Journal articles: 'Neutron – density cross plots'

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Jassim, Karrar Hayder, and Jalal A. Al-Sudani. "Re-evaluation of Petro physical Properties in Yammama Formation at Nasiriya Field." Iraqi Journal of Chemical and Petroleum Engineering 20, no. 3 (September 30, 2019): 59–66. http://dx.doi.org/10.31699/ijcpe.2019.3.8.

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Nasiriya field is located about 38 Km to the north – west of Nasiriya city. Yammama, a giant lower cretaceous reservoir in Nasiriya field which is lithologically formed from limestone. Yammama mainly was divided into three main reservoir units YA, YB1, YB2 and YB3 and it is separated by impermeable layers of variable thickness. An accurate petro physical evolution of the reservoir is of great importance perform an excellent geological model so that four petro physical properties which are shale volume, porosity, water saturation and permeability was re-evaluated. The volume of shale was calculated using the density and neutron logs (VSH-DN) rather than using gamma ray log because of presence a uranium content in the formation that makes overestimation of shale volume. Cross plots of Density Neutron logs are used to determine porosity by using IP software, which is correcting automatically Density Neutron logs for the effect of shale. Indonesian equation was used to estimate water saturation for five wells rather than Archie equation in order to consider shale volume. Fuzzy logic was adopted to predict permeability instead of regression analysis (cross plot) because of presence of errors in the results in this method. The results are shown that units YB2 and YB3 have best reservoir quality.

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Al-Baldawi, Buraq Adnan. "Evaluation of Petrophysical Properties Using Well Logs of Yamama Formation in Abu Amood Oil Field, Southern Iraq." Iraqi Geological Journal 54, no. 1E (May 31, 2021): 67–77. http://dx.doi.org/10.46717/igj.54.1e.6ms-2021-05-27.

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The petrophysical analysis is very important to understand the factors controlling the reservoir quality and production wells. In the current study, the petrophysical evaluation was accomplished to hydrocarbon assessment based on well log data of four wells of Early Cretaceous carbonate reservoir Yamama Formation in Abu-Amood oil field in the southern part of Iraq. The available well logs such as sonic, density, neutron, gamma ray, SP, and resistivity logs for wells AAm-1, AAm-2, AAm-3, and AAm-5 were used to delineate the reservoir characteristics of the Yamama Formation. Lithologic and mineralogic studies were performed using porosity logs combination cross plots such as density vs. neutron cross plot and M-N mineralogy plot. These cross plots show that the Yamama Formation consists mainly of limestone and the essential mineral components are dominantly calcite with small amounts of dolomite. The petrophysical characteristics such as porosity, water and hydrocarbon saturation and bulk water volume were determined and interpreted using Techlog software to carried out and building the full computer processed interpretation for reservoir properties. Based on the petrophysical properties of studied wells, the Yamama Formation is divided into six units; (YB-1, YB-2, YB-3, YC-1, YC-2 and YC-3) separated by dense non porous units (Barrier beds). The units (YB-1, YB-2, YC-2 and YC-3) represent the most important reservoir units and oil-bearing zones because these reservoir units are characterized by good petrophysical properties due to high porosity and low to moderate water saturation. The other units are not reservoirs and not oil-bearing units due to low porosity and high-water saturation.

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Movahed, Ata, Mohsen Masihi, and Abdonabi Hashemi. "Investigation of Petrophysical Parameters of Upper Sarvak Formation in One of the Iran South Oilfields." Current World Environment 10, Special-Issue1 (June 28, 2015): 740–51. http://dx.doi.org/10.12944/cwe.10.special-issue1.89.

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In this study, the upper Sarvak’s petrophysical parameters have been investigated in two A and B wells in one of the oil field in southern Iran. Based on this assessment and the use of conventional cross plots (neutron-density, sonic- neutron, MID_PLOT and M-N PLOT), lithology of upper Sarvak has been identified as a combination of limestone, dolomite and in small amounts, shale. With respect to calculated petrophysical properties and to more precise evaluation, the upper Sarvak in the studied area has been divided into 5 Zones. With respect to the specific petrophysical properties, zone S2 has been divided into 8 subdivisions. Finally, zone S2 with dominant lithology of limestone and with the lowest amount of shale in subdivision 2 and 3, have been recognized as the best reservoir parts.

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Kassab, Mohamed A., Ali El-Said Abbas, Mostafa A. Teama, and Musa A. S. Khalifa. "Prospect evaluation and hydrocarbon potential assessment: the Lower Eocene Facha non-clastic reservoirs, Hakim Oil Field (NC74A), Sirte basin, Libya—a case study." Journal of Petroleum Exploration and Production Technology 10, no. 2 (September 24, 2019): 351–62. http://dx.doi.org/10.1007/s13202-019-00773-8.

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Abstract Petrophysical assessment of Facha Formation based on log data of six wells A1, A3, A4, A5, A8 and A13 recorded over the entire reservoir interval was established. Hakim Oil Field produces from the Lower Eocene Facha reservoir, which is located at the western side of Sirte basin. Limestone, dolostone and dolomitic limestone are the main lithologies of the Facha reservoir. This lithology is defined by neutron porosity—density cross-plot. Noteworthily, limestone increases in the lowermost intervals of the reservoir. Structurally, the field is traversed by three northwest–southeast faults. The shale of the Upper Cretaceous Sirte Formation is thought to be the source rock of the Facha Formation, whereas the seals are the limestone and anhydrite of the Lower Eocene Gir Formation. In this study, the Facha reservoir’s cutoff values were obtained from the cross-plots of the calculated shale volume, porosity and water saturation values accompanied with gamma ray log data and were set as 20%, 10% and 70%, respectively. Isoparametric maps for the thickness variation of net pay, average porosity, shale volume and water saturation were prepared, and the authors found out that the Facha Formation has promising reservoir characteristics in the area of study; a prospective region for oil accumulation trends is in the north and south of the study area.

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Azeez, Hasan Saleh, Dr Abdul Aali Al-Dabaj, and Dr Samaher Lazim. "Petrophysical Analysis of an Iraqi Gas Field (Mansuriya Gas Field)." Journal of Engineering 26, no. 3 (March 1, 2020): 100–116. http://dx.doi.org/10.31026/j.eng.2020.03.09.

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Mansuriya Gas field is an elongated anticlinal structure aligned from NW to SE, about 25 km long and 5-6 km wide. Jeribe formation is considered the main reservoir where it contains condensate fluid and has a uniform thickness of about 60 m. The reservoir is significantly over-pressured, (TPOC, 2014). This research is about well logs analysis, which involves the determination of Archie petrophysical parameters, water saturation, porosity, permeability and lithology. The interpretations and cross plots are done using Interactive Petrophysics (IP) V3.5 software. The rock parameters (a, m and n) values are important in determining the water saturation where (m) can be calculated by plotting the porosity from core and the formation factor from core on logarithmic scale for both and the slope which represent (m) then Pickett plot method is used to determine the other parameters after calculating Rw from water analysis . The Matrix Identification (MID), M-N and Density-Neutron crossplots indicates that the lithology of Jeribe Formation consists of dolomite, limestone with some anhydrite also gas-trend is clear in the Jeribe Formation. The main reservoir, Jeribe Formation carbonate, is subdivided into 8 zones namely J1 to J8, based mainly on porosity log (RHOB and NPHI) trend, DT trend and saturation trend. Jeribe formation was considered to be clean in terms of shale content .The higher gamma ray because of the uranium component which is often associated with dolomitisationl and when it is removed and only comprises the thorium and potassium-40 contributions, showed the gamma response to be low compared to the total gamma ray response that also contains the uranium contribution.While the Jeribe formation is considered to be clean in terms of shale content so the total porosity is equal to the effective porosity.No porosity cut off is found if cutoff permeability 0.01 md is applied while the porosity cut off approximately equal to 0.1 only for unit J6 & J8 if cutoff permeability 0.1 md is applied . It can be concluded that no saturation cutoff for the units of Jeribe formation is found after a cross plot between water saturation and log porosity for the reservoir units of Jeribe formation and applied the calculated cut off porosity. The permeability has been predicted using two methods: FZI and Classical, the two methods yield approximately the same results for all wells.

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BRINE, M. P., P. D. STEVENSON, J. A. MARUHN, and P. G. REINHARD. "DIPOLE RESPONSE IN NEUTRON-RICH MAGNESIUM." International Journal of Modern Physics E 15, no. 07 (October 2006): 1417–23. http://dx.doi.org/10.1142/s0218301306005009.

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The time-dependent Hartree-Fock method, using the Skyrme interaction, is used to study the isovector giant dipole response of neutron-rich 34 Mg . The response is separately examined along the major and minor axes of this prolate nucleus, with a pygmy-like peak in the direction of the major axis at around 10 MeV. Time-dependent density plots show a superimposed surface mode not fully coupled to the bulk motion.

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ZHANG, HONGFEI, JIANMIN DONG, WEI ZUO, and UMBERTO LOMBARDO. "NUCLEON-NUCLEON CROSS SECTIONS IN ISOSPIN ASYMMETRIC NUCLEAR MATTER." International Journal of Modern Physics E 19, no. 08n09 (September 2010): 1788–93. http://dx.doi.org/10.1142/s0218301310016211.

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The in medium nucleon-nucleon (NN) cross sections in isospin asymmetric nuclear matter at various densities are investigated in the framework of Brueckner-Hartree-Fock theory with the Bonn B two-body nucleon-nucleon interaction supplemented with a new version microscopic three-body force (TBF). The TBF depresses the amplitude of cross sections at high density region. At low densities, the proton-proton and neutron-neutron cross sections decrease while the proton-neutron one increases as the asymmetry increases. But the sensitivity of the NN cross sections to the isospin asymmetry are reduced with the increasing density.

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Mishima, Kenji, Toshiya Otomo, Kazutaka Ikeda, and Hidetoshi Ohshita. "Neutron scattering cross section of diamond nanoparticles." EPJ Web of Conferences 219 (2019): 10005. http://dx.doi.org/10.1051/epjconf/201921910005.

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Due to their large coherent scattering cross section, diamond nanoparticles (DNPs) are considered as a promising candidate material for a new neutron reflector. For investigation of scattering cross sections of packed samples, we have developed a technique for mechanical compression of DNP powder. Application of 220 MPa allowed us to increase the bulk density from 0.40 g/cm3 to 1.1 g/cm3. The differential cross sections of uncompressed and packed samples were measured using the high-intensity total diffractometer instrument NOVA at J-PARC, covering transfer wavenumbers (q) from 0.6 to 100 nm−1. The q dependence for the compressed sample agreed with the theoretical expectation derived from the Born approximation applied to homogeneous spheres with inclusion of a hard-sphere model to account for the inter-particle structure, whereas the results obtained from the powder sample disagreed. This implies that the theoretical description does not well represent the mesoscopic structure of the DNP powder sample.

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RASHDAN, M. "STRUCTURE AND REACTIONS OF NEUTRON-RICH OXYGEN ISOTOPES." International Journal of Modern Physics E 21, no. 10 (October 2012): 1250083. http://dx.doi.org/10.1142/s0218301312500838.

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The structure of 16-26 O is investigated within the relativistic mean field (RMF) as well as high-energy nuclear collisions. The reaction cross-sections of 16-24 O +12 C around 1 GeV are calculated within the multiple scattering theory, where the multiple integrals are evaluated by Monte Carlo method as well as by the optical limit approximation of the Glauber model. In-medium effects are investigated within the optical limit, where it is found to be important in order to get reliable information about nuclear radii and density distributions. The reaction cross-sections indicate to a halo structure for 23 O . This neutron halo is also found in the rms matter radii and nuclear densities especially when Fermi shape is used in the optical limit, including in-medium effects, in extracting the parameters of the density distributions from the experimental reaction cross-sections.

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Saeed, Aly, Shazly El, Mohamed El-Okr, Ali El-Azm, Yahia Elbashar, Mohamed Comsan, Wagdy Kansouh, and Ahmed El-Sersy. "Neutron shielding properties of a borated high-density glass." Nuclear Technology and Radiation Protection 32, no. 2 (2017): 120–26. http://dx.doi.org/10.2298/ntrp1702120s.

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The neutron shielding properties of a borated high density glass system was characterized experimentally. The total removal macroscopic cross-section of fast neutrons, slow neutrons as well as the linear attenuation coefficient of total gamma rays, primary in addition to secondary, were measured experimentally under good geometric condition to characterize the attenuation properties of (75-x) B2O3-1Li2O-5MgO-5ZnO-14Na2O-xBaO glassy system. Slabs of different thicknesses from the investigated glass system were exposed to a collimated beam of neutrons emitted from 252Cf and 241Am-Be neutron sources in order to measure the attenuation properties of fast and slow neutrons as well as total gamma rays. Results confirmed that barium borate glass was suitable for practical use in the field of radiation shielding.

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Gedela, Satyanarayana, Ravindra K. Bisht, and Neeraj Pant. "Relativistic modeling of Vela X-1 using the Karmarkar condition." Modern Physics Letters A 34, no. 20 (June 28, 2019): 1950157. http://dx.doi.org/10.1142/s0217732319501578.

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The objective of this work is to explore a new parametric class of exact solutions of the Einstein field equations coupled with the Karmarkar condition. Assuming a new metric potential [Formula: see text] with parameter (n), we find a parametric class of solutions which is physically well-behaved and represents compact stellar model of the neutron star in Vela X-1. A detailed study specifically shows that the model actually corresponds to the neutron star in Vela X-1 in terms of the mass and radius. In this connection, we investigate several physical properties like the variation of pressure, density, pressure–density ratio, adiabatic sound speeds, adiabatic index, energy conditions, stability, anisotropic nature and surface redshift through graphical plots and mathematical calculations. All the features from these studies are in excellent conformity with the already available evidences in theory. Further, we study the variation of physical properties of the neutron star in Vela X-1 with the parameter (n).

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Fu, Xuelong, Zhengbo Ji, Wei Lin, Yunfeng Yu, and Tao Wu. "The Advancement of Neutron Shielding Materials for the Storage of Spent Nuclear Fuel." Science and Technology of Nuclear Installations 2021 (May 7, 2021): 1–13. http://dx.doi.org/10.1155/2021/5541047.

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With the development of nuclear industry, spent nuclear fuel (SNF) generated from nuclear power plants arouses people’s attention as a result of its high radioactivity, and how to guarantee the reliable operation of nuclear facilities and the staff’s safety occupies a crucial position. To avoid the lethal irradiation, a lot of functional neutron shielding composites have been developed to transform fast neutrons into thermal neutrons which can be absorbed with high macroscopic cross-sectional elements. Irradiation characteristics of nuclear industry have promoted the advancement of neutron shielding materials. Here, we review the latest neutron shielding materials for the storage of spent nuclear fuel containing additives such as boron carbide (B4C), boron nitride (BN), boric acid (H3BO3), and colemanite. Different types of neutron shielding materials, including metal matrix alloys, polymer composites, high density concrete, heavy metals, paraffin, and other neutron shielding composites with high macroscopic cross-sectional elements, arediscussed. The elemental composition, density, and thermal and mechanical properties of neutron shielding materials are also summarized and compared.

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13

Sönmez, Ö., and O. Karaman. "Investigation of level density parameter dependence for some 233U, 235U, 237U, 239U, 249Cf, 251Cf, 237Pu and 247Cm nuclei in neutron fission cross sections with the incident energy up to 20 MeV." Kerntechnik 86, no. 1 (March 1, 2021): 78–85. http://dx.doi.org/10.1515/kern-2020-0086.

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Abstract Level density models have increasing importance to gain more in-depth into the nature of nuclear reactions. Many novel and advanced medical application use radioisotopes, which are produced with nuclear reactions. In this study, the effect of the level density parameters of the nucleus on the cross sections of neutron-fission reactions for 233U, 235U, 237U, 239U, 249Cf, 251Cf, 237Pu and 247Cm nuclei were investigated for up to 20 MeV neutrons. TALYS 1.8 software was used to calculate the cross-sections of neutron-fission reactions for different level density parameters. The calculations were compared with the EXFOR nuclear data library and the level density parameters, and the closest fit were searched. As outputs of the study, the effect of selection of level density parameter on cross section calculations was observed. The theoretically obtained data were compared with the experimental data taken from the literature. The results are presented graphically for better interpretation.

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Turenko, S. K., and E. A. Cherepanov. "USING THE DATA OF NEUTRON LOGGING FOR CONSTRUCTING SEISMIC AND GEOLOGICAL MODELS OF OIL AND GAS IN WESTERN SIBERIA OBJECTS." Oil and Gas Studies, no. 2 (May 1, 2016): 27–32. http://dx.doi.org/10.31660/0445-0108-2016-2-27-32.

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There are two methods under consideration of using neutron logging data for the construction of seismic and geological models of oil and gas facilities in Western Siberia. The first method - the reconstruction of the acoustic properties of the well according to the neutron log. The second method - the development of a well-known technique Gardner L. A. determining density properties according acoustic logging. To the point neutron logging data are used to account the lithology. Combining these methods can restore acoustic and density properties of the geological cross-section only by using neutron logging data.

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NISHIMURA, D., M. FUKUDA, M. TAKECHI, M. MIHARA, J. KOMURASAKI, R. MATSUMIYA, K. MATSUTA, et al. "EXOTIC NUCLEAR STRUCTURES OF LIGHT UNSTABLE NUCLEI VIA REACTION CROSS SECTION MEASUREMENT." Modern Physics Letters A 25, no. 21n23 (July 30, 2010): 2014–15. http://dx.doi.org/10.1142/s0217732310000915.

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Reaction cross sections for 11 Be and 8 B on proton targets at 40A - 120A MeV have been measured by the transmission method. With these data, we can discuss the proton- and neutron- density distributions at the nuclear surface independently in principle using the Glauber theory. Our experimental results support that the constituent of halo in 11 Be is neutron dominantly and that of 8 B is proton dominantly.

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Hassan, M. A. M., M. S. M. Nour El-Din, A. Ellithi, E. Ismail, and H. Hosny. "The effect of halo nuclear density on reaction cross-section for light ion collision." International Journal of Modern Physics E 24, no. 08 (August 2015): 1550062. http://dx.doi.org/10.1142/s0218301315500627.

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In the framework of the optical limit approximation (OLA), the reaction cross-section for halo nucleus — stable nucleus collision at intermediate energy, has been studied. The projectile nuclei are taken to be one-neutron halo (1NHP) and two-neutron halo (2NHP). The calculations are carried out for Gaussian–Gaussian (GG), Gaussian-Oscillator (GO), and Gaussian-2S (G2S) densities for each considered projectile. As a target, the stable nuclei in the range 4–28 of the mass number are used. An analytic expression of the phase shift function has been derived. The zero range approximation is considered in the calculations. Also, the in-medium effect is studied. The obtained results are analyzed and compared with the geometrical reaction cross-section and the available experimental data.

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Del Popolo, Antonino, Morgan Le Delliou, and Maksym Deliyergiyev. "Neutron Stars and Dark Matter." Universe 6, no. 12 (November 26, 2020): 222. http://dx.doi.org/10.3390/universe6120222.

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Neutron stars change their structure with accumulation of dark matter. We study how their mass is influenced from the environment. Close to the sun, the dark matter accretion from the neutron star does not have any effect on it. Moving towards the galactic center, the density increase in dark matter results in increased accretion. At distances of some fraction of a parsec, the neutron star acquire enough dark matter to have its structure changed. We show that the neutron star mass decreases going towards the galactic centre, and that dark matter accumulation beyond a critical value collapses the neutron star into a black hole. Calculations cover cases varying the dark matter particle mass, self-interaction strength, and ratio between the pressure of dark matter and ordinary matter. This allow us to constrain the interaction cross section, σdm, between nucleons and dark matter particles, as well as the dark matter self-interaction cross section.

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Luo, J., R. Liu, L. Jiang, Z. Liu, G. Sun, and S. Ge. "Cross-sections of 45Sc(n, 2n)44m,gSc reaction from the reaction threshold to 20 MeV." Radiochimica Acta 101, no. 10 (October 2013): 607–12. http://dx.doi.org/10.1524/ract.2013.2065.

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Summary Cross sections of 45Sc(n, 2n)44m,g Sc reactions and their isomeric cross section ratios σm/σg have been measured at three neutron energies between 13.5 and 14.8 MeV using the activation technique. The pure cross section of the groundstate was then obtained by utilizing the absolute cross section of the metastable state and analysis methods of residual nuclear decay. The monoenergetic neutron beam was produced via the 3H(d, n)4He reaction. The cross sections were also estimated with the TALYS-1.2 nuclear model code using different level density options, at neutron energies varying from the reaction threshold to 20 MeV. Results are also discussed and compared with some corresponding values found in the literature.

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Ummukulsu, Erumban, Nithu Ashok, and Antony Joseph. "Study of level density and reaction cross-sections in Thorium isotopes." Modern Physics Letters A 34, no. 12 (April 20, 2019): 1950091. http://dx.doi.org/10.1142/s0217732319500913.

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A theoretical study of nuclear level density of Thorium nuclei that exist on and off the beta-stability line is carried out using Talys 1.6. The level density parameter a and spin cut-off factor [Formula: see text] for Thorium isotopes [Formula: see text]Th are estimated. The values of both these parameters decrease towards the neutron drip line and the proton drip line. Cross-sections for [Formula: see text] and [Formula: see text] reactions for Thorium isotopes are also calculated. The estimated and experimental values of cross-sections for [Formula: see text]Th are comparable. These evaluated data are useful in understanding the mechanism of nuclear reactions taking place under extreme conditions including those in nucleosynthesis.

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Luo, Junhua, Li Jiang, and Long He. "Measurement of cross sections and isomeric cross-section ratios for the (n,2n) reactions on 85,87Rb in energies between 13 and 15 MeV." Radiochimica Acta 106, no. 9 (September 25, 2018): 709–17. http://dx.doi.org/10.1515/ract-2018-2951.

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Abstract The (n,2n) cross sections and their isomeric cross-section ratios (σm/σg) in the neutron energy range 13–15 MeV have been measured for 85,87Rb by an activation and off-line γ-ray spectrometric technique using the Pd-300 Neutron Generator at the Chinese Academy of Engineering Physics (CAEP). The natural Rb samples and Nb monitor foils were activated together to determine the reaction cross section and the incident neutron flux. The neutrons were produced via the 3H(d,n)4He reaction. The pure cross section of the ground-state was derived from the absolute cross section of the metastable state and the residual nuclear decay analysis. The 85Rb(n,2n)84m,gRb and 87Rb(n,2n)86m,gRb reaction excitation functions and their isomeric cross-section ratios were also calculated theoretically using the TALYS-1.8 code with different level density options. Results are discussed and compared with the corresponding literature data.

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Patronis, N., C. T. Papadopoulos, S. Galanopoulos, M. Kokkoris, G. Perdikakis, S. Harissopulos, A. Lagoyannis, and R. Vlastou. "Study of the 191Ir(n,2n)190Ir cross section." HNPS Proceedings 15 (January 1, 2020): 97. http://dx.doi.org/10.12681/hnps.2625.

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The 191Ir(n,2n)190Ir cross section was measured by using of the activation technique at four neutron energies in the range 10.0-11.3 MeV. The quasimonoenergetic neutron beam was produced via the 2H(d,n)3He reaction at the 5.5 MV Tandem Van de Graaff accelerator of NCSR ”Demokritos”. After the irradiations the induced activity of the samples was measured through a 56% relative efficiency HPGe detector. The cross section for the population of the second high spin (11−) isomeric state was measured along with the sum of the reaction cross section populating both the ground (4−) and the first isomeric state (1−). The experimental data will be combared to theoretical calculations in order to deduce information for the spin dependence of the level density parameters.

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Xu, Yong-Li, Hai-Rui Guo, Yin-Lu Han, and Qing-Biao Shen. "The neutron microscopic optical potential based on skyrme interaction." International Journal of Modern Physics E 25, no. 02 (February 2016): 1650013. http://dx.doi.org/10.1142/s0218301316500130.

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The neutron microscopic optical potential (MOP) based on Skyrme interaction has been achieved by the Green function method in the nuclear matter, and given by the local density approximation (LDA) for finite nuclei. The total cross-sections, nonelastic cross-sections, elastic scattering angular distributions and analyzing powers are predicted for some light nuclei and actinide nuclei below 100[Formula: see text]MeV by the obtained neutron MOP with the Skyrme interaction SkC. These data are also predicted for targets in the mass range of [Formula: see text] which are too deformed and have rich nuclear structure properties. All of the theoretical results give reasonable agreements with the corresponding experimental data.

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Abdullah, Ahmed N. "Density distributions, form factors and reaction cross sections for exotic 11Be and 15C nuclei." Iraqi Journal of Physics (IJP) 12, no. 24 (February 17, 2019): 10–24. http://dx.doi.org/10.30723/ijp.v12i24.316.

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The ground state proton, neutron and matter densities of exotic 11Be and 15C nuclei are studied by means of the TFSM and BCM. In TFSM, the calculations are based on using different model spaces for the core and the valence (halo) neutron. Besides single particle harmonic oscillator wave functions are employed with two different size parameters Bc and Bv. In BCM, the halo nucleus is considered as a composite projectile consisting of core and valence clusters bounded in a state of relative motion. The internal densities of the clusters are described by single particle Gaussian wave functions. Elastic electron scattering proton form factors for these exotic nuclei are analyzed via the plane wave born approximation (PWBA). As the calculations in the BCM do not distinguish between protons and neutrons, the calculations of the proton form factors are restricted only by the TFSM. The reaction cross sections for these exotic nuclei are studied by means of the Glauber model with an optical limit approximation using the ground state densities of the projectile and target, where these densities are described by single Gaussian functions. The calculated reaction cross sections at high energy are in agreement with the experimental data.

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Li, Bao-An, and Lie-Wen Chen. "Neutron–proton effective mass splitting in neutron-rich matter and its impacts on nuclear reactions." Modern Physics Letters A 30, no. 13 (April 13, 2015): 1530010. http://dx.doi.org/10.1142/s0217732315300104.

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The neutron–proton effective mass splitting in neutron-rich nucleonic matter reflects the spacetime nonlocality of the isovector nuclear interaction. It affects the neutron/proton ratio during the earlier evolution of the Universe, cooling of proto-neutron stars, structure of rare isotopes and dynamics of heavy-ion collisions. While there is still no consensus on whether the neutron–proton effective mass splitting is negative, zero or positive and how it depends on the density as well as the isospin-asymmetry of the medium, significant progress has been made in recent years in addressing these issues. There are different kinds of nucleon effective masses. In this mini-review, we focus on the total effective masses often used in the non-relativistic description of nuclear dynamics. We first recall the connections among the neutron–proton effective mass splitting, the momentum dependence of the isovector potential and the density dependence of the symmetry energy. We then make a few observations about the progress in calculating the neutron–proton effective mass splitting using various nuclear many-body theories and its effects on the isospin-dependence of in-medium nucleon–nucleon cross-sections. Perhaps, our most reliable knowledge so far about the neutron–proton effective mass splitting at saturation density of nuclear matter comes from optical model analyses of huge sets of nucleon–nucleus scattering data accumulated over the last five decades. The momentum dependence of the symmetry potential from these analyses provide a useful boundary condition at saturation density for calibrating nuclear many-body calculations. Several observables in heavy-ion collisions have been identified as sensitive probes of the neutron–proton effective mass splitting in dense neutron-rich matter based on transport model simulations. We review these observables and comment on the latest experimental findings.

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Butler, Dwain K. "Generalized gravity gradient analysis for 2-D inversion." GEOPHYSICS 60, no. 4 (July 1995): 1018–28. http://dx.doi.org/10.1190/1.1443830.

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Gravity gradient profiles across subsurface structures that are approximately 2-D contain diagnostic information regarding depth, size, and structure (geometry). Gradient space plots, i.e., plots of horizontal gradient versus vertical gradient, present the complete magnitude and phase information in the gradient profiles simultaneously. Considerable previous work demonstrates the possibility for complete structural interpretation of a truncated plate model from the gradient space plot. The qualitative and quantitative diagnostic information contained in gradient space plots is general, however. Examination of the characteristics of gradient space plots reveals that 2-D structures are readily classified as extended or localized. For example, the truncated plate model is an extended model, while the faulted plate model is a localized model. Comparison of measured or calculated gradient space plots to a model gradient space plot catalog allows a rapid, qualitative determination of structure or geometry. “Corners” of a polygonal cross‐section model are then determined as profile points corresponding to maxima on the vertical gradient profile. A generalized approach to structural interpretation from gravity data consists of (1) determining vertical and horizontal gradient profiles perpendicular to the strike of a 2-D gravity anomaly, (2) determining the structural geometry from the gradient space plot, and (3) locating profile positions of structural corners from the vertical gradient profile. This generalized inversion procedure requires no quantitative information or assumption regarding density contrasts. Iterative forward modeling then predicts the density contrasts. Application of this generalized gravity gradient inversion procedure to high quality gravity data results in an effective density prediction consistent with measured near‐surface densities and the known increase in density with depth in deep sedimentary basins.

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Mäkinen, Harri, Pekka Saranpää, and Sune Linder. "Wood-density variation of Norway spruce in relation to nutrient optimization and fibre dimensions." Canadian Journal of Forest Research 32, no. 2 (February 1, 2002): 185–94. http://dx.doi.org/10.1139/x01-186.

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The effect of fertilization on wood density, fibre length, fibre diameter, lumen diameter, proportion of cell wall area, and cell wall thickness of Norway spruce (Picea abies (L.) Karst.) were studied in a nutrient optimization experiment in northern Sweden. On the fertilized plots, all essential macronutrients and micronutrients were supplied in irrigation water every second day during the growing season. After 12 years' treatment, data were collected from 24 trees (40 years old) on the fertilized and control plots. Fertilization increased radial growth more than threefold, especially earlywood width, and decreased wood density by over 20% at 1.3 and 4 m height. The decrease in wood density was closely related to the proportion of latewood. The absolute wood density also decreased across the whole annual ring but proportionately more in latewood than in earlywood. A close relationship was found between the wood density and fibre properties, especially with the proportion of cell wall in a cross section of each annual ring, as well as with fibre and lumen width. The absolute cell wall thickness was clearly less related to wood density. However, rather large variations were found between individual trees in the relationship between wood density and fibre properties.

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MA, C. W., Y. FU, D. Q. FANG, Y. G. MA, X. Z. CAI, W. D. TIAN, K. WANG, and C. ZHONG. "ISOSPIN EFFECT AND ISOSCALING PHENOMENON IN PROJECTILE FRAGMENTATION." International Journal of Modern Physics E 17, no. 09 (October 2008): 1669–80. http://dx.doi.org/10.1142/s0218301308010684.

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We have studied the isospin effect and isoscaling behavior in projectile fragmentation using a modified statistical abrasion-ablation (SAA) model. The relationship between neutron skin thickness (δnp) and neutron abrasion cross section (σ nabr ) has also been investigated. We find the normalized peak differences and reduced isoscaling parameters decrease with (Z proj - Z)/Z proj or the excitation energy per nucleon and have no significant dependence on the size of the reaction systems. The excitation energy dependence of the symmetry energy coefficients are tentatively extracted from α and β. Assuming Fermi-type density distributions for proton and neutron and introducing a parameter to adjust the diffuseness of the neutron density distribution for neutron-rich nucleus, δnp and σ nabr for neutron-rich nucleus were found to have a linear correlation. It is suggested that σ nabr could be used as an observable to extract the neutron skin thickness for neutron-rich nucleus.

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Al-Qasir, Iyad, and Abdallah Qteish. "Neutron filter efficiency of beryllium and magnesium fluorides." Journal of Applied Crystallography 50, no. 2 (March 7, 2017): 441–50. http://dx.doi.org/10.1107/s1600576717000851.

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The neutron filter efficiency of MgF2 and BeF2 has been investigated as a function of neutron incident energy at different temperatures, starting from the phonon density of states (PDOS) calculated using first-principles techniques, and the results are compared with those of MgO and BeO. Recently, MgF2 has been suggested as a neutron filter and neutron transmission through it has been experimentally studied. For MgF2, excellent agreement between calculated and available experimental data has been achieved for the phonon dispersion relations, constant-volume specific heat, inelastic scattering cross sections and neutron transmission. The PDOSs of MgF2 and BeF2 are found to differ significantly owing to the crystal structure and the cations' mass difference. The inelastic scattering cross sections and filter efficiencies of MgF2 and BeF2 show different behaviours, which can be understood to originate from the above PDOS incongruity and the large difference in absorption cross sections of Be and Mg nuclei. BeF2 is predicted to be a better neutron filter than MgF2 and MgO, over the temperature range of interest, while it has less ability than BeO to transmit low-energy neutrons.

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29

Thies, Walter G., Earl E. Nelson, and Darlene Zabowski. "Removal of stumps from a Phellinusweirii infested site and fertilization affect mortality and growth of planted Douglas-fir." Canadian Journal of Forest Research 24, no. 2 (February 1, 1994): 234–39. http://dx.doi.org/10.1139/x94-034.

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A 2 × 4 set of factorial treatments of stump removal in combination with nitrogen fertilization was applied to 0.04-ha circular plots within a clearcut on the west slope of the Cascade Range (44°21′N, 122°39′W). Treatments included stump removal (either all stumps removed or the plot left undisturbed) and broadcast fertilization with ammonium nitrate (0, 336, 672, or 1345 kg N•ha−1). Diameter at breast height and height of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seedlings, planted 4 months after treatment, were recorded five and nine seasons after outplanting. Soil bulk density in the upper 20 cm was measured with a single-probe neutron densimeter. Stump removal reduced the number of seedlings killed by laminated root rot (Phellinusweirii (Murr.) Gilb.) but had no significant effect on seedling growth. Stump removal increased soil bulk density only 7% as measured 9.7 years after treatment. Fertilization increased the growth in diameter at breast height, and height growth of the seedlings. Elevated total soil nitrogen could still be detected on fertilized, nonstumped plots 9.7 years after treatment.

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Kaki, Kaori. "Neutron density distributions analyzed in terms of relativistic impulse approximation for nickel isotopes." International Journal of Modern Physics E 24, no. 03 (March 2015): 1550015. http://dx.doi.org/10.1142/s0218301315500159.

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Observables of proton elastic scattering from nickel isotopes (48–82 Ni ) are calculated based on relativistic impulse approximation (RIA), and nuclear density distributions are provided by relativistic mean-field (RMF) calculations. Contributions of a medium effect and multiple scattering to observables are evaluated and shown to be small at incident proton energies from 200 MeV through 500 MeV so that it is confirmed to perform a model analysis based on the fundamental RIA calculation. For 58,60,62,64 Ni isotopes, are considered proton distributions which are obtained by means of unfolding the charge form factor of proton from charge densities determined by the experiments of electron scattering. Through comparisons between results for the different proton densities, contributions of proton form factor to proton distributions and to elastic scattering observables at 300 MeV are discussed. It is shown that the neutron distribution is determined from the restricted observables, reaction cross-section and the first dip of differential cross-section, based on a model analysis of Woods–Saxon distribution in the case of 64 Ni target at 300 MeV. Contributions of tensor density and empirical proton density are shown to obtaining the neutron distribution with the model analysis. Compared with the similar studies for 40,60 Ca and 208 Pb , problems of the model analysis, which arise out of errors in observables, are discussed.

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Sideris, I., S. Kolovi, A. Khaliel, A. Stamatopoulos, and T. J. Mertzimekis. "237Np reactions with fast neutrons: a phenomenological study." HNPS Proceedings 27 (April 17, 2020): 14. http://dx.doi.org/10.12681/hnps.2478.

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Neptunium presents various opportunities as nuclear fuel, especially in deep–space mission power generators. As it is part of the nuclear spent fuel in PWR, waste management concerns due to 237Np long α-emitting half-life have attracted some attention recently. The scarcity of experimental data in the fast neutron energy range highlights the necessity to investigate the radiative neutron capture and neutron–induced fission cross sections of this radioisotope. In the present work, statistical modeling of these reactions is performed using TALYS in an extended range of neutron energies between 10 keV and 20 MeV. In total, 72 different combinations of code parameters were selected to study the level density and γ-strength function dependence of the cross section in 238Np. Preequilibrium and compound nucleus formation phenomena are also examined. Theoretical calculations are compared to available experimental total cross section data found in literature in an attempt to investigate any discrepancies between experiment and theory and validate statistical uncertainties.

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Серебров, А. П., В. А. Лямкин, В. М. Пусенков, М. С. Онегин, А. К. Фомин, О. Ю. Самодуров, А. Т. Опрев, et al. "Нейтроноводная система ультрахолодных и холодных нейтронов на реакторе ВВР-М." Журнал технической физики 89, no. 5 (2019): 788. http://dx.doi.org/10.21883/jtf.2019.05.47485.2516.

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AbstractThe results of calculation of fluxes of ultracold (UCNs), very cold, and cold neutrons at the output of neutron guides of the UCN source with superfluid helium at the WWR-M reactor are presented. UCN density ρ_35L = 1.3 × 10^4 n/cm^3 in the trap of the electric dipole moment (EDM) spectrometer was obtained by optimizing source parameters. This UCN density in the EDM spectrometer is two orders of magnitude higher than the UCN density at the output of the available UCN sources. The flux density of cold neutrons with a wavelength of 2–20 Å at the output of a neutron guide with a cross section of 30 × 200 mm^2 should be as high as 1.1 × 10^8 n/(cm^2 s), while the flux density of very cold neutrons (50–100 Å) at the output of the same neutron guide should be 2.3 × 10^5 n/(cm^2 s). An extensive program of fundamental and applied physical research was mapped out for this source.

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Woo, Juhwan, Hyun Suk Lee, Carl Ozyer, and Chul Woo Rhee. "Effect of Lamination on Shale Reservoir Properties: Case Study of the Montney Formation, Canada." Geofluids 2021 (February 9, 2021): 1–14. http://dx.doi.org/10.1155/2021/8853639.

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The presence of lamination on sedimentary rocks is a distinct characteristic, particularly in shales. They are distinct due to the contrast between successive layers with regard to grain size, composition, color, and sedimentary structures, such as graded beds. Typically, the degree of lamination is controlled by the sedimentation rate and flow regime. Herein, we developed a mudstone classification scheme in terms of lamination because lamination-based shale facies are related to differing features in mineral composition, porosity, and Young’s modulus. This study also attempts to verify whether wireline log patterns are relevant to shale lithofacies. The relationship between the porosity and lamination of the Montney Formation can be used to estimate reservoir properties. Our results show that an increased silt lamina in mudstone leads to an increase in the quartz and calcite contents and a decrease in the clay content, which increases the porosity, permeability, and Young’s modulus. However, reservoir quality is not solely dependent on lamination because of the complex interaction between components. The degree of lamination affected the neutron, density, and sonic log responses. Furthermore, the presence of lamination tends to decrease the neutron percentage, with similar trends in density and sonic log box plots in the study area. When the percentage of clay or cement material decreases, the neutron and density log responses diminish. Meanwhile, when the rock texture variation increases with an increase in the degree of lamination, the sonic log response decreases.

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Domra Kana, Janvier, Ahmad Diab Ahmad, Daniel Hervé Gouet, Xavier Djimhoudouel, and Serge Parfait Koah Na Lebogo. "Sandstone reservoir characteristics of Rio Del Rey basin, Cameroon, using well-logging analysis." Journal of Petroleum Exploration and Production Technology 11, no. 6 (June 2021): 2621–33. http://dx.doi.org/10.1007/s13202-021-01211-4.

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AbstractThe present work deals with an interpretation of well log data (gamma ray (GR), resistivity, density, and neutron) from four wells, namely P-1, P-2, P-3 and P-4 in the study area of the Rio Del Rey basin. The well logs analysis indicates five potential sandstone reservoirs at the P-1, two at the P-2, four at the P-3 and six at the P-4. The neutron–density-GR logs highlight the sandstone gas reservoir characterized by high resistivity and crossover between neutron density. The neutron–density-GR cross-plot confirms the presence of sandstone containing hydrocarbons by a displacement of the cloud of points, from low to medium GR values, from the sandstone line to the left. Petrophysical parameters exhibit the value 12–41% for a volume of shale, 15–34% for effective porosity, 29–278 mD for permeability and 3–63% for water saturation. The three potential hydrocarbon reservoir saturation ranges from 22 to 45%. The study will contribute to future offshore oil and gas exploration and development in the Rio Del Rey basin, based on the geological and geophysical characteristics of the reservoirs delineated.

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35

Zec, Nebojša, Gaetano Mangiapia, Alex C. Hendry, Robert Barker, Alexandros Koutsioubas, Henrich Frielinghaus, Mario Campana, José Luis Ortega-Roldan, Sebastian Busch, and Jean-François Moulin. "Mutually Beneficial Combination of Molecular Dynamics Computer Simulations and Scattering Experiments." Membranes 11, no. 7 (July 5, 2021): 507. http://dx.doi.org/10.3390/membranes11070507.

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We showcase the combination of experimental neutron scattering data and molecular dynamics (MD) simulations for exemplary phospholipid membrane systems. Neutron and X-ray reflectometry and small-angle scattering measurements are determined by the scattering length density profile in real space, but it is not usually possible to retrieve this profile unambiguously from the data alone. MD simulations predict these density profiles, but they require experimental control. Both issues can be addressed simultaneously by cross-validating scattering data and MD results. The strengths and weaknesses of each technique are discussed in detail with the aim of optimizing the opportunities provided by this combination.

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Tang, Hewei, John E. Killough, Zoya Heidari, and Zhuang Sun. "A New Technique To Characterize Fracture Density by Use of Neutron Porosity Logs Enhanced by Electrically Transported Contrast Agents." SPE Journal 22, no. 04 (April 20, 2017): 1034–45. http://dx.doi.org/10.2118/181509-pa.

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Summary Fracture-density evaluation has always been challenging for the petroleum industry, although it is a required characteristic for reliable reservoir characterization. Production can be directly controlled by fracture density, especially in tight reservoirs. Previous publications showed that use of high thermal neutron-capture cross-sectional (HTNCC) contrast agents can enhance the sensitivity of neutron logs to the presence of fractures. However, all these studies focus on locating the proppants. In this paper, we introduce a method of injecting electrically transported charged boron carbide (B4C) contrast agents to naturally fractured formations to enhance the propagation of the contrast agents into the secondary-fracture (natural and induced) network by use of an externally applied electric field and to characterize the fracture density in the unpropped region by use of the enhanced neutron porosity logs. We perform numerical simulations to validate the feasibility of the proposed technique. A physical model derived from electrophoretic velocity and material-balance formulations is proposed and solved to simulate the spatial distribution of contrast agents. Furthermore, we simulate neutron porosity logs by solving the neutron-diffusion equation, which allows a fast analysis for the proposed technique. The simulation results confirmed that an external electric field can significantly enhance the transport of charged contrast agents into the secondary-fracture network. Sensitivity analysis revealed that increasing particle ζ-potential can efficiently decrease the transport time. Furthermore, we applied the introduced technique on synthetic cases with variable secondary-fracture density ranging from 1 to 8%. The relative variation in the simulated neutron porosity before and after applying the electric potential field was up to 50% in a formation with 8% fracture density after applying an electric field for 6 hours. The proposed technique can potentially enable application of neutron porosity logs in fracture characterization, including assessment of secondary-fracture density, if combined with other well logs.

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KAKI, K. "A MODEL ANALYSIS OF NEUTRON DISTRIBUTION OF 208Pb BASED ON THE RELATIVISTIC IMPULSE APPROXIMATION OF PROTON ELASTIC SCATTERING." International Journal of Modern Physics E 13, no. 04 (August 2004): 787–99. http://dx.doi.org/10.1142/s0218301304002466.

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Tow parameters of a WoodsγSaxon form assumed for the neutron distribution of 208 Pb nucleus are determined with the reaction cross-section and the dip position of the differential cross-section. These observables are calculated based on the relativistic impulse approximation. For the proton density we take the profile obtained from the electron scattering by unfolding the proton form factor.

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Jasim, Mahdi Hadi. "The effect of deformation parameter of heavy nuclei on level density parameter." Iraqi Journal of Physics (IJP) 12, no. 25 (February 12, 2019): 38–43. http://dx.doi.org/10.30723/ijp.v12i25.302.

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The possible effect of the collective motion in heavy nuclei has been investigated in the framework of Nilson model. This effect has been searched realistically by calculating the level density, which plays a significant role in the description of the reaction cross sections in the statistical nuclear theory. The nuclear level density parameter for some deformed radioisotopes of (even- even) target nuclei (Dy, W and Os) is calculated, by taking into consideration the collective motion for excitation modes for the observed nuclear spectra near the neutron binding energy. The method employed in the present work assumes equidistant spacing of the collective coupled state bands of the considered isotopes. The present calculated results for first excited rotational band have been compared with the accumulated values from the literature for s-wave neutron resonance data, and were in good agreement with those data.

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Crupi, Vincenza, Aldo Fontana, Marco Giarola, Stéphane Longeville, Domenico Majolino, Gino Mariotto, Andrea Mele, et al. "Vibrational Density of States and Elastic Properties of Cross-Linked Polymers: Combining Inelastic Light and Neutron Scattering." Journal of Physical Chemistry B 118, no. 2 (January 6, 2014): 624–33. http://dx.doi.org/10.1021/jp410448y.

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Nishimura, D., M. Fukuda, M. Takechi, M. Mihara, D. Ishikawa, J. Komurasaki, K. Matsuta, et al. "Distinction between Proton-Neutron Density Distribution of Halo Nuclei at the Nuclear Surface via Reaction Cross Sections." Nuclear Physics A 834, no. 1-4 (March 2010): 470c—472c. http://dx.doi.org/10.1016/j.nuclphysa.2010.01.067.

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Zhang, Yu Bai, Yu Jun Zhang, and Jia Xing Zhao. "Preparation and Performance of Neutron Absorbing Dysprosium Oxide Ceramic." Key Engineering Materials 697 (July 2016): 404–8. http://dx.doi.org/10.4028/www.scientific.net/kem.697.404.

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Dysprosium is a kind of potential neutron absorption material with the thermal neutron absorption cross area of 950 Barn. In this paper, dysprosium oxide (Dy2O3) ceramic was prepared by pressureless sintering. The density, bending strength, fracture toughness and hardness of Dy2O3 ceramics under different sintering schedule were analyzed. The density of Dy2O3 ceramics was enhanced accompanied with the increase in sintering temperature, and it was close to the theoretical value when heated at 1630 °C. Bending strength reached a maximum of 117 MPa when sintering temperature was 1570 °C. However, fracture toughness was inversely proportional to the hardness approximately. As a consequence, the optimum sintering temperature for mechanical property of Dy2O3 ceramics was 1570 °C. The morphology of fracture surface was examined by SEM. The results showed that the porosity of Dy2O3 ceramics decreased with increasing temperature. Meanwhile, the Monte-Carlo software was used to simulate the neutron absorption property. The absorbtivity was about 99.13% when the neutron source was uniform energy spectrum of 10-11 Mev~10-5 Mev and the thickness of Dy2O3 was of 20 mm.

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Hinde, Alan L. "PRINSAS– a Windows-based computer program for the processing and interpretation of small-angle scattering data tailored to the analysis of sedimentary rocks." Journal of Applied Crystallography 37, no. 6 (November 11, 2004): 1020–24. http://dx.doi.org/10.1107/s0021889804021260.

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PRINSASis a Windows program that takes as input raw (post-reduction) small-angle neutron and small-angle X-ray scattering (SANS and SAXS) data obtained from various worldwide facilities, displays the raw curves in interactive log–log plots, and allows processing of the raw curves. Separate raw SANS and ultra-small-angle neutron scattering (USANS) curves can be combined into complete scattering curves for an individual sample. The combined curves can be interpreted and information inferred about sample structure, using built-in functions. These have been tailored for geological samples and other porous media, and include the ability to obtain an arbitrary distribution of scatterer sizes, the corresponding specific surface area of scatterers, and porosity (when the scatterers are pores), assuming spherical scatterers. A fractal model may also be assumed and the fractal dimension obtained. A utility for calculating scattering length density from the component oxides is included in the program.

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IBRAHEEM, AWAD A. "MICROSCOPICAL ANALYSIS OF THE REACTION CROSS-SECTIONS OF 11Li+12C and 22C+12C ELASTIC SCATTERING." International Journal of Modern Physics E 20, no. 03 (March 2011): 721–32. http://dx.doi.org/10.1142/s0218301311018186.

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Total reaction cross-sections of the two neutron halo nuclei 11Li and 22C elastic scattering from 12C target at E = 30–1000 MeV/nucleon have been analyzed using the eikonal phase shift based, for the first time, on the semi-phenomenological nucleon density. The obtained results reasonably agree with those of previous theoretical calculations as well as the corresponding experimental data.

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Lana, Maria do Carmo, Leandro Rampim, Tatiane Ohland, and Fernando Fávero. "Spacing, population density and nitrogen fertilization in corn grown in an Oxisoil." Revista Ceres 61, no. 3 (June 2014): 424–33. http://dx.doi.org/10.1590/s0034-737x2014000300018.

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The objective of this study was to evaluate yield components, leaf nitrogen content and grain yield in corn as affected by row spacing, plant density and nitrogen topdressing. The experiment was conducted with the single-cross hybrid AG 8021, in the municipality of Toledo-PR, in an Oxisoil under no-tillage system, in the crop year 2005/ 2006. The experiment was arranged in a randomized block design and treatments in split-split-plots, with four replications. The two row spacings (0.45 and 0.90 m) were allocated in the main plots, the two plant densities (60,000 and 80,000 plants ha-1) were allocated in the subplots and the three nitrogen rates (80, 100, 120 and 140 kg ha-1 N) were allocated in the sub-subplots. Topdress nitrogen was applied using urea as N source. The rise of the plant population from 60,000 to 80,000 plants ha-1 and the application of topdress nitrogen resulted in increased production components. The application of topdress fertilization provided increase in leaf N content and grain yield for the spacings 0.45 m and 0.90 m. Yield was higher in the spacing 0.45 m than 0.90 m. Yield was higher with 60,000 plants than with 80,000 plants at 0.90 m, while at 0.45 m there was no difference in relation to the plant density.

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OKUDUCU, Ş., N. N. AKTI, H. SARAÇ, M. H. BÖLÜKDEMIR, and E. TEL. "CALCULATION OF NUCLEAR LEVEL DENSITY PARAMETERS OF SOME LIGHT DEFORMED MEDICAL RADIONUCLIDES USING COLLECTIVE EXCITATION MODES OF OBSERVED NUCLEAR SPECTRA." Modern Physics Letters A 24, no. 33 (October 30, 2009): 2681–91. http://dx.doi.org/10.1142/s0217732309030977.

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In this study the nuclear energy level density based on nuclear collective excitation mechanism has been identified in terms of the low-lying collective level bands near the neutron binding energy. Nuclear level density parameters of some light deformed medical radionuclides used widely in medical applications have been calculated by using different collective excitation modes of observed nuclear spectra. The calculated parameters have been used successfully in estimation of the neutron-capture cross section basic data for the production of new medical radionuclides. The investigated radionuclides have been considered in the region of mass number 40<A<100. The method used in the present work assumes equidistance spacing of the collective coupled state bands of the interest radionuclides. The present calculated results have been compared with the compiled values from the literatures for s-wave neutron resonance data.

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Gheith, A. T., M. A. El-Sarraf, I. E. Hasan, N. L. Helal, R. A. Rizk, Amal A. El-Sawy, and A. El-Sayed Abdo. "Assessment of a polymeric composite as a radiation attenuator and a restoration mortar for cracking in biological shields." Nuclear Physics and Atomic Energy 21, no. 4 (December 25, 2020): 361–68. http://dx.doi.org/10.15407/jnpae2020.04.361.

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This work is dedicated to figuring out robust epoxy/magnetite/boron carbide (EP/Mag/B4C) composite for radiation attenuation at multiple applications related to nuclear installations, as well as restoration mortar for cracking developed in concrete biological shields. The mechanical properties (flexural, compressive, and impact strengths) and the physical properties (water absorption, porosity, and dry bulk density), each, have been performed to label the composite integrity for practical application. In practice, attenuation properties have been performed by using a collimated beam emitted from spontaneous fission 252Cf (100 μg) neutron source and neutron gamma spectrometer with stilbene scintillator. The pulse shape discrimination technique which would come of the zero cross over method was used to measure the fast neutron and gamma-ray spectra. Thermal neutron fluxes have been measured by using the thermal neutron detection system and the BF-3 detector. The attenuation parameters: precisely, macroscopic effective removal cross-sections ΣR (cm-1), macroscopic cross-sections Σ (cm-1), and total attenuation coefficients μ (cm-1) of fast and thermal neutrons and total gamma-rays respectively were evaluated using the attenuation relations. Also, the MCNP5 code and MERCSF-N program have been used to compute the parameters theoretically. When applicable, measured and calculated results were compared, and it tells us a comprehensive agreement.

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Çapalı, Veli. "Analysis of neutron capture cross section using different level density models on cadmium isotopes up to 250 keV neutron-induced energy and GEANT4 simulation." Indian Journal of Physics 94, no. 7 (June 25, 2019): 1041–49. http://dx.doi.org/10.1007/s12648-019-01534-3.

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Wilson, DJ, and AIM Ritchie. "Neutron moisture meter : the dependence of their response on soil parameters." Soil Research 24, no. 1 (1986): 11. http://dx.doi.org/10.1071/sr9860011.

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A multigroup diffusion theory calculation based on a nuclear reactor neutronics code is used to determine the response of a neutron moisture meter to changes in soil parameters such as dry soil density, soil water content, thermal neutron absorption cross-section and neutron scattering crosssection. Empirical equations which fit the results can be used to estimate the response at values of the soil parameters other than those used in the calculations. These equations can also be used to estimate the accuracy with which the parameters must be known to achieve a required accuracy in the derived soil water content.

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MADANI, JAMAL H. "EFFECT OF COULOMB ENERGY SHIFT ON PROTON TOTAL REACTION CROSS-SECTION." International Journal of Modern Physics E 13, no. 04 (August 2004): 827–33. http://dx.doi.org/10.1142/s021830130400248x.

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In this work we study the effect of the Coulomb energy shift on proton total reaction cross-section (σ R ) at 25, 50, and 100 MeV for several nuclei in the mass region 12≤A≤208. The cross-sections are computed using the Coulomb modified Glauber model in the optical limit approximation, and the semi-phenomenological proton and neutron density distributions. We find that the Coulomb energy shift has a significant effect on the calculated σ R , and that it brings the theory quite close to the experiment.

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Kukhotska, О., I. Ovdiienko, and M. Ieremenko. "Uncertainty Analysis of WWER-1000 Core Macroscopic Cross Sections due to Spectral Effects." Nuclear and Radiation Safety, no. 4(88) (December 11, 2020): 39–46. http://dx.doi.org/10.32918/nrs.2020.4(88).05.

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The paper presents the results of uncertainty analysis of WWER‑1000 core macroscopic cross sections due to spectral effects during WWER‑1000 fuel burnup and the analysis of cross section sensitivity from thermophysical parameters of the calculated cell, which affect energy spectrum of neutron flux density. The calculation of changes in the isotopic composition during burnup and the preparation of macroscopic cross sections used the developed HELIOS computer model [1] for TVSA, which is currently operated at most Ukrainian WWER‑1000 units. The GRS approach applying Software for Uncertainty and Sensitivity Analyses (SUSA) [2] was chosen to assess the uncertainty of the macroscopic cross sections due to spectral effects and analysis of cross section sensitivity from thermophysical parameters. The spectral effect on macroscopic cross sections was taken into account by calculating the fuel burnup for variational sets of thermophysical parameters (fuel temperature, coolant temperature and density, boric acid concentration) prepared in advance by the SUSA program, as a result of which fuel isotopic composition vectors were obtained. After that, neutronic constants for the reference state were developed for each of the sets of isotopic composition, which corresponded to a certain set of thermophysical parameters. At the next stage, the uncertainty of macroscopic cross sections of the interaction due to the spectral effects on the isotopic composition of the fuel was analyzed using SUSA 4, followed by the analysis of cross section sensitivity from thermophysical parameters of the calculated cell affecting energy spectrum of neutron flux density. In the future, the uncertainty of two-group macroscopic diffusion constants can be used to estimate the overall uncertainty of neutronic characteristics in large-grid core calculations, in particular, in the safety analysis.

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Journal articles on the topic 'Neutron – density cross plots'

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