Article on the serology of aerobic aquatic actinomycetes.

Over the past few years we have developed a system which allows several different liquid hydrogen and liquid deuterium targets to be placed in the electron beam of the Stanford Mark III accelerator and which can be operated from a remote position. The geometry of our scattering chamber requires that the motion (of the various targets into position) must be in the vertical direction, but that the overall height of the system be constant. These requirements are met by using an internal retractable bellows arrangement to raise and lower the target cells. As many as five cells can be used in conjunction with a single reservoir system.

Several difficulties involved in accelerating heavy ions in a tandem Van de Graaff are discussed, and experiments with Br and I ions to determine the response of silicon detectors to fission fragments are described. The pulseheight spectra of the ions are given, and the stopping cross section for I ions in Au, Ni, Al, and C at 20--120 Mev are plotted. (C.E.S.)

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The mean square fluctuation voltage in neutron sensitiv ion chambers was measured rather than the d-c current to improve gamma discrimination and eliminate d-c cable leakage interference currents. The circuitry and chambe are described, and performance in the mean square volta mode is compared with that in the d-c current mode. (D.C.W.)

The possibility of using thermal-neutron radiography for inspecting heavy metals and hydrogenous materials was examined. The data include exposure curves, contrast sensitivities, and an assessment of the influence of higher energy neutrons and interfering gamma radiation on image quality. It is shown that, in the case of homogeneous materials, neutron radiography presents definite advantages for the inspection of heavier metals such as uranium, bismuth, and lead, and that the images obtained in such inspections are influenced very little by other radiation in the thermal-neutron beam. This is somewhat less true for intermediate metals such as steel and tungsten, although in these cases too, some exposure time advantage can usually be gained. Nevertheless, neutron radiographic inspection of these intermediate materials may be limited to those cases in which some complication, such as radioactivity of the sample, is involved. Thermal-neutron inspection of hydrogenous materials having a thickness greater than about an inch is not recommended and may be useful primarily in special cases such as one in which the light material is in some combination with a heavier, x-ray absorbing material. (auth)

Colloidal aggregates (10 to 20 m mu ) of human serum albumin /sup 131/I may be used safely by intravenous injection to perform photoscans of the heart, liver, spleen, stomach, and salivary glands in man. Large particle size suspensions (10 to 50 mu ) of the same material were investigated experimentally in animals for scanning the lungs after intravenous injection and the brain following injection into an internal carotid artery. The advantages of this test material are the relatively low radiation exposure to the target organs and the number of organs that may be examined. Radiation exposure is low because of the rapid turnover in the target organs and removal from the body, mainly by urinary excretion, within 72 hr. The mechanism of liverspleen localization with this organic colloid is the same as for inorganic colloidal /sup 198/Au, namely, rapid removal from the blood by the phagocytic cells of the liver and spleen. However, in contrast to the inorganic colloid, which remains in the phagocytic cells permanently, albumin is digested by proteolytic enzymes and the /sup 131/I label is set free to re-enter the general circulation. With the thyroid blocked, the / sup 131/ is excreted mainly in the urine …

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The qualitative dependence of the neutron strength function upon optical model parameters is discussed with emphasis on the effects of variations in the magnitude and spatial dependence of the absorptive potential. A model is presented that gives a good account of strength functions and potential scattering radii, as well as neutron scattering cross sections below 1 Mev for spherical nuclei. (auth)

Methods for determination of calcium turnover in man with radioisotopes are presented and the clinical use of various techniques is evaluated. In the discussion of kinetic analyses, some important observations were made. The accretion rate calculation can be made independent of the number of compartments in the exchangeable calcium pool, and thus is not distorted by approximate estimations of this pool. However, if the exchangeable calcium pool is calculated with the isotope dilution technique, and the accretion rate obtained from this value by the total turnover equation, then an error is introduced into the value of the accretion rate. It was also pointed out that the multicompartment treatment is more appropriate than the customary single compartment analysis and utilizes all available information. Since the pool size has been of little clinical use so far, it was suggested that multicompantment analyses be used in the future. At present, no accepted model exists which can account for all data obtained in tracer studies and in particular for the last part of the serum disappearance curve. Preliminary results of long term studies of the retention in bones of strontium-85 was presented. These show that there is measurable turnover of tracer deposited in bone …

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This paper presents data concerning the breeding ratio and doubling time possible with LIMB technology.

vention of the Society for Nondestructive Testing. The elastic and plastic properties are reviewed with special emphasis on metal films prepared by vacuum evaporation, although work with both non-metals and other preparation techniques is discussed when it is the only existing data or has particular importance. A definite lack of agreement exists among the various workers and as a result detailed explanations are not possible although general suggestions do exist. The structure of thick polycrystalline films is reviewed as it is important to a discussion of the mechanical properties, but the structure is in itseif poorly understood in the case of thick fllms. The general behavior may be summarized as follows: The elastic modulus seems to be the same as that of bulk material. Breaking strengths are normally 3 to 7 times larger than those of annealed bulk material and compare with values for very heavily cold-worked samples. Creep is usually observed at relatively low strains. The increased strength undoubtedly arises from a restriction of dislocation motion, as well as source limitations, and in this respect differ from whiskers which often have a low dislocation concentration. The relative importhnce of pinning by point defects or impurities, limitations of dislocation length …

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The exact form for the contribution of a single Regge pole is given both for positive and negative angular momentum without making the usual approximations. This exact form involves Legendre functions of the first and second kind with nonintegral index and argument greater than one. These functions are plotted. A one-parameter fit is made to the high-energy p-p elastic scattering data that give good agreement with experiment. (auth)

For applications involving the routine laboratory measurement of gamma radiation, an instrument is described which is simple to opeiate, versatile, compact, and reliable. It consists of a pulse amplifier with charge-sensitive input and delay-line shaping, a differential discriminator capable of covering the range from 2 kev to 7 Mev, a calibration pulser, and a power supply. All controls are calibrated directly in terms of gamma energy. Construction is modular for ease of maintenance, and all circuits use solid-state components. (auth)

The solution time of analog multipliers using field-effect transistors is investigated. This time is ultimately limited by the charging time of the transistor junction. In typical devices suitable for analog multiplication, the charging time is found to be about 10 to 20 nsec for a multiplication error of < 1%. A four quadrant pulse amplitude multiplier circuit with a solution time equal to the transistor charging time is described. (auth)

A review was made of the effects of fluoride ions on the corrosion behavior of zirconium alloys in high-temperature water. Corrosion was found to occur as the result of contamination of the water or the zirconium surface. A major source of fluorides is undue delay in rinsing the HF--HNO/sub 3/ pickling solution during surface preparation. The oxide on corrosion-resistant material has been found to contain up to 7600 ppm fluoride from this source. The threshold concentration of fluoride in the oxide film which produces poor corrosion resistance ranges from 8500 to 17,000 ppm. Accelerated corrosion from fluorides in water at 300 to 360 deg C occurs at about 100 ppm, although increased corrosion has been reported at 10 ppm fluoride in water at 300 deg C. Fluorocarbon plastics degrade and contribute fluorides to the hightemperature water or to the alloy surface when in direct contact with zirconium. Chlorides (1 to 10,000 ppm) and iodides (1270 ppm) do not adversely affect the corrosion behavior of zirconium alloys in water at 360 deg C. The mechanism of corrosion is not well understood but apparently is related to the formation of insoluble zirconium oxyfluorides during pickling and during exposure to fluoride- contaminated water. …

From International Conference on Nuclear Physics with Reactor Neutrons, Argonne, Ill., Oct. 1963. Experiments were performed in which the kinetic energies of correlated fragment pairs from thermal- and resonance-neutron-induced fission were measured. In addition, a three-parameter ternary fission experiment was performed in which the energies of correlated fragments were measured in coincidence with the energy of a third emitted particle, usually a long-range alpha particle. The detectors were large-area silicon surface barrier detectors. The instrumentation associated with these experiments is discussed in detail. The complete system is described, with attention given to the problems of background reduction (fast-coincidence requirements), stability, linearity, and resolution. Particular attention is given to the reduction of spectrum distortion by pile-up pulses (alphaon-fission pile-up within the amplifier resolving time). Methods and limitations of pile-up detection are discussed. A new method for inspection and removal of pile-up pulses is described. (auth)

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From American Nuclear Society Meeting, New York, Nov. 1963. The use of the asymptotic solution to the one-velocity transport equation is considered. The angular distribution for fast neutron elastic scattering by heavy elements is discussed. An exponential angular distributi on is assumed to simplify the decay length calculation. The diffusion length of 1 to 15 Mev neutrons in iron is calculated, as well as the vector flux angular dependence. The asymptotic solution for an arbitrary angular distribution of a plane delta -function source is also found. An isotropic source is investigated, and some applications of the model are examined. (auth)

An investigation was conducted on the impossible use of beta radiation to promote chemical reactions at high temperatures and pressures. The advantages of beta sources over other radiation sources are enumerated. A radiation processing apparatus is described which allows operations to 10,000 psi and 500 deg C and uses 90 C of Sr/sup 90/-Y/sup 90/. The dosimetry of the source was accomplished with an iodineheptane system, and the mean dose rate within the chemical reactor was determined to be 0.98 x 10/sup 6/ rad/hr. The radiation utilization efficiency in the dosimetry measurements was determined to be 34.7%. Results of runs on hydrogenation of coal extract indicate that radiation does not increase the extent of hydrogenation, but that radiation reduces the content of hetero atoms N and S in the 100 x 400 deg C boiling oil products. The use of beta radiation in the hydrorefining of oils is suggested. (D.L.C.)

The program KRUDE, which solves the slowing down and adjoint equations for a mixture of resonance and nonresonance isotopes in an infinite homogeneous medium, was used to evaluate some resonance capture approximations (variational and successive) that use linear combinations of narrow and wide resonance fluxes. Results obtained for resonance capture in the 291-ev resonance of Zr/sup 91/ and the 192-ev resonance of U/sup 238/ are compared, and three methods for including Doppler effects in the variational method are considered. (D.C.W.)