2.26 MB - KFUPM Resources v3
... The system is heated and the piston is allowed to float and thus the pressure will be constant. T and v will increase until the system reaches 100 C at which any addition of heat will cause some of the liquid to vaporize The temperature at which a pure substance changes phase is called the saturatio ...
... The system is heated and the piston is allowed to float and thus the pressure will be constant. T and v will increase until the system reaches 100 C at which any addition of heat will cause some of the liquid to vaporize The temperature at which a pure substance changes phase is called the saturatio ...
NEPHRON Review WS KEY - Mr. Lesiuk
... D) The active transport of almost 100% of nutrients like glucose and amino acids back into the blood. 1. Tubular Reabsorption 2. Proximal Convoluted Tubule E) When salt (NaCl) passively diffuses out of the nephron at the bottom of this structure but then active transport finishes off the passing out ...
... D) The active transport of almost 100% of nutrients like glucose and amino acids back into the blood. 1. Tubular Reabsorption 2. Proximal Convoluted Tubule E) When salt (NaCl) passively diffuses out of the nephron at the bottom of this structure but then active transport finishes off the passing out ...
Chemistry II
... of _____________________ ( 1818 -1889) – a British Scientist who investigated heat and work. 12.) A ____________________ was originally defined as the amount of energy required to raise the temperature of 1gram of water from 14.5 to 15.5 degrees Celsius 13.)Today it is defined in terms of the Joule ...
... of _____________________ ( 1818 -1889) – a British Scientist who investigated heat and work. 12.) A ____________________ was originally defined as the amount of energy required to raise the temperature of 1gram of water from 14.5 to 15.5 degrees Celsius 13.)Today it is defined in terms of the Joule ...
Chapter 5
... we do need to account for this work, we can generally do so with approximations that take advantage of the relative incompressibility of liquids and solids (this point is addressed later in this chapter). The form of work we have described is sometimes referred to as boundary work since it involves ...
... we do need to account for this work, we can generally do so with approximations that take advantage of the relative incompressibility of liquids and solids (this point is addressed later in this chapter). The form of work we have described is sometimes referred to as boundary work since it involves ...
Countercurrent exchange
Countercurrent exchange is a mechanism occurring in nature and mimicked in industry and engineering, in which there is a crossover of some property, usually heat or some component, between two flowing bodies flowing in opposite directions to each other. The flowing bodies can be liquids, gases, or even solid powders, or any combination of those. For example, in a distillation column, the vapors bubble up through the downward flowing liquid while exchanging both heat and mass.The maximum amount of heat or mass transfer that can be obtained is higher with countercurrent than co-current (parallel) exchange because countercurrent maintains a slowly declining difference or gradient (usually temperature or concentration difference). In cocurrent exchange the initial gradient is higher but falls off quickly, leading to wasted potential. For example, in the diagram at the right, the fluid being heated (exiting top) has a higher exiting temperature than the cooled fluid (exiting bottom) that was used for heating. With cocurrent or parallel exchange the heated and cooled fluids can only approach one another. The result is that countercurrent exchange can achieve a greater amount of heat or mass transfer than parallel under otherwise similar conditions. See: flow arrangement.Countercurrent exchange when set up in a circuit or loop can be used for building up concentrations, heat, or other properties of flowing liquids. Specifically when set up in a loop with a buffering liquid between the incoming and outgoing fluid running in a circuit, and with active transport pumps on the outgoing fluid's tubes, the system is called a Countercurrent multiplier, enabling a multiplied effect of many small pumps to gradually build up a large concentration in the buffer liquid.Other countercurrent exchange circuits where the incoming and outgoing fluids touch each other are used for retaining a high concentration of a dissolved substance or for retaining heat, or for allowing the external buildup of the heat or concentration at one point in the system.Countercurrent exchange circuits or loops are found extensively in nature, specifically in biologic systems. In vertebrates, they are called a Rete mirabile, originally the name of an organ in fish gills for absorbing oxygen from the water. It is mimicked in industrial systems. Countercurrent exchange is a key concept in chemical engineering thermodynamics and manufacturing processes, for example in extracting sucrose from sugar beet roots.Countercurrent multiplication is a similar but different concept where liquid moves in a loop followed by a long length of movement in opposite directions with an intermediate zone. The tube leading to the loop passively building up a gradient of heat (or cooling) or solvent concentration while the returning tube has a constant small pumping action all along it, so that a gradual intensification of the heat or concentration is created towards the loop. Countercurrent multiplication has been found in the kidneys as well as in many other biological organs.