Wet Bubble

Class Fungi Imperfecti Order Moniliales Family Hyphomyceteae Common Names Bubble Wet Bubble White Mushroom Mold and La Mole. Greek Root From myco or fungal and the suffix gone meaning reproductive body. This mold is named in reference to this mold s tendency to parasitize the mushroom fruitbody. 

Very common, infecting the mushroom itself and causing significant losses to crops. M /cogone naturally occurs in Joils from which this aggressive contaminant attacks the mushroom fruitbody. It does not grow well at temperatures lower than 60 °F. 

Medium Through Which Contamination Is Spread Mostly through soils debris (stem butts, etc.) and spent compost. Workers, especially harvesters, are one of the primary vehicles for spore dispersal. Watering infected areas further spreads this contaminant. 

Macroscopic Appearance Appearing as a whitish mold attacking primordia and turning them into a soft whitish ball of mycelia. From the brown and rotting interior of these bubbles , amber fluid containing spores and bacteria ooze. More mature mushrooms that are afflicted with this disease have a felt-like covering of mycelium and a disproportionately small cap relative to The size of the stem. 

Microscopic Characteristics Conidiophores short generally hyaline relatively undeveloped lateral and altogether similar to the mycelia. Two types of conidia, terminally produced, can occur. The first and most distinctive type of chlamydospore is dark, round and two celled with one being 

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This is normally taken as the wet bubble cap pressure drop plus the mean dynamic slot seal in inches of clear or unaerated liquid on the tray. 

Figure 213 Mycogone, Wet Bubble, on cased rye grain spawn.

Figures 10 and 11 summarize the effects of SDS concentration on the phenomena mentioned as well as on other related phenomena. Figure 10 shows typical phenomena in liquid-gas systems, and Fig. 11 shows typical phenomena in liquid-liquid and solid-liquid systems. It is evident that each of these phenomena exhibits a maximum or minimum at 200 mM SDS, depending on the molecular process involved. Thus the take-home message emerging from our extensive studies of the past decades is that micellar stability can be the rate-controlling factor in the performance of various technological processes such as foaming, emulsification, wetting, bubbling, and solubilization [19].

Bianco and Marmur [143] have developed a means to measure the surface elasticity of soap bubbles. Their results are well modeled by the von Szyszkowski equation (Eq. III-57) and Eq. Ill-118. They find that the elasticity increases with the size of the bubble for small bubbles but that it may go through a maximum for larger bubbles. Li and Neumann [144] have shown the effects of surface elasticity on wetting and capillary rise phenomena, with important implications for measurement of surface tension. 

The foregoing is an equilibrium analysis, yet some transient effects are probably important to film resilience. Rayleigh [182] noted that surface freshly formed by some insult to the film would have a greater than equilibrium surface tension (note Fig. 11-15). A recent analysis [222] of the effect of surface elasticity on foam stability relates the nonequilibrium surfactant surface coverage to the foam retention time or time for a bubble to pass through a wet foam. The adsorption process is important in a new means of obtaining a foam by supplying vapor phase surfactants [223]. 

If the gas-flow rate is increased, one eventuaHy observes a phase transition for the abovementioned regimes. Coalescence of the gas bubbles becomes important and a regime with both continuous gas and Hquid phases is reestabHshed, this time as a gas-flUed core surrounded by a predominantly Hquid annular film. Under these conditions there is usuaHy some gas dispersed as bubbles in the Hquid and some Hquid dispersed as droplets in the gas. The flow is then annular. Various qualifying adjectives maybe added to further characterize this regime. Thus there are semiannular, pulsing annular, and annular mist regimes. Over a wide variety of flow rates, the annular Hquid film covers the entire pipe waH. For very low Hquid-flow rates, however, there may be insufficient Hquid to wet the entire surface, giving rise to rivulet flow. 

Fig. 1. Photograph illustrating the microstmcture of the foam which stiU persists two hours after shaking an aqueous solution containing 5% sodium dodecylsulfate. The bubble shapes ate more polyhedral near the top, where the foam is dry, and more spherical near the bottom, where the foam is wet.

I, have a fairly broad distribution of bubble sizes and can therefore maintain spherical bubbles with significantly less Hquid. Empirically, foams with greater than about 5% Hquid tend to have bubbles that are stiH approximately spherical, and are referred to as wet foams. Such is the case for the bubbles toward the bottom of the foam shown in Figure 1. Nevertheless, it is important to note that even in the case of these wet foams, some of the bubbles are deformed, if only by a small amount. 

Fig. 3. Two-dimensional schematic illustrating the distribution of Hquid between the Plateau borders and the films separating three adjacent gas bubbles. The radius of curvature r of the interface at the Plateau border depends on the Hquid content and the competition between surface tension and interfacial forces, (a) Flat films and highly curved borders occur for dry foams with strong interfacial forces, (b) Nearly spherical bubbles occur for wet foams where...

Although aH these models provide a description of the rheological behavior of very dry foams, they do not adequately describe the behavior of foams that have more fluid in them. The shear modulus of wet foams must ultimately go to zero as the volume fraction of the bubbles decreases. The foam only attains a solid-like behavior when the bubbles are packed at a sufficiently large volume fraction that they begin to deform. In fact, it is the additional energy of the bubbles caused by their deformation that must lead to the development of a shear modulus. However, exactly how this modulus develops, and its dependence on the volume fraction of gas, is not fuHy understood. 

Froth flotation (qv) is a significant use of foam for physical separations. It is used to separate the more precious minerals from the waste rock extracted from mines. This method reHes on the different wetting properties typical for the different extracts. Usually, the waste rock is preferentially wet by water, whereas the more valuable minerals are typically hydrophobic. Thus the mixture of the two powders are immersed in water containing foam promoters. Also added are modifiers which help ensure that the surface of the waste rock is hydrophilic. Upon formation of a foam by bubbling air and by agitation, the waste rock remains in the water while the minerals go to the surface of the bubbles, and are entrapped in the foam. The foam rises, bringing... 

Wet Oxidation Reactor Design. Several types of reactor designs have been employed for wet oxidation processes. Zimpro, the largest manufacturer of wet oxidation systems, typically uses a tower reactor system. The reactor is a bubble tower where air is introduced at the bottom to achieve plug flow with controlled back-mixing. Residence time is typically under one hour. A horizontal, stirred tank reactor system, known as the Wetox process, was initially developed by Barber-Cohnan, and is also offered by Zimpro. 

Wetox uses a single-reactor vessel that is baffled to simulate multiple stages. The design allows for higher destmction efficiency at lower power input and reduced temperature. Its commercial use has been limited to one faciHty in Canada for treatment of a complex industrial waste stream. Kenox Corp. (North York, Ontario, Canada) has developed a wet oxidation reactor design (28). The system operates at 4.1—4.7 MPa (600 to 680 psi) with air, using a static mixer to achieve good dispersion of Hquid and air bubbles. 

Fig. 2. Problems in wetting A, Hquids that wet the exterior before displacing gas from pores leave gas trapped in the submerged clump B, fully wetted clumps of buoyant particles do not sink C, nonwetting Hquids do not penetrate and displace gas from pores, so clump remains buoyant and caimot submerge and D, foam produced from air is drawn under the surface, sheared into small bubbles, and stabilized by the wetting agent.

Complete wetting caimot occur until either the clump is broken up to let the gas escape or the trapped gas dissolves in the Hquid. A sudden decrease in hydrostatic pressure can help remove gas trapped in a submerged clump by expanding the bubble volume to break up the clump or extend the bubble past the clump s exterior so that it may escape. 

Since 1970, new analytical techniques, eg, ion chromatography, have been developed, and others, eg, atomic absorption and emission, have been improved (1—5). Detection limits for many chemicals have been dramatically lowered. Many wet chemical methods have been automated and are controlled by microprocessors which allow greater data output in a shorter time. Perhaps the best known continuous-flow analy2er for water analysis is the Autoanaly2er system manufactured by Technicon Instmments Corp. (Tarrytown, N.Y.) (6). Isolation of samples is maintained by pumping air bubbles into the flow line. Recently, flow-injection analysis has also become popular, and a theoretical comparison of it with the segmented flow analy2er has been made (7—9). 

Zinc ores are generally floated at the mine (18). In the case of simple zinc sulfide ores, flotation is carried out by treatment with copper sulfate to activate the sphalerite causing it to be wet by the organic collector (eg, xanthate). The now-hydrophobic zinc ore particles attach themselves to the rising bubbles. Oxidized ore particles present must be sulftdized with sodium sulfide to be floated (19). Flotation produces concentrates which are ca 50—60% zinc. In mixed ore, the lead and copper are usually floated after depressing the sphalerite with cyanide or zinc sulfate. The sphalerite is then activated and floated. 

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