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Russian Sap
Sapping is a term used in siege operations to describe the digging of a covered trench (a "sap") to approach a besieged place without danger from the enemy's fire. (verb) The purpose of the sap is usually to advance a besieging army's position towards an attacked fortification. It is excavated by specialised military units, whose members are often called sappers. By using the sap, the besiegers could move closer to the walls of a fortress, without exposing the sappers to direct fire from the defending force. To protect the sappers, trenches were usually dug at an angle in zig-zag pattern (to protect against enfilading fire from the defenders), and at the head of the sap a defensive shield made of gabions (or a mantlet) could be deployed. Once the saps were close enough, siege engines or cannon could be moved through the trenches to get closer to—and enable firing at—the fortification. The goal of firing is to batter a breach in the curtain walls, to allow attacking infan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sap Roller
Sap is a fluid transported in xylem cells (vessel elements or tracheids) or phloem sieve tube elements of a plant. These cells transport water and nutrients throughout the plant. Sap is distinct from latex, resin, or cell sap; it is a separate substance, separately produced, and with different components and functions. Honeydew (secretion), Insect honeydew is called sap, particularly when it falls from trees, but is only the remains of eaten sap and other plant parts. Types of sap Saps may be broadly divided into two types: xylem sap and phloem sap. Xylem sap Xylem sap (pronounced ) consists primarily of a watery solution of plant hormone, hormones, dietary mineral, mineral elements and other nutrients. Transport of sap in xylem is characterized by movement from the roots toward the leaf, leaves. Over the past century, there has been some controversy regarding the mechanism of xylem sap transport; today, most plant scientists agree that the cohesion-tension theory best e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
