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A method uses molecular constants and two parameters that characterize each type of bond in a molecule to determine the compression wave velocities of organic fluids. The fluids are useful in acoustic microscopy studies of low-speed materials. 2-dichloropentafluoropopane is suitable for acoustic microscopy of epoxy surfaces. A theoretical study and experimental measurements determine the acoustic velocity and attenuation of different fluorine-containing compounds.

Copper has been used in the marine environment for decades as cladding on ships and pipes to prevent biofouling by marine mussels (Mytilus edulis L.). This motivated the present investigation into the possibility of using copper to prevent biofouling in freshwater by both zebra mussels and quagga mussels (Dreissena polymorpha and D. bugensis collectively referred to as 'zebra mussels'). Copper and copper alloy sheet proved to be highly effective in preventing bitfouling by zebra mussels over a three-year period. Further studies were conducted with copper and copper-nickel mesh (lattice of expanded metal) and screen (woven wire with a smaller hole size), which reduced the amount of copper used. Copper screen was also found to be strongly biofouling-resistant with respect to zebra mussels, while copper mesh reduced zebra mussel biofouling in comparison to controls, but did not prevent it entirely. Preliminary investigations into the mechanism of copper antifouling, using galvanic couples, indicated that the release of copper ions from the surface of the exposed metal into the surrounding water is directly or indirectly responsible for the biofouling resistance of copper.

Zebra mussel (Dreissena polymorpha and D. bugensis) fouling has increased operating and maintenance costs for marine and industrial facilities. An understanding of zebra mussel attachment strength on various substrates of different surface roughness is useful for the development of control strategies. Mussel attachment strength was inferred directly through tensile loading experiments using a calibrated force scale, and indirectly through fluid detachment using a wall jet. The results of both techniques were consistent and yielded statistically significant differences for different substrate types (natural [greater than or equal to] metallic > polymeric). Attachment varied significantly with material (P < 0.01) and with surface roughness within a material (P < 0.05). The lowest attachment strengths were measured on (in increasing order of attachment strength) smooth polytetrafluoroethylene, polymethylmethacrylate, and aluminum. The strongest attachment was measured on rough limestone/dolomite cobble, and mild steel of all roughnesses. Zebra mussel attachment strength was intermediate on, marine concrete, marine plywood, polyvinylchloride, stainless steel, and coal tar epoxy coated mild steel. These results provide preliminary design guidelines for the control of zebra mussels.

We present a Preston tube device that combines both total and static pressure readings for the measurement of wall shear stress. As such, the device facilitates the measurement of wall shear stress under conditions where there is streamline curvature and/or over surfaces on which it is difficult to either manufacture an array of static-pressure taps or to position a single tap. Our 'Preston-static' device is easily and conveniently constructed from commercially available regular and side-bored syringe needles. The pressure difference between the total pressure measured in the regular syringe needle and the static pressure measured in the side-bored one is used to determine the wall shear stress. Wall shear stresses measured in pipe flow were consistent with independently determined values and values obtained using a conventional Preston tube. These results indicate that Preston-static tubes provide a reliable and convenient method of measuring wall shear stress.