Gharibzahedi S.M.T., Etemad V., Mirarab-Razi J., Fos'hat M., 2010. Study on some engineering attributes of pine nut (Pinus pinea) to the design of processing equipment. Res. Agr. Eng., 56: 99-106.Moisture-dependent engineering properties of pine nut were studied at 6. 3, 8.2, 10.8, 14.5, 18.9, and 20.1% moisture content (dry basis). The length, width, thickness, and geometric mean diameter increased significantly (P < 0.05) from 21.75 to 21.85 mm, 7.39 to 7.47 mm, 6.07 to 6.14 mm, and 9.89 to 9.98 mm, respectively, with an increase in moisture content from 6.3% to 20.1%, whereas the increase in sphericity from 45.49% to 45.69% was not significant. Similarly, thousand seed mass, true density, porosity, terminal velocity, and angle of repose increased (P < 0.05) from 0.85 to 0.93 kg, 1043.3 to 1071 kg/m 3 , 41.31% to 44.57%, 8.67 to 8.83 m/s, and 35.4° to 39°, respectively, with an increase in moisture content under the experimental condition. Moreover, the bulk density decreased significantly (P < 0.05) from 612.3 to 593.6 kg/m 3 . Coefficient of static friction increased (P < 0.05) from 0.251 to 0.292, 0.241 to 0.271, 0.227 to 0.262, and 0.218 to 0.247 on plywood, galvanized iron sheet, stainless steel, and glass surfaces, respectively, with an increase in moisture content from 6.3% to 20.1%.

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Structurally complex forests provide more diverse conditions in comparison to homogenous forests because of greater variety of microhabitats and trees. This study assesses the association of bird species richness, abundance, and distributional pattern with habitat complexity (HC) in Kheyrud Forest in the north of Iran. Birds were surveyed during spring 2009 by 100 point counts. In each point count six habitat features related to the index of HC were computed and scored from 0 to 3. Then the scores were summed and divided into two groups of low and high complexity, HC ≤ 6 and HC > 6, respectively. To compare bird richness and abundance in different HCs, a two sample t-test was used. Presence and absence of bird species at each plot as a dependent variable were compared with the vegetation characteristics as an independent variable by means of the Canonical Correspondence Analysis. The results revealed bird species richness and abundance were significantly higher in more complex habitats. Bird species can be divided into two groups, the first group including species which associated with late successional stages and the second group, species belonging to early successional stages. Numbers of birds belonging to the first group declined in less complex forests, whereas the numbers of birds belonging to the second group increased. At the stand scale, our results reveal that bird abundance and richness are strongly associated with the complexity of vegetation structure in the study area.

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