transport network

Examples of transport network in the following topics:

• Routing

  • Routing is performed for many kinds of networks, including the telephone network (circuit switching), electronic data networks (such as the internet), and transportation networks.
  • This chapter focuses on the role of routing in transportation networks.
  • A transport network, (or transportation network in American English), is typically a network of roads, streets, pipes, aqueducts, power lines, or nearly any structure which permits either vehicular movement or flow of some commodity.
  • Transport engineers use mathematical graph theory to analyze a transport network to determine the flow of vehicles (or people) through it.
  • A transport network may combine different modes of transport.

• The Role of the Circulatory System

  • The circulatory systems is a network of blood vessels supplying the body with oxygen and nutrients, while removing carbon dioxide and waste.
  • Most animals are complex, multicellular organisms that require a mechanism for transporting nutrients throughout their bodies and for removing waste products.
  • This extensive network supplies the cells, tissues, and organs with oxygen and nutrients, while removing carbon dioxide and waste, the byproducts of respiration.
  • However, in organisms that possess lungs and gills, oxygen must be transported from these specialized respiratory organs to the body tissues via a circulatory system.
  • Just as highway systems transport people and goods through a complex network, the circulatory system transports nutrients, gases, and wastes throughout the animal body.

• Transportation: Roads, Canals, and Railroads

  • Water and river transportation were central to the national economy, while most overland transportation was by horse, which made it difficult to move large quantities of goods.
  • During the nineteenth century, transportation routes and means of transport underwent dramatic changes, greatly increasing national mobility.
  • New and improved transportation technology made it easier and faster to transport goods: first national roads, then canals, and finally the railroad revolution.
  • As the nation expanded, however, the government came to see the transportation network as a public good worthy of government support.
  • Other railway initiatives would follow, subsequently creating a network linking all corners of the nation.

• Absorption in the Small Intestine

  • Each villus has a network of capillaries and fine lymphatic vessels called lacteals close to its surface.
  • The epithelial cells of the villi transport nutrients from the lumen of the intestine into these capillaries (amino acids and carbohydrates) and lacteals (lipids).
  • The absorbed substances are transported via the blood vessels to different organs of the body where they are used to build complex substances such as the proteins required by our body.
  • Absorption of the majority of nutrients takes place in the jejunum, with the following notable exceptions: iron is absorbed in the duodenum; vitamin B12 and bile salts are absorbed in the terminal ileum; water and lipids are absorbed by passive diffusion throughout the small intestine; sodium bicarbonate is absorbed by active transport and glucose and amino acid co-transport; and fructose is absorbed by facilitated diffusion.

• Blood Vessel Function

  • The circulatory system is key in transporting blood around the body to perform these actions which is facilitated by the network of blood vessels distributed throughout the body.
  • Upon reaching the capillary networks gas exchange between the tissue and blood can occur, facilitated by the narrow walls of the capillaries.
  • Leaving the heart through right ventricle the blood passes through the pulmonary artery, the only artery in the body that contains de-oxygenated blood, and into the capillary network within the lungs.
  • Blood vessels also facilitate the rapid distribution and efficient transport into the tissue of other factors such as glucose, amino acids or lipids and the removal of waste products for processing elsewhere such as lactic acid to the liver or urea to the kidneys.
  • Additionally, blood vessels provide the ideal network for immune system surveillance and distribution.

• Streamlining Distribution

  • One of the main transport planning functions is allowing and performing collective (bundled) transport of goods, and the inclusion of intermodal transport systems into the logistics and distribution processes.
  • This element optimizes the use of the necessary means in the current logistic network that includes suppliers, production locations, locations of distribution means, and end users.
  • By performing various methods of logistic networks planning, the locations of new infrastructure facilities may be determined, which would meet the customers' needs in an optimal way.
  • Transport planning uses current transport prices for the minimization of dispatch costs.
  • One of the main transport planning functions is allowing and performing collective (bundled) transport of goods, and the inclusion of intermodal transport systems into the logistics and distribution processes.

• Skin, Gills, and Tracheal Systems

  • A dense network of capillaries lies just below the skin, facilitating gas exchange between the external environment and the circulatory system.
  • Insect respiration is independent of its circulatory system; therefore, the blood does not play a direct role in oxygen transport.
  • Insects have a highly-specialized type of respiratory system called the tracheal system, which consists of a network of small tubes that carries oxygen to the entire body.
  • These openings connect to the tubular network, allowing oxygen to pass into the body, regulating the diffusion of CO2 and water vapor .

• Supply Chain Management

  • Supply chain management is the management of the network of interconnected steps involved in the provision of product and service packages.
  • Supply chain management (SCM) is the management of a network of interconnected businesses involved in the provision of product and service packages required by the end customers in a supply chain.
  • Distribution network configuration: number, location and network missions of suppliers, production facilities, distribution centers, warehouses, cross-docks and customers.
  • Distribution strategy: questions of operating control (centralized, decentralized or shared); delivery scheme (e.g., direct shipment, pool point shipping, or cross docking), DSD (direct store delivery), closed loop shipping; mode of transportation (e.g., motor carrier, including truckload, LTL, or parcel); railroad; intermodal transport, including TOFC (trailer on flatcar), and COFC (container on flatcar); ocean freight; airfreight; replenishment strategy (e.g., pull, push or hybrid); and transportation control (e.g., owner-operated, private carrier, common carrier, contract carrier, or 3PL).
  • If, however, a full truckload of a product is ordered to reduce transportation costs, there will be an increase in inventory holding costs, which may increase total logistics costs.

• Kidney Function and Physiology

  • First, the nephrons filter blood that runs through the capillary network in the glomerulus .
  • Almost all nutrients are reabsorbed; this occurs either by passive or active transport.
  • Sodium (Na+) is the most abundant ion; most of it is reabsorbed by active transport and then transported to the peritubular capillaries.
  • Every solute, however, has a transport maximum; the excess solute is not reabsorbed.
  • Further up, Na+ is actively transported out of the filtrate and Cl- follows.

• Tubular Secretion

  • Hydrogen, creatinine, and drugs are removed from the blood through the peritubular capillary network into the collecting duct.
  • This secretion is caused mainly by active transport and passive diffusion.
  • Active transport-movement of molecules via ATPase pumps, that transport the substance through the renal epithelial cell into the lumen of the nephron.