (T), Grashof number (Gr), Boltzmann-Rosseland radiation parameter (K1), and plate inclination (α) on velocity (u) and temperature (θ) distributions are studied. The flow is found to be accelerated with increasing inclination of the plane, increasing free convection effects, and for greater thermal radiation contribution but decelerated with progression of time. Temperature is found to be enhanced with progression of time and with greater thermal radiation contribution. Applications of the model arise in solar energy collector analysis and industrial materials processing. [ABSTRACT FROM AUTHOR]