Commonly-used sizes are,,,,, 1,,, and 2 inch, appearing on pipes and fittings by most U. S. suppliers.

Examples of such situations are ( aerial ) night reconnaissance, the recording of radioactive tracers in live body tissues, special radiography in medical or industrial applications, track recording of high energy particles, etc..

An excellent method for the measurement of self-diffusion coefficients is pulsed field gradient ( PFG ) NMR, where no isotopic tracers are needed.

Radionuclides of familiar elements such as carbon can serve as tracers because they are chemically very similar to the non-radioactive nuclides, so most chemical, biological, and ecological processes treat them in a near identical way.

Beta particles can be used to treat health conditions such as eye and bone cancer and are also used as tracers.

Bacterial lawns ( often of Serratia marcescens ) are also used extensively when as an assay method when using bacteriophage as tracers in studies of groundwater flow.

These rare-earth oxides are used as tracers to determine which parts of a drainage basin are eroding.

Antimony-124, cadmium-109, and cadmium-113m are also mentioned as tracers.

Tracer ammunition ( tracers ) are bullets that are built with a small pyrotechnic charge in their base.

When used, tracers are usually loaded as every fifth round in machine gun belts, referred to as four-to-one tracer.

There are three types of tracers: bright tracer, subdued tracer and dim tracer.

Bright tracers are the standard type, which start burning immediately after exiting the muzzle.

Dim tracers burn very dimly but are clearly visible through night-vision equipment.

Radioactive tracers are also used to determine the location of fractures created by hydraulic fracturing in natural gas production.

There are two main ways in which radioactive tracers are used

While radioactive tracers are sometimes still used in human studies, stable isotope tracers such as < sup > 13 </ sup > C are more commonly used in current human clamp studies.

Radioactive tracers are also used to study lipoprotein metabolism in humans and experimental animals.

In medicine, tracers are applied in a number of tests, such as < sup > 99m </ sup > Tc in autoradiography and nuclear medicine, including single photon emission computed tomography ( SPECT ), positron emission tomography ( PET ) and scintigraphy.

In natural gas exploration and production, radioactive tracers are used in conjunction with hydraulic fracturing, a technique used to release natural gas ( including shale gas, tight gas and coal seam gas ), or other substances for extraction.

This basic technique can be significantly enhanced by the use of glucose tracers.

These include radiotherapy in medical applications ; the use of radioactive tracers within industry, science and the environment ; and the use of radiation to modify materials such as polymers.

The principle behind the use of radioactive tracers is that an atom in a chemical compound is replaced by another atom, of the same chemical element.

An extensive list of radioactive tracers used in hydraulic fracturing can be found below.

The NRC guidelines also list a wide range or radioactive materials in solid, liquid and gaseous forms that are used as field flood or enhanced oil and gas recovery study applications tracers used in single and multiple wells.

The older methods are SPECT and PET, which depend on injection of radioactive tracers into the bloodstream.

* Gamma camera and other scintillographical methods, such as Positron Emission Tomography ( PET ) and Single-Photon Emission Tomography ( SPECT ), using radioactive tracers in the body

In order to track absorption, several radioactive calcium tracers were given orally or intravenously.

The diffusion coefficient describing the intensity of bioturbation is usually determined by fitting mathematical models to vertical distributions of natural radioactive tracers, radioisotopes resulting from nuclear weapon testing, or introduced particles, such as glass beads tagged with radionuclides or inert fluorescent particles.

Hollow spheres also have uses ranging from storage and slow release of pharmaceuticals and radioactive tracers to research in controlled storage and release of hydrogen.

Since late 1940s, radioactive tracers have been used by the oil industry.

This method is often used for processing small amounts of pure isotopes for research or specific use ( such as isotopic tracers ), but is impractical for industrial use.

The main advantage to using stable isotope analysis as opposed to stomach content observations is that no matter what the status is of the animal's stomach ( empty or not ), the isotope tracers in the tissues will give us an understanding of its trophic position and food source.

The gamma-emitting isotopes iodine-123 ( half-life 13 hours ), and ( less commonly ) the longer-lived and less energetic iodine-125 ( half-life 59 days ) are used as nuclear imaging tracers to evaluate the anatomic and physiologic function of the thyroid.

Isotope ratios in food, especially plant food, are directly and predictably reflected in bone chemistry, allowing researchers to partially reconstruct recent diet using stable isotopes as tracers.

Other modifications use inert gas as tracers and measure the change in inspired and expired gas concentrations to calculate Q ( Innacor, Innovision A / S, Denmark ).

The assumptions upon which the example shown in Figure 3 is based are: ( A ) One man can direct about six subordinates if the subordinates are chosen carefully so that they do not need too much personal coaching, indoctrinating, etc..

Of types of message listed in Table 1, commands and statements are the only ones sent through the vertical network shown in Figure 3.

Questions and, particularly, exclamations are usually channeled along informal, horizontal lines not indicated in Figure 3 and seldom are carried beyond the nearest neighbor.

Furthermore, the network in Figure 3 is only the basic net through which other networks pertaining to logistics and the like are interlaced.

They feel that World War 3, has already begun, and they are setting themselves up as a `` last line of defense '' against the Communist advance.

Taxation of tangible movable property in Rhode Island has been generally of a `` hands off '' nature due possibly to several reasons: ( 1 ) local assessors, in the main, are not well paid and have inadequate office staffs, ( 2 ) the numerous categories of this component of personal property make locating extremely difficult, and ( 3 ) the inexperience of the majority of assessors in evaluating this type of property.

Assuming an adjustment to the July 1 to June 30 fiscal year, the required adjustment of the tax collection years and the towns involved are shown in Table 3.

after completing the payments prescribed by paragraphs ( 2 ) and ( 3 ) of this subsection, to make payments, from time to time in ratable proportions, on account of the unpaid principal of all awards in the principal amount of more than $1,000, according to the proportions which the unpaid principal of such awards bear to the total amount in the fund available for distribution at the time such payments are made ; ;

Inventory and evaluate wildlife habitat resources in cooperation with other Federal agencies and with the States in which National Forests and Grasslands are located, as a basis for orderly development of wildlife habitat improvement and coordination programs, including ( A ) big-game, gamebird, and small-game habitat surveys and investigations on the 186 million acres of National Forests and Grasslands, ( B ) fishery habitat surveys and investigations on the 81,000 miles of National Forest fishing streams and nearly 3 million acres of lakes and impoundments, and ( C ) participation in planning, inspection, and control phases of all habitat improvement, land and water use projects conducted on National Forest lands by States, other Federal agencies, and private groups to assure that projects will benefit wildlife and be in harmony with other resource values.

The same restrictions apply after local sunset in the case of class 3, stations operating on regional channels, which after that time are required to operate under nighttime restrictions in order to protect each other.

With respect to other frequencies, these are designated as regional or local, and assigned for use by class 3, and class 4, stations, respectively, stations operating generally with lower power.

Work-outs for the week are as follows: Plain Scotch, 3 ( by Scotch Victor ), Demon Law, 3 ( by Demon Hanover ), Coffee Royal, p ( by Royal Blackstone ) and Beauty Way, p, 3 ( by Demon Hanover ) in 25 ; ;

Among them, according to the U.S. Department of Commerce, are: ( 1 ) shorter work weeks, ( 2 ) higher pay, ( 3 ) longer paid vacations, ( 4 ) better transportation, ( 5 ) earlier retirement, and ( 6 ) more education.

Made in lengths from 3 to 10 ft., the bars are shaped in cross section to provide a secure fit for the tapered slots molded in back of the letters.

( 3 ) hydrogen atoms are asymmetrically placed, either randomly or in an ordered way, so that some hydrogen atoms are closer to the upper oxygen atoms while others are closer to the lower oxygen atoms.

A randomization of `` ups '' and `` downs '' is more likely than ordered `` ups '' and `` downs '' in position ( 3 ) since the hydrogen atoms are well separated and so the position of one could hardly affect the position of another, and also since ordered `` up '' and `` down '' implies a larger unit cell, for which no evidence exists.

Therefore, the only unknown structural feature would appear to be whether the hydrogen atoms are located symmetrically ( 1 ) or asymmetrically ( 3 ).

The pleura and interlobular septa are thick in types 1 and 3.

True terminal bronchioles comprise the most frequent form taken by the distal airways in types 1 and 3, although small numbers of poorly developed respiratory bronchioles are present.