The International Association for the Properties of Water and Steam (IAPWS) encouraged an extensive research effort to update the IAPS Formulation 1985 for the Viscosity of Ordinary Water Substance, leading to the adoption of a Release on the IAPWS Formulation 2008 for the Viscosity of Ordinary Water Substance. This manuscript describes the development and evaluation of the 2008 formulation, which provides a correlating equation for the viscosity of water for fluid states up to 1173K and 1000MPa with uncertainties from less than 1% to 7% depending on the state point.

No abstract

We present modifications to an extended corresponding states (ECS) model for thermal conductivity and viscosity originally developed by Ely and Hanley (Ind. Eng. Chem. Fundam. 1981, 20, 323−332). We apply the method to 17 pure refrigerants and present coefficients for the model and comparisons with experimental data. The average absolute viscosity deviation for the 17 pure fluids studied ranges from a low of 0.56% for R236ea to a high of 5.68% for propylene, with an average absolute deviation for all fluids of 3.13% based on a total of 3737 points. The average absolute thermal conductivity deviation for the 17 pure fluids studied ranges from a low of 1.37% for R116 to a high of 6.78% for R115, with an average absolute deviation for all fluids of 3.75% based on a total of 12 156 points. We also present a new correlation for the viscosity of R134a (1,1,1,2-tetrafluoroethane), which is used as a reference fluid for the description of properties of some refrigerants. The new correlation represents the viscosity to within the uncertainty of the best experimental data.

The International Association for the Properties of Water and Steam (IAPWS) encouraged an extensive research effort to update the IAPS Formulation 1985 for the Thermal Conductivity of Ordinary Water Substance, leading to the adoption of a Release on the IAPWS Formulation 2011 for the Thermal Conductivity of Ordinary Water Substance. This paper describes the development and evaluation of the 2011 formulation, which provides a correlating equation for the thermal conductivity of water for fluid states from the melting temperature up to 1173 K and 1000 MPa with uncertainties from less than 1% to 6%, depending on the state point.

Cochlear innervation patterns were studied in infant cats and rats with the rapid Golgi method. Examination of thick serial sections and surface preparations with the differential interference contrast microscope (Nomarski optics) allowed direct visualization of individually impregnated spiral ganglion cells, complete with their peripheral processes and endings in the organ of Corti. Individually impregnated efferent fibers could be recognized as heavily varicose axons that project radially to endings beneath inner and outer hair cells after taking a tangential course in the intraganglionic spiral bundle. It was often possible to visualize unimpregnated hair cells in contact with the impregnated endings of both types of fibers. There are at least two types of spiral ganglion cells in the cochlea of the infant cat and rat. One type innervates only inner hair cells by means of radial fibers. These ganglion cells constitute the overwhelming majority of ganglion cells impregnated in our preparations, and each cell typically innervates two inner hair cells. Hence, these ganglion cells establish nearly "point-to-point" connections between the auditory nerve and the organ of Corti. The other type of ganglion cell innervates outer hair cells by means of long spiral fibers; each cell typically innervates many outer hair cells through the numerous angular enlargements and short end branches of its spiral fiber. In addition, a few of these spiral fibers also send branches to inner hair cells by means of short collaterals; it remains to be seen if such fibers also occur in mature cochleas. Efferent fibers have been traced to inner and outer hair cell regions. The simplest pattern is formed by fine beaded axons with only a few branches ending mainly beneath inner hair cells. More complex patterns are formed by larger axons with many branches ending beneath inner or outer hair cells. Many efferent fibers send branches to both inner and outer hair cells. Electrophysiological studies so far have not demonstrated different populations of units that clearly correspond to the spiral and radial fibers. Therefore, the physilogical differences between inner and outer hair cell innervation remain undefined.

We have surveyed literature data and developed correlations for the viscosity and thermal conductivity of n-dodecane that are valid over a wide range of fluid states. The new correlations are applicable from the triple point (263.59 K) to 800 K, and at pressures up to 200 MPa. The viscosity correlation has an estimated uncertainty of 0.5% along the saturation boundary in the liquid phase, 3% in the compressed liquid region, and 3% in the vapor (where the uncertainties can be considered as estimates of a combined expanded uncertainty with a coverage factor of 2). The thermal conductivity correlation has an estimated uncertainty of 4% along the liquid saturation boundary and in the compressed liquid, and ∼5% in the vapor region.

No abstract

No abstract