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We describe an experiment involving a mass oscillating in a viscous fluid. The mechanical oscillator is tracked using a simple webcam, and an image processing algorithm records the position of the geometrical center as a function of time. Interesting information can be extracted from the displacement-time graphs, in particular, for the underdamped case. For example, we use these oscillations to determine the viscosity of the fluid. Our mean value of 1.08 [+ or -] 0.07 mPa s for distilled water is in good agreement with the accepted value at 20[degrees]C. The experiment has been successfully employed in an introductory laboratory setting. [c] 2010 American Association of Physics Teachers. [DOI: 10.1119/1.3298370]

An upper division undergraduate laboratory module to study Brownian motion was developed using polystyrene microspheres suspended in a sample liquid cell that was isolated from its surroundings. The dependence of the Brownian motion of the microspheres on their radius, the time, the viscosity of the suspension liquid, and the temperature were measured using a CCD camera interfaced with a frame grabber and a computer. The motion of each particle was monitored for 5 minutes and was found to be consistent with the Langevin formula for Brownian motion. [DOI: 10.1119/1.2386163]

The effect of friction is analyzed to understand turbulence and temperature dependence of viscosity of the ideal working fluid and for this the optimal motion of a piston to complete a process in finite time is sought and the optimal motion is compared to a sinusoidal motion. Results reveal that in the externally dissipative mode optimizing power or frictional losses are equivalent, while in the internally dissipative mode the optimal motions are different.

We describe a simple framework for teaching the principles that underlie the dynamical laws of transport: Fick's law of diffusion, Fourier's law of heat flow, the Newtonian viscosity law, and the mass-action laws of chemical kinetics. In analogy with the way that the maximization of entropy over microstates leads to the Boltzmann distribution and predictions about equilibria, maximizing a quantity that E. T. Jaynes called 'caliber' over all the possible microtrajectories leads to these dynamical laws. The principle of maximum caliber also leads to dynamical distribution functions that characterize the relative probabilities of different microtrajectories. A great source of recent interest in statistical dynamics has resulted from a new generation of single-particle and single-molecule experiments that make it possible to observe dynamics one trajectory at a time. [DOI: 10.1119/1.2142789]

A technique for viscosity measurement is developed based on the principle of laser-induced surface deformation. The technique is useful at high viscosities since the measurement takes only a few seconds even in the specimen with 10 to thee poser of 6 cSt, and the method has a great advantage of a noncontact feature and is appropriate for measuring the liquids that strongly dislike contamination.

The reed vibration technique was used to measure the internal friction and Young's modules of perovskites SrBi2Ta209.

Research was conducted to examine the theory of interaction between a solid inclusion in a liquid with nonuniform viscosity with an advancing solidification front. A model was used in which the weight of the particle, its buoyancy and that of viscous drag were essential. Focus was made on the velocities of the inclusion and of the solidification front move in the same direction. The investigation into the inclusion behavior was carried out in terms of three dimensionless variables.

A study was conducted to analyze the preparation of Zr55Al10Cu30Ni5 based metallic glass composites supporting up to 17.5% vol% tungsten particles using mechanical alloying. The diffraction peaks of tungsten superimposed on the broad diffuse scattering maxima of the amorphous phasE were examined. Results indicated that increases in effective viscosity of the composites in the supercooled liquid state correlate with a rise in the volume fraction of the tungsten particles.

The correlation between the magnetic viscosity in CoPtCr thin film media and the concentration of local fcc-like regions was described. Results showed that the concentration of the defects was varied by growth on different underlayers and was measured with grazing incidence x-ray scattering using synchrotron radiation. It was shown that a substantial percentage of local fcc regions in a cobalt alloy film leads to a significant magnetic viscosity effects at modest magnetic fields.

The viscosities of metaphosphate, pyrophosphate, molybdate and fluorophosphate glasses were measured in the shear deformation mode by applying the sandwich method from room temperature to the glass transition temperature Tg. Two relaxations were observed at lower and higher temperatures for glasses with long molecular chains, while only one relaxation was found at higher temperatures in glasses without the chain. A relationship between the frequency factor and the activation energy was observed for the high temperature relaxation.

The influence of quantum tunneling on nonthermal viscosity in magnets was investigated. The results showed that there were two magnetic relaxation regimes. At high temperatures, the magnetic viscosity was proportional to temperature. At lower temperatures, the magnetic viscosity was not dependent on the temperature. This independence indicated the quantum tunneling of the magnetization.

Magnetic viscosity, thermal relaxation and related thermal noise in Co-based amorphous and soft ferromagnetic alloys at milliKelvin temperatures were investigated using a superconducting quantum interference device magnetometer. The results showed that magnetic viscosity was not dependent on the temperature. In addition, thermal relaxation of the spin subsystem to the heat bath was observed.

The effect of a polymer network on the alignment and rotational viscosity of a nematic liquid crystal was investigated. The results showed that the application of a field destroyed the uniform alignment induced by a monodomain network. The mesh size of the network was estimated at one micrometer, smaller than the magnetic field of the solvent. In addition, the diamagnetic anisotropies of the aligned samples were not affected by the polymer.

Dynamic light scattering measurements using a diamond anvil cell were used to investigate the dynamics of fluids. The use of a diamond anvil cell eliminated the need to confine data to moderate pressures. However, the small size of the cell's pressure chamber resulted in a weak scattered intensity. In addition, scattering from the diamon/air and diamond/sample interfaces further complicated analysis of the measurements.

With the help of a hand-held jigsaw and a tin of syrup, the little known dynamically stablized inverted liquid experiment can be demonstrated to large clases. Lengthy effective potential arguments are short-circuited by a simple inverted U-tube theory accessible to most. The role of viscosity and wall effects is discussed. The first dynamic stabilization experiment with water is reported.

By using the constitutive equation for the stress tensor that yields a viscosity formula similar to the Eyring formula for non-Newtonian fluids and solving the hydrodynamic equation for a tube flow of such fluids, a generalization is obtained of the Hagen-Poiseuille formula for velocity profile in tube flow under pressure. The volume flow rate is calculated with the velocity profile, and a method of measuring zero shear rate viscosity is suggested. As the pressure difference increases, the calculated velocity profiles become increasingly flatter in the midportion of the tube than that predicted by the Hagen-Poiseuille formula, which remains parabolic for all values of the pressure difference.

The surface tension and viscosity of tantalum was measured with a vacuum electrostatic levitation furnace over temperature ranges covering both superheated and undercooled phases. Electrostatic levitation and multibeam radiative heating overcame contamination and sample position stability problems associated with handling of liquid tantalum.

ac demagnetization processes are investigated for different starting remanence states and compared to dc demagnetization process. In all cases, an offset of the ac demagnetization relative to that expected from dc measurements was observed, which could be to higher or lower fields?

We present a revised estimate of the relaxation time at room temperature for a window glass based on extrapolated isostructural viscosity data. This estimate, while several orders of magnitude less than the previous estimate of Zanotto [Am. J. Phys. 66 (5), 392-395 (1998)], supports his conclusion that window glass cannot flow at room temperature in human time scales.

A physical limit is obtained for the minimum reachable size of a thermoacoustic engine in order to understand the affect of gas behavior in the energy dissipation of such smallest devices. The results have shown that the bulk viscosity is not an important fluid property while calculating the dissipation, which is normally expected when free acoustic multiatomic gases are used.

A method is developed for estimating the viscosity from the optical basicity of glass melts. The dependence of viscosity on optical basicity has led to a viscosity-temperature relation that is a modified form of the well-known Vogel-Fulcher-Tamman equation.

A vibration analysis is presented of piezodriven pipette in the microinjection when different liquids are used as the plug inside the pipette as the fluid surrounding the pipette. Results reveal that mercury does significantly affect the vibration characteristics of the injection pipette, namely, the resonance frequency of the pipette is significantly lower.

Magnetic aftereffect phenomena are studied by using the Monte Carlo technique. The models are computationally much more efficient than the models with global history such as the Preisach model and numerical results related to the decay of the magnetization as a function of time, as well as to the viscosity coefficient, are given.

Quartz-crystal resonators are coated with a layer of alumina nanopores in order to allow for simultaneous measurement of density and viscosity of a liquid. The viscous loading and mass loading can be distinguished based on the increase in bandwidth allowing for an independent determination of the density and the viscosity of Newtonian liquids.

The viscosity of tungsten, the highest melting point metal (3695K), measured by a levitation technique is reported. The data obtained is found to agree with the proposed theoretical and empirical models of liquid metals but presents atypical temperature dependence, which suggests a basic change in the mechanism of momentum transfer.

A study of thermal noise of commercially available atomic force microscopy (AFM) cantilevers in air and water is presented. The purpose of this study is to investigate the oscillation behavior of a clamped AFM microlever in liquids.

The theory, simulation, and measurement of the dependence of lateral ion transport in supertwisted nematic (STN) displays on driving frequency, ion mobility, ion concentration, and liquid crystal (LC) rotational viscosity is presented. The ions in the display can undergo lateral transport in different directions with different speeds depending on these parameters.

The transient behavior of an Ar-H2 radio frequency (RF) induction plasma under turbulent flow conditions was investigated employing a two-dimensional, axisymmetric equilibrium (LTE) time-dependent renormalization RNG K-epsilon turbulence model. However, plasma turbulence only in small variations was observed in the turbulent viscosity in the fringes of the plasma.

The model developed within the Doremus approach of defect-mediated diffusion and viscous flow of network liquids is discussed which would help to derive an analytical formula for the viscosity that would be valid for the entire temperature interval. The formula for the viscosity of silica glass was in excellent agreement with experimental data showing high activation energy at low temperature and lower activation energy at high temperatures.

The biaxial modulus and the linear coefficient of thermal expansion of sputtered amorphous Ge4Sb1Te5, Ge2Sb2Te5, and Ag0.055In0.065Sb0.59Te0.29 thin films are determined from stress versus temperature measurements on two different substrates. The study shows that the shear viscosity increased linearly with time, which is attributed to bimolecular structural relaxation kinetics.

Equivalence of the sweep-rate and magnetic-viscosity dynamics is discussed. The physical reason is that sweep-rate experiments are less effective in probing individual switching events than magnetic-viscosity experiments.

Experimental and theoretical analysis prove piezoelectric unimorph cantilever as a liquid viscosity-and-density sensor. The calculated viscosity-and-density closely agree with the known values indicating that cantilever-based sensor is effective in determining viscosity-and-density simultaneously.