The International System of Units (SI)
Total Page:16
File Type:pdf, Size:1020Kb

Load more
Recommended publications
-
Calculating Growing Degree Days by Jim Nugent District Horticulturist Michigan State University
Calculating Growing Degree Days By Jim Nugent District Horticulturist Michigan State University Are you calculating degree day accumulations and finding your values don't match the values being reported by MSU or your neighbor's electronic data collection unit? There is a logical reason! Three different methods are used to calculate degree days; i.e., 1) Averaging Method; 2) Baskerville-Emin (BE) Method; and 3) Electronic Real-time Data Collection. All methods attempt to calculate the heat accumulation above a minimum threshold temperature, often referred to the base temperature. Once both the daily maximum and minimum temperatures get above the minimum threshold temperature, (i.e., base temperature of 42degrees, 50degrees or whatever other base temperature of interest) then all methods are fairly comparable. However, differences do occur and these are accentuated in an exceptionally long period of cool spring temperatures, such as we experienced this year. Let me briefly explain: 1. Averaging Method: Easy to calculate Degree Days(DD) = Average daily temp. - Base Temp. = (max. + min.) / 2 - Base temp. If answer is negative, assume 0. Example: Calculate DD Base 50 given 65 degrees max. and 40 degrees min. Avg. = (65 + 40) / 2 = 52.5 degrees DD base 50 = 52.5 - 50 = 2.5 degrees. But look what happens given a maximum of 60 degrees and a minimum of 35 degrees: Avg. = (60 + 35) / 2 = 47.5 DD base 50 = 47.5 - 50 = -2.5 = 0 degrees. The maximum temperature was higher than the base of 50° , but no degree days were accumulated. A grower called about the first of June reporting only about 40% of the DD50 that we have recorded. -
Lecture 3: the Sensor
4.430 Daylighting Human Eye ‘HDR the old fashioned way’ (Niemasz) Massachusetts Institute of Technology ChriChristoph RstophReeiinhartnhart Department of Architecture 4.4.430 The430The SeSensnsoror Building Technology Program Happy Valentine’s Day Sun Shining on a Praline Box on February 14th at 9.30 AM in Boston. 1 Happy Valentine’s Day Falsecolor luminance map Light and Human Vision 2 Human Eye Outside view of a human eye Ophtalmogram of a human retina Retina has three types of photoreceptors: Cones, Rods and Ganglion Cells Day and Night Vision Photopic (DaytimeVision): The cones of the eye are of three different types representing the three primary colors, red, green and blue (>3 cd/m2). Scotopic (Night Vision): The rods are repsonsible for night and peripheral vision (< 0.001 cd/m2). Mesopic (Dim Light Vision): occurs when the light levels are low but one can still see color (between 0.001 and 3 cd/m2). 3 VisibleRange Daylighting Hanbook (Reinhart) The human eye can see across twelve orders of magnitude. We can adapt to about 10 orders of magnitude at a time via the iris. Larger ranges take time and require ‘neural adaptation’. Transition Spaces Outside Atrium Circulation Area Final destination 4 Luminous Response Curve of the Human Eye What is daylight? Daylight is the visible part of the electromagnetic spectrum that lies between 380 and 780 nm. UV blue green yellow orange red IR 380 450 500 550 600 650 700 750 wave length (nm) 5 Photometric Quantities Characterize how a space is perceived. Illuminance Luminous Flux Luminance Luminous Intensity Luminous Intensity [Candela] ~ 1 candela Courtesy of Matthew Bowden at www.digitallyrefreshing.com. -
Standard Conversion Factors
Standard conversion factors 7 1 tonne of oil equivalent (toe) = 10 kilocalories = 396.83 therms = 41.868 GJ = 11,630 kWh 1 therm = 100,000 British thermal units (Btu) The following prefixes are used for multiples of joules, watts and watt hours: kilo (k) = 1,000 or 103 mega (M) = 1,000,000 or 106 giga (G) = 1,000,000,000 or 109 tera (T) = 1,000,000,000,000 or 1012 peta (P) = 1,000,000,000,000,000 or 1015 WEIGHT 1 kilogramme (kg) = 2.2046 pounds (lb) VOLUME 1 cubic metre (cu m) = 35.31 cu ft 1 pound (lb) = 0.4536 kg 1 cubic foot (cu ft) = 0.02832 cu m 1 tonne (t) = 1,000 kg 1 litre = 0.22 Imperial = 0.9842 long ton gallon (UK gal.) = 1.102 short ton (sh tn) 1 UK gallon = 8 UK pints 1 Statute or long ton = 2,240 lb = 1.201 U.S. gallons (US gal) = 1.016 t = 4.54609 litres = 1.120 sh tn 1 barrel = 159.0 litres = 34.97 UK gal = 42 US gal LENGTH 1 mile = 1.6093 kilometres 1 kilometre (km) = 0.62137 miles TEMPERATURE 1 scale degree Celsius (C) = 1.8 scale degrees Fahrenheit (F) For conversion of temperatures: °C = 5/9 (°F - 32); °F = 9/5 °C + 32 Average conversion factors for petroleum Imperial Litres Imperial Litres gallons per gallons per per tonne tonne per tonne tonne Crude oil: Gas/diesel oil: Indigenous Gas oil 257 1,167 Imported Marine diesel oil 253 1,150 Average of refining throughput Fuel oil: Ethane All grades 222 1,021 Propane Light fuel oil: Butane 1% or less sulphur 1,071 Naphtha (l.d.f.) >1% sulphur 232 1,071 Medium fuel oil: Aviation gasoline 1% or less sulphur 237 1,079 >1% sulphur 1,028 Motor -
An Atomic Physics Perspective on the New Kilogram Defined by Planck's Constant
An atomic physics perspective on the new kilogram defined by Planck’s constant (Wolfgang Ketterle and Alan O. Jamison, MIT) (Manuscript submitted to Physics Today) On May 20, the kilogram will no longer be defined by the artefact in Paris, but through the definition1 of Planck’s constant h=6.626 070 15*10-34 kg m2/s. This is the result of advances in metrology: The best two measurements of h, the Watt balance and the silicon spheres, have now reached an accuracy similar to the mass drift of the ur-kilogram in Paris over 130 years. At this point, the General Conference on Weights and Measures decided to use the precisely measured numerical value of h as the definition of h, which then defines the unit of the kilogram. But how can we now explain in simple terms what exactly one kilogram is? How do fixed numerical values of h, the speed of light c and the Cs hyperfine frequency νCs define the kilogram? In this article we give a simple conceptual picture of the new kilogram and relate it to the practical realizations of the kilogram. A similar change occurred in 1983 for the definition of the meter when the speed of light was defined to be 299 792 458 m/s. Since the second was the time required for 9 192 631 770 oscillations of hyperfine radiation from a cesium atom, defining the speed of light defined the meter as the distance travelled by light in 1/9192631770 of a second, or equivalently, as 9192631770/299792458 times the wavelength of the cesium hyperfine radiation. -
3 Litre User's Manual
™ 3 Litre User’s Manual Please visit www.drewandcole.com for video instructions and cooking demonstrations. 1 IMPORTANT SAFETY INFORMATION IMPORTANT SAFETY INFORMATION BEFORE YOU GET STARTED, PLEASE READ THE FOLLOWING IMPORTANT SAFETY INFORMATION, ALONG WITH THE MANUAL ENCLOSED AND KEEP PRESSURE RELEASE METHODS BOTH FOR FUTURE REFERENCE. WARNING YOU ARE WORKING WITH • When the programme is finished and you wish to commence pressure release press the “Cancel” button to cancel HOT LIQUIDS. YOU MUST READ THIS BEFORE USE. the Keep Warm function. • When releasing the pressure valve, always use tongs and please wear oven gloves to turn the pressure valve to the open position. This will protect against hot steam. The valve will lift up slightly and steam will release. The lid won’t BEFORE COOKING open until the steam has vented and pressure has released. • When opening the lid food will be hot, please always wear oven gloves and an apron to protect against any • ALWAYS ensure the INNER POT is in place before cooking. splashing of the hot food. • Food with skins (e.g sausages, chicken and fruit) MUST be pierced before cooking. Not piercing QUICK RELEASE SLOW RELEASE the skin may result in the food expanding and may cause splashing of hot food after the lid is Recommended for: Recommended for: released. - Quick cooking recipes and steaming, including - Food with skins (e.g sausages, chicken and fruit) and vegetables and seafood. foods with large liquid volume or high starch content • Do not overfill the inner pot. (such as porridge, soup, pasta, rice, fruit and grains, and When the Keep Warm function has been also delicate foods such as meats and potato) can trap air cancelled, move the pressure release valve to and cause the food to foam and expand which may cause To Max the open position and only attempt to open lid MAX MAX splashing of hot food after the lid is removed. -
Light and Illumination
ChapterChapter 3333 -- LightLight andand IlluminationIllumination AAA PowerPointPowerPointPowerPoint PresentationPresentationPresentation bybyby PaulPaulPaul E.E.E. Tippens,Tippens,Tippens, ProfessorProfessorProfessor ofofof PhysicsPhysicsPhysics SouthernSouthernSouthern PolytechnicPolytechnicPolytechnic StateStateState UniversityUniversityUniversity © 2007 Objectives:Objectives: AfterAfter completingcompleting thisthis module,module, youyou shouldshould bebe ableable to:to: •• DefineDefine lightlight,, discussdiscuss itsits properties,properties, andand givegive thethe rangerange ofof wavelengthswavelengths forfor visiblevisible spectrum.spectrum. •• ApplyApply thethe relationshiprelationship betweenbetween frequenciesfrequencies andand wavelengthswavelengths forfor opticaloptical waves.waves. •• DefineDefine andand applyapply thethe conceptsconcepts ofof luminousluminous fluxflux,, luminousluminous intensityintensity,, andand illuminationillumination.. •• SolveSolve problemsproblems similarsimilar toto thosethose presentedpresented inin thisthis module.module. AA BeginningBeginning DefinitionDefinition AllAll objectsobjects areare emittingemitting andand absorbingabsorbing EMEM radiaradia-- tiontion.. ConsiderConsider aa pokerpoker placedplaced inin aa fire.fire. AsAs heatingheating occurs,occurs, thethe 1 emittedemitted EMEM waveswaves havehave 2 higherhigher energyenergy andand 3 eventuallyeventually becomebecome visible.visible. 4 FirstFirst redred .. .. .. thenthen white.white. LightLightLight maymaymay bebebe defineddefineddefined -
Modern Physics Unit 15: Nuclear Structure and Decay Lecture 15.1: Nuclear Characteristics
Modern Physics Unit 15: Nuclear Structure and Decay Lecture 15.1: Nuclear Characteristics Ron Reifenberger Professor of Physics Purdue University 1 Nucleons - the basic building blocks of the nucleus Also written as: 7 3 Li ~10-15 m Examples: A X=Chemical Element Z X Z = number of protons = atomic number 12 A = atomic mass number = Z+N 6 C N= A-Z = number of neutrons 35 17 Cl 2 What is the size of a nucleus? Three possibilities • Range of nuclear force? • Mass radius? • Charge radius? It turns out that for nuclear matter Nuclear force radius ≈ mass radius ≈ charge radius defines nuclear force range defines nuclear surface 3 Nuclear Charge Density The size of the lighter nuclei can be approximated by modeling the nuclear charge density ρ (C/m3): t ≈ 4.4a; a=0.54 fm 90% 10% Usually infer the best values for ρo, R and a for a given nucleus from scattering experiments 4 Nuclear mass density Scattering experiments indicate the nucleus is roughly spherical with a radius given by 1 3 −15 R = RRooA ; =1.07 × 10meters= 1.07 fm = 1.07 fermis A=atomic mass number What is the nuclear mass density of the most common isotope of iron? 56 26 Fe⇒= A56; Z = 26, N = 30 m Am⋅⋅3 Am 33A ⋅ m m ρ = nuc p= p= pp = o 1 33 VR4 3 3 3 44ππA R nuc π R 4(π RAo ) o o 3 3×× 1.66 10−27 kg = 3.2× 1017kg / m 3 4×× 3.14 (1.07 × 10−15m ) 3 The mass density is constant, independent of A! 5 Nuclear mass density for 27Al, 97Mo, 238U (from scattering experiments) (kg/m3) ρo heavy mass nucleus light mass nucleus middle mass nucleus 6 Typical Densities Material Density Helium 0.18 kg/m3 Air (dry) 1.2 kg/m3 Styrofoam ~100 kg/m3 Water 1000 kg/m3 Iron 7870 kg/m3 Lead 11,340 kg/m3 17 3 Nuclear Matter ~10 kg/m 7 Isotopes - same chemical element but different mass (J.J. -
Lord Kelvin and the Age of the Earth.Pdf
ME201/MTH281/ME400/CHE400 Lord Kelvin and the Age of the Earth Lord Kelvin (1824 - 1907) 1. About Lord Kelvin Lord Kelvin was born William Thomson in Belfast Ireland in 1824. He attended Glasgow University from the age of 10, and later took his BA at Cambridge. He was appointed Professor of Natural Philosophy at Glasgow in 1846, a position he retained the rest of his life. He worked on a broad range of topics in physics, including thermody- namics, electricity and magnetism, hydrodynamics, atomic physics, and earth science. He also had a strong interest in practical problems, and in 1866 he was knighted for his work on the transtlantic cable. In 1892 he became Baron Kelvin, and this name survives as the name of the absolute temperature scale which he proposed in 1848. During his long career, Kelvin published more than 600 papers. He was elected to the Royal Society in 1851, and served as president of that organization from 1890 to 1895. The information in this section and the picture above were taken from a very useful web site called the MacTu- tor History of Mathematics Archive, sponsored by St. Andrews University. The web address is http://www-history.mcs.st-and.ac.uk/~history/ 2 kelvin.nb 2. The Age of the Earth The earth shows it age in many ways. Some techniques for estimating this age require us to observe the present state of a time-dependent process, and from that observation infer the time at which the process started. If we believe that the process started when the earth was formed, we get an estimate of the earth's age. -
Units and Magnitudes (Lecture Notes)
physics 8.701 topic 2 Frank Wilczek Units and Magnitudes (lecture notes) This lecture has two parts. The first part is mainly a practical guide to the measurement units that dominate the particle physics literature, and culture. The second part is a quasi-philosophical discussion of deep issues around unit systems, including a comparison of atomic, particle ("strong") and Planck units. For a more extended, profound treatment of the second part issues, see arxiv.org/pdf/0708.4361v1.pdf . Because special relativity and quantum mechanics permeate modern particle physics, it is useful to employ units so that c = ħ = 1. In other words, we report velocities as multiples the speed of light c, and actions (or equivalently angular momenta) as multiples of the rationalized Planck's constant ħ, which is the original Planck constant h divided by 2π. 27 August 2013 physics 8.701 topic 2 Frank Wilczek In classical physics one usually keeps separate units for mass, length and time. I invite you to think about why! (I'll give you my take on it later.) To bring out the "dimensional" features of particle physics units without excess baggage, it is helpful to keep track of powers of mass M, length L, and time T without regard to magnitudes, in the form When these are both set equal to 1, the M, L, T system collapses to just one independent dimension. So we can - and usually do - consider everything as having the units of some power of mass. Thus for energy we have while for momentum 27 August 2013 physics 8.701 topic 2 Frank Wilczek and for length so that energy and momentum have the units of mass, while length has the units of inverse mass. -
Having Regard to the Opinion of the European Chapter 1 of the Annex Binding Within Five Years of Parliament1 ; the Date of Entry Into Force of This Directive
878 Official Journal of the European Communities 29.10.71 Official Journal of the European Communities No L 243/29 COUNCIL DIRECTIVE of 18 October 1971 on the approximation of the laws of the Member States relating to units of measurement (71/354/EEC ) THE COUNCIL OF THE EUROPEAN COMMUNITIES, particular their names, symbols and use are not identical in the Member countries ; Having regard to the Treaty establishing the European Economic Community, and in particular HAS ADOPTED THIS DIRECTIVE : Article 100 thereof; Article 1 Having regard to the proposal from the Commission ; 1 . Member States shall make the provisions of Having regard to the Opinion of the European Chapter 1 of the Annex binding within five years of Parliament1 ; the date of entry into force of this Directive. 2 . Member States shall, with effect from 31 Having regard to the Opinion of the Economic and December 1977 at the latest, prohibit the use of the Social Committee2; units of measurement listed in Chapter III of the Annex. Whereas - the laws which regulate the use of units of measurement in the Member States differ from one 3 . The units of measurement temporarily" retained Member State to another and therefore hinder trade ; in accordance with the provisions of Chapter II or whereas application of the rules relating to measuring Chapter III of the Annex may not be brought into instruments is closely linked to the use of units of compulsory use by the Member States where they ' are measurement in the metrological system ; whereas, in not authorised at the date when this Directive enters into force . -
Conversion Factors for SI and Non-SI Units
Conversion Factors for SI and non-SI Units To convert Column 1 To convert Column 2 into Column 2, into Column 1, multiply by Column 1 SI Unit Column 2 non-SI Units multiply by Length 0.621 kilometer, km (103 m) mile, mi 1.609 1.094 meter, m yard, yd 0.914 3.28 meter, m foot, ft 0.304 6 1.0 micrometer, mm (10- m) micron, m 1.0 3.94 × 10-2 millimeter, mm (10-3 m) inch, in 25.4 10 nanometer, nm (10-9 m) Angstrom, Å 0.1 Area 2.47 hectare, ha acre 0.405 247 square kilometer, km2 (103 m)2 acre 4.05 × 10-3 0.386 square kilometer, km2 (103 m)2 square mile, mi2 2.590 2.47 × 10-4 square meter, m2 acre 4.05 × 103 10.76 square meter, m2 square foot, ft2 9.29 × 10-2 1.55 × 10-3 square millimeter, mm2 (10-3 m)2 square inch, in2 645 Volume 9.73 × 10-3 cubic meter, m3 acre-inch 102.8 35.3 cubic meter, m3 cubic foot, ft3 2.83 × 10-2 6.10 × 104 cubic meter, m3 cubic inch, in3 1.64 × 10-5 2.84 × 10-2 liter, L (10-3 m3) bushel, bu 35.24 1.057 liter, L (10-3 m3) quart (liquid), qt 0.946 3.53 × 10-2 liter, L (10-3 m3) cubic foot, ft3 28.3 0.265 liter, L (10-3 m3) gallon 3.78 33.78 liter, L (10-3 m3) ounce (fluid), oz 2.96 × 10-2 2.11 liter, L (10-3 m3) pint (fluid), pt 0.473 Mass 2.20 × 10-3 gram, g (10-3 kg) pound, lb 454 3.52 × 10-2 gram, g (10-3 kg) ounce (avdp), oz 28.4 2.205 kilogram, kg pound, lb 0.454 0.01 kilogram, kg quintal (metric), q 100 1.10 × 10-3 kilogram, kg ton (2000 lb), ton 907 1.102 megagram, Mg (tonne) ton (U.S.), ton 0.907 1.102 tonne, t ton (U.S.), ton 0.907 Yield and Rate 0.893 kilogram per hectare, kg ha-1 pound per acre, lb acre-1 -
Angles ANGLE Topics • Coterminal Angles • Defintion of an Angle
Angles ANGLE Topics • Coterminal Angles • Defintion of an angle • Decimal degrees to degrees, minutes, seconds by hand using the TI-82 or TI-83 Plus • Degrees, seconds, minutes changed to decimal degree by hand using the TI-82 or TI-83 Plus • Standard position of an angle • Positive and Negative angles ___________________________________________________________________________ Definition: Angle An angle is created when a half-ray (the initial side of the angle) is drawn out of a single point (the vertex of the angle) and the ray is rotated around the point to another location (becoming the terminal side of the angle). An angle is created when a half-ray (initial side of angle) A: vertex point of angle is drawn out of a single point (vertex) AB: Initial side of angle. and the ray is rotated around the point to AC: Terminal side of angle another location (becoming the terminal side of the angle). Hence angle A is created (also called angle BAC) STANDARD POSITION An angle is in "standard position" when the vertex is at the origin and the initial side of the angle is along the positive x-axis. Recall: polynomials in algebra have a standard form (all the terms have to be listed with the term having the highest exponent first). In trigonometry, there is a standard position for angles. In this way, we are all talking about the same thing and are not trying to guess if your math solution and my math solution are the same. Not standard position. Not standard position. This IS standard position. Initial side not along Initial side along negative Initial side IS along the positive x-axis.