Boats

In addition to their use in boat hull construction, plastics and RPs have been used in a variety of shipboard structures (internal and external). They are used generally to save weight and to eliminate corrosion problems inherent in the use of aluminum and steel or other metallic constructions. 

Examples of a large boat are the U.S. Navy s upgraded minehunter fleet, the Osprey class minehunter that withstands underwater explosions. Design used longitudinal or transverse framing inside the piece hull. It has a one piece RP super structure. Material of construction used was glass fiber-TS polyester plastic. The designer and fabricator was Interimarine S.P.A., Sarzana, Italy. The unconventional. 

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Used as fibres, particularly in textiles and film. Many other polyester polymers are of importance, e.g. unsaturated polyester resins from phthalic anhydride, propylene glycol and maleic anhydride used with reinforcement in boats, cars, etc. (alkyd resins). U.S. production 1983 1-7 megatonnes. 

Flash point Luchaire (NF T 60-103) Pensky-Martens (NF EN 22719) > 70°C > 60°C (bunker and fishing boats) ... 

For a typical operation in the North Sea, the transport of personnel to and from the facilities is by helicopter. The transport of materials is normally by supply boat. 

Figure A3.6.11. Viscosity dependence of transmission coefficient of the rate of cyclohexane chair-boat inversion in liquid solution (data from [100]).

As an example of the effect that corrosion can have on connnercial industries, consider the corrosive effects of salt water on a seagoing vessel. Corrosion can drastically affect a ship s perfonnance and fiiel consumption over a period of time. As the hull of a steel boat becomes corroded and fouled by marine growths, the... 

Reaction (13.4) is exothermic and reversible, and begins at about 700 K by Le Chatelier s Principle, more iron is produced higher up the furnace (cooler) than below (hotter). In the hotter region (around 900 K), reaction (13.5) occurs irreversibly, and the iron(II) oxide formed is reduced by the coke [reaction (13.6)] further down. The limestone forms calcium oxide which fuses with earthy material in the ore to give a slag of calcium silicate this floats on the molten iron (which falls to the bottom of the furnace) and can bo run off at intervals. The iron is run off and solidified as pigs —boat-shaped pieces about 40 cm long. 

Figure 8-6. Comparison of the radial distribution function of the ctiair, boat, and twist conformations of cyclohexane (hydrogen atoms are not considered).

The combustion tube is empty, with the exception of the boat, up to the furnace mouth. The packing of the tube is considered in detail below. 

As the substance is heated in the boat—it usually melts before the Bunsen quite reaches the boat itself and runs forward to the front end—... 

At the end of the sweeping out, the tap Ti is first closed, and then the taps T3, T4, Ts and Tj in this order. The tubes R and S are then detached from the beak of the combustion tube, the guard tube V is then detached from them and replaced on the combustion tube beak. The furnace and thermostatic mortar are then switched off and the combustion tube allowed to cool with the tap to the oxygen supply open. The bung J is removed, and the boat withdrawn by means of a piece of rigid copper wire with a small hook in the end that fits into the small hole in the lip at the back of the boat the bung is then replaced and the boat transferred to its block in the desiccator. 

The Zimmerman-Traxler like transition state model can involve either a chair or boat geometry. 

Technically, the chemist could avoid the complex glassware apparatus of this procedure for a more crude approach [104]. This report shows some dudes de-methylating an amphetamine with concentrated HCI in a pressure cooker. A similar approach with good yields was also employed in ref. 83 and should work as well or better on guaiacol. Hydroiodic acid or hydrobromic acid will work better than hydrochloric acid but, you know, whatever floats the chemist s boat. To do this the chemist can just plain reflux HI or HBr with the guaiacol for a few hours and process as before or she can use HI, HBr or HCI and place the reactants in a pipe bomb for a few hours. 

A highly successful route to stereoisomers of substituted 3-cyclohexene-l-carboxylates runs via Ireland-Claisen rearrangements of silyl enolates of oj-vinyl lactones. The rearrangement proceeds stereospeaifically through the only possible boat-like transition state, in which the connecting carbon atoms come close enough (S. Danishefsky, 1980 see also section 4.8.3, M. Nakatsuka, 1990). 

A second but much less stable nonplanar conformation called the boat is shown in Eigure 3 14 Like the chair the boat conformation has bond angles that are approximately tetrahedral and is relatively free of angle strain It is however destabi hzed by the torsional strain associated with eclipsed bonds on four of its carbons The... 

FIGURE 3 14 (a) A ball and spoke model and (b) a space filling model of the boat confor mation of cyclohexane Torsional strain from eclipsed bonds and van der Waals strain involving the flagpole hydrogens (red) make the boat less stable than the chair... 

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