Statistical Analysis of Silicon Grease Coated Bushings Characteristics Under Various Contaminated Conditions

The contamination seriousness level in the working condition of transformers turns into the most critical factor in deciding the protection level of bushings. Flashover because of contamination on bushings makes a noteworthy danger the unwavering quality of the transformers and power framework arrange as well. In order to reduce the pollution flashover of bushings, the silicon grease coating is applied on the surface of bushings. Then, silicon grease coated and non-coated the bushings are polluted with Nacl and Kaolin blend using brushing method. After dried, breakdown voltage of polluted bushings is measured as per standard and the statistical analysis has been carried out to understand the performance of bushings under polluted environment.

The surface characteristics of pedal mucus: a potential aid to the settlement of marine organisms?

Surface characteristics including wettability, thickness and adhesive potential of the pedal mucus produced by Patella vulgata and Littorina littorea were measured, to determine their effects on the settlement of marine organisms. The pedal mucus produced by P. vulgata was less wettable than that produced by L. littorea. For organisms that prefer to settle on hydrophobic substrata the pedal mucus produced by P. vulgata would be their preferred settlement site. The pedal mucus produced by stationary P. vulgata was thicker (mean thickness±SE=0·37±0·004 mm) than the pedal mucus produced by mobile P. vulgata and/or that produced by L. littorea, neither of which differed in their thickness (mean thickness±SE =0·10±0·01 mm). The pedal mucus produced by P. vulgata had a greater adhesive potential (mean force of adhesion for the size range of mimics examined=3715–5380 Nm2) than the pedal mucus produced by L. littorea (mean force of adhesion for the size range of mimics examined=2846–3361 Nm2). Comparison of the adhesive potential of the pedal mucuses with a pedal mucus analogue, silicon grease, suggests that the pedal mucuses function as a Stefan (1874) adhesive when adhering organisms.

The effect of pedal mucus on barnacle cyprid settlement: a source for indirect interactions in the rocky intertidal?

Laboratory assessment of barnacle cyprid settlement showed that it was increased by a multiple of ∼6 and by a multiple of ∼3 by the pedal mucus produced by Patella vulgata and by Littorina littorea, respectively. Field experiments showed that pedal mucus produced by P. vulgata could increase cyprid settlement by a multiple of ∼4, but that there was no effect of the pedal mucus produced by L. littorea. Evaluation of the effect of pedal mucus coated with nitro-cellulose and various pedal extracts, on cyprid settlement, ascertained that there appeared to be no chemotactic or chemotaxic effect of pedal mucus on cyprid settlement. In contrast, the use of a physical analogue to pedal mucus, silicon grease, increased cyprid settlement by a multiple of ∼18. Pedal mucus produced by P. vulgata and by L. littorea increased the time spent by cyprids in surface suitability testing by a multiple of ∼10 and ∼3, respectively. Only the pedal mucus produced by P. vulgata had any effect on the exploratory behaviour of cyprids increasing the time spent on this behaviour by a multiple of ∼3. Pedal mucus affects the settlement of cyprids through adhesive enmeshment, resulting in positive feedback to the mechanoreceptors housed in the antennules of cyprids, in what is effectively a settlement cascade. Pedal mucus produced by P. vulgata and L. littorea can affect the settlement of the majority of settling marine organisms through physical entrapment. Pedal mucus produced by L. littorea will have little, if any, effect on the settlement of organisms in the field whereas the pedal mucus produced by P. vulgata may be of major importance in determining the adult distribution patterns.

[Co4(ν3-NPEt3)2(HNPEt3)2(O2C-CH3)2- (ν-OSiMe2OSiMe2O)2] - ein vierkerniger Cobalt(II)-Komplex mit Leiterstruktur / [Co4(ν3-NPEt3)2(HNPEt3)2(O2C-CH3)2-(ν-OSiMe2OSiMe2O)2] - a Tetranuclear Cobalt(II) Complex with Ladder Structure

The title compound has been prepared from cobalt( II) acetate and Me3SiNPEt3 in boiling toluene in the presence of silicon grease and traces of water as blue single crystals which were characterized by IR spectroscopy and by a crystal structure determination. Space group Pbca, Z = 8, lattice dimensions at -50 °C: a = 1449.3(1), b = 1724.9(1), c = 2356.6(2) pm, R = 0.0548. [Co4(ν3-NPEt3)2(HNPEt3)2(O2C-CH3)2-(v-OSiMe2OSiMe2O)2] has a centrosymmetric structure. The four cobalt atoms which are coordinated tetrahedrally are v3-bridged via the N atoms of the two (NPEt3-) groups and v2-bridged by the O atoms of the chelating (OSiMe2OSi-Me2O2-) units. The core atoms are arranged in three four-membered rings which are connected in a stair-like way.

Characterization of Ice Nucleation and Propagation in Bean (Phaseolus vulgaris cv. Bush Blue Lake) using Infrared Video Thermography

Frost-sensitive plant species have a limited ability to tolerate ice formation in their tissues. Most plants can supercool below 0°C and avoid ice formation. Discrepancies exist about the role of intrinsic and extrinsic ice-nucleating agents in initiating ice formation in plants. Previous research has demonstrated the ability of infrared video thermography to directly observe and record the freezing process in plants (Wisniewski et al., 1997. Plant Physiol. 113:4378–4397). In the present study, the ability of droplets of a suspension of the ice-nucleating-active (Ice+) bacterium, Pseudomonas syringae, and droplets of deionized water, to induce ice formation in bean plants was compared. The activity of these agents were also compared to intrinsic ice formation in dry plants. Results indicated that the presence of the Ice+ bacteria in droplets ranging from 0.5–4.0 μL always induced freezing at a warmer temperature than droplets of deionized water alone (no bacteria) or intrinsic nucleators in dry plants. When droplets of Ice+ bacteria were allowed to dry, they were no longer effective but were active again upon rewetting. Droplets of water would often supercool below temperatures at which ice formation was initiated by intrinsic agents. When a silicon grease barrier was placed between the droplets of Ice+ bacteria and the leaf surface, the bacteria were no longer capable of inducing ice formation in the plant, despite the droplets being frozen on the plant surface. This indicates that ice crystals must penetrate the cuticle in order to induce freezing of the plant.