PHOTOPROTON YIELDS FROM THE TITANIUM ISOTOPES

1967 ◽  
Vol 45 (10) ◽  
pp. 3235-3239 ◽  
Author(s):  
H. L. Pai ◽  
K. G. McNeill
Keyword(s):  
Experimental Data ◽  
Constant Temperature ◽  
Compound Nucleus ◽  
High Yield ◽  
Direct Emission ◽  
Nuclear Temperature ◽  
Titanium Isotopes ◽  
Model Fits

Measurements have been made of the yields of protons ejected as the first particle after excitation of nuclei of the titanium isotopes by bremsstrahlung of 22 and 30 MeV energy. It is found that for 47Ti, 48Ti, and 49Ti, a constant-temperature compound-nucleus model fits the experimental data, the nuclear temperature being the same as that found to give a good fit to (n, p) data. 50Ti, however, has a relatively high yield, and it is suggested that this is due to direct emission.

THE (n, p) CROSS SECTIONS OF TITANIUM ISOTOPES FOR NEUTRON ENERGIES BETWEEN 13.6 MeV AND 19.5 MeV

1966 ◽  
Vol 44 (10) ◽  
pp. 2337-2352 ◽  
Author(s):  
H. L. Pai
Keyword(s):  
Experimental Data ◽  
Cross Section ◽  
Cross Sections ◽  
Emission Cross Section ◽  
Closed Shell ◽  
Proton Emission ◽  
Neutron Energy Range ◽  
Nuclear Temperature ◽  
Good Agreement ◽  
Titanium Isotopes

Using enriched titanium samples, the activation (n, p) and (n, pn; n, np; n,d) cross sections have been measured for the five isotopes of titanium in the neutron energy range from 13.6 to 19.5 MeV. The results were compared with calculations based primarily upon Bodansky's theory (1962), where the first proton emission cross section was taken to be the sum of (n, p) and (n, pn). The (n, pn) cross section was separated from the experimental (n, pn; n, np; n, d) cross section by a multiple-emission calculation. Using the nuclear temperature derived from the experimental data, good agreement was achieved between experiment and theory. It was found that the parameters of Bodansky's equation for the titanium isotopes could be adopted directly from the mass parabolas (Dewdney 1963). It was also found that the (n, p) cross sections were not influenced appreciably by the neutron closed shell.

Optimal temperature for alpha-decay half-lives with Yukawa proximity potential

2016 ◽  
Vol 25 (12) ◽  
pp. 1650109 ◽  
Author(s):  
S. S. Hosseini ◽  
H. Hassanabadi ◽  
S. Zarrinkamar
Keyword(s):  
Experimental Data ◽  
Excited State ◽  
Coulomb Potential ◽  
Alpha Decay ◽  
Nuclear Surface ◽  
Optimal Temperature ◽  
Proximity Potential ◽  
Excited System ◽  
Nuclear Temperature ◽  
Comparison Of The Results

The paper investigates the alpha-decay half-lives of some nuclei by modifying the Coulomb potential with Yukawa proximity potential for the excited state decays. A new relation is found for the width diffuseness of the nuclear surface [Formula: see text] and the sharp radii [Formula: see text] for the excited system. The parameters are fitted to the experimental data for the nuclear temperature in the range [Formula: see text] (MeV). A comparison of half-life indicates that the probability of decay increases with increasing nuclear temperature for the excited system. The comparison of the results with the existing experimental data is motivating.

Aqueous Reactions of Sparingly Soluble Tellurites I. Silver Tellurite

1972 ◽  
Vol 50 (11) ◽  
pp. 1788-1791 ◽  
Author(s):  
M. C. Mehra ◽  
S. M. Kahn
Keyword(s):  
Experimental Data ◽  
Stability Constant ◽  
Constant Temperature ◽  
Solubility Product ◽  
Complex Species ◽  
Ionic Medium ◽  
The Stability ◽  
Aqueous Reactions

The aqueous interactions of the sparingly soluble silver tellurite show that in a controlled ionic medium and at a constant temperature, an aqueous complex,[Formula: see text] is formed in presence of free tellurite ions. The solubility product of silver tellurite and the stability constant of the complex species have been evaluated from the experimental data.

scholarly journals Statistical model calculations of the 7Li +11 Β reaction

2019 ◽  
Vol 10 ◽  
pp. 165
Author(s):  
C. Tsabaris ◽  
C. T. Papadopoulos ◽  
R. Vlastou ◽  
A. A. Pakou ◽  
P. A. Assimakopoulos ◽  
...  
Keyword(s):  
Experimental Data ◽  
Statistical Model ◽  
Energy Range ◽  
Cross Section ◽  
Compound Nucleus ◽  
Cross Sections ◽  
Coulomb Barrier ◽  
Reaction Channel ◽  
Model Calculations ◽  
The Individual

The 7Li + 11 Β reaction has been studied in the energy range from a little below to about three times the Coulomb barrier by measuring the cross section of the 7- ray transitions in the residual nuclei produced. Statistical compound nucleus calculations have been performed in order to interpret the experimental data as well as to extract cross sections of the individual exit channels. The statistical compound nucleus theory can reproduce rather well the absolute j - ray and the various reaction channel excitation functions.

A comparison of turbulent thermal convection between conditions of constant temperature and constant heat flux

2008 ◽  
Vol 595 ◽  
pp. 203-219 ◽  
Author(s):  
R. VERZICCO ◽  
K. R. SREENIVASAN
Keyword(s):  
Experimental Data ◽  
Heat Flux ◽  
Heat Transport ◽  
Constant Temperature ◽  
Thermal Convection ◽  
Constant Heat Flux ◽  
Constant Heat ◽  
Experimental Conditions ◽  
Thermal Plumes ◽  
Dimensional Argument

We numerically investigate turbulent thermal convection driven by a horizontal surface of constant heat flux and compare the results with those of constant temperature. Below Ra ≈ 109, where Ra is the Rayleigh number, when the flow is smooth and regular, the heat transport in the two cases is essentially the same. For Ra > 109 the heat transport for imposed heat flux is smaller than that for constant temperature, and is close to experimental data. We provide a simple dimensional argument to indicate that the unsteady emission of thermal plumes renders typical experimental conditions closer to the constant heat flux case.

Reaction mechanism of the 16O + d reactions

1970 ◽  
Vol 48 (19) ◽  
pp. 2235-2253 ◽  
Author(s):  
N. E. Davison ◽  
W. K. Dawson ◽  
G. Roy ◽  
W. J. McDonald
Keyword(s):  
Experimental Data ◽  
Compound Nucleus ◽  
Cross Sections ◽  
Direct Interaction ◽  
Scattering Data ◽  
Orbit Potential ◽  
Spectroscopic Factors ◽  
Theoretical Predictions ◽  
Using Data ◽  
Good Agreement

The reactions 16O(d,d)16O, 16O(d,p)17O, and 16O(d,n)17F have been studied in the deuteron energy range 4.00–6.00 MeV in order to determine to what extent current theories can satisfactorily describe these reactions. It was found that the theoretical curves from both the optical and DWBA models fit the experimental data significantly better when the deuteron optical-model potentials had been obtained using a spin–orbit potential in the analysis of the elastic scattering data. Spectroscopic factors obtained for the ground and first-excited states of 17O and 17F using the DWBA theory are in satisfactory agreement with theoretical predictions and with values obtained by previous workers. Small, but nonzero, spectroscopic factors have been obtained for the states at 3.058 and 3.846 MeV excitation in 17O using data measured in this work and in previous experiments. The sum of the calculated direct interaction and compound-nucleus cross sections is in good agreement with experimental data for all states studied, whether they were populated primarily by direct or compound-nucleus reactions. The calculated compound-nucleus lifetimes are also in agreement with values obtained from an analysis of the fluctuations in the yield curves.

Measurements of Heat Transfer Coefficients From Supercritical Carbon Dioxide Flowing in Horizontal Mini/Micro Channels

2002 ◽  
Vol 124 (3) ◽  
pp. 413-420 ◽  
Author(s):  
S. M. Liao ◽  
T. S. Zhao
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Constant Temperature ◽  
Transfer Coefficients ◽  
Circular Tubes ◽  
Horizontal Tubes ◽  
Micro Channels ◽  
Supercritical Carbon

Heat transfer from supercritical carbon dioxide flowing in horizontal mini/micro circular tubes cooled at a constant temperature has been investigated experimentally. Six stainless steel circular tubes having inside-diameters of 0.50 mm, 0.70 mm, 1.10 mm, 1.40 mm, 1.55 mm, and 2.16 mm were tested. Measurements were carried out for the pressures ranging from 74 to 120 bar, the temperatures ranging from 20 to 110°C, and the mass flow rates ranging from 0.02 to 0.2 kg/min. It is found that the buoyancy effect was still significant, although supercritical CO2 was in forced motion through the horizontal tubes at Reynolds numbers up to 105. The experimental results also indicate that the existing correlations developed in the previous studies for large tubes deviate significantly from the experimental data for the present mini/micro tubes. Based on the experimental data, a correlation was developed for the axially averaged Nusselt number in terms of appropriate dimensionless parameters for forced convection of supercritical carbon dioxide in horizontal mini/micro tubes cooled at a constant temperature.

scholarly journals Comparing Thixotropic and Herschel-Bulkley Models for Avalanches and Subaqueous Debris Flows

2017 ◽  
Author(s):  
Chan-Hoo Jeon ◽  
Ben R. Hodges
Keyword(s):  
Experimental Data ◽  
Newtonian Fluid ◽  
Debris Flows ◽  
Stokes Equations ◽  
Fluid Model ◽  
Newtonian Fluids ◽  
Time Dependent ◽  
High Yield ◽  
Time Space ◽  
Independent Model

Abstract. Debris flows such as avalanches and landslides are heterogeneous mixtures of solids and liquids but are often simulated as homogeneous non-Newtonian fluids using a Herschel-Bulkley model. By representing the heterogeneous debris as a homogeneous non-Newtonian fluid, it is possible to use standard numerical approaches for the Navier-Stokes equations where viscosity is allowed to vary in time and space (e.g. eddy-viscosity turbulence models). Common non-Newtonian models are time-independent so that the relationship between the time-space-varying effective viscosity and flow stress is unchanging. However, the complex behaviors of debris flows at flow initiation (jamming) and cessation (restructuralization) imply that the viscosity-stress relationships should have time-dependent behaviors, which is a feature of thixotropic non-Newtonian fluids. In this paper, both Herschel-Bulkley and thixotropic non-Newtonian fluid models are evaluated for simulating avalanches along a slope and subaqueous debris flows. A numerical solver using a multi-material level set method is applied to track multiple interfaces simultaneously. The numerical results are validated with analytical solutions and available experimental data using parameters selected based on the experimental setup and without post-hoc calibration. The thixotropic (time-dependent) fluid model shows reasonable agreement with all the experimental data. For most of the experimental conditions, the Herschel-Bulkley (time-independent) model results were similar to the thixotropic model, a critical exception being conditions with a high yield stress. Where the flow initiation is strongly dominated by the structural jamming and the initial yield behavior the time-independent model performed poorly.

STUDY OF EXCITATION FUNCTIONS IN Rh(α, xn) Ag REACTIONS

1996 ◽  
Vol 05 (02) ◽  
pp. 345-352 ◽  
Author(s):  
M. AFZAL ANSARI ◽  
N.P.M. SATHIK ◽  
B.P. SINGH ◽  
M.G.V. SANKARACHARYULU ◽  
R. PRASAD
Keyword(s):  
Experimental Data ◽  
Compound Nucleus ◽  
Alpha Particle ◽  
Computer Code ◽  
Particle Energy ◽  
Activation Technique ◽  
Excitation Functions ◽  
Foil Activation ◽  
Alpha Particle Energy ◽  
Stacked Foil Activation Technique

The excitation functions for the reactions 103 Rh (α, n)106 m Ag , 103 Rh (α, 2n)105 Ag , and 103 Rh (α, 3n)104 Ag have been measured between 10 and 40 MeV alpha-particle energy, using the stacked foil activation technique. Excitation functions are also calculated theoretically using the Geometry Dependent Hybrid (GDH) model. The computer code ALICE/LIVERMORE-82 has been used which takes into account the pre-equilibrium contribution along with the equilibrium decay of the compound nucleus. It has been found that initial exciton number n0=4 gives a satisfactory reproduction of experimental data.

Excited quasiparticles and entropy in 161,162Dy

2015 ◽  
Vol 24 (11) ◽  
pp. 1550090 ◽  
Author(s):  
R. Razavi ◽  
A. Rashed Mohassel ◽  
S. Mohammadi
Keyword(s):  
Experimental Data ◽  
Microscopic Theory ◽  
Pairing Interaction ◽  
Nuclear Level ◽  
Level Densities ◽  
Neutron Hole ◽  
Harmonic Oscillator Model ◽  
Nuclear Temperature ◽  
The Difference ◽  
Good Agreement

In this paper, the nuclear level densities of [Formula: see text]Dy is studied by the use of a microscopic theory which includes nuclear pairing interaction. It is based on the modified harmonic oscillator model according to the Nilsson potential. The entropy of even–odd and even–even nuclei as a function of nuclear temperature is obtained. The entropy excess of [Formula: see text]Dy is compared with that of [Formula: see text]Dy. It is concluded that the difference is related to the entropy carried by the neutron hole coupled to the even–even core. The numbers of excited quasiparticles are calculated. Good agreement was observed between calculated results and the experimental data.

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