Modeling of Ignition and Combustion of a Coflowing Hydrogen Jet in a Supersonic Air Flow

Combustion, Explosion, and Shock Waves - Results of a numerical study of mixing, ignition, and combustion of a cold hydrogen jet propagating along the lower wall of a channel parallel to a...     

Light Quality and Intensity Modulate Cold Acclimation in Arabidopsis

Plant survival in temperate zones requires efficient cold acclimation, which is strongly affected by light and temperature signal crosstalk, which converge in modulation of hormonal responses. Cold under low light conditions affected Arabidopsis responses predominantly in apices, possibly because energy supplies were too limited for requirements of these meristematic tissues, despite a relatively high steady-state quantum yield. Comparing cold responses at optimal light intensity and low light, we found activation of similar defence mechanisms—apart from CBF1–3 and CRF3–4 pathways, also transient stimulation of cytokinin type-A response regulators, accompanied by fast transient increase of trans-zeatin in roots. Upregulated expression of components of strigolactone (and karrikin) signalling pathway indicated involvement of these phytohormones in cold responses. Impaired response of phyA, phyB, cry1 and cry2 mutants reflected participation of these photoreceptors in acquiring freezing tolerance (especially cryptochrome CRY1 at optimal light intensity and phytochrome PHYA at low light). Efficient cold acclimation at optimal light was associated with upregulation of trans-zeatin in leaves and roots, while at low light, cytokinin (except cis-zeatin) content remained diminished. Cold stresses induced elevation of jasmonic acid and salicylic acid (in roots). Low light at optimal conditions resulted in strong suppression of cytokinins, jasmonic and salicylic acid.     

Effect of Moisture on the Insulation Condition of Twisted Coils

Method IEEE 841 is used to test endurance of insulation system of stators to 100% humidity at 40 ℃ for168 h. Insulation resistance after this test between phases or between phase and frame has not been lover as 5 × 10^6 Ohm. Some producers of motors use this method for determining quality of impregation resin. On such test insulation resistance between phases was lover as between phase and frame. Because between phases is only wire insulation impregnating resins on insulation resistance of insulation system an impregnating resin we observe influence of type of wires and after humidity test. With diagnostic of insulation, the state is dealt. We compare our impregnation resin with competitive impregnation resin. We made test on twisted coils prepared after STN IEC from two parallel wires. In this test, we succeed in demonstrating that the main influence on insulation resistance of insulation system wire and impregnation resin has insulation of wire. Impregnation resin has influenced on data dispersion.     

Microstructural evaluation of the mucin balls and their relations to the corneal surface—Insights by in vivo confocal microscopy

Purpose

The purpose of the current study was to observe and correlate the characteristics of mucin balls to the ocular surface properties, and furthermore, to report the effect of different mucin balls size and number on structural alteration of the anterior cornea.

Numerical simulation and experimental study of emulsification in a narrow-gap homogenizer

The present experimental and theoretical study investigates the fragmentation of the oil phase in an emulsion on its passage through a high-pressure, axial-flow homogenizer. The considered homogenizer contains narrow annular gap(s), whereupon the initially coarse oil drops break into fine droplets. The experiments were carried out using either a facility with one or two successive gaps, varying the flow rate and the material properties of the dispersed phase. The measured drop size distributions in the final emulsion clearly illustrated that the flow rate, as well as the dispersed-phase viscosity, and the interfacial tension can significantly affect the drop size after emulsification. The larger mean and maximum drop diameters obtained for the homogenizer with one gap in comparison to those obtained with two gaps (at the same Reynolds number and material parameters of the emulsion phases), highlighted the strong relevance of the flow geometry to the emulsification process. The numerical simulation of the carrier phase flow fields evolving in the investigated homogenizer was proven to be a very reliable method for providing appropriate input to theoretical models for the maximum drop size. The predictions of the applied droplet breakup model using input values from the numerical simulations showed very good agreement with the experimental data. In particular, the effect of the flow geometry—one-gap versus two-gaps design—was captured very well. This effect associated with the geometry is missed completely when using instead the frequently adopted concept of estimating input values from very gross correlations. It was shown that applying such a mainly bulk flow dependent estimate correlation makes the drop size predictions insensitive to the observed difference between the one-gap and the two-gaps cases. This obvious deficit, as well the higher accuracy, strongly favors the present method relying on the numerical simulation of the carrier phase flow.     

Short communication: Usage of mechanical brushes by lactating dairy cows

The objective of this experiment was to investigate how the provision of a mechanical brush affects the grooming (scratching) behavior of group-housed dairy cattle. To do this, we compared the grooming behavior of 72 dairy cows, split into 6 groups of 12, in the absence of a brush (control) and when provided with a mechanical brush (experimental). We analyzed the duration and frequency of scratching on pen objects (wall and water trough) and on the mechanical brush between the control and experimental treatments. Further, we compared the relative frequency of scratching on parts of the cow's body (head, neck, back, tail, and thigh) between the control and experimental treatments. Within 24 h of installation of the mechanical brush, 56.9% of the cows utilized the brush. Within 7 d, 93.0% of cows used the brush, and by the end of the treatment period, all but one of the cows had used the brush. When the mechanical brush was added to the pen, cows dramatically increased the total time spent scratching by 508% and the frequency of scratching events by 226%. These increases were primarily driven by use of the mechanical brush, which accounted for 91.1% of total scratching time and 79.8% of scratching events. When cows were provided with the mechanical brush, they decreased the frequency of scratching their heads, increased the frequency of scratching on their necks, backs, and tails, and tended to decrease the frequency of scratching their thighs. In conclusion, the results of this study show that the use of a mechanical brush makes it easier for cows to groom themselves, particularly in places that are hard to reach by the cow. This may help satisfy this natural behavior and keep them clean, as well as possibly reducing frustration or stress due to boredom when housed in freestall barns.