Explore Related Concepts

Best Results From Wikipedia Yahoo Answers Youtube

From Wikipedia

Temperature conversion

This is a compendium of temperatureconversion formulas and comparisons.


Celsius (Centigrade)








Comparison of temperature scales

* Normal human body temperature is 36.8 Â°C ±0.7 Â°C, or 98.2 Â°F ±1.3 Â°F. The commonly given value 98.6 Â°F is simply the exact conversion of the nineteenth-century German standard of 37 Â°C. Since it does not list an acceptable range, it could therefore be said to have excess (invalid) precision.

Some numbers in this table have been rounded.

Conversion table between different temperature units

Indentation hardness

Indentation hardness tests are used to determine the hardness of a material to deformation. Several such tests exist, wherein the examined material is indented until an impression is formed; these tests can be performed on a macroscopic or microscopic scale.

When testing metals, indentation hardness correlates linearly with tensile strength. This important relation permits economically important nondestructive testing of bulk metal deliveries with lightweight, even portable equipment, such as hand-held Rockwell hardness testers.

Material hardness

As the direction of materials science continues towards studying the basis of properties on smaller and smaller scales, different techniques are used to quantify material characteristics and tendencies. Measuring mechanical properties for materials on smaller scales, like thin films, can not be done using conventional uniaxialtensile testing. As a result, techniques testing material "hardness" by indenting a material with an impression have been developed to determine such properties.

Hardness measurements quantify the resistance of a material to plastic deformation. Indentation hardness tests compose the majority of processes used to determine material hardness, and can be divided into two classes: microindentation and macroindentation tests. Microindentation tests typically have forces less than 2|N|abbr=on. Hardness, however, cannot be considered to be a fundamental material property. Instead, it represents an arbitrary quantity used to provide a relative idea of material properties. As such, hardness can only offer a comparative idea of the material's resistance to plastic deformation since different hardness techniques have different scales.

The main source of error with indentation tests is the strain hardening effect of the process. However, it has been experimentally determined through "strainless hardness tests" that the effect is minimal with smaller indentations.

Surface finish of the part and the indenter do not have an effect on the hardness measurement, as long as the indentation is large compared to the surface roughness. This proves to be useful when measuring the hardness of practical surfaces. It also is helpful when leaving a shallow indentation, because a finely etched indenter leaves a much easier to read indentation than a smooth indenter.

The indentation that is left after the indenter and load are removed is known to "recover", or spring back slightly. This effect is properly known as shallowing. For spherical indenters the indentation is known to stay symmetrical and spherical, but with a larger radius. For very hard materials the radius can be three times as large as the indenter's radius. This effect is attributed to the release of elastic stresses. Because of this effect the diameter and depth of the indentation do contain errors. The error from the change in diameter is known to be only a few percent, with the error for the depth being greater.

Another effect the load has on the indentation is the piling-up or sinking-in of the surrounding material. If the metal is work hardened it has a tendency to pile up and form a "crater". If the metal is annealed it will sink in around the indentation. Both of these effects add to the error of the hardness measurement.

The equation based definition of hardness is the pressure applied over the projected area between the indenter and the material being tested. As a result hardness values are typically reported in units of pressure, although this is only a "true" pressure if the indenter and surface interface is perfectly flat.

{{anchor|macrohardness}}Macroindentation tests

The term "macroindentation" is applied to tests with a larger test load, such as 1 kgf or more. There are various macroindentation tests, including:

There is, in general, no simple relationship between the results of different hardness tests. Though there are practical conversion tables for hard steels, for example, some materials show qualitatively different behaviors under the various measurement methods. The Vickers and Brinell hardness scales correlate well over a wide range, however, with Brinell only producing overestimated values at high loads.

{{anchor|microhardness}}Microindentation tests

The term "microhardness" has been widely employed in the literature to describe the hardness testing of materials with low applied loads. A more precise term is "microindentation hardness testing." In microindentation hardness testing, a diamond indenter of specific geometry is impressed into the surface of the test specimen using a known applied force (commonly called a "load" or "test load") of 1 to 1000 gf. Microindentation tests typically have forces of 2 N (roughly 200 gf) and produce indentations of about 50 μm. Due to their specificity, microhardness testing can be used to observe changes in hardness on the microscopic scale. Unfortunately, it is difficult to standardize microhardness measurements; it has been found that the microhardness of almost any material is higher than its macrohardness. Additionally, microhardness values vary with load and work-hardening effects of materials. The two most commonly used microhardness tests are tests that also can be applied with heavier loads as microindentation tests:

In microindentation testing, the hardness number is based on measurements made of the indent formed in the surface of the test specimen. The hardness number is based on the surface area of the indent itself divided by the applied force, giving hardness units in kgf/mm². Microindentation hardness testing can be done using Vickers as well as Knoop indenters. For the Vickers test, both the diagonals are measured and the average value is used to compute the Vickers p

From Yahoo Answers

Question:the density of air at ordinary atmospheric pressure and 25*C is 1.19 g/L. what is the mass, in kilograms, of the air in a room that measures 12.5 x 15.5 x 8.0 ft? pleasure show your work and explain thanks:) sorry theres another one... how many moles of chloride ions are in 0.0750 g of magnesium chloride?

Answers:1st question: (1 ft3)[(12 in/ft)(2.54cm/in)(1dm/10cm)]3 = 28.32 dm3 Room = (12.5 ft)(15.5 ft)(8.0 ft) =1550 ft3 (1550 ft3)(28.32 dm3/1 ft3) = 43896 dm3 = 43896 L (43896 L)(1.19 g/L) = 52236 g = 52.236 kg 2nd question: magnesium chloride = MgCl2 -- so there are 2 chloride ions per magnesium chloride. 1 mole of magnesium chloride has a mass of 95.22 g (0.0750 g MgCl2)(1 mol MgCl2/95.22 g MgCl2)( 2 Cl/MgCl2) = 0.00158 mol Cl

Question:I want to know the above formula.

Answers:if I=d.c. i=a.c. then, i=Isinwt where, w=frequency t=time

Question:I am having a hard time with conversions. A question on my home work goes like this. It is valuable to know that 1 milliliter equals 1cubic centimeter (cm3 or cc). How many cubic centimeters are in am 8.00oz bottle of cough medicine?(1.00 oz=29.6mL) If anyone could show me how you would convert this I would greatly appreciate it.

Answers:8.00 oz x ( 29.6 mL / 1 oz) = X X will have units of mL. You know that there is a 1:1 ratio between 1 cc and 1 mL ( 1 cm^3 = 1 mL). So, all you have to do is say that there were X cubic centimetres (because cc and mL are interchangable).

Question:I'm very interested in mathematics and stuff, but we learn way to simple math at school and i'm not really willing to wait years till i'm in college. So where can i learn hard mathematics online? By hard mathematics i mean those that are used in physics formula's like sigma, delta and stuff like that. Physics mathematics actually, so I can understand physics formula's. Thanks

Answers:You can learn calculus at any time. I'd be willing to work with you on a small project to get you started. Look up derivative and integral. Look up differentiation and integration. The area under a function is important. The slope of a line at a point is important. Have fun reading articles about physics topics on Wikipedia. You mentioned Delta. velocity = change of position vs. time acceleration = change of velocity vs. time Using calculus we can move back and forth between position, velocity and acceleration. I wouldn't worry about Sigma just yet, but it will come soon. Can you get a hold of a Dummie's book on Physics? Please don't take this as an insult. I have a Ph.D. in Chemistry and I used a Dummie's book to learn Javascript--their eccentric style is enjoyable to me. My senior year in high school I wanted to take calculus but it wasn't offered. My physics teacher was a wonderful guy and he loaned me his calculus book for the year. I'm willing to email back and forth with you a couple of times if you are interested.

From Youtube

Degrees Fahrenheit Celsius Conversion Formula Problem Video :Degrees Fahrenheit Celsius Conversion Formula Problem Video

Beg Algebra: Temperature Conversion Formula, Rate :www.mindbites.comTaught by Professor Edward Burger, this lesson was selected from a broader, comprehensive course, Beginning Algebra. This course and others are available from Thinkwell, Inc. The full course can be found atwww.thinkwell.com The full course covers linear equations, inequalities, polynomials, rational expressions, relations and functions, roots and radicals, quadratic equations and systems of equations. Edward Burger, Professor of Mathematics at Williams College, earned his Ph.D. at the University of Texas at Austin, having graduated summa cum laude with distinction in mathematics from Connecticut College. He has also taught at UT-Austin and the University of Colorado at Boulder, and he served as a fellow at the University of Waterloo in Canada and at Macquarie University in Australia. Prof. Burger has won many awards, including the 2001 Haimo Award for Distinguished Teaching of Mathematics, the 2004 Chauvenet Prize, and the 2006 Lester R. Ford Award, all from the Mathematical Association of America. In 2006, Reader's Digest named him in the "100 Best of America". Prof. Burger is the author of over 50 articles, videos, and books, including the trade book, Coincidences, Chaos, and All That Math Jazz: Making Light of Weighty Ideas and of the textbook The Heart of Mathematics: An Invitation to Effective Thinking. He also speaks frequently to professional and public audiences, referees professional journals, and publishes articles in leading math journals ...