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
... isotope abundances (especially differences in natural abundance)
e.g. Carbon 0 ‰ = 1.1057 atom% 13C
5 ‰ = 1.1111 atom% 13C
...
pressure
... Error Vp = 24-33 m/s
Error Vs = 15-18 m/s
...
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
... 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
... 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
... 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
... 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
... • 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
... 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 ...
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
... 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
... 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
... 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
... 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
... 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
... 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
... 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 ...
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 ...
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.