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Settling velocities in batch sedimentation. [Mixtures containing one and two sizes of resin beads, 44 and 62. mu. m in diameter]

Description: The sedimentation of mixtures containing one and two sizes of spherical particles (44 and 62 ..mu..m in diameter) was studied. Radioactive tracing with /sup 57/Co was used to measure the settling velocities. The ratio of the settling velocity U of uniformly sized particles to the velocity predicted to Stokes' law U/sub 0/ was correlated to an expression of the form U/U/sub 0/ = epsilon/sup ..cap alpha../, where epsilon is the liquid volume fraction and ..cap alpha.. is an empirical constant, determined experimentally to be 4.85. No effect of viscosity on the ratio U/U/sub 0/ was observed as the viscosity of the liquid medium was varied from 1x10/sup -3/ to 5x10/sup -3/ Pa.s. The settling velocities of particles in a bimodal mixture were fit by the same correlation; the ratio U/U/sub 0/ was independent of the concentrations of different-sized particles.
Date: October 1, 1982
Creator: Fricke, A.M. & Thompson, B.E.
Partner: UNT Libraries Government Documents Department

Subcellular site and nature of intracellular cadmium in plants

Description: The mechanisms underlying heavy metal accumulation, toxicity and tolerance in higher plants are poorly understood. Since subcellular processes are undoubtedly involved in all these phenomena, it is of interest to study the extent of, subcellular site of and nature of intracellularly accumulated cadmium in higher plants. Whole plants supplied /sup 109/CdCl/sub 2/ or /sup 112/CdSO/sub 4/ accumulated Cd into roots and aerial tissues. Preparation of protoplasts from aerial tissue followed by subcellular fractionation of the protoplasts to obtain intact vacuoles, chloroplasts and cytosol revealed the presence of Cd in the cytosol but not in vacuoles or chloroplasts. Particulate materials containing other cell components were also labeled. Of the /sup 109/Cd supplied to plants, 2 to 10% was recovered in both cytosol preparations and in particulate materials. Cytosol contained proteinaceous--Cd complexes, free metal and low molecular weight Cd complexes. Labeling of protoplasts gave similar results. No evidence was obtained for the production of volatile Cd complexes in tobacco.
Date: January 1, 1979
Creator: Wagner, G.J.
Partner: UNT Libraries Government Documents Department

/sup 123/I research and production at Brookhaven

Description: The procedures for preparing high purity /sup 123/I at the BLIP using the /sup 127/I(p,5n)/sup 123/Xe reaction on an NaI target are described. The activity is supplied in a glass ampoule with anhydrous /sup 123/I deposited on the interior walls, allowing maximum flexibility in subsequent iodinations. Preliminary experience with a continuous flow target is also described. The results of a series of measurements of specific activity by neutron activation, x-ray fluorescence, uv absorption, and wet chemistry generally showed no detectable carrier. HPLC methods to analyse the chemical form of radioiodine and to characterize various iodinated radiopharmaceuticals have been developed. These methods provide higher sensitivity, speed and resolution than commonly used techniques. 19 refs., 6 figs., 2 tabs.
Date: January 1, 1985
Creator: Mausner, L.F.; Srivastava, S.C.; Mirzadeh, S.; Meinken, G.E. & Prach, T.
Partner: UNT Libraries Government Documents Department

Physiopathology of blood platelets and development of platelets substitutes. Progress report, August 1, 1976--October 31, 1977. [/sup 51/Cr]

Description: Progress is reported on the following research projects: the effect of estrogen on platelet aggregability and thrombus formation; the antithrombotic effect of platelet inhibiting agents in a bench model of artificial kidney; the arrest of hemorrhage in severely alloimmunized thrombocytopenic patients; and in vivo elution of /sup 51/Cr from labeled platelets induced by antibody. (HLW)
Date: July 31, 1977
Creator: Baldini, M G
Partner: UNT Libraries Government Documents Department

Evaluation of an in-situ x-ray fluorescence analyzer for inorganic pollutants in sediments and water columns

Description: The applicability of an energy dispersive x-ray fluorescence spectrometer for measurement of trace elements in sediments and in water columns from Coast Guard vessels has been investigated. This investigation was conducted in both freshwater and saltwater areas and included Puget Sound, Lake Washington, Lake Union, and the ship canal in the State of Washington. The spectrometer system consisted of a solid cryogen-cooled Si(Li) detector and a /sup 109/Cd excitation source. Sediments and water columns were viewed through a 0.2 mm Be window. This study showed the feasibility of measuring trace elements at concentrations ranging from 20 to about 100 ppM. Measurements of this sensitivity with a 100 mCi /sup 109/Cd source are possible for time intervals as short as 5 minutes. This in-situ measurement capability permits the on-site mapping of pollution and avoids the problem of sediment disturbance which is inherent in the collection of grab samples of the sediment surface. Recommendations for an improved analyzer system included a detector assembly which could be towed, or allow continuous sediment surface analysis thereby recording the average composition of a large area.
Date: September 1, 1979
Creator: Wogman, N.A.
Partner: UNT Libraries Government Documents Department

Whole-body autoradiographic microimaging: Applications in radiopharmaceutical and drug research

Description: The whole-body autoradiographic (WBARG) microimaging technique is used for evaluation of the temporo-spatial distribution of radiolabeled molecules in intact animals as well as to determine the sites of accumulation of parent compounds and their metabolites. This technique is also very useful to determine the metabolism of a compound, toxicity, and effects of therapeutic interventions on the distribution of a compound in the whole body, by studying animals at different time intervals after injection of the radiolabeled compound. This report discusses various aspects of WBARG.
Date: January 1, 1991
Creator: Som, P. & Sacker, D.F.
Partner: UNT Libraries Government Documents Department

Description of an XRF system for multielemental analysis

Description: An X-ray fluorescence (XRF) system which uses radioisotopes in an orthogonal configuration between the source, sample, and detector is described. The advantage of such a system is that for large (bulk) samples or for in vivo measurements the background due to Compton scattering in the sample is minimized. High reproducibility for nonuniform samples is obtained by reducing the sample size and thus the effects of non-uniformity in the spatial response of such a system. Germane to any accurate analytical method is the use of proper mathematical algorithms for data evaluation. The problem is acute, in particular, when photopeaks with low counting statistics are to be analyzed. In the case of a single photopeak on flat, background optimal energy window size, which maximizes the signal-to-noise ratio, for trapezoidal intergration is described. The sensitivity and minimum detection limit at different energies together with background considerations are discussed. 13 refs., 8 figs., 2 tabs.
Date: January 1, 1986
Creator: Wielopolski, L.; Zhang, R. & Cohn, S.H.
Partner: UNT Libraries Government Documents Department

Soudan 2 detector as a time-projection calorimeter

Description: The Soudan 2 Nucleon Decay Detector uses Hytrel plastic tubes to cause ionization electrons to drift up to 50 cm prior to gas multiplication and collection. The drift tubes are embedded in a matrix of thin steel sheets. Readout is accomplished by flash digitizers in a system with distributed intelligence. This design is usable as a general-purpose calorimeter in which 3 spatial coordinates and pulse height are measured at all points where ionization occurs. Several 4.3 ton modules of this detector have now been studied in detail. We will present information about the detector performance and its dependence on manufacturing tolerances.
Date: January 1, 1986
Creator: Allison, W. W. M.; Alner, J.; Ambats, I.; Ayres, D.; Barr, G. D.; Barrett, L. et al.
Partner: UNT Libraries Government Documents Department

Design and biological properties of iodine-123 labeled. beta. -methyl-branched fatty acids

Description: The synthetic strategy, synthesis, preclinical evaluation and potential clinical applications of 3-methyl-branched radioiodinated iodophenyl- and iodovinyl-substituted fatty acids are reviewed for use as myocardial imaging agents. 50 references, 6 figures. (ACR)
Date: January 1, 1984
Creator: Knapp, F.F. Jr. & Goodman, M.M.
Partner: UNT Libraries Government Documents Department

UNISOR Nuclear Orientation Facility

Description: The combination of an on-line isotope separator and a dilution refrigerator has increased the applicability of the nuclear orientation technique to a wide range of nuclei, especially those very far from stability. The UNISOR Nuclear Orientation Facility (UNISOR/NOF) is among the two (the other being NICOLE at CERN) that have recently become operational. The following is an overall view of the UNISOR system and recent results. 24 refs., 3 figs.
Date: January 1, 1988
Creator: Girit, I.C.
Partner: UNT Libraries Government Documents Department

Cosmogenic /sup 36/Cl production rates in meteorites and the lunar surface

Description: Activity-versus-depth profiles of cosmic-ray-produced /sup 36/Cl were measured in metal from two cores each in the St. Severin and Jilin chondrites and in lunar core 15008. Production of /sup 36/Cl in these samples range from high-energy reactions with Fe and Ni to low-energy reactions with Ca and K and possibly neutron-capture reactions with /sup 35/Cl. The cross sections used in the Reedy-Arnold model for neutron-induced reactions were adjusted to get production rates that fit the measured /sup 36/Cl activities in St. Severin metal and in the lunar soil of core 15008. The /sup 36/Cl in metal from St. Severin has a fairly flat activity-versus-depth profile, unlike most other cosmogenic nuclides in bulk samples from St. Severin, which increase in concentration with depth. In metal from Jilin, a decrease in /sup 36/Cl was observed near its center. The length of Jilin's most recent cosmic-ray exposure was /approximately/0.5 My. Lunar core 15008 has an excess in /sup 36/Cl of about 4 dpm/kg near its surface that was produced by solar-proton-induced reactions. The calculated production rates are consistent with these measured trends in 15008. 39 refs., 4 figs., 3 tabs.
Date: January 1, 1988
Creator: Nishiizumi, K.; Kubik, P. W.; Elmore, D.; Reedy, R. C. & Arnold, J. R.
Partner: UNT Libraries Government Documents Department

Positron emission camera for transverse section tomography

Description: A transverse section tomographic positron camera is discussed for quantitative imaging of the heart in gated studies using positron emitters such as /sup 82/Rb, /sup 68/Ga, and /sup 18/F. The system consists of a circular ring of 288 NaI(Tl) crystals 8 mm x 30 mm x 50 mm. The crystals are read out by coded light pipes that permit complete data transfer with only 72 photomultipliers. This and other features lead to an economic design that permits 6 to 9 mm FWHM over sections having 40 cm diameter. Digital image reconstruction can be performed on a small dedicated computer using known algorithms. The device is applicable for either static or dynamic imaging of the brain and other organs as well as gated images of the heart. The major application is for the detection and understanding of cardiac and cerebral vascular disease and physiology.
Date: December 1, 1975
Creator: Derenzo, S. E.; Zaklad, H. & Budinger, T. F.
Partner: UNT Libraries Government Documents Department

Sources for proportional tube gain variation: What to do about it

Description: In the high-energy domain systematic uncertainties become a substantial fraction of attainable energy resolution of a proportional tube electromagnetic calorimeter. Sources of nonuniformity and fluctuation of calorimeter response are discussed and test data on the magnitude of the effects are presented. Possible ways of maintaining these effects under control are discussed and test data are discussed which demonstrated that such effects could in fact be monitored and corrected to less than 1%.
Date: October 1, 1985
Creator: Fukui, Y.; Mishina, M.; Hayashide, Y.; Kanda, S.; Kim, S.; Kondo, K. et al.
Partner: UNT Libraries Government Documents Department

Fission barriers of hot rotating nuclei: Theoretical predictions and experimental tests

Description: Recent theoretical developments in calculating fission barriers of hot rotating nuclei and their experimental tests are reviewed. The discussions are limited to macroscopic fission models (no shell effects), since experimental tests come primarily from heavy-ion induced reactions involving large angular momenta and internal excitation energies. The physics of the rotating finite range models with temperature is emphasized and the predictions of our model are compared with those of other macroscopic models and with statistically deduced experimental results. The difficulties associated with the statistical model analysis at high temperatures are discussed. 43 refs., 8 figs., 1 tab.
Date: July 7, 1987
Creator: Mustafa, M.G.
Partner: UNT Libraries Government Documents Department

Nuclear collectivity and complex alignment mechanisms in light tungsten and osmium nuclei

Description: During the past few years there have been significant advances in our understanding of nuclei excited into states of high angular momentum. The development of large multi-detector arrays for {gamma}-{gamma} coincidence spectroscopy studies has propelled the amount of new experimental information available and this has been complemented by notable advances in the theoretical treatments of high-spin phenomena. To provide yet a more detailed understanding of the structure of these high-spin states and to provide a stringent test of these models, we have resorted to measurements of their dynamic electromagnetic multipole moments which are a direct reflection of the collective aspects of the nuclear wave functions. For the most part, these multipole moments are obtained by lifetime measurements utilizing Doppler-shift techniques. Let me stress that the great value of lifetime measurements is that they provide the transition matrix elements without the necessity to rely on nuclear models. 24 refs., 10 figs.
Date: January 1, 1989
Creator: Johnson, N.R.
Partner: UNT Libraries Government Documents Department

Precision measurement of the half-life of sup 56 Co

Description: Gamma rays from a mixed source of {sup 56}Co + {sup 46}Sc were measured in a Ge(Li) detector. The {sup 56}Co/{sup 46}Sc intensity ratios I{sub 847}/I{sub 889} were determined by careful analysis of line shapes and underlying backgrounds. Based on the known {sup 46}Sc adopted half-life value of 83.810(10) d, the fit to the intensity ratios corrected for {sup 46}Sc decay from 107 runs over an elapsed time of 172 days gave a half-life of 77.29(3) d. By combining this result with other published data we obtain a half-life of t{sub 1/2} = 77.27(3) d for {sup 56}Co. 16 refs., 3 figs.
Date: January 1, 1990
Creator: Alburger, D.E. (Brookhaven National Lab., Upton, NY (USA)) & Wesselborg, C. (Brookhaven National Lab., Upton, NY (USA) Giessen Univ. (Germany, F.R.). Inst. fuer Kernphysik)
Partner: UNT Libraries Government Documents Department

Cosmic ray half life of sup 54 Mn

Description: A search for the {beta}{sup +} decay of {sup 54}Mn has established an upper limit of 4.4 {times} 10{sup {minus}8} for this branching ratio, and a lower limit of 13.3 for the log ft value for this second forbidden unique transition. Assuming that the {beta}{sup {minus}} decay branch has the same log ft value, then its partial half life must be greater than 4 {times} 10{sup 4} years. Experiments to directly measure the {beta}{sup {minus}} decay rate of {sup 54}Mn are now in progress. 6 refs., 2 figs.
Date: August 1, 1989
Creator: Norman, E.B.; Sur, B.; Vogel, K.R.; Lesko, K.T.; Larimer, R.M. & Browne, E.
Partner: UNT Libraries Government Documents Department

Calculated late time spectra of supernovae

Description: We consider here the nebular phase spectra of supernovae whose late time luminosity is provided by the radioactive decay of /sup 56/Ni and /sup 56/Co synthesized in the explosion. A broad variety of supernovae are known or suspected to fall in this category. This includes all SNIa and SNIb, and at least some SNII, in particular SN1987a. At sufficiently late times the expanding supernova becomes basically nebular in character due to its decreasing optical depth. The spectra produced during this stage contain information on the density and abundance structure of the entire supernova, as opposed to spectra near maximum light which are affected only by the outermost layers. A numerical model for nebular spectrum formation is therefore potentially very valuable for answering currently outstanding questions about the post-explosion supernova structure. As an example, we can hope to determine the degree of mixing which occurs between the layers of the ''onion-skin'' abundance structure predicted by current one dimensional explosion calculations. In the sections which follow, such a numerical model is briefly described and then applied to SN1972e, a typical SNIa, SN1985f, an SNIb, and finally to SN1987a. In the case of SN1987a predicted spectra are presented for the wavelength range from 1 to 100 microns at a time 300 days after explosion. 18 refs., 6 figs.
Date: October 30, 1987
Creator: Axelrod, T.S.
Partner: UNT Libraries Government Documents Department

Double blocking in the superdeformed sup 192 Tl nucleus

Description: Six superdeformed bands have been found in the nucleus {sup 192}Tl. For two of the bands, the dynamic moment of inertia J{sup (2)} is found to be constant with the rotational frequency {Dirac h}. This result can be understood in terms of Pauli blocking of quasiparticle alignments in intruder orbitals, and represents the first experimental evidence that the alignment of these intruders is responsible for the smooth rise in J{sup (2)} seen in other superdeformed nuclei of this mass region.
Date: January 1, 1992
Creator: Liang, Y.; Carpenter, M. P.; Janssens, R. V. F.; Ahmad, I.; Henry, R.; Khoo, T. L. et al.
Partner: UNT Libraries Government Documents Department

Electromagnetic properties of sup 181 Ir: Evidence of. beta. -stretching

Description: We have calculated the B(Ml)/B(E2) ratios in {sup 18l}Ir within a shape-fixed particle + rotor model, in order to investigate how sensitive these may be to the nuclear shapes under consideration, and whether or not there is evidence of shape coexistence in the electromagnetic data alone. The model calculations employed the same Woods-Saxon potential that has been used previously for TRS and bandhead calculations and all parameters have been taken at their standard values, without any adjustments. To the extent possible with present models, these calculations should represent predictions for the B(M1)/B(E2) ratios at the deformations expected from the TRS and bandhead calculations. A comparison with the {sup 181}Ir data is stimulated by the fact that this is the lightest-mass Ir nucleus for which the spins and parities am firmly established experimentally; we find that the electromagnetic transition rates in this nucleus are well reproduced under the assumption of a single, fixed shape.
Date: January 1, 1991
Creator: Garg, U.; Reviol, W. (Notre Dame Univ., IN (United States). Dept. of Physics) & Semmes, P. (Tennessee Technological Univ., Cookeville, TN (United States). Dept. of Physics)
Partner: UNT Libraries Government Documents Department

Superdeformed bands in sup 194 Tl

Description: Superdeformation was first observed in the mass-190 region in {sup 191}Hg. Since then, SD bands have been found in {sup 190-194}Hg nuclei. Here we report the discovery of two such bands in {sup 194}Tl which are the first SD bands fond in this mass region that are not in Hg nuclei. Subsequently, bands have been found in two Pb nuclei. 5 refs., 1 fig.
Date: May 1, 1990
Creator: Azaiez, F.; Kelly, W. H.; Korten, W.; Deleplanque, M. A.; Stephens, F. S.; Diamond, R. M. et al.
Partner: UNT Libraries Government Documents Department

Higher superdeformed band members in sup 190 Hg: Evidence for a band interaction

Description: The superdeformed band of {sup 190}Hg has been traced up to a frequency {Dirac h} {ge} 0.4 MeV by combining data from several experiments. A distinct change in the slope of the dynamic moment of inertia J{sup 2} vs {Dirac h} is observed at {Dirac h} = 0.32 MeV. This result is interpreted as evidence for a band interaction at the highest frequencies. Possible interpretations are reviewed.
Date: January 1, 1992
Creator: Bearden, I.G.; Daly, P.J. (Purdue Univ., Lafayette, IN (United States)); Janssens, R.V.F.; Carpenter, M.P.; Ahmad, I.; Khoo, T.L. et al.
Partner: UNT Libraries Government Documents Department

Bioenergetics of three aquatic insects determined by radioisotopic analyses. [/sup 51/Cr and /sup 14/C tracer techniques]

Description: The bioenergetics of Simulium spp. and Cheumatopsyche analis from Rattlesnake Springs and Snively Creek, respectively, Benton County, Washington and Tricorthodes minutus from Deep Creek, Oneida County, Idaho were studied using a variety of techniques. Ingestion rates were measured using food sources (diatoms, finely ground watercress, bacteria, and blue-green algae) labelled with /sup 51/Cr and /sup 14/C. Theoretical ingestion rates were calculated from analyses of gut weights and digestion times. Assimilation efficiencies (AE) were determined using the /sup 14/C and dual-label (/sup 51/Cr, /sup 14/C) methods and the ash-ratio technique. The dual-label method provided reliable results when leaching of isotopes from food and feces were not significant. Provided the /sup 51/Cr activity density of food is sufficient, the time required for digestion can also be more accurately determined with /sup 51/Cr than with /sup 14/C. The ash-ratio method provided a wide range of AE values and is not as reliable as the dual-label method because mineral assimilationis unpredictable. Assimilation rates were derived for these animals using the ingestion rate and AE, by several methods employing /sup 14/C uptake curves, and by differences in /sup 51/Cr- and /sup 14/C-derived accumulation values. Methods used to measure other energy budget components are also given. A system was developed for combusting biological samples containing /sup 14/C and determining cpm /sup 14/C and total carbon from a single sample. This method employs Van Slyke wet oxidation, forced circulation and scrubbing of the gases of combustion, and collection of CO/sub 2/ in ethanolamine. Radioactivity in this system was determined by scintillation counting and total carbon by a gravimetric precipitation method. (auth)
Date: August 1, 1975
Creator: McCullough, D. A.
Partner: UNT Libraries Government Documents Department

Mathematical simulation of sediment and radionuclide transport in the Columbia River

Description: Mathematical simulation of radionuclide transport was conducted by applying the finite element sediment and contaminant transport model, SERATRA, to the Columbia River between the Priest Rapids and McNary Dams near the ERDA Hanford Reservation. Model computations were performed to solve time-dependent, longitudinal and vertical distributions of sediments and radionuclides by taking into account sediment-radionuclide interaction. Sediment transport was modeled for three sediment size fractions (i.e., sand, silt, and clay), and radionuclide transport was simulated for dissolved and particulate nuclides. Particulate radionuclides were analyzed for those adsorbed by sediment in each sediment size fraction. Five cases were simulated in this study to identify the effects of river sediments on radionuclide migration: continuous release of /sup 65/Zn without adsorption mechanics; continuous release of /sup 65/Zn with adsorption; instantaneous release of /sup 65/Zn without adsorption; instantaneous release of /sup 65/Zn with adsorption; and radionuclide resuspension. Sediment and radionuclide results indicate very good agreement with measured data.
Date: August 1, 1977
Creator: Onishi, Y.
Partner: UNT Libraries Government Documents Department