Boat dock

We had a farewell word with the Morrises as the boat docked at Staten Island. Mrs. Morris said to me "Well, I suppose you re going back to your home in New York City."... 

Mixed recycled plastic lumber bridge decks, boat docks, doors, floors, furniture, windows, fences, pallets, etc. are product examples in service. Plastic lumber would be maintenance-free for at least half a century, as opposed to 15 years for treated wood and 5 yeare for untreated wood. Extensive use is made in applying plastics in wood to improve their structural and decorative properties. 

Different forms/profiles of plastic/wood are used. Extruded profiles can contain at least 70 wt%, some up to 90%, wood content and produce wood-like appearance. Proper drying of the wood is required since it is hygroscopic otherwise burning can occur and properties are reduced. These products compete in different markets particularly the building and construction market and where water is located like a boating dock. It is entering the 8 billion USA residential siding market that is now at least half vinyl. 

Secondary recycling is the recycle of plastic resins into new products with less demanding physical and chemical characteristics than the original application. Mixed plastics are applied most easily in the secondary recycling market because less separation of resin types and less complicated production methods are necessary to achieve a finished product. The most readily recognized secondary plastic product is "plastic lumber" (thick extrusion molded slabs of resin in which some types of resins act as fillers). Plastic lumber is used to make park benches, fence posts, boat docks, playground equipment and the like. The fabrication of mixed plastic lumber is discussed in Part II of the book. 

Buoyancy. The low density, closed-ceUed nature of many ceUular polymers coupled with their moisture resistance and low cost resulted in their immediate acceptance for buoyancy in boats and floating stmctures such as docks and buoys. Since each ceU in the foam is a separate flotation member, these materials caimot be destroyed by a single puncture. 

A boat is tied to a dock by a line from the stern of the boat to the dock. A pump inside the boat takes water in through the bow and discharges it out the stem at the rate of 3 ft3/s through a pipe running through the hull. The pipe inside area is 0.25 ft2 at the bow and 0.15 ft2 at the stern. Calculate the tension on the line, assuming inlet and outlet pressures are equal. 

The persistence of polymers in the environments is useful for long term durability of structures such as buildings, vehicles, docks, boats and navigation aids. Unfortunately, when the polymers are unintentional byproducts of recreational or commercial activities, collateral wildlife loss may result from entanglement in packaging materials, lost nets, lines and ropes. These wildlife losses due to litter have received significant public visibility. The critical degradation to address this... 

This is the basis of a successful trial to build a PEER boat in 1995 in Florida. This 21 ft fishing boat is docked at a pier near Orlando in excellent shape after... 

Robert and Meunier also observed that the most promising leads for antimalarial drug development are all lipophilic (allowing rapid diffusion through ceU membranes) and all adopt a boat conformation of the peroxide ring, allowing the peroxide bond to dock closely with heme and initiate alkylation. 

When a boat is tied to a dock, enough line (rope) has to be attached to account for changes in the distance from the boat to the dock occurring due to the tides. When the tide comes in, the boat sits higher and is closer to the dock. When it goes out, the distance is greater. And the movement of the tide will make the boat change positions. 

The Problem A boat is tied to a dock with a rope that s 17 feet long. If the height difference from where the rope is tied to the dock and where it s tied to the boat is 8 feet, then how far from the dock is the boat ... 

Let the height difference be vertical and the distance from the boat to the dock be horizontal — giving you a right triangle whose hypotenuse is the rope stretched from the dock to the boat. Figure 18-12 shows those vertical and horizontal distances — and the rope as hypotenuse of the triangle. 

When a boat moves away from a dock because of the movement of the water, the rope that s on a slant and attached to the boat pulls away at a different rate of speed than the speed at which the boat and tide are moving. 

The Problem The tide is moving out at a rate of 2 feet per second. The height difference between where a rope is connected to the dock and the boat is 8 feet. How far out did the boat drift after 5 seconds, how long is the rope extended, and how fast is the rope playing out Do the same computations for 10 seconds and 20 seconds. 

After 5 seconds, at a rate of 2 feet per second, the boat has moved 10 feet. Using the height of the dock as 8 feet and the distance from the dock as 10 feet, then 82 + 102 = 164 = c2. The value of c (length of the rope) is about 12.81 feet. Divide that by 5 seconds, and the rope is playing out (being pulled out) at an average rate of about 2.56 feet per second. 

Performance can be unsuitable for either of two reasons. The first reason is that the machine does not get the job done. A couple fishing in the middle of a lake in a boat with a slow-turning propeller would not get to the dock random currents of the water and wind would knock their boat off course. The second reason that performance might be unsuitable is if it is less efficient than can be achieved with... 

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