What is differential heating?
Differential heating is the disparity in heating of air over land versus water. Sea breezes occur when land heats up faster than water, rising and creating a low pressure system. The high pressure air from the sea influxes, creating a sea breeze.
What is differential hardening?
Differential hardening will produce two different zones of hardness, which respond differently to grinding, sharpening, and polishing. The back and center of the blade will grind away much quicker than the edge, so the polisher will need to carefully control the angle of the edge, which will affect the geometry of the blade.
What is differential tempering?
Differential tempering is obtained by quenching the sword uniformly, then tempering one part of it, such as the spine or the center portion of double edged blades. This is usually done with a torch or some other directed heat source. The heated portion of the metal is softened by this process, leaving the edge at the higher hardness.
What is the heat equation for thermal diffusivity?
For a final simplification to the heat equation let’s divide both sides by cρ and define the thermal diffusivity to be, k = K0 cρ The heat equation is then, ∂u ∂t = k∂2u ∂x2 + Q(x, t) cρ
Where does differential heating occur?
Differential heating occurs when the earth leans and rotates around the sun that heats the globe year long. Because of so many changes of solar radiation, lower latitudes have more energy than the higher latitudes from the sun.
What does differential heating mean in geography?
Differential heating refers to the difference in how land and water surfaces absorb heat. Heat absorbed by the oceans is distributed, through mixing, over a greater depth than is the heat absorbed by land surfaces.
Why is there differential heating on earth?
Solar heating of the Earth's surface is uneven because land heats faster than water, and this causes air to warm, expand and rise over land while it cools and sinks over the cooler water surfaces.
What causes differential heating of land and water?
Land gets more solar radiation than water. Land is a better conductor of heat than water and so it heats up and also cools down faster than water. Water is a better conductor of heat than land and so it heats up and also cools down faster than land.
What is differential heating and what causes it quizlet?
What is differential heating? The different concentrations of sun that hit the earth's surface.
What kind of differential heating occurs affecting winds during the monsoon season?
The direction of monsoon winds is reversed due to a change in air pressure. - Temperature variations arise from uneven heating, which allows air currents (wind) to form, which then transfer heat from where there is more heat (higher temperatures) to where there is less heat (lower temperatures) (lower temperatures).
How does differential heating and cooling of land and water affect the monsoon of India?
* The differential heating and cooling of land and water creates low pressure on the landmass of India while the seas around experience comparatively high pressure.
How the differential heating and cooling of land and water affect the climate?
It takes less energy to change the temperature of land compared to water. This means that land heats and cools more quickly than water and this difference affects the climate of different areas on Earth. Different energy transfer processes also contribute to different rates of heating between land and water.
How does global circulation relate to differential heating?
1:562:51What is global circulation? | Part One | Differential heating - YouTubeYouTubeStart of suggested clipEnd of suggested clipFrom the Sun global circulation acts as a clever air conditioning system redistributing the heatMoreFrom the Sun global circulation acts as a clever air conditioning system redistributing the heat stopping the equator becoming hotter and hotter and the poles becoming colder and colder.
Why is sea water warm even after sunset?
The heat that the ocean absorbs is mixed with the lower water quickly. That mixing spreads the heat around. At night, while the land cools off quickly, the water at the surface is kept warmer because the water is mixed around with the warmer water underneath.
What is differential heating?
Differential heating is the disparity in heating of air over land versus water. Sea breezes occur when land heats up faster than water, rising and creating a low pressure system. The high pressure air from the sea influxes, creating a sea breeze. This can lead to thunderstorms when moist air rises and sea breezes collide, ...
Which way do monsoons blow?
Monsoons generally blow one direction, northeast for six months and then reverse for the next six months, blowing southwest. Summers in the tropical climate of India are incredibly hot. India is situated on the equator and gets intense sunlight all year round.
What is differential heat treatment?
Differential heat treatment (also called selective heat treatment or local heat treatment) is a technique used during heat treating to harden or soften certain areas of a steel object, creating a difference in hardness between these areas. There are many techniques for creating a difference in properties, but most can be defined as ...
What is differential hardened blade?
A differentially hardened blade will usually be coated with an insulating layer, like clay, but leaving the edge exposed. When it is heated to red-hot and quenched, the edge cools quickly, becoming very hard, but the rest cools slowly, becoming much softer. The insulation layer is quite often a mixture of clays, ashes, polishing stone powder, and salts, which protects the back of the blade from cooling very quickly when quenched. The clay is often applied by painting it on, coating the blade very thickly around the center and spine, but leaving the edge exposed. This allows the edge to cool very quickly, turning it into a very hard microstructure called martensite, but causes the rest of the blade to cool slowly, turning it into a soft microstructure called pearlite. This produces an edge that is exceptionally hard and brittle, but is backed-up by softer, tougher metal. The edge, however, will usually be too hard, so after quenching the entire blade is usually tempered to around 400 °F (204 °C) for a short time, to bring the hardness of the edge down to around HRc60 on the Rockwell hardness scale.
Why do swords have differential hardening?
Differential hardening is a method used in heat treating swords and knives to increase the hardness of the edge without making the whole blade brittle.
What is induction hardening?
Induction hardening is a surface hardening technique which uses induction coils to provide a very rapid means of heating the metal. With induction heating, the steel can be heated very quickly to red-hot at the surface, before the heat can penetrate any distance into the metal. The surface is then quenched, hardening it, and is often used without further tempering. This makes the surface very resistant to wear, but provides tougher metal directly underneath it, leaving the majority of the object unchanged. A common use for induction hardening is for hardening the bearing surfaces, or "journals", on automotive crankshafts or the rods of hydraulic cylinders.
How does differential hardening affect swords?
Although differential hardening produces a very hard edge , it also leaves the rest of the sword rather soft, which can make it prone to bending under heavy loads, such as parrying a hard blow. It can also make the edge more susceptible to chipping or cracking. Swords of this type can usually only be resharpened a few times before reaching the softer metal underneath the edge. However, if properly protected and maintained, these blades can usually hold an edge for long periods of time, even after slicing through bone and flesh, or heavily matted bamboo to simulate cutting through body parts, as is in iaido.
How to cool edge faster than spine?
To achieve this, the edge is cooled faster than the spine by adding a heat insulator to the spine before quenching. Clay or another material is used for insulation. To prevent cracking and loss of surface carbon, quenching is usually performed before beveling, shaping, and sharpening the edge.
How does a smith remove heat?
Before the yellow or "light-straw" color reaches the edge, the smith removes the heat. The heat will continue to conduct, moving the colors toward the edge for a short time after the heat is removed. When the light-straw color reaches the edge, the smith will usually dip the steel in water, to stop the process.
What is the equation for the heat flow of a bar?
In other words, the bar is hotter than the surrounding fluid and so at x = 0 x = 0 the heat flow (as given by the left side of the equation) must be to the left, or negative since the heat will flow from the hotter bar into the cooler surrounding liquid.
Can lateral surfaces be insulated?
The assumption of the lateral surfaces being perfectly insulated is of course impossible, but it is possible to put enough insulation on the lateral surfaces that there will be very little heat flow through them and so, at least for a time, we can consider the lateral surfaces to be perfectly insulated.
