Direct Scanning Densitometry: An Effect of Sample Heterogeneity and Aperture Area

Direct scanning radiation densitometry is finding increased application in forestry and wood products research. Radiation densitometry is often used for tree ring analysis and density profile analysis of reconstituted panel products. This paper discusses some limitations to accuracy in the use of a scanning or stepping densitometry system. The effect of aperture area and sample heterogeneity on accuracy of the density determination is discussed. The "edge effect" in the densitometry of panel products is discussed

A Procedure To Determine Water Absorption Distribution In Wood Composite Panels

A procedure is presented to determine the water absorption distribution of wood composite panels. The procedure is based on the direct measurement of the vertical density distribution before water soak, the vertical density distribution after the water-soaked specimens have been reconditioned to pre-soak weights, and the construction of the vertical density distribution for the specimens immediately after water soak. The separation of "wood mass" and water was achieved through the application of radiation absorption principles involving the two elements. The procedure was used to examine the water absorption distributions of medium density fiberboard, oriented strandboard, and particle-board. A good agreement was obtained between the estimated average water absorptions and measured water absorptions. Water absorption distribution in relation to the layer density and layer thickness swell was discussed

Fundamentals of Vertical Density Profile Formation in Wood Composites. Part I. In-Situ Density Measurement of the Consolidation Process

We have designed a radiation-based system for measuring density of wood composite mats during consolidation. The system is installed on a laboratory hot-press and has been used to study consolidation of medium density fiberboard (MDF) and oriented strandboard (OSB) mats. Measuring density of the wood mat during consolidation is a key parameter for understanding subsequent product performance. The in-situ measuring system provides for density measurement at three horizontal planes in the wood mat, at positions of 25%, 50%, and 75% of the mat thickness at any time during the press cycle. The system incorporates three cesium137 sources and electronic detection equipment, collimated to move in concert with the up-acting press platen. Radiation count data taken through the mat during pressing are converted to density after pressing. Press position and time are simultaneously recorded with the count data. Moisture migration during hot-pressing resulted in significant density changes as measured by the in-press radiation-based system. Clearly established in all laboratory pressing studies is the indication that the vertical density profile of wood composite panels is formed from a combination of actions that occur both during consolidation and also after the press has reached final position; measurements recorded in the press show that mat densification continues after the press has reached final position. A description of the radiation system and data from elementary pressing examples are presented, along with experimental results of the effects of moisture migration in the mat on measured density during pressing

Mammalian Late Vacuole Protein Sorting Orthologues Participate in Early Endosomal Fusion and Interact with the Cytoskeleton

In Saccharomyces cerevisiae, the class C vacuole protein sorting (Vps) proteins, together with Vam2p/Vps41p and Vam6p/Vps39p, form a complex that interacts with soluble N-ethylmaleimide-sensitive factor attachment protein receptor and Rab proteins to “tether” vacuolar membranes before fusion. To determine a role for the corresponding mammalian orthologues, we examined the function, localization, and protein interactions of endogenous mVps11, mVps16, mVps18, mVam2p, and mVam6. We found a significant proportion of these proteins localized to early endosome antigen-1 and transferrin receptor-positive early endosomes in Vero, normal rat kidney, and Chinese hamster ovary cells. Immunoprecipitation experiments showed that mVps18 not only interacted with Syntaxin (Syn)7, vesicle-associated membrane protein 8, and Vti1-b but also with Syn13, Syn6, and the Sec1/Munc18 protein mVps45, which catalyze early endosomal fusion events. Moreover, anti-mVps18 antibodies inhibited early endosome fusion in vitro. Mammalian mVps18 also associated with mVam2 and mVam6 as well as with the microtubule-associated Hook1 protein, an orthologue of the Drosophila Hook protein involved in endosome biogenesis. Using in vitro binding and immunofluorescence experiments, we found that mVam2 and mVam6 also associated with microtubules, whereas mVps18, mVps16, and mVps11 associated with actin filaments. These data indicate that the late Vps proteins function during multiple soluble N-ethylmaleimide-sensitive factor attachment protein receptor-mediated fusion events throughout the endocytic pathway and that their activity may be coordinated with cytoskeletal function

AN EMPIRICAL STUDY ON THE RELATIONSHIP BETWEEN LOGISTICS PERFORMANCE AND EDUCATION

Logistics occupations require skills that involve blue- and white-collar activities and different levels of educational skills. With the increase in global trade and competition, the varying skills necessary for different parts of the logistics sector have attracted attention. In this regard, this empirical study examines the relationship between logistics performance indicators and education assessment scores and identifies associations. The presented results, by using canonical correlation analysis, indicate that certain education assessment scores contribute more to improving logistics performance than do other variables. The variables that influence logistics performance are also highlighted