Development of transition mat scour protection design methodology and comparison to the state-of-the-practice
2011 annual AGU hydrology days was held at Colorado State University on March 21 - March 23, 2011.
Hydraulic Design of Energy Dissipators for Culverts and Channels
This aid to selecting and designing an energy dissipator wihch will meet the requirements indicated by an erosion hazard assessment, details the design concept, and the erosion hazards, and discusses such aspects as culvert outlet velocity, velocity modification, flow transitions and the erosion of culvert outlets. Forced hydraulic jump and increased resistance, and details of impact basins, drop structures, stilling wells and riprap are also discussed. Preliminary energy dissipator selection is made by comparing the input constraints or design criteria flow regime, debris problems, location, channel characteristics, allowable scour, etc., with the attributes of the various energy distributiors. The attributes of individual dissipators include: Froude number (Fr) range for best performance; discharge velocity or other limitations; possible maintenance; operational or location problems; maximum size; and limiting features such as culvert slope or shape. Dissipator designs fall into 2 general groups: those with Fr less than 3 (most designs are in this group), and those with Fr greater than 3. The designs are treated as illustrated by the conceptual models, and are related to actual situations through example problems.
Evaluation of Impact of Yarn Count and Stitch Length on Pilling, Abrasion, Shrinkage and Tightness Factor of 1 ? 1 Rib Cotton Knitted Fabrics
This study investigates the impact of yarn count and stitch length of 100% cotton knitted fabrics. 1 × 1 ribs structured fabrics were used in this research work. The stitch length 2.50 mm, 2.52 mm, 2.60 mm, 2.70 mm, 2.80 mm and 2.96 mm were used of the yarn count of 26Ne, 28Ne and 36Ne. The areal densities of the grey fabrics were in various amounts. The impacts of yarn count and stitch length were measured concerning pilling resistance, abrasion resistance, and shrinkage and tightness factor. The result showed that the fabric pilling grade decreased while number of cycle increased. Abrasion resistance decreased but length wise shrinkage increased despite the fact that the stitch length increased. The results also exposed that the tightness factor of the fabric increased with the increase of the stitch length in both dyeing and washing state and finished state compared to grey state for the yarn count 26Ne and homogeneous result not found for yarn count 28Ne and 36 Ne. Evaluation of Impact of Yarn Count and Stitch Length on Pilling, Abrasion, Shrinkage and Tightness Factor of 1 × 1 Rib Cotton Knitted Fabrics