Mediated Perceptions: Contributions of Phenomenological Film Theory to Understanding the Interactive Video Experience

This article examines the spatial relationships between avatars (i.e., graphical identities or icons) over time in a 2-dimensional online chat environment. The Spatial Distance Analysis Program (SDAP) was developed to measure the distance between avatars in a specially designed Palace environment. Correlations between distance and interpersonal communication constructs of (1) conversational appropriateness, (2) social attraction, and (3) uncertainty reduction indicate that distance effects are significant in an online environment. Specifically, it was found that general conversational appropriateness mediated between uncertainty reduction and specific conversational appropriateness for individuals who moved closer together and farther apart over time, respectively. Furthermore, the relationship between social attraction and distance indicated a significant positive parabolic function; that social attraction (i.e., liking) decreased at middle distances and increased at low and high distances. This finding suggests that there are three interpersonal distance zones in online communication.     

The Moldflow system of computer aided polymer flow analysis

The problems associated with injection moulding are listed. The uses of the Moldflow program to assist in the practical solution of these are described.     

Simultaneous determination of proline and betaines by high performance liquid chromatography

A method is described for the simultaneous determination by reversed-phase h.p.l.c. of proline, glycinebetaine, trigonelline and stachydrine. The mobile phase was water containing 0.02M dibutylamine phosphate at pH 3.0. The compounds were separated in a Dextropak Radial-PAK Cartridge and were detected by a differential refractometer. Total time of elution was 8 min. The method was applied to the analysis of leaves of two tropical grasses and a tropical legume which had been subjected to water stress.     

Base metal Co-fired (Na,K)NbO3 structures with enhanced piezoelectric performance

A NaF-Nb₂O₅ flux doped (Na,K)NbO₃ (NKN) based lead-free ceramic was successfully co-fired with nickel inner electrodes in reduced atmospheres. No chemical reactions and/or inter-diffusion were detected at the interface between the nickel (Ni) electrodes and the NKN-based piezoelectrics. Dielectric, resistivity, and electromechanical performance were measured with processing under different firing conditions and flux additions to obtain high densities. Ceramics are obtained with submicron grain structures with the NaF-Nb₂O₅ sintering aids (2 and 4 wt%) fluxes, and high densities when firing at low pO₂ (10^?10 atms) atmospheres at sintering temperatures ~1150 °C for 2 hours. High resistivities and low losses can be obtained through a second annealing condition at 850 °C and 10^?7 atms at 8 hours. High d ₃₃ values (over 350 pm/V) determined under unipolar converse electromechanical measurements were obtained in the simple prototyped co-fired structures to show feasibility towards base metal electrodes in multilayer actuators.     

MECHANISMS OF DRYING OF SKIN-FORMING MATERIALS.III. DROPLETS OF NATURAL PRODUCTS.

ABSTRACT

Drying studies were carried out on single droplets suspended from a rotating nozzle in a horizontal wind tunnel. Droplets were of solution of a third type of skin-forming material, namely the natural products skim milk or fructose. Droplet weight and temperature were measured during the drying process. Dried crusts were recovered and examined by Scanning Electron Microscopy.

With this type of material a skin first forms at any drying condition on the surface of the droplet at a cerlain stage of drying. A crust subsequently forms beneath the skin. The final dried panicle retains the structure and properties of the original powder, unless the material is dried at very high temperatures. e.g. >300 °C. which result in burning.

An increase in air temperature resulted in the formation of a smoother skin offering a higher resistance to vapour diffusion. At temperatures over 100 °C droplets exhibited puffing or ballooning phenomena; i.e. they inflated and deflated many times before forming the final dried particles.     

Structural evolution of a Ta-filament during hot-wire chemical vapour deposition of Silicon investigated by electron backscatter diffraction

We report on the application of electron backscatter diffraction to investigate the structural changes of a tantalum filament operated at typical hot-wire chemical vapour deposition conditions for the synthesis of hydrogenated nanocrystalline silicon. Various tantalum-silicides, identified by electron backscatter diffraction, form preferentially along the length of the filament. The filament has a recrystallized Ta inner core and a TaSi₂ layer encapsulated with a Si layer at the cooler ends. The αTa₅Si₃, metastable Ta₅Si₃ and Ta₂Si phases formed in addition to recrystallized Ta and TaSi₂ at the centre regions. Cracks and porosity were prevalent throughout the length of the filament. The microstructural evolution of the aged tantalum filament can be ascribed to the thermal gradient along the filament length, recrystallization of Ta and the variation of silicon content within the filament.     

PRELIMINARY PHASE DIAGRAMS FOR BITUMEN/ HEAVY OILS AND RELATED MIXTURES

ABSTRACT

The phase behaviour of heavy oil mixtures was studied using an X-ray imaging system. Batch phase experiments were performed at temperatures and pressures up to 725 K and 7 MPa. Complex phase behaviour such as liquid-liquid-vapour and solid-liquid-liquid-vapour were observed and preliminary experimental phase diagrams were constructed. This observed complex phase behaviour is consistent with thermodynamic theory and such phase behaviour can be modelled using the Peng-Robinson equation of state and the tangent plane criterion. These latter points are illustrated through the phase diagram for a model reservoir fluid (ethane + propane + n-butane + phenanthrene) which exhibits solid-liquid-liquid-vapour phase behaviour. Example predicted and experimental phase diagrams are presented for this model system.     

Short communication: The effect of centrifugation and resuspension on the recovery of Mycoplasma species from milk

Low sensitivity of a single bulk tank milk culture is a major limitation for detection of mycoplasma organisms. We hypothesized that sedimentation of Mycoplasma spp. in a milk sample by centrifugation followed by resuspension in a small volume of fluid before agar plating would increase the ability to detect Mycoplasma spp. compared with direct conventional culture. The experiment was conducted to determine recovery of Mycoplasma spp. from milk as affected by 1) treatment (centrifugation vs. conventional method); 2) 2 species (Mycoplasma bovis and Mycoplasma californicum and 4 strains for each species); and 3) 4 different concentrations of Mycoplasma spp. (1,000, 100, 10, and 1 cfu/mL). A 5-mL portion of mycoplasma suspension from each strain was inoculated into 45 mL of fresh bulk tank milk to achieve concentrations of 1,000, 100, 10, and 1 cfu/mL. Treatment samples were vigorously mixed and centrifuged at 5,000 × g for 30 min. Control samples were vigorously mixed. All samples were plated on modified Hayflick agar. Plates were incubated at 37°C and 5% CO₂ for 5 d. Mean (±SE) log₁₀ mycoplasma counts (cfu/mL) in the treatment groups (1.91 ± 0.15) were higher than those in the control groups (1.70 ± 0.16). Recovery of at least 1 mycoplasma colony on agar culture was 100% in both treatment and control groups at high, medium, and low concentrations. At the lowest concentration, recovery of at least 1 mycoplasma colony on agar culture in treatment and control groups was 75% (n = 12/16) and 18.75% (n = 3/16), respectively. Centrifugation of milk followed by suspension in a smaller volume of saline before conventional culture increased the ability to detect mycoplasma microorganisms in the milk sample compared with controls. Recovery by centrifugation appeared best at the lowest concentration where detection of a positive sample was 4 times more likely than when conventional methods were used.