Clamp time

Maple Block Screening Method. A series of experimental procedures were performed on bonding maple block wood (Cook, P. M., Eastman Kodak at Kingsport, TN, personal communications, 1987). The procedure adopted was the ASTM D 905 standard, modified as follows Sugar maple (Acer saccharum) wood, 76 by 25 by 5.7 mm in size (3 inches long, 1 inch wide, and 0.25 inch thick), with 6% moisture content was planed to obtain fresh surfaces for bonding. The desired amount of resin (with no mix additives) was weighed (58.6 g/m2, 12 lb/1000 ft2, resin solids basis) and applied to one block surface and then a second clean block was overlapped so that 25 square mm (1 square inch) surface area common to each block was coated. The resin coated blocks were placed directly in the hot press (no clamp time). The blocks were hot pressed at 177°C (350°F) for 4 to 6 minutes at 3.44 MPa (500 psi). All bonded blocks were allowed to... 

The next step to drive changeover time further down is to implement press and tool modifications with the introduction of new quick change hardware. Figures 4 and 5 summarize before and after quick change retrofits reducing die exchange and clamp time—an average of 49 min down to 3 min. For more detailed information see Ref. 1. 

The fast cure of cyanoacrylates can in many applications offer benefits to the production engineer, as process times will be fast and clamp times are usually short. The thinner the bond line the faster the cure. Note however that the joint must not be disturbed during the cure cycle as the cyanoacrylate will not properly re-configure itself if the molecular chains are broken at the start of the polymerisation. 

Before leaving the donor hospital the explanting surgeon briefly informs the implanting surgeon in the recipient hospital about special findings, about the exact cross-clamp time, and the estimated arrival time of the donor explant team. 

Two types of surgical interventions are commonly utilized to address valvular disease—valve replacement and valve repair. Of these, the advantages of valve replacement are superior valve mechanical and hemodynamic performance, ease of implantation, and reduced cross-clamp times. However, valve replacements are associated with increased risk of stroke, as well as the requirement... 

Place 20 g. of dry powdered benzoic acid in C, add 15 ml. (25 g., i.e., a 30% excess) of thionyl chloride and some fragments of porcelain, and then clamp the apparatus on a boiling water-bath as shown so that no liquid can collect in the side-arm of C. Heat for one hour (with occasional gentle shaking), by which time the evolution of gas will be complete. Cool the flask C, detach the condenser and fit it to the side-arm for distillation, using a 360° thermometer for the neck of C. To the lower end of the condenser fit a small conical flask G (Fig. 67(B)) by a cork carrying also a calcium chloride tube. 

The following alternative procedure is recommended and it possesses the advantage that the same tube may be used for many sodium fusions. Support a Pyrex test tube (150 X 12 mm.) vertically in a clamp lined with asbestos cloth or with sheet cork. Place a cube (ca. 4 mm. side = 0 04 g.) of freshly cut sodium in the tube and heat the latter imtil the sodium vapour rises 4 5 cm. in the test-tube. Drop a small amount (about 0-05 g.) of the substance, preferably portionwise, directly into the sodium vapour CAUTION there may be a slight explosion) then heat the tube to redness for about 1 minute. Allow the test tube to cool, add 3-4 ml. of methyl alcohol to decompose any unreacted sodium, then halffill the tube with distilled water and boil gently for a few minutes. Filter and use the clear, colourless filtrate for the various tests detailed below. Keep the test-tube for sodium fusions it will usually become discoloured and should be cleaned from time to time with a little scouring powder. 

Semibatch Reactors. Semibatch reactors are the most versatile of reactor types. Thermoplastic injection molds are semibatch reactors in which shaped plastic articles are produced from melts. In mol ding thermoplastics, large clamping forces of up to 5000 metric tons are needed to keep molds together, while highly viscous polymers are forced into their cavities. Heat transfer is critical. If the molds are too cold, polymers soHdify before filling is completed if they are too hot, the time required for cooling delays production. 

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