A normalization procedure has been applied to improve the descriptive and predictive power of the enhanced generalized superfluid (EGS) model for the nuclear level density (NLD). In this procedure, ...the EGS model is normalized based on the experimental average level spacing at the neutron binding energy
D
0
and the cumulative number of experimental discrete levels in the low-energy region
N
(
E
). The values of normalization parameters are determined by systematically analyzing a set of 288 nuclei from
25
Mg to
251
Cf, whose experimental
D
0
and
N
(
E
) data are available. The systematical analysis permits to determine the values of the normalization parameters for any nucleus. The descriptive and predictive power of the normalized EGS (NEGS) model are demonstrated by making the comparison of the NEGS NLDs with the experimental NLD data of 70 nuclei obtained from the Oslo method. The results obtained show that the NEGS model describes reasonably well almost all the experimental NLDs and should be better used in the reaction codes than the conventional EGS, in particular for nuclei whose experimental NLDs are not available.
The aim of this work is to update the coefficients of our empirical formula as a tool for quickly and better estimating the stopping range of different charged particles ranging in
Z
=
2
-
103
at ...various energies from 2.5 to 500 AMeV in aluminum material. A graphical-user-interface computer code (SRC v1.0) was also programmed to execute the calculation based on the empirical model. The reliability of the common computer codes, SRIM2013 and ATIMA, was examined together with the empirical formula by comparing the computed results to the experimental data evaluated by Hubert et al. (Atom Data Nucl Data Tables 46:1–213, 1990) for the practical use. The ranges based on the empirical model computed using the self-developed SRC code with the updated coefficients are in an excellent agreement with the experimental data and better than those computed using the SRIM2013 and ATIMA codes. The maximum deviation of the empirical model from the evaluated measured database is only 3% while it is about 10% (or 15%) for the SRIM2013 (or ATIMA) code. The results of the present study are useful for radiation shielding and nuclear experiments at radioactive-isotope accelerator facilities.
The radioactivity concentrations of 226Ra, 232Th and 40K natural radionuclides in Lao Portland cement samples were measured using a gamma-spectrometry with a HPGe detector. The activity ...concentrations were found to vary from 28.32 ± 2.23 to 65.50 ± 2.83 Bq kg-1 with a mean value of 41.12 ± 2.44 Bq kg-1 for 226Ra; from 7.25 ± 2.00 to 44.01 ± 2.45 Bq kg-1 with a mean of 16.60 ± 2.37 Bq kg-1 for 232Th and from 49.19 ± 4.27 to 196.74 ± 4.75 Bq kg-1 with a mean of 141.48 ± 4.50 Bq kg-1 for 40K, respectively. The radiological parameters were estimated to assess the potential radiological hazard including radium equivalent activity, total external absorbed dose rate in outdoor air at 1 m above the earth's surface, the annual effective dose, the gamma and alpha-indices were calculated using the activity concentrations of 226Ra, 232Th and 40K. The results obtained in this study show no significant radiological hazards arising from using Lao Portland cement for building construction.
Yeast
may be regarded as a cost-effective and environmentally friendly biosorbent for complex effluent treatment. The effect of pH, contact time, temperature, and silver concentration on metal ...removal from silver-containing synthetic effluents using
was examined. The biosorbent before and after biosorption process was analysed using Fourier-transform infrared spectroscopy, scanning electron microscopy, and neutron activation analysis. Maximum removal of silver ions, which constituted 94-99%, was attained at the pH 3.0, contact time 60 min, and temperature 20 °C. High removal of copper, zinc, and nickel ions (63-100%) was obtained at pH 3.0-6.0. The equilibrium results were described using Langmuir and Freundlich isotherm, while pseudo-first-order and pseudo-second-order models were applied to explain the kinetics of the biosorption. The Langmuir isotherm model and the pseudo-second-order model fitted better experimental data with maximum adsorption capacity in the range of 43.6-108 mg/g. The negative Gibbs energy values pointed at the feasibility and spontaneous character of the biosorption process. The possible mechanisms of metal ions removal were discussed.
have all necessary characteristics to be applied to the development of the technology of silver-containing effluents treatment.
This paper presents the results of the first observation of airborne trace elements using
Barbula Indica
moss in Hai Phong city, one of the two largest seaport cities in Vietnam. A total of 39 moss ...samples were collected at 39 different locations in January 2020 in Hai Phong. Neutron activation analysis method was used to analyze the concentration of 36 chemical elements in the collected moss samples and the obtained data were compared with the data obtained in other regions of Vietnam, China and Europe. The level of chemical elemental contamination in the air of Hai Phong was categorized and the possible sources of pollutant emissions were identified by applying principal component analysis.
For the first time, the active moss biomonitoring technique has been used in Vietnam for investigation of atmospheric elemental contamination in the air of Hanoi region. The
Sphagnum girgensohnii
...moss harvested in the clean area were used to produce the moss-bags. After 2 months of expose in 45 different sites in Hanoi area, the moss samples were prepared and the concentration of 27 heavy metal elements were determined by proton induced X-ray emission at Cyclotron Research Center of Iwate Medical University (Japan). The comparison of the obtained results with those in several cities in Europe shows that Hanoi’s air pollution of heavy metal is much more serious. Based on the values of contamination coefficient, it is shown that Hanoi’s air is extremely polluted by Co; seriously polluted by V and Se; moderately polluted by Cl, Cr, As, Br, Zr, Nb, Mo and Hg; slightly polluted by Mg, Al, Si, K, Ca, Ti, Fe, Cu, Zn, Ga, Rb, Sr, Mo, Ba, W and Pb Statistical analysis has been applied to the original concentration data of the detected elements to find the possible pollution sources.
Forty-five moss samples were collected at the end of the 2019 rainy season in Hanoi capital and some other cities in Red River Delta and the south central region in Vietnam. Twenty-nine elements were ...determined in the moss samples by neutron activation analysis at the reactor IBR-2 in the Joint Institute for Nuclear Research in Dubna, Russia. Factor Analysis allowed the extraction of five main factors that characterized five expected pollution sources and estimation of the factor probability at each sampling site.
•The atomic mixing occurred at TiO2/SiO2 interface after being irradiated with Xe+ ions of energies from 100 to 250 keV.•The mixing amount increases with ion energy, as evidenced by a decrease in the ...FWHM of TiO2 peaks and an increase in the thickness of TiO2/SiO2 transition layers.•The mixing amount is proportional to the number of displaced atoms, whereas the ion energy transfer to target atoms plays a crucial role in the inward broadening of mixed TiO2/SiO2 layers.•The refractive index n and the extinction coefficient k of mixed TiO2/SiO2 layers increase after irradiation with Xe ion up to 200 keV, then decrease for 250 keV.
The broadening and changes in optical parameters of TiO2/SiO2 transition layers irradiated with Xe+ ions of energies 100, 150, 200, and 250 keV have been investigated using the Rutherford Backscattering Spectrometry (RBS) and Spectroscopic Ellipsometry (SE) methods. We observed that a rise in atomic mixing at the TiO2/SiO2 interface increases its transition layer thickness with increasing ion energy. The discrepancies in transition layers are interpreted by employing the defect profiles and ion energy loss obtained from Stopping and Range of Ions in Matter (SRIM) calculations. The refractive index and the extinction coefficient of irradiated TiO2/SiO2 samples were found to be higher than those of virgin ones with irradiating ion energies below 250 keV. Their disparity heightens with increasing ion energy up to 200 keV and then decreases at 250 keV.
In this paper, two multielement analysis techniques, Neutron Activation Analysis (NAA) and Total Reflection X-ray Fluorescence (TXRF), are combined to detect elemental concentrations in Barbula ...indica moss collected at Dalat, Vietnam. Combining these two techniques has improved the qualitative detection of elements due to atmospheric deposition on moss samples. The concentrations of 40 elements, including Na, Mg, Al, Si, P, S, Cl, K, Ar, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Kr, Rb, Y, Sb, I, Cs, Ba, La, Ce, Sm, Eu, Tb, Dy, Yb, Hf, Ta, Pb, Th, and U in the Barbula indicamoss samples collected at 19 locations at Dalat have been determined. It is shown that the air in Dalat is suspected of contamination by Na, Mg, Si, P, S, V, Mn, Cu, Se, Br, and U; slightly contaminated by Mg, Cl, K, Cr, Ni, S, and Ni; moderately contaminated by Sc, Fe, Co, Zn, As, Kr, Rb, Y, Sb, Cs, Ba, La, Ce, Sm, Eu, Dy, Yb, Ta, Pb, and Th; and seriously contaminated by Tb. Factor analysis has been used to explain the contamination sources of these elements, including V, As, Fe, Zn, Se, Rb, Sb, Cs, Al, Cu, and Pb in the investigated area. Four factors have been extracted that can explain 86% of the total variance, and the results suggest that the main sources of atmospheric pollution in Dalat originate from traffic and windblown dust.
The effect of Ni substitution on the magnetic properties and the critical behavior of La
0.7
Sr
0.3
Mn
1−
x
Ni
x
O
3
compounds, which were prepared by the solid-state reaction method has been ...investigated. Based on our investigations of the temperature and the magnetic field dependences of magnetization
M
(
T
,
H
) data, it is shown that the Curie temperature (
T
C
) of La
0.7
Sr
0.3
Mn
1−
x
Ni
x
O
3
compounds will be shifted toward room temperature with increasing Ni concentration (
x
),
T
C
= 359–307 K for
x
= 0.0–0.1. By using the modified Arrott plots and the Kouvel–Fisher methods together with
M
(
H
,
T
)
data in the vicinity of the ferromagnetic (FM)–paramagnetic phase transition, the critical exponents (
β
,
γ
, and
δ
) have been determined. Our results show the existence of a short-range FM order in the undoped sample (
x
= 0). The values of
β
,
γ
, and
δ
will be shifted gradually toward those of the mean-field theory when
x
increases, suggesting that the long-range FM order is favored in Ni-doped samples. The results calculated on the effective exponents of
β
eff
(
ε
)
and
γ
eff
(
ε
)
in the asymptotic region indicate the existence of a magnetic disorder in all the samples.
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