1. If the primary purpose of a dam is power generation, the dam height is critical, for the power generated increases in direct ratio to the head (height) of water impounded. 2. The St Lawrence system has long been the most important, because it provides a waterway 4.3 m (14 ft) deep from the head of Lake Superior to the Gulf of St Lawrence. 3. The vessel has five thrusters mounted along its hull and can rotate around the turret so that it is always lying head to the wind. 4. The lower section consists of four immense arched legs set on masonry piers. As they extend upwards, the legs curve inwards until they unite in a single tapered tower. 5. High archtype dams in rock canyons usually have downstream faces too steep for an overflow spillway. 6. It is the reciprocal of the resistivity, which is defined as the resistance between opposite faces of a cube of the material. 7. Tunnels through mountains or underwater are usually worked from the two opposite ends, or faces, of the passage. 8. Dipper, or bucket, dredges have a bucket on the end of a movable arm that scoops up underwater material. 9. When more than one oar was used in steering, the steering oars were attached to each other and were directed by means of a single steering arm. 10. Bridge is a structure providing continuous passage over a body of water, roadway, or valley. 11. One of the great advantages of metals as materials lies in their ability to be formed into the desired shape, such as car body parts. 12. Knots are areas of the trunk in which the base of a branch has become embedded in the body of the wood. 13. The Aare is about 280 km (175 miles) long and is navigable from the mouth to the town of Thun, Switzerland. 14. Stanley descended the Lualaba-Congo river system in 1876 and 1877 to its mouth, travelling more than 2,575 km (1,600 miles). 15. Situated at the foot of Ben Venue, a mountain 726 m (2,382 ft) high, and west of the wooded valley known as The Trossachs, the loch is noted for its beauty.
Завдання для самостійної підготовки:
Military strategy is in many ways the centerpiece of military science. It studies the specifics of combat, and attempts to reduce the many factors to a set of principles that govern all interactions of the field of battle. As such, it directs the planning and execution of battles, operations, and wars as a whole. Two major systems prevail on the planet today. Broadly speaking, these may be described as the "Western" system, and the "Russian" system. Each system reflects and supports strengths and weakness in the underlying society. Generally, "Western" societies have higher levels of education and technology. In contrast, third-world (based on the Russian system) societies have lower levels of education and technology, but have much more raw manpower in their military than Western societies are willing (or able) to devote.
Modern Western military art is composed primarily of an amalgam of French, German, British, and American systems. The Russian system borrows from these systems as well, either through study, or personal observation in the form of invasion (Napoleon's War of 1812, and The Great Patriotic War), and form a unique product suited for the conditions practitioners of this system will encounter. The system that is produced by the analysis provided by Military Art is known as doctrine.
Western military doctrine relies heavily on technology, the use of a well-trained and empowered NCO cadre, and superior information processing and dissemination to provide a level of battlefield awareness that opponents cannot match. Its advantages are extreme flexibility, extreme lethality, and a focus on removing an opponent's C3I (command, communications, control, and intelligence) to paralyze and incapacitate rather than destroying their combat power directly (hopefully saving lives in the process). Its drawbacks are high expense, a reliance on difficult to replace personnel, an enormous logistic train, and a difficulty in operating without high technology assets if depleted or destroyed.
Soviet military doctrine (and its descendants, in CIS countries) relies heavily on masses of machinery and troops, a highly educated (albeit very small) officer corps, and pre-planned missions. Its advantages are that it does not require well educated troops, does not require a large logistic train, is under tight central control, and does not rely on a sophisticated C3I system after the initiation of a course of action. Its disadvantages are inflexibility, a reliance on the shock effect of mass (with a resulting high cost in lives and material), and overall inability to exploit unexpected success or respond to unexpected loss.
Chinese military doctrine is currently in a state of flux as the People's Liberation Army is evaluating military trends of relevance to China. Chinese military doctrine is influenced by a number of sources including an indigenous classical military tradition characterized by strategists such as Sun Tzu, Western and Soviet influences, as well as indigenous modern strategists such as Mao Zedong. One distinctive characteristic of Chinese military science is that it places emphasis on the relationship between the military and society as well as views military force as merely one part of an overarching grand strategy.
Each system trains its officer corps in its philosophy regarding military art. The differences in content and emphasis are illustrative.
United States of America
The United States Army principles of war/military science are as follows (derived from U.S. Army Field Manual FM 100-5):
Objective - Direct every military operation toward a clearly defined, decisive and attainable objective. The ultimate military purpose of war is the destruction of the enemy's ability to fight and will to fight.
Offensive - Seize, retain, and exploit the initiative. Offensive action is the most effective and decisive way to attain a clearly defined common objective. Offensive operations are the means by which a military force seizes and holds the initiative while maintaining freedom of action and achieving decisive results. This is fundamentally true across all levels of war.
Mass - Mass the effects of overwhelming combat power at the decisive place and time. Synchronizing all the elements of combat power where they will have decisive effect on an enemy force in a short period of time is to achieve mass. Massing effects, rather than concentrating forces, can enable numerically inferior forces to achieve decisive results, while limiting exposure to enemy fire.
Economy of Force - Employ all combat power available in the most effective way possible; allocate minimum essential combat power to secondary efforts. Economy of force is the judicious employment and distribution of forces. No part of the force should ever be left without purpose. The allocation of available combat power to such tasks as limited attacks, defense, delays, deception, or even retrograde operations is measured in order to achieve mass elsewhere at the decisive point and time on the battlefield. ...
Maneuver - Place the enemy in a position of disadvantage through the flexible application of combat power. Maneuver is the movement of forces in relation to the enemy to gain positional advantage. Effective maneuver keeps the enemy off balance and protects the force. It is used to exploit successes, to preserve freedom of action, and to reduce vulnerability. It continually poses new problems for the enemy by rendering his actions ineffective, eventually leading to defeat. ...
Unity of Command - For every objective, seek unity of command and unity of effort. At all levels of war, employment of military forces in a manner that masses combat power toward a common objective requires unity of command and unity of effort. Unity of command means that all the forces are under one responsible commander. It requires a single commander with the requisite authority to direct all forces in pursuit of a unified purpose.
Security - Never permit the enemy to acquire unexpected advantage. Security enhances freedom of action by reducing vulnerability to hostile acts, influence, or surprise. Security results from the measures taken by a commander to protect his forces. Knowledge and understanding of enemy strategy, tactics, doctrine, and staff planning improve the detailed planning of adequate security measures.
Заняття № 9.