Blooming phenomenon

The final article, by S. G. Bell and G. A. Codd of the University of Dundee Department of Biological Services, is concerned with detection, analysis, and risk assessment of cyanobacterial toxins. These can be responsible for animal, fish, and bird deaths and for ill-health in humans. The occurrence of toxic cyanobacterial blooms and scums on nutrient-rich waters is a world-wide phenomenon and cases are cited from Australia, the USA, and China, as well as throughout Europe. The causes, indentification and assessment of risk, and establishment of criteria for controlling risk are discussed. 

Environmental conditions under which solvent release from the adhesive on the substrate is produced must be carefully controlled. Humidity is critical because loss of heat due to solvent evaporation may allow attainment of the dew point (the evaporation of the solvent is an endothermic process), and then condensation of water on the adhesive can result. This phenomenon is often called moisture blooming. The presence of water on the adhesive film causes a detrimental effect because the autoadhesion of rubber chains is greatly inhibited. Therefore, humidity must be controlled and avoided by increasing the temperature during solvent evaporation. 

An antiozonant should have adequate solubility and diffusivity characteristics. Since ozone attack is a surface phenomenon, the antiozonant must migrate to the surface of the rubber to provide protection. Poor solubility in rubber may result in excessive bloom. 

Blooming is the phenomenon of the formation of a white residue of cured adhesive near a bond line. It is the result of the evaporation of a small amount of the adhesive monomer from where it was applied onto the adjoining surfaee and its subsequent polymerization. The use of higher molecular weight monomers, such as the alkoxy esters, eliminates this problem. 

Although we made no attempt to elucidate the mechanism of friction decreases in rubbers after surface fluorination, it seems to us that apart from the substitution of H atoms to F in the polymer macromolecule, which forms a fluoropolymer on the surface, there is another phenomenon that makes a significant contribution to the friction decreases, i.e., fluorination of carbon black, which is used in rubber recipes for reinforcement. It appears that when the carbon black in the surface of the rubber is fluorinated it produces a lubricating effect, followed by blooming on the surface of the treated rubber while it is under a friction load. So, in our opinion, two effects contribute to friction decrease of carbon-filled rubbers fluorination of the rubber macromolecules and fluorination of the carbon black rubbers that do not contain carbon black show a much smaller decrease in friction after XeF2 treatment. 

During our studies, we observed an abundance of the small needle-shaped Pseudo-nitzschia species on Phaeocystis colonies provoking interest in both qualitative and quantitative analysis of this phenomenon. If Pseudo-nitzschia species comprise a significant fraction of total Phaeocystis colony biomass, it is essential to take this fact into consideration in the studies of food webs, vertical fluxes, biogeochemical element fluxes, etc. since Phaeocystis is a widely distributed phytoplankter and it often develops massive blooms (Schoemann et al. 2005). 

With the accumulation of data, there is developing a gradual realization of the generality of polymorphic behavior, but to many chemists polymorphism is still a strange and unusual phenomenon. (Buerger and Bloom 1937)... 

Some additional aspects of the definition deserve mention here. Since polymorphism involves different states of matter with potentially different properties, debates about definitions of the phenomenon have centred alternatively on differences in thermodynamic, structural, or other physical properties. For instance, Buerger and Bloom (1937) cited Goldschmidt s use of building blocks , polarization properties , and thermodynamic environment to describe the state of the art and understanding of polymorphism at that time ... 

In the particulate phase it was observed that the amount of all the four metals increases after the pack melting. This increase is very pronounced for Cd (almost ten times) and is significant for Cu and Fe (about two and three times, respectively), while it is not very important for Ni that, moreover, maintains the same profile trend. For Cd and Fe, on the other hand, the phenomenon is rather intense in the first 50 m where the phytoplanktonic bloom occurs, thus indicating an uptake of these two metals, in accordance with the dissolved metal data (Figures 8.3 and 8.4). 

Most investigators have observed a decrease in the rate of dissolution as weathering reactions proceed (Fig. 7-12). Commonly, the initial rate of weathering decreases by an order of magnitude within the 1st d of reaction, and may decrease by an additional one to three orders of magnitude within 2 wk to 1 yr or more. This decrease is not due to the presence of a reverse reaction, as it can be readily observed in continuous-flow reactor systems where dissolution product concentrations are carefully maintained at very low levels (Chou and Wollast, 1984 Holdren and Speyer, 1985). The dissolution rate may be nonlinear even after extensive weathering curvilinear rates have been observed after more than 400 d of reaction for labradorite at pH 4 (Erich and Bloom, 1987, unpublished data). This phenomenon has been related to several mechanisms ... 

SIT, ISIT. Blooming will occur when diodes are saturated, i.e., signal will spill over to adacent diodes. This is partially reduced by the electrical isolation between adjacent diodes. Another phenomenon with similar results is halation or light reflected back to the photocathode from the target (the photocathode is semi-transparent). This is, in essence, a stray light phenomenon that produces an halo around high intensity spectral lines. 

The upper dynamic range is limited by the amount of charge that can be quantitively stored in a single pixel well. Over-illumination of a pixel causes the charge to spill over into surrounding pixel wells, a phenomenon known as "blooming". 

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