Iodine potassium iodide improves the contrast‐to‐noise ratio of micro‐computed tomography images of the human middle ear

High‐resolution imaging of middle‐ear geometry is necessary for finite‐element modeling. Although micro‐computed tomography (microCT) is widely used because of its ability to image bony structures of the middle ear, it is difficult to visualize soft tissues – including the tympanic membrane and the suspensory ligaments/tendons – because of lack of contrast. The objective of this research is to quantitatively evaluate the efficacy of iodine potassium iodide (IKI) solution as a contrast agent. Six human temporal bones were used in this experiment, which were obtained in right‐left pairs, from three cadaveric heads. All bones were fixed using formaldehyde. Three bones (one from each pair) were stained in IKI solution for 2 days, whereas the other three were not stained. Samples were scanned using a microCT system at a resolution of 20 μm. Eight soft tissues in the middle ear were segmented: anterior mallear ligament, incudomallear joint, lateral mallear ligament, posterior incudal ligament, stapedial annular ligament, stapedius muscle, tympanic membrane and tensor tympani muscle. Contrast‐to‐noise ratios (CNRs) of each soft tissue were calculated for each temporal bone. Combined CNRs of the soft tissues in unstained samples were 6.1 ± 3.0, whereas they were 8.1 ± 2.7 in stained samples. Results from Welch's t‐test indicate significant difference between the two groups at a 95% confidence interval. Results for paired t‐tests for each of the individual soft tissues also indicated significant improvement of contrast in all tissues after staining. Relatively large soft tissues in the middle ear such as the tympanic membrane and the tensor tympani muscle were impacted by staining more than smaller tissues such as the stapedial annular ligament. The increase in contrast with IKI solution confirms its potential application in automatic segmentation of the middle‐ear soft tissues.     

SURFACE TENSION-DRIVEN CONVECTION IN A CYLINDRICAL GEOMETRY

Three aspects of surface tension-driven natural convection in a bounded cylindrical geometry are investigated. First, the linear stability of the steady subcritical and supercritical convective solutions near the critical point is examined using a perturbation analysis and the theory of differential operators. Second, the effect of small surface tension gradients on free surface flows in deep fluid layers is studied. It is shown that surface tension effects produce subcritical convective solutions for this buoyancy-dominated flow. Finally, solutions are obtained for finite amplitude surface tension-driven flows in a cylindrical container.     

INVESTIGATION INTO THE THEORIES OF DESORPTION ISOTHERMS FOR ROUGH RICE AND PEANUTS

SUMMARY— Several existing mathematical models are investigated with respect to their range of applicability to biological materials. It is found that a logarithmic plot of vapor pressure of water in the material vs. vapor pressure of pure water can best describe the sorption phenomenon. The general form of the equation is: In P = f₁ (W) In P_s+ f₂ (W). The functions f₁ (W) and f₂ (W) may differ significantly from material to material. The method of determining these functional relationships is described in detail for rough rice and peanuts. The comparison of experimental and computed values for peanuts shows that this method can predict the required sorption isotherm data within 2% deviation from the experimental values.     

A Study of Solvent Extraction of Lipids from Whole Peanut Kernels Using All-Purpose Automatic Solvent Extractor

Extraction of lipids from whole peanut kernels can be accomplished much faster in an automatic solvent extractor with a lower solvent: seed ratio than by immersion or in a Soxhlet extractor. A possible explanation of the function of moisture in the extraction of lipids from the whole peanut kernels has been put forward. This mode of extraction is expected to produce economically fat-lean kernels, while oil is obtained as a co-product.     

Experimental force modeling for deformation machining stretching mode for aluminum alloys

Deformation machining is a hybrid process that combines two manufacturing processes—thin structure machining and single-point incremental forming. This process enables the creation of complex structures and geometries, which would be rather difficult or sometimes impossible to manufacture. A comprehensive experimental study of forces induced in deformation machining stretching mode has been performed in the present work. A table-type force dynamometer has been used to record the deforming forces in three Cartesian directions. The influence of five process parameters—floor thickness, tool diameter, wall angle, incremental step size, and floor size on the deforming forces—is investigated. Individual as well as combined empirical models of the parameters with regard to the forces have been formed. The results of this study indicate that the average resultant force primarily depends on the floor thickness to be deformed and the incremental depth in the tool path. This could be due to the variation in local stiffness of the sheet with change in floor thickness. The effect of tool diameter, deforming wall angle, and floor size is not significant.     

LUBRICITY INDEX OF MAYONNAISE

The Lubricity Index (LI) is defined as a new parameter to quantitatively evaluate mouthfeel. Rheological data were collected using a helical ribbon mixer viscometer with commercial mayonnaise products. The LI is calculated from changes in apparent viscosity due to temperature and moisture variations that mirror those found in the mouth during mastication. The rate of change in apparent viscosity with moisture and temperature was much lower with a fat free product than regular products resulting in a low LI value. The LI provides a basis for future efforts to understand, and mathematically model, the complicated process of fluid food mastication.     

Optimization of process parameters for the development of a cheese analogue from pigeon pea (Cajanus cajan) and soy milk using response surface methodology

Response surface methodology was used to optimize starter culture concentration (3–7%), pigeon pea–soy solids ratio (1 : 0.3–1 : 1.1), pigeon pea–water ratio (1 : 12–1 : 9), incubation temperature (37–45C) and coagulation temperature (75–95C) in the development of a cheese analogue from pigeon pea and soy milk. Pigeon pea milk and soy milk were prepared by a hot water grinding method, followed by filtration and inoculation. Cheese analogue was obtained through coagulation of the fermented milk by boiling for 15 min, followed by filtration using double-layered muslin cloth and pressing at 1 kg/cm ² pressure for 1 h. The results showed that the total solids recovery (TSR), protein content, fat content and pH varied from 51.09–62.61%, 40.04–55.93%, 9.35–15.36% and 4.48–4.9, respectively, depending on the experimental conditions. The optimum conditions of process parameters for maximum total solids recovery were 6.0% starter culture concentration, 1 : 0.4 pigeon pea–soy solids ratio, 1 : 11 pigeon pea–water ratio, 40.5C incubation temperature and 88.5C coagulation temperature.     

Effect of pulsation on the near flow field of a submerged water jet

The current study investigates the effect of pulsation frequency on the near field characteristics of a submerged water jet using the technique of dye visualization. Flow visualization was performed in water over the range: Reynolds number 540–1540, Strouhal number 0.16–1.75, and at constant amplitude of pulsation of 18%. The results show that the mixing and entrainment process at lower Reynolds number occurs due to diffusion process owing to relatively stable shear layer for the case of a steady jet, whereas the external pulsation promotes an early instability in the shear layer where irregular structures promotes mixing between the jet and surrounding fluids. Images of streaklines show that initial mixing and entrainment processes in the potential core of the jet is due to the development of large vortical structures. While beyond the potential core, mixing and entrainment are governed by the small-scale structures. Further results show that the initiation and growth of vortices in the shear layer depends on the pulse frequency. For a given Reynolds number and amplitude, the number of vortical structures and their size changes with frequency. With an increase in the pulsation frequency, there is an increase in the spreading of the jet along with stretching of the vortical structures. An optimum pulsating frequency at which the effect of pulsation on the flow is maximum occurs at St = 0.44, independent of Reynolds number. These results should eventually lead to a better understanding of the physical phenomena responsible for enhanced mixing and entrainment processes in the presence of pulsating jets.     

Characteristics of double-dielectric fin-line resonators

Broadside-coupled and broadside edge-coupled slot resonators in a fin-line using two dielectric substrates with an intervening air gap have been analysed using the spectral-domain technique. Numerical results on the resonant frequencies of structures with single as well as coupled resonators on each substrate are reported as a function of the air gap and other structural parameters. The resonator patterns on the two substrates are mirror images of each other. Coupled configurations include parallel-coupled, parallel-coupled offset, and end-coupled resonators on each substrate. The resonant frequency has been measured as a function of slot width for the case of a single resonator on each substrate. Agreement with the computed results is found to be good.