Spread volatility

Samples of styrene-dimethylsiloxane and poly (2,6-diphenyl )phenylene ether-dimethylsiloxane block copolymers were also examined as spread films. The styrene-siloxane copolymers included AB, ABA, and repeating block copolymer types. In these cases, as with the polycarbonate, the organic homopolymers do not form monolayers when we try to spread volatile solvent solutions on water. The characteristics of the copolymer spread films, however, were similar to those of the BPAC—DMS copolymers. In all cases, sigmoidal 7r-A curves were obtained, and surface pressures above 10 dynes/cm were unstable. (All of the samples examined had organic blocks of 15 or more monomer units.) A typical curve, for a styrene-dimethylsiloxane repeating block copolymer (19), is shown in Figure 4. 

In the Euro corporate market s short life, the level of credit spreads and spread volatility have increased almost beyond recognition. As we show in Exhibit 6.9, with the exception of the recovery from the market shock of 11 September 2001, credit spreads moved out more or less in a straight... 

EXHIBIT 6.10 Euro Corporate Market Monthly Spread Volatility (12-month moving average)... 

The appropriateness of either model (cash-flow-based versus market value-based) will depend on the asset manager s trading style as well as the particulars of the asset class the asset s market liquidity, duration profile, and credit spread volatility. In terms of mechanics, cash flow arbitrage CDOs are no different than balance sheet CDOs, (again, the only difference being their intended pnrpose and asset sourcing strategy). Consequently, one should see the section on Balance Sheet CDOs for further details. Now, we shift the discussion to market value CDOs. 

The Das-Tufano (DT) model is an extension of the JLT model. The model aims to produce the risk-neutral transition matrix in a similar way to the JLT model however, this model uses stochastic recovery rates. The final risk neutral transition matrix should be computed from the observable term structures. The stochastic recovery rates introduce more variability in the spread volatility. Spreads are a function of factors that may not only be dependent on the rating level of the credit as in practice, credit spreads may change even though credit ratings have not changed. Therefore, to some extent, the DT model introduces this additional variability into the risk-neutral transition matrix. 

Swap spread volatilities for several currencies are shown in Exhibit 23.6, with values that vary from about 15 bp/year to 40 bp/year. Also shown are the resulting spread risks in the euro and sterling markets for several rating categories. We will see further below that the swap model predicts reasonably accurately both the absolute magnitude of the spread risk in each market and their relative values. 

Panel B Comparison between Typical Euro and Sterling Spread Volatilities Computed Using the Swap Factor for Different Rating Categories... 

Emerging market spread volatilities are shown in Exhibit 23.10. The spread risk of Latin American obligors tend to be above average, currently largest for Argentinean and Brazilian markets that have a spread risk comparable to a B to CCC rated euro corporate. The risk of Asian issuers is on the other hand below average and comparable to the interest rate observed in developed markets. We clearly observe a wide spectrum of risk characteristics that confirms the need to build a separate factor for each market. 

DCHIBIT 23.10 Emerging Market Spread Volatilities as of 30 November 2002... 

The material of interest is dissolved in a volatile solvent, spread on the surface and allowed to evaporate. As the sweep moves across, compressing the surface, the pressure is measured providing t versus the area per molecule, a. Care must be taken to ensure complete evaporation [1] and the film structure may depend on the nature of the spreading solvent [78]. When the trough area is used to calculate a, one must account for the area due to the meniscus [79]. Barnes and Sharp [80] have introduced a remotely operated barrier drive mechanism for cleaning the water surface while maintaining a closed environment. 

Emulsives are solutions of toxicant in water-immiscible organic solvents, commonly at 15 ndash 50%, with a few percent of surface-active agent to promote emulsification, wetting, and spreading. The choice of solvent is predicated upon solvency, safety to plants and animals, volatility, flammabiUty, compatibihty, odor, and cost. The most commonly used solvents are kerosene, xylenes and related petroleum fractions, methyl isobutyl ketone, and amyl acetate. Water emulsion sprays from such emulsive concentrates are widely used in plant protection and for household insect control. 

The second type of thin-film evaporator, termed a wiped-film evaporator, introduces feed material on a heated waU of a cylinder. Rotating wiper blades continuously spread the feed along the inner waU of the cylinder to maintain uniformity of thickness and to ensure contact with the heated surface. The volatile components are driven off and coUected on an internal chilled condenser surface. The condensate or distUlate is removed continuously. At the end of the process, the residual becomes dry and heavy and drops to the bottom of the unit for removal. The wiped-film evaporator is best suited for treatment of viscous or high-solids content feed. 

Thymus ciliatus Desf. is a wild growing plant spread in northeastern Algeria. Although the ehemieal eomposition of the volatile oils from several Thymus speeies is well studied, to our best knowledge no researeh has so far been eondueted on this Algerian thyme. 

Organosols (Mix B, Table 12.5) are characterised by the presence of a volatile organic diluent whose function is solely to reduce the paste viscosity. After application it is necessary to remove the diluent before gelling the paste. Organosols are therefore restricted in use to processes in which the paste is spread into a thin film, such as in the production of leathercloth. Because of the extra processes involved, organosols have not been widely used, in Europe at least. 

Typical precautions with trichloroethylene are summarized in Table 5.52. An important factor is that the vapours are much heavier than air they will therefore spread and may accumulate at low levels, particularly in undisturbed areas. Because of its volatility, releases to the environment usually reach the atmosphere. Here it reacts with hydroxyl or other radicals (estimated half-life for reaction with hydroxyl radicals is less than a week) and is not therefore expected to diffuse to the stratosphere to any significant extent. There is some evidence for both aerobic and anaerobic biodegradation of trichloroethylene. 

Liquid epoxy resin based on the reaction product of epichlorohydrin and bisphenol A or bisphenol F mild to moderate irritants mild to moderate sensitizers low volatility, exposure unlikely unless heated, sprayed, or spread over large unventilated surface low toxicity... 

Acetonitrile serves to greatly enlarge the spread of relative volatilities so that reasonably sized distillation equipment can be used to separate butadiene from the other components in the C4 fraction. The polar ACN acts as a very heavy component and is separated from the product without much difficulty.The feed stream is carefully hydrogenated to reduce the acetylene level rerun, and then fed to the single stage extractive distillation unit. Feed enters near the middle of the extractive distillation tower, while (lean) aqueous ACN is added near but not at the top. Butenes and butanes go overhead as distillate, with some being refluxed to the tower and the rest water washed for removal of entrained ACN. 

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