The Formation of Freckles in Binary Alloys
... region over which the concentration changes in the liquid is much thinner than the corresponding region over which the temperature changes, and one can think of the dendrite zone as performing the function of smearing out the concentration jump over a much larger distance than in the planar case. If ...
... region over which the concentration changes in the liquid is much thinner than the corresponding region over which the temperature changes, and one can think of the dendrite zone as performing the function of smearing out the concentration jump over a much larger distance than in the planar case. If ...
Chapter
... Nusselt theory is based on a laminar waveless film flow. Whereas waves can be found which cause the film thickness and the velocity at the interface in simulation to be faintly higher than that in Nusselt theory. As a conclusion from Figure 4 (left) can be drawn that CFD simulation with VOF model ca ...
... Nusselt theory is based on a laminar waveless film flow. Whereas waves can be found which cause the film thickness and the velocity at the interface in simulation to be faintly higher than that in Nusselt theory. As a conclusion from Figure 4 (left) can be drawn that CFD simulation with VOF model ca ...
GCE Physics - Thermodynamics Notes Word Document
... There is a sudden huge rise in the temperature and pressure in the vessel. What has happened to the internal energy of the system (i.e. the contents of the vessel)? Has heat flowed into or out of the system? Hardly at all in the short time of the chemical reaction. The spark itself contributes negli ...
... There is a sudden huge rise in the temperature and pressure in the vessel. What has happened to the internal energy of the system (i.e. the contents of the vessel)? Has heat flowed into or out of the system? Hardly at all in the short time of the chemical reaction. The spark itself contributes negli ...
Dynamic van der Waals theory
... originally devised to describe dynamics of the thermal fluctuations 关5兴, but has also been used to describe phase separation processes 关39兴 and steady states under shear flow 关6,40兴. We mention Kawasaki’s hydrodynamic equations for van der Waals fluids with long-range interaction 关36兴, where the str ...
... originally devised to describe dynamics of the thermal fluctuations 关5兴, but has also been used to describe phase separation processes 关39兴 and steady states under shear flow 关6,40兴. We mention Kawasaki’s hydrodynamic equations for van der Waals fluids with long-range interaction 关36兴, where the str ...
Unit One: Introduction to Physiology: The Cell and General Physiology
... • Total peripheral vascular resistance is equal to the sum of resistances of vessels. • Effect of blood hematocrit and viscosity on flow and resistance. a. The viscosity of normal blood is 3X that of water b. Hematocrit-portion of blood that is rbcs c. Viscosity increases as the hematocrit increase ...
... • Total peripheral vascular resistance is equal to the sum of resistances of vessels. • Effect of blood hematocrit and viscosity on flow and resistance. a. The viscosity of normal blood is 3X that of water b. Hematocrit-portion of blood that is rbcs c. Viscosity increases as the hematocrit increase ...
MET -303 THERMAL ENGINNERING-1 CHAPTER 1:
... currents i.e. transfer of heat between the wall and fluid system in motion. In this case, the particles of the body move relative to each other. 3. Radiation : Heat transfer between two bodies separated by empty space or gases through electromagnetic waves is radiation. ...
... currents i.e. transfer of heat between the wall and fluid system in motion. In this case, the particles of the body move relative to each other. 3. Radiation : Heat transfer between two bodies separated by empty space or gases through electromagnetic waves is radiation. ...
UNIT I PART B 1). (i). A spherical balloon of diameter
... final state without producing any changes in the thermodynamics properties of the universe is called a reversible process. In the figure below, let us suppose that the system has undergone a change from state A to state B. If the system can be restored from state B to state A, and there is no change ...
... final state without producing any changes in the thermodynamics properties of the universe is called a reversible process. In the figure below, let us suppose that the system has undergone a change from state A to state B. If the system can be restored from state B to state A, and there is no change ...
Kidneys- complete!
... segment is right next to the thick segment, and they share peritubular space. Remember that the thin segment is highly permeable to water. Fluid entering the thin segment is suddenly thrown into highly hypertonic surroundings. Water gets sucked right out of the thin segment, moving passively by osmo ...
... segment is right next to the thick segment, and they share peritubular space. Remember that the thin segment is highly permeable to water. Fluid entering the thin segment is suddenly thrown into highly hypertonic surroundings. Water gets sucked right out of the thin segment, moving passively by osmo ...
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.