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The conclusions drawn by researchers on the source of changing shrinkage rates are discussed. The objective of this study was to determine the source of changing shrinkage rates early in drying and whether shrinkage would make a useful parameter for an automated kiln control system. In this study, four loads of red oak and one of maple were kiln dried usingestablished schedules. Shrinkageofthelumberwascontinuously recorded,and moisture content and released elastic strain were periodically recorded. The moisture content and strain data showed that the changing shrinkage rates early in drying boards were caused by reduced internal stress levels, not the occurrence of fiber saturation point or temperature as reported by some. Resultsofthis study indicate it may be possible to develop an automated kiln system using shrinkage as the controlling parameter. This would reduce the drying time while avoiding additional drying defects.Cappighl O 2000 by Marccl Dckkcr. Inc

Performance of wood-stud walls depends on the integrity of nailed connections between the sheathing and the framing members. The performance of nailed connections has been studied at room temperature, but the effects of intense thermal loads, such as those from fire, are still poorly understood. This study examines the temperature distribution within nailed joints exposed to fire; this information is essential in modeling strength and stiffness of connections in wall systems. The finite-element method was used to determine the effects of wood density, nail size, and type of gypsum board on temperature distribution within a set of connections. Temperature distributions were verified in nailed joints exposed in fire tests conducted in accordance with ASTM E119-88. The principal path of heat flow through the connection was along the nail, rather than directly through the interface between gypsum board and wood. Wood species, type of gypsum board, and nail length did not change temperature distribution significantly. ~~

The pmng test often displays ambiguous responsff as shown in recent research The objective ofthis paper war to learn how diierent drying/condiiioning schedules influence the m s s developmntlrelief of lumber and therefore the prong response. During each drying/conditioning schedule, residual mess analysis was used to obtain stress levels, moisture content gndients and prong responses. The analysis of the data revealed the following: suess levels are strongly influenced by differem schedules; in contrast. prong responsessreonly slightly i&uencedbydiffmnt schedules Stress levels are moreeffectively relieved by using a multiple-step increase of the equilibrium moisture content than a singlestep increase. It is wncluded that the schedule govern (he final stress level. Even h u g h differem in Ness level are masmble by the slice test, the prong test does not reliably diilay t h w diierences.

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