• Study Resource
  • Explore
    • Arts & Humanities
    • Business
    • Engineering & Technology
    • Foreign Language
    • History
    • Math
    • Science
    • Social Science

    Top subcategories

    • Advanced Math
    • Algebra
    • Basic Math
    • Calculus
    • Geometry
    • Linear Algebra
    • Pre-Algebra
    • Pre-Calculus
    • Statistics And Probability
    • Trigonometry
    • other →

    Top subcategories

    • Astronomy
    • Astrophysics
    • Biology
    • Chemistry
    • Earth Science
    • Environmental Science
    • Health Science
    • Physics
    • other →

    Top subcategories

    • Anthropology
    • Law
    • Political Science
    • Psychology
    • Sociology
    • other →

    Top subcategories

    • Accounting
    • Economics
    • Finance
    • Management
    • other →

    Top subcategories

    • Aerospace Engineering
    • Bioengineering
    • Chemical Engineering
    • Civil Engineering
    • Computer Science
    • Electrical Engineering
    • Industrial Engineering
    • Mechanical Engineering
    • Web Design
    • other →

    Top subcategories

    • Architecture
    • Communications
    • English
    • Gender Studies
    • Music
    • Performing Arts
    • Philosophy
    • Religious Studies
    • Writing
    • other →

    Top subcategories

    • Ancient History
    • European History
    • US History
    • World History
    • other →

    Top subcategories

    • Croatian
    • Czech
    • Finnish
    • Greek
    • Hindi
    • Japanese
    • Korean
    • Persian
    • Swedish
    • Turkish
    • other →
 
Sign in Sign up
Upload
Removal of hydrogen fluoride from gas streams
Removal of hydrogen fluoride from gas streams

... I would like to thank my supervisors, Professor N. J. Coville, University of Witwatersrand and Dr. P. A. B. Carstens, South African Nuclear Energy Corporation Limited (Necsa) for their support, suggestions and guidance. ...
Document
Document

... isotope abundances (especially differences in natural abundance) e.g. Carbon 0 ‰ = 1.1057 atom% 13C 5 ‰ = 1.1111 atom% 13C ...
pressure
pressure

...  Error Vp = 24-33 m/s  Error Vs = 15-18 m/s ...
Lactose/D-Galactose
Lactose/D-Galactose

... time to time. For clarification, add 5 ml of Carrez-I-solution (3.60 g potassium hexacyanoferrate(II), K4[Fe(CN)6] × 3 H2O/100 ml), 5 ml of Carrez-II-solution (7.20 g of zinc sulfate, ZnSO4 × 7 H2O/100 ml) and 10 ml of NaOH (0.1 M); mix after each addition, adjust to 20-25°C and fill up to the mark ...
Lactose/D-Galactose
Lactose/D-Galactose

... time to time. For clarification, add 5 ml of Carrez-I-solution (3.60 g potassium hexacyanoferrate(II), K4[Fe(CN)6] × 3 H2O/100 ml), 5 ml of Carrez-II-solution (7.20 g of zinc sulfate, ZnSO4 × 7 H2O/100 ml) and 10 ml of NaOH (0.1 M); mix after each addition, adjust to 20-25°C and fill up to the mark ...
Isotopes of Volatile Organic Compounds: An Emerging Approach for
Isotopes of Volatile Organic Compounds: An Emerging Approach for

... processes have distinctly different isotopic signatures.4,5 So far, 13C/12C is the only stable isotope system which has been used in published studies of VOCs in the ambient atmosphere.1,3,5-14 However, source or sink characterizations have been done for a wider set of isotope pairs, including 2H/1H ...
ХИМИЯ НА АНГЛИЙСКОМ ЯЗЫКЕ
ХИМИЯ НА АНГЛИЙСКОМ ЯЗЫКЕ

... 1.38. A standard solution of Mn2+ was prepared by dissolving 0.250 g of Mn in 10 mL of concentrated HNO3 (measured with a graduated cylinder). The resulting solution was quantitatively transferred to a 100-mL volumetric flask and diluted to volume with distilled water. A 10-mL aliquot of the soluti ...
radiometric dating - Tulane University
radiometric dating - Tulane University

... Prior to 1905 the best and most accepted age of the Earth was that proposed by Lord Kelvin based on the amount of time necessary for the Earth to cool to its present temperature from a completely liquid state. Although we now recognize lots of problems with that calculation, the age of 25 my was acc ...
Unit 2 Lesson 3
Unit 2 Lesson 3

... • The type of isotope used depends on the type of material being dated. • The half-life of the isotope used is also very important. It can’t be too short or too long compared to the age of the sample. ...
Lab 77 Nuclear Radiation Detection
Lab 77 Nuclear Radiation Detection

... of mass equal to one-twelfth of the mass of an isotope called carbon-12. An atomic mass unit is equal to 1.6605 x 10-27 kilograms, and is specified by the letter u. Isotopes of certain elements are unstable and therefore are in a process of decay. As they decay they emit unseen radiations. This phen ...
Radiometric Dating - Tulane University
Radiometric Dating - Tulane University

... breathing, feeding, and photosynthesis. Thus, so long as the organism is alive, it will have the same ratio of 14C to 14N as the atmosphere. ...
Practice Exam I solutions
Practice Exam I solutions

... of nitrate in drinking water samples. Both labs were given a National Institute of Standards and Technology (NIST) standard to analyze and results of 5 measurements by each lab are shown below. Shaky Hands Testing: 3.50, 3.57, 3.38, 3.47, 3.41 ppm High Accuracy, Inc.: 3.23, 3.21, 3.29, 3.30, 3.24 pp ...
TANNIC ACID
TANNIC ACID

... sources; the substance is not an acid in the chemical sense. The common name "Tannic acid" has been adopted to distinguish the commercial substance from other tannins, such as condensed tannins. These specifications relate only to hydrolysable gallotannins, i.e., those which yield gallic acid on hyd ...
Effects of antioxidants for the degradation of flame
Effects of antioxidants for the degradation of flame

... 6 MGy in 0.1 vol% NH3 at 500 °C. The irradiated powder was then subjected to carbonization at 800 °C for 1 h in Ar. The synthesis conditions are summarized in Table 1. The resulting samples were analyzed by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The electr ...
2013 Q9 - Loreto Balbriggan
2013 Q9 - Loreto Balbriggan

... Iodine–131 decays with the emission of a beta-particle and has a half-life of 8 days. Write an equation for the beta-decay of iodine–131. Estimate the fraction of the iodine–131 that remained after 40 days. (15) Caesium–137 has a half-life of 30 years and it remains a significant contaminant in the ...
4550-15Lecture29 - Cornell Geological Sciences
4550-15Lecture29 - Cornell Geological Sciences

... Cosmogenic Nuclides • Cosmic rays are high energy nuclei (mainly of H and He) from space. When they collide with nuclei in the atmosphere or the surface of the Earth, they induce nuclear reactions. The resulting particles also have high energies and can induce further reactions. The one of greatest ...
Lecture 33 - Cornell Geological Sciences
Lecture 33 - Cornell Geological Sciences

... Cosmogenic Nuclides • Cosmic rays are high energy nuclei (mainly of H and He) from space. When they collide with nuclei in the atmosphere or the surface of the Earth, they induce nuclear reactions. The resulting particles also have high energies and can induce further reactions. The one of greatest ...
lect6_geomorphology
lect6_geomorphology

... 5730 year ½ life Useful between 100 and about 50,000 years old Can date things that contain organic carbon (Used to be living): bones, shells, wood, charcoal, plants, paper, cloth, pollen, seeds) ...
Geologic Dating! - rgreenbergscience
Geologic Dating! - rgreenbergscience

... lowest layer is the oldest, the top most layer, the most recent (youngest). These are called “strata”. • Stratification: enables a scientist to establish the “relative age” of something based on where it is found compared to other layers. • Relative Dating – estimating the age of a fossil by compari ...
Real time observation of granular analogue rock material
Real time observation of granular analogue rock material

Radiocarbon dating
Radiocarbon dating

... radiocarbon dating is to estimate the age of organic remains from archaeological sites. • When plants fix atmospheric carbon dioxide (CO2) into organic material during photosynthesis they incorporate a quantity of 14C that approximately matches the level of this isotope in the atmosphere. After plan ...
1

Radiocarbon dating

Radiocarbon dating (also referred to as carbon dating or carbon-14 dating) is a method for determining the age of an object containing organic material by using the properties of radiocarbon (14C), a radioactive isotope of carbon.The method was developed by Willard Libby in the late 1940s and soon became a standard tool for archaeologists. Libby received the Nobel Prize for his work in 1960. The radiocarbon dating method is based on the fact that radiocarbon is constantly being created in the atmosphere by the interaction of cosmic rays with atmospheric nitrogen. The resulting radiocarbon combines with atmospheric oxygen to form radioactive carbon dioxide, which is incorporated into plants by photosynthesis; animals then acquire 14C by eating the plants. When the animal or plant dies, it stops exchanging carbon with its environment, and from that point onwards the amount of 14C it contains begins to reduce as the 14C undergoes radioactive decay. Measuring the amount of 14C in a sample from a dead plant or animal such as piece of wood or a fragment of bone provides information that can be used to calculate when the animal or plant died. The older a sample is, the less 14C there is to be detected, and because the half-life of 14C (the period of time after which half of a given sample will have decayed) is about 5,730 years, the oldest dates that can be reliably measured by radiocarbon dating are around 50,000 years ago, although special preparation methods occasionally permit dating of older samples.The idea behind radiocarbon dating is straightforward, but years of work were required to develop the technique to the point where accurate dates could be obtained. Research has been ongoing since the 1960s to determine what the proportion of 14C in the atmosphere has been over the past fifty thousand years. The resulting data, in the form of a calibration curve, is now used to convert a given measurement of radiocarbon in a sample into an estimate of the sample's calendar age. Other corrections must be made to account for the proportion of 14C in different types of organisms (fractionation), and the varying levels of 14C throughout the biosphere (reservoir effects). Additional complications come from the burning of fossil fuels such as coal and oil, and from the above-ground nuclear tests done in the 1950s and 1960s. Because the time it takes to convert biological materials to fossil fuels is substantially longer than the time it takes for its 14C to decay below detectable levels, they contain almost no 14C, and as a result there was a noticeable drop in the proportion of 14C in the atmosphere beginning in the late 19th century. Conversely, nuclear testing increased the amount of 14C in the atmosphere, which attained a maximum in 1963 of almost twice what it had been before the testing began.Measurement of radiocarbon was originally done by beta-counting devices, which counted the amount of beta radiation emitted by decaying 14C atoms in a sample. More recently, accelerator mass spectrometry has become the method of choice; it counts all the 14C atoms in the sample and not just the few that happen to decay during the measurements; it can therefore be used with much smaller samples (as small as individual plant seeds), and gives results much more quickly. The development of radiocarbon dating has had a profound impact on archaeology. In addition to permitting more accurate dating within archaeological sites than previous methods, it allows comparison of dates of events across great distances. Histories of archaeology often refer to its impact as the ""radiocarbon revolution"". Radiocarbon dating has allowed key transitions in prehistory to be dated, such as the end of the last ice age, and the beginning of the Neolithic and Bronze Age in different regions.
  • studyres.com © 2022
  • DMCA
  • Privacy
  • Terms
  • Report