Drip Line Research Articles

Influence of Nuclear Potential Diffuseness on the Neutron Halo Structure in Zr Isotopes near the Neutron Drip Line

Influence of Nuclear Potential Diffuseness on the Neutron Halo Structure in Zr Isotopes near the Neutron Drip Line

Polymer fertilizer and the fertigation of grape tomatoes in protected cultivation

Efficient fertilization alternatives are needed in protected environments that do not cause soil salinization, as with fertigation. Thus, it is important to advance knowledge with new technologies to meet these lacks. Hence, the objective was to compare the use efficiency of polymer fertilizer to fertigation for a tomato cultivar, the Milla cultivar (grape tomato type). The experiment was conducted in a protected environment, with seedlings transplanted to areas along surface drip lines, with a randomized block experimental design consisting of two treatments with six replications. The evaluated treatments were controlled-release polymers (POL) and nutrient fertigation (FERT). Quantitative and qualitative parameters were evaluated, as well as the production of fresh and dry plant masses in each treatment. Monitoring the electrical conductivity in the soil ensured that the POL treatment maintained crop nutrition throughout the experiment by an average of 0.68 dS m − 1. In addition, Tukey's test at 5% showed any significant difference in the quantitative and qualitative analysis of the fruits between the types of fertilization. Thus, we concluded the polymer fertilizer met the nutritional demand of the grape tomato plants and can replace fertigation in a protected environment without compromising productivity.

Covariances from model variation: Application to quantities for astrophysics

In this work, covariance matrices coming from model variations, in contrast to the usual parameter variations, are presented. The considered phenomenological and microscopic models are included in the code TALYS, and concern level densities, gamma strength functions, optical potentials and masses. A total of 288 model sets for each isotope is used to estimate both uncertainties and correlations from systematical origin. The calculated quantities are of interest for astrophysical applications, such as capture cross sections, and reaction rates. The isotopes (3 ≤ Z ≤ 100) are from the proton to neutron drip lines, covering about 8800 cases, and are included in the TENDL-2021 library.

Reducing aluminum is the key nutrient management strategy for ameliorating soil acidification and improving root growth in an acidic citrus orchard

AbstractAluminum (Al) toxicity is one of the most serious hazards of soil acidification, which limits root formation and hinders crop growth. Soil acidification in orchards has been widely reported. However, there is little information about the effect of Al3+ on citrus roots in acidified red soil. Taking pomelo (Citrus grandis), the main citrus variety in Southeast China, as an example, soil surveys were conducted to analyze the status and characteristics of acidification in pomelo orchards. Subsequently, we explored whether optimized fertilization and liming can effectively reduce Al toxicity in roots and increase yield by three treatments, including farmer fertilization practice (FFP), NPK optimization (OPT), and OPT combined with lime (OPT+L). The results showed that (1) rapid soil acidification occurred in pomelo orchards in the past 40 years (with a decrease of 0.81 units). The severity of soil acidification increases with orchard age. In addition, the soil pH and base saturation (BS) at the drip line (DL; i.e., fertilization site) were the lowest, while the concentration of exchangeable acid (Ex.Acid) and exchangeable Al (Ex.Al), and the ratio of Ex.Al to cation exchange capacity (Ex.Al%) was highest compared to other locations away from DL. Random forest analysis indicated Ex.Al was the most important factor to reflect soil acidification. (2) Under the OPT+L treatment, the concentrations of soil Ex.Acid and Ex.Al decreased, and BS increased, which markedly reduced the Al3+ concentration in the roots and promoted root growth. OPT+L significantly decreased the Al concentrations in soils (by 71.3%) and roots (by 47.8%) but increased root activity, root length, root tips and root surface area by 119.2%, 80.3%, 124.6% and 136.6%, respectively. In addition, structural equation modeling further proved that increasing soil pH and BS while decreasing Ex.Al was beneficial to citrus production in acidic soil, and optimized fertilization and lime application are necessary.

Interactive Effects of Nitrogen Application and Irrigation on Water Use, Growth and Tuber Yield of Potato under Subsurface Drip Irrigation

Potatoes are a high-value crop with a shallow root system and high fertilizer requirements. The primary emphasis in potato production is minimizing nitrogen-leaching losses from the shallow root zone through fertigation. Therefore, a field experiment was conducted for two consecutive years, 2018–2019 2019–2020 to assess the effect of nitrogen and irrigation amount and frequency on tuber yield, water balance components and water productivity of potatoes under surface and subsurface drip irrigation. The experiment was laid out in a split-plot design with three nitrogen levels (187.5 kg N ha−1 (N1), 150 kg N ha−1 (N2) and 112.5 kg N ha−1 (N3)) in main plots and six irrigation levels in the subsurface (drip lines were laid at 20 cm depth) and one surface drip in subplots. Irrigation scheduling was based on 100% of cumulative pan evaporation at an alternate (I1) and two-day interval (I2), 80% of cumulative pan evaporation at an alternate (I3) and two-day interval (I4), 60% of cumulative pan evaporation at an alternate (I5) and two-day interval (I6) and 80% of cumulative pan evaporation at alternate days with surface drip (I7). Our results showed that potato transpiration was higher in N1 and N2 compared to N3, while soil evaporation was higher in N3 over N1 and N2. Irrigation regimes I5 and I6 had lower transpiration than I1, I2, I3 and I7, while I7 had more soil evaporation than I1, I2 and I3. Leaf area index (LAI), dry matter accumulation (DMA), root mass density (RMD) and tuber yield in N1 and N2 were at par but significantly higher than N3. The LAI and DMA were statistically at par in I1, I2 and I3 but significantly higher than recommended irrigation (I7). Tuber yield was statistically at par in I1, I2, I3 and I7 but I3 and I7 saved 20% irrigation water compared to I1 and I2. On the other hand, real water productivity (WPET) under N1 and N2 were comparable in I3 and I4 but significantly higher than recommended practice (I7) as pooled evapotranspiration (ET) and soil evaporation (E) in I7 were 19.5 and 20.6 mm higher, respectively, than in I3. Among interactive treatment combinations, N1I1, N1I2, N1I3, N1I7, N2I1, N2I2 and N2I3 recorded the highest tuber yields without any significant differences among them. Treatment N2I3 saved 20% nitrogen and irrigation water compared to all other combinations. Water productivity in N1 and N2 was comparable in I3 and I4 but significantly higher than recommended practice (I7).

Observation of a Strongly Isospin-Mixed Doublet in ^{26}Si via β-Delayed Two-Proton Decay of ^{26}P.

β decay of proton-rich nuclei plays an important role in exploring isospin mixing. The β decay of ^{26}P at the proton drip line is studied using double-sided silicon strip detectors operating in conjunction with high-purity germanium detectors. The T=2 isobaric analog state (IAS) at 13 055keV and two new high-lying states at 13 380 and 11 912keV in ^{26}Si are unambiguously identified through β-delayed two-proton emission (β2p). Angular correlations of two protons emitted from ^{26}Si excited states populated by ^{26}P β decay are measured, which suggests that the two protons are emitted mainly sequentially. We report the first observation of a strongly isospin-mixed doublet that deexcites mainly via two-proton decay. The isospin mixing matrix element between the ^{26}Si IAS and the nearby 13 380-keV state is determined to be 130(21)keV, and this result represents the strongest mixing, highest excitation energy, and largest level spacing of a doublet ever observed in β-decay experiments.

Two-neutron drip lines of a few single lambda hypernuclei

Two-neutron drip lines of a few single lambda hypernuclei are studied through a phenomenological binding energy model. This model, which is built from the Bethe-Weizsäcker formula, explicitly takes into account hyperon mass and strangeness. For the hypernuclear isotopic chains of the elements C—Mn, the heaviest isotope in each chain that is stable with respect to two-neutron decay is located.

Evaluation of Soil-N Distribution and Corn Yield in Fertigation Systems

In Korea, field crop yields are steadily declining due to drought though it can be managed through irrigation. To address this problem, irrigation technology using subsurface drip line (SDL) has only recently been developed and distributed in Korea. In this study, fertilizer was supplied through SDL while growing corn on the arable land where SDL were buried. SDL was installed and a venturi system was connected for fertilizer injection. Irrigation and fertigation were controlled by connecting to the control panel. During corn cultivation, soil moisture levels were maintained at 100% and above 100% of the field capacity by soil moisture sensor. Nitrogen amounts and distributions of nitrate contents were measured by distance from SDL. Corn growth and yield characteristics were also measured. As a result, the total amount of nitrogen by distance released from the SDL was uniform, When evaluating the distributions of nitrate contents in the soil released from the SDL, NO3 was spread first to the upper part of the soil (after 1 day). And, after 9 day NO3 was spread evenly over the upper part of the soil rather than leaking to the lower part. It was determined that nutrients could be stably supplied to crops. There was a tendency that weight and diameter of ear during the growth of corn were greater than those supplied with topsoil, and the corn yield was also increased. Subsurface drip fertigation system is expected to have a positive effect on agricultural automation for better agriculture production.Distributions of nitrate content in the soil released from the subsurface drip over time; red dot: location of subsurface drip line, unit of legend: nitrate concentration (mg kg-1) - Each color represents a certain range of values, nday: n day after fertigation.

Crossing N=28 Toward the Neutron Drip Line: First Measurement of Half-Lives at FRIB

New half-lives for exotic isotopes approaching the neutron drip-line in the vicinity of N∼28 for Z=12-15 were measured at the Facility for Rare Isotope Beams (FRIB) with the FRIB decay station initiator. The first experimental results are compared to the latest quasiparticle random phase approximation and shell-model calculations. Overall, the measured half-lives are consistent with the available theoretical descriptions and suggest a well-developed region of deformation below ^{48}Ca in the N=28 isotones. The erosion of the Z=14 subshell closure in Si is experimentally confirmed at N=28, and a reduction in the ^{38}Mg half-life is observed as compared with its isotopic neighbors, which does not seem to be predicted well based on the decay energy and deformation trends. This highlights the need for both additional data in this very exotic region, and for more advanced theoretical efforts.

Influence of entrance channel on production cross sections of exotic actinides in multinucleon transfer reactions

Within the framework of the dinuclear system model, the influence of mass asymmetry and the isospin effect on the production of exotic actinides have been investigated systematically. The isotopic yields populate in multinucleon transfer reactions of Ca(48), Kr(86), Xe(136), and U(238) bombarding on Cm(248) are analyzed and compared to the available experimental data. Systematics on the production of unknown actinides from Ac to Lr via the available stable elements on the earth (from Ar to U) as projectiles-induced reactions with $^{232}$Th, $^{238}$U and $^{248}$Cm are investigated thoroughly. Potential energy surface and total kinetic energy distribution for the reaction system are calculated and can be used to predict the production cross-section trends. It is found that the heavier projectile leads to the wider isotopic chain distribution for the same target. The heavier target-based reactions prefer to produce plenty of exotic actinides through both mechanisms of deep-inelastic and quasi-fission reactions. Isospin relaxation plays a crucial role in the colliding process, resulting in actinide isotopic distribution tends to shift to the drip lines. Massive new actinides have been predicted at the level of nanobarn to millibarn. The optimal projectile-target combinations and beam energies were proposed for the forthcoming experiments.

Proton drip line for light hypernuclei

Proton drip line for light hypernuclei

A study of shape transition and bubbleness in Ne isotopes

We have studied shape transition and development of quadrupole deformation in even-even 18-36Ne isotopes by employing covariant density functional theory (CDFT) with density-dependent meson exchange (DD-ME2) and density-dependent point coupling (DD-PC1) parameter sets. A sudden shape transition is observed in the Ne isotopic chain and can be related to the evolution of shell structure of single-particle orbitals. The correlations between shape transition and discontinuity in the other physical observables are also examined. Our results for ground-state properties are in good agreement with the available experimental data and the result of various theoretical models. The present calculations infer the neutron drip line at 34Ne. In addition to shape transition, the bubble structure is also studied for magic nuclei in this chain.

Study of Multinucleon Transfer Mechanisms in 86Kr-Induced Peripheral Reactions at 15 and 25 MeV/nucleon

This paper presents our recent studies of the multinucleon transfer in peripheral collisions in reactions near the Fermi regime. Specifically, the reactions of a 86Kr beam at 15 MeV/nucleon with targets of 124Sn ,112Sn, 64Ni and 58Ni and reactions of a 86Kr beam at 25 MeV/nucleon with targets of 124Sn and 112Sn. The experimental data were obtained from the previous work of our group with the MARS spectrometer at the Cyclotron Institute of Texas A&M University. Our current focus is the thorough study of the experimental mass and momentum distributions of the projectile-like fragments. The momentum distributions are characterised by a narrow quasi-elastic peak and a broader deep-inelastic peak. We employed two-body kinematics to characterize the excitation energies of these reactions. We also compared the data with model calculations. The dynamical stage is described with either the Deep-Inelastic Transfer Model (DIT), or with the microscopic Constrained Molecular Dynamics model (CoMD). The de-excitation of the hot projectile-like fragments is performed with the Gemini model. Studying these reactions will provide us with a better understanding as to how the energy of the beam and the different targets affect the mechanism of the multinucleon transfer reactions. With the recent work, our continued efforts in the study of peripheral reactions in the Fermi energy regime delineate new opportunities to elucidate the reaction mechanism(s) of rare isotope production and may effectively contribute to the study of unexplored regions of the nuclear chart toward the r-process and the neutron drip line.

IoT based smart irrigation system for communal use

Kenya is experiencing a rapid human population growth and consequently rising demand for food. This is happening at the backdrop of adverse climatic changes currently being experienced. The problem is further aggravated by the fact that more than 80% of the country’s landmass is classified as Arid and Semi-Arid Lands (ASALs). In order to meet the food demand, there is need to divorce from rain-fed agriculture and put most of the arable land under irrigation. Since Kenya is a water scarce country, efficient irrigation systems are required. An efficient irrigation system that promotes use of rain water harvesting technologies and maximizes crop water productivity through use of appropriate sensors and wireless communication technology has been developed. The innovation involves use of farmers’ earth pans for harvesting and storing rain water and irrigating fields through drip lines. In addition, smart soil moisture sensors are fitted to each field under irrigation for real-time monitoring of soil moisture content and automatically notifying an irrigation administrator through mobile phone when crops require watering. The administrator is equipped with a tricycle fitted with solar powered water pumping system for pumping water from the earth pan to the crops. When the operator receives a signal request from water sensors in field he/she moves with the tri-cycle and services it. The smart sensors (IoT based) installed in the field will then notify him/her when sufficient amount of water has been received so that irrigation can be stopped. The operator waits for the next request from another farmer’s field to service. The technology has been tested in different portions of the university land under irrigation. The results indicate that crops receive timely watering and show no water stress. The innovation has the potential of making high tech irrigation system accessible to small scale farmers at an affordable cost and enhance food production and in turn food security in the country.

The eye wash technique: A simple and effective technique for intraoperative ocular surface lavage

Objectives: The author proposes an extremely effective and practical method of ocular surface hydrating and cleaning during anterior segment surgery, the Eye Wash Technique (EWT), in substitution for the traditional methods employing a syringe and cannula for ocular irrigation. Materials and Methods: The EWT utilizes the intraocular irrigating solution (IS) used in the surgery. It is performed by employing the irrigating line of the phacoemulsification (phaco) machine or the irrigating fluid IV drip in case of manual cataract surgery. The eye irrigation is performed directly from the Luer end attachment of these irrigating lines, which is positioned above the inner cantus pointing to the globe’s nasal limbal region. With the phaco machine pedal in position 1 (irrigation only) or in panel continuous irrigation mode in case of phaco surgery, or by opening the roller clamp of the IV drip line in case of manual surgery, IS flow ensues and is directed to the eye from a nasal direction to provide a steady flow to wash the exposed eye surface as well as the lid margins and lid speculum. The irrigation is maintained for two to five seconds with side-to-side jiggling if needed, to ensure complete ocular surface coverage. Cornea hydration is achieved and any unwanted material on the ocular surface is washed out. Results: The EWT was easily incorporated into the surgical routine with no difficulty in adaptation to the technique or in its employment. The surgical time was not prolonged when employing the technique. The EWT effectively provided both corneal hydration and ocular surface cleaning every time it was used, with no need to resort to the traditional syringe and cannula irrigation method at any time. Conclusion: The EWT should be incorporated into the anterior segment surgical routine and performed at the beginning of surgery, before inserting the intraocular lens, and at the end of the surgery; also, at any time during surgery should the need arise, enhancing anterior segment surgical visualization and safety.

Enhanced moments of inertia for rotation in neutron-rich nuclei

Ground-state moments of inertia (MoI) are investigated for approximately 1700 even–even nuclei from the proton drip line to the neutron drip up to Z=120 and N=184. The cranked Hartree–Fock–Bogoliubov equation is solved in the coordinate space using the Skyrme and pairing energy density functionals. This model well describes the available experimental data of the first excited Iπ=2+ state energy of more than 300 nuclides possessing appreciable deformation. The MoI is found to greatly increase near the drip line, whereas the deformation is found to be not as strong as estimated by the empirical relation when the pairing functional including the isovector-density dependence is adopted. The currently used pairing functionals produce large uncertainties in the prediction of E(21+) values near the neutron drip line.

Weak process for Iron isotopes chain used as seed for heavy elements nucleosynthesis

The weak processes are a key to understand the nucleosynthesis of heavy elements in the universe. In this work we have studied weak processes such as β-decay and neutrino capture that are very important for the r-process. This process takes place in a region between neutron drip and β-stability line. For nuclei far from β-stability line the experimental data are very scarce. To study the nucleosynthesis of heavy elements in astrophysics sites like Binary Neutron Star merger (BNS) and Supernova explosions, we have employed the Gross Theory of Beta Decay (GTBD) to evaluate the neutrino-nucleus cross sections and β-decay half-lives. Our 56Fe(νe , e −)56Co cross section show a excelent agreement with microscopic models and the half-lives well reproduce the experimental data with a satisfactory accuracy. We have fitted the neutrino-nucleus cross sections obtained by GTBD using a four degree polynomial dependence of the incident neutrino energy. This dependence allows us to systematically calculate the neutrino-nucleus cross sections for a large amount of nuclei, as occurs in the r-process nucleosynthesis calculation (more than 4000 nuclei). Our fitting and interpolation procedures are shown to be in a good agreement and the GTBD cross sections are successfully reproduced.

Superconducting Curved Canted–Cosine–Theta (CCT) for the HIE-ISOLDE Recoil Separator Ring at CERN

The ISOLDE facility at CERN delivers the largest range of low-energy radioactive beams, exploited by several detector systems to investigate nuclear properties from the stable isotopes to the very exotic systems close to the neutron or proton drip lines. These studies can largely benefit from the use of a high-resolution fragment separator. To achieve this goal, an innovative spectrometer based on a compact superconducting (SC) ring, the Isolde Superconducting Recoil Separator (ISRS), is being studied. The ring will operate as an isochronous non-scaling fixed-field alternating-gradient (FFAG) system based on Canted-Cosine-Theta (CCT) magnets. These multifunction magnets have two alternating-gradient quadrupoles nested inside an outer dipole. According to preliminary beam dynamics studies, the dipole will need to generate a maximum field of 2.2 T. A maximum quadrupole gradient of approximately 14 T/m will guarantee orbit stability for heavy ions with a maximum kinetic energy of 10 MeV/u. Fine tuning of the CCT magnets and the FFAG optics will provide very large solid angles > 100 msr and momentum acceptances Δp/p > 20%. In this paper we present, the magnet designs and their optimisation. A cost-effective active stray field superconducting coil shield design has been introduced to be able to remove approximate 4000 kg of iron yoke and the complexity of building a tightly curved yoke.

Systematic study of two-proton radioactivity within various versions of proximity formalisms

In this work, we study the two-proton (2p) radioactivity half-lives for nuclei near or beyond the proton drip line within the Coulomb and proximity potential model (CPPM). We investigate the 28 versions of proximity potential formalisms, which were proposed for heavy-ion fusion reactions, heavy-ion elastic scattering, ternary fission and other applications. The results indicate that BW91 and Bass77 are inappropriate for handling 2p radioactivity since the classical turning point r in cannot be obtained for the depth of the total interaction potential between the released two protons and daughter nucleus being greater than the 2p radioactivity released energy. Among the other 26 proximity potential formalisms, the one proposed by Royer et al in 1984 denoted as Prox.77-8 is the best version with the lowest rms deviations between experimental data and relevant theoretical results. It is worth mentioning that the calculations of Coulomb and Proximity Potential Model for Deformed Nuclei (2021 PRC 104, 064 613) has least standard deviation (σ = 0.592) compared with present model and other models/formulae. Furthermore, we use CPPM with Prox.77-8 to predict the 2p radioactivity half-lives of 35 potential candidates whose 2p radioactivity is energetically allowed or observed but not yet quantified in NUBASE2020. The predicted results are consistent with previous theoretical models such as the unified fission model (UFM), generalized liquid drop model (GLDM) and effective liquid drop model (ELDM).

Excitation spectra of the heaviest carbon isotopes investigated within the CD-Bonn Gamow shell model

Neutron-rich carbon isotopes have been investigated within the Gamow shell model (GSM) based on a realistic nuclear force. $^{14}\mathrm{C}$ was chosen as the core in the shell-model calculations of the neutron-rich carbon isotopes. The effect from the coupling to the continuum is well considered by using the complex-momentum Berggren representation which treats bound, resonant, and continuum states on an equal footing. Using the many-body perturbation theory named the $\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{Q}$-box folded-diagram method, the complex GSM effective interaction was derived from the CD-Bonn interaction. We find that the inclusion of the continuum coupling in the calculation is important in the description of neutron-rich carbon isotopes, especially in reproducing the experimental $1/{2}^{+}$ ground states of $^{19}\mathrm{C}$ and $^{21}\mathrm{C}$. Our calculation indicates a shell closure at $N=16$ in the carbon chain, while the $N=14$ shell, which exists in the next even-$Z$ chain of oxygen isotopes, disappears. The calculation suggests that $^{22}\mathrm{C}$ is the heaviest bound carbon isotope, i.e., the neutron drip line.