Empirical Saturation Research Articles

Bayesian mixture model approach to quantifying the empirical nuclear saturation point

Bayesian mixture model approach to quantifying the empirical nuclear saturation point

Numerical analysis study on determination of unfrozen water saturation curve for sandy soil

The presence of unfrozen water in frozen soils considerably affects the thermal, hydraulic, and mechanical behaviors of the ground. A thorough examination and accurate estimation of the unfrozen-water saturation curve of target soil materials are required to reliably predict the behavior of frozen soils. This study presents a methodology for accurately determining the curve-fitting coefficients included in an empirical model equation. This study differentiates itself from existing research by presenting a method for easily determining the fitting curve coefficient of empirical unfrozen water saturation model through simple freezing experiment data (time-temperature data) and iterative calculation of numerical analysis. An appropriate unfrozen-water saturation curve of sandy soil specimens was obtained by conducting iterative numerical analyses based on indoor experimental data. The reliability of the determined unfrozen-water saturation curve was evaluated by comparing the simulation results for a single freeze-pipe freezing example with an analytical solution.

Rationalization, enchantment, and subjectivation – lessons for risk communication from a New Phenomenology of everyday reasoning

The success of risk communication in democratic societies depends on a good understanding of people’s knowledge and ways of reasoning, which requires a broader perspective of ‘societal risk communication’. This includes all kinds of rationales how people and social institutions communicate, make sense of, and engage with risk and uncertainty to better understand the epistemological challenges for risk communication by experts and social decision-makers. For this purpose, we utilize insights from New Phenomenology and specify three rationales how people and social institutions engage with risk and uncertainty, following earlier work: ‘rational’ evidence-based modes of engaging with risk are accompanied by ‘non-rational’ (e.g. faith, hope) and ‘in-between’ modes (e.g. intuition, trust). In everyday life these idealtype modes rarely occur in pure but modified form. Therefore, we advance Zinn’s original work by introducing a dynamic model of decision-making under risk and uncertainty along the three types drawing on New Phenomenology. There are systematic differences in the embodied and the abstract forms of knowledge people refer to when making sense of risk and uncertainty while the abstract forms differ in their empirical saturation. The dynamized framework helps to understand institutional challenges as well as people’s sense-making, which show tendencies of ‘rationalization’, ‘enchantment’ and ‘subjectivation’.

Optimizing elastic optical networks quality of transmission with an empirical optical amplifier gain saturation model

In this paper, we revisit the problem of adjusting transceiver power, amplifier gain, and nodal gain in optical-bypass-enabled networks, taking into account an empirical model of erbium-doped fiber amplifier (EDFA) gain saturation. We assume that network demands have been routed via the shortest possible paths. A heuristic algorithm, which estimates the degradation of the signal-to-noise ratio (SNR) for each demand, is used to assign the modulation level and spectrum slots to the routed demands. Our optimization process aims to maximize the minimum SNR margins of demands, by adjusting EDFA small-signal gain, variable optical attenuator (VOA) attenuation, and transceiver power. Constraints and impairments imposed by the physical-layer include EDFA and VOA gain limits, transceiver power limits, receiver sensitivity, insertion loss of optical switch input ports, EDFA gain saturation, EDFA noise, and fiber non-linear interference. These are modeled using the Gaussian noise model. The proposed optimization problem is formulated as a geometric programming problem and then converted into an equivalent convex problem.Numerical results suggest that in the optimal solution of our optimization, all demands are served with typically low bit error rates (BER) (<10−4). We calculate the operational gains of the EDFA to set the spans to full compensation whenever possible. Pre-amplifiers and line amplifiers do not experience gain saturation due to relatively small input powers, while approximately 10% of boosters undergo more than a 1 dB gain reduction due to high input powers. We observe that overlooking the effect of EDFA gain saturation and physical-layer-imposed constraints such as nodal gain limits or transceiver power limits during network optimization leads to a considerable number of blocked demands due to SNR degradation or high BER (>10−3).

Theory genesis in the design-based research process – a subject didactic view on theory application, verification and development by using design principles

This article intends to provide answers to the overarching question of how theories, which are transferred into concrete design principles, develop in a DBR process. Theories from three completed DBR projects in geography didactics will be examined regarding their genesis in the research process and their function in individual phases of a DBR cycle. The chosen theories differ in scope, depth and empirical saturation. The aim is to analyse the role that these theories take in the DBR research process and to discuss them in terms of their contribution to the output of DBR projects and a possible generalisability of the findings. Finally, the results of the analyses are synthesised into a model for theory genesis in DBR projects.

Comparison of Log and Empirical High Function Saturation and It’s Effect on Volumetric Calculations

This paper discusses the comparison of the Saturation Height Function between the saturation calculation method based on log data using various equations such as Archie, Indonesia and Dual Water with the empirical method which is popularly used in the oil and gas industry, namely the Cuddy method. The advantages and disadvantages of each method will be discussed. Each method of calculating saturation with log data is compared with the Cuddy method to get an idea of ​​which geological conditions are most suitable for the Cuddy method. This study was carried out by modeling the well oil saturation height profile from an Oligocene well from the North West Java Basin of Indonesia. This well was chosen because it did not have complete data, only a series of Electrical logs and no conventional core and SCAL data. Apart from comparing each method on the well, this paper also compares volumetric calculations based on the resulting oil saturation height profile model.By comparing the results of each volumetric calculation, we can find out which method gives better results so that without core data we can still make STOIIP predictions quite validly.

The Typologization of the Beliefs of History Teachers in Planning the Teaching-Learning of History in Secondary Schools in Cameroon

The question the identification of key beliefs in the teaching-learning history is relevant. However, if the typology of beliefs exists in the educational files, it faces an uneven development of the littrature. Many studies have deepened the typologization of epistemological beliefs as well as the typologization of psychological and pedagogical beliefs which remains fallow in Cameroon. Hence the following reseach question: what beliefs do history teachers believe? This article focuses on the study of the typologization of programming of teaching-learning of history. To meet this objective, an exploratory-descrpitive reseach combining a quantitative component and qualitative component was carried out, involving 65 teachers and 160 educational sheets. In order to type the beliefs of the teachers in planing of teaching –learning, we asssociated the questionnaire, individual interview and documentary analysis which only made it possible to triangulate the data but also to reach the empirical saturation. Data revealed positive beliefs in history reaching –learning. This result summons teachers to a triple vigilance: constructivist epistemological vigilance, constructivist pedagogical vigilance, constructivist psychological vigilance.

Saturation evaluation for fine-grained sediments

Accurate quantification of the gas hydrate content in the deep sea is useful for assessing the resource potential and understanding the role of gas hydrates in the global carbon cycle. Resistivity logging data combined with Archie's equation are often used to calculate gas hydrate saturation, but the reliability is dependent on the rationality of the empirical parameter cementation factor and saturation index. At present, an increasing number of fine-grained hydrate-rich sediment regions have been discovered worldwide through drilling efforts, and the reservoir types and hydrate distribution are diverse, which differs greatly from that of coarse-grained reservoirs of hydrate-bearing sediment. This results in vertical variations in m and n through stratigraphy. At present, the saturation evaluation effect of these reservoirs cannot be improved. In this work, a theory for the determination of the cementation factor and saturation index was first proposed to obtain reliable and variable values of the empirical parameters. Then, a hydrate saturation evaluation technique with variables m and n was formed based on the well logging data. This technique was used to evaluate complex fine-grained hydrate-bearing reservoirs in several regions worldwide. It was found that the highest n could be 16, and the log calculation results were more consistent with the core hydrate saturation. Additionally, the cause of the excessively high n values was explained from physical principles, and the result was verified with actually well log data. In future evaluations of the amount of hydrate resources in fine-grained sediment reservoirs worldwide, new saturation estimation methods should be taken into account to advance hydrate research.

Covariant density functional theory with localized exchange terms

A new density-dependent point-coupling covariant density functional PCF-PK1 is proposed, where the exchange terms of the four-fermion terms are local and are taken into account with the Fierz transformation. The coupling constants of the PCF-PK1 functional are determined by empirical saturation properties and ab initio equation of state and proton-neutron Dirac mass splittings for nuclear matter as well as the ground-state properties of selected spherical nuclei. The success of the PCF-PK1 is illustrated with properties of the infinite nuclear matter and finite nuclei including the ground-state properties and the Gamow-Teller resonances. In particular, the PCFPK1 eliminates the spurious shell closures at Z = 58 and Z = 92, which exist commonly in many covariant density functionals without exchange terms. Moreover, the Gamow-Teller resonances are nicely reproduced without any adjustable parameters, and this demonstrates that a self-consistent description for the Gamow-Teller resonances can be achieved with the localized exchange terms in the PCF-PK1. ?

¿Boca sana o boca enferma? Representaciones de la salud bucal en sectores vulnerables

Background: The society and the State must provide dental care and help prevent oral health problems by implementing public policies with cultural relevance that allow society to address and improve the inequity in health care that systematically affects people's well-being. The present study seeks to understand the representations of dental health in people who attend primary care services in vulnerable urban and rural areas of the central zone of Chile. Specifically, the representations of the causes, morbidities, and symptoms attributed to the healthy and diseased mouth. Material and Methods: A qualitative study based on the Grounded Theory was conducted, analyzing the social representations of oral health in a sample of 161 adult people receiving treatment at public primary care services and dental emergency units in rural and urban communes. Empirical saturation and triangulation by time, place, and subjects give reliability to the study. Results: The data obtained show that dental health is mainly valued for its implications for self-esteem and social integration. A naturalization of dental health problems is evidenced as an adaptive strategy to traditional access barriers, which is counterproductive with preventive strategies. Conclusion: The results of the study suggest the need to reinforce education in dental health implemented in a transversal manner, having aesthetic values and the population's expectations of sociability as the key to action.

Appearance of a peak in the symmetry energy at N=126 for the Pb isotopic chain within the relativistic energy density functional approach

The newly derived relativistic energy density functional [\textcolor{blue}{ Phys. Rev. C \textbf{103}, 024305 (2021)}], which stems from the effective field theory motivated relativistic mean-field (E-RMF) is employed to establish the appearance of peak/kink in the symmetry energy over the isotopic chain of Pb-nuclei. The coherent density fluctuation model parametrization procedure for finite nuclei is adopted here to obtain the relativistic energy density functional at local density. The relativistic energy density functional from E-RMFT takes precedence over the Br\"uckner energy density functional as it accurately predicts the empirical saturation density and binding energy per nucleon $E/A$, so-called 'Coester Band Problem'. Interestingly, using the relativistic energy density functional, it is possible to predict the peak at $N=126$ for recently developed G3 and widely used NL3 parameter sets, which is not observed for Br\"uckener's functional in-spite of using the E-RMF density. From the present analysis, the newly fitted energy density functional is found to be minutely sensitive to the choice of the parameter sets employed.

Logging-based assessment of low-resistivity oil zones: A case study from Sudan

The reservoirs in the N oilfield in Sudan feature a complex sedimentary environment, which has led to a widespread development of low-resistivity oil zones, accounting for as high as 37% of the total oil zones. In this case, a large number of oil zones will be misinterpreted using conventional methods. Based on the analysis of the core data and logging curves of the study area, this study concludes that the low-resistivity oil zones are formed mainly due to the high irreducible water saturation caused by the high content of illite and smectite and complex pore structure, the additional electrical conductivity induced by clay minerals, and the difference in formation water salinity between the oil zones and water zones. Furthermore, four methods are proposed to qualitatively identify these oil zones and water zones, namely the relationship analysis of five reservoir properties, cross-plotting of sensitive parameters, analysis of pressure testing data, and multi-well correlation. Furthermore, the study quantitatively calculates the initial oil saturation using the capillary pressure data, thus avoiding the conventional empirical saturation formulas depending on electrical resistivity and solving the difficulty in calculating oil saturation of low-resistivity oil zones. Finally, precise logging processing and interpretation of 95 wells in the study area are conducted using the above-mentioned comprehensive assessment system for low-resistivity oil zones. As a result, 59 oil zones are newly discovered in 43 wells. Moreover, it is recommended that 17 oil zones in 12 wells should be tested, of which 11 oil zones have been tested as recommended, all proven to be high production oil zones after perforation. The coincidence rate of logging interpretation increases from 75% to 94.3%, and the original oil in place (OOIP) increases by 57.42 million barrels. All these indicate that the assessment system proposed is suitable for low-resistivity zones.

Nuclear matter in relativistic Brueckner-Hartree-Fock theory with Bonn potential in the full Dirac space

Starting from the Bonn potential, relativistic Brueckner-Hartree-Fock (RBHF) equations are solved for nuclear matter in the full Dirac space, which provides a unique way to determine the single-particle potentials and avoids the approximations applied in the RBHF calculations in the Dirac space with positive-energy states (PESs) only. The uncertainties of the RBHF calculations in the Dirac space with PESs only are investigated, and the importance of the RBHF calculations in the full Dirac space is demonstrated. In the RBHF calculations in the full Dirac space, the empirical saturation properties of symmetric nuclear matter are reproduced, and the obtained equation of state agrees with the results based on the relativistic Green's function approach up to the saturation density.

Prediction of Porosity and Water Saturation Using Neural Networks in Shaly Sand Reservoirs, Western Deseret, Egypt

Petrophysical properties evaluation of shaly sandstone reservoirs is a challenging task in comparison to clean sand reservoirs. Logging derived porosity in shaly sands requires shale correction and Archie’s formula cannot be used in shaly sands for the determination of water saturation, therefore many water saturation models were proposed to get accurate water saturation of shaly sand reservoirs. In this paper, three water saturation models were used; two empirical models (Simandoux and total shale) and one theoretical model (effective medium model). Shale corrected density log was used in all models. The use of computer-generated algorithm, fuzzy log neural network is of increasing interest in the petroleum industry. This paper presents artificial neural network (ANN) as an effective tool for determining porosity and water saturation in shaly sand reservoir using well logging data. ANN technique utilizes the prevailing unknown nonlinear relationship in data between input logging data and output petrophysical parameters. Results of this work showed that ANN can be supplement or replacement of the existing conventional techniques to determine porosity and water saturation using empirical or theoretical water saturation models. Two neural networks were presented to determine porosity and water saturation using GR, resistivity and density logging data and adapted cut off for porosity and water saturation. Water saturation and porosity were determined using conventional techniques and neural network approach for two wells in a shaly sand reservoir. Neural network approach was trained for porosity and water saturation using the available well logging data. The predicted porosity and water saturation values have shown good matching with the core data in the two wells in comparison to the porosity and water saturation derived from the conventional techniques. This work showed that developed neural network (ANN) could provide an accurate porosity and water saturation in shaly sands reservoirs, it is subject to volume of available well logging data.

Asymmetric nuclear matter and realistic potentials

The equation of state for asymmetric nuclear matter is presented within the Brueckner–Hartree–Fock (BHF) approach by using recent high-quality soft nucleon–nucleon potentials from next-to-leading order (NLO) up to fifth order (N4LO) of the chiral expansion for the wide range of densities and asymmetry parameter, which are very interesting these days in the heavy-ion collisions and neutron stars. For comparison purposes, the same calculations are performed for Brueckner–Hartree–Fock approach plus two-body density-dependent Skyrme potential which is equivalent to three-body forces. Also the results are compared with the other theoretical models, especially the Brueckner–Hartree–Fock plus three-body forces and the Dirac–Brueckner–Hartree–Fock approaches. Our equation-of-state models are able to reproduce the empirical symmetry energy $$\hbox {E}_\mathrm{{sym}}$$ and its slope parameter L at the empirical saturation density $$\rho _{0}$$ and are compatible with experimental data from collisions between heavy nuclei. The symmetry energy of about 30 MeV is obtained at the saturation nuclear matter density. There is very good agreement between the experimental symmetry energy value and those calculated in the Brueckner–Hartree–Fock approach.

The Effect of Various Three-Body Forces on Nuclear Matter and Neutron Stars Properties

The binding energy per nucleon for nuclear matter, i.e., equation of state (EOS), within the Brueckner–Hartree–Fock (BHF) approach with the consideration of various three-body forces (3BFs) like the phenomenological 3BF and by adding a contact term to the BHF calculations are considered at variance densities. The 3BF contribution turns out to be nonnegligible contribution and to have a substantial saturation effect. The calculations are done utilizing the CD-Bonn and Argonne V18 nucleon–nucleon (NN) potentials. These NN potentials give great fitting to the deuteron properties and are phase-shift equivalent. The resultant EOS is compatible with the phenomenological analysis on the saturation point. It is demonstrated that the 3BF influences significantly on the nuclear matter EOS at high densities. Moreover, it is necessary for reproducing the empirical saturation properties for symmetric nuclear matter. The pressure has been also calculated and the suggested approaches reproduce fairly well agreement with the empirical data. We also examined the maximum neutron star masses which are close to two solar masses, which is again compatible with recent observational data. Comparison with other microscopic EOS is presented and discussed.

Nuclear and neutron-star matter from local chiral interactions

We report a quantum Monte Carlo calculation of the equation of state of symmetric nuclear matter using local interactions derived from chiral effective field theory up to next-to-next-to-leading order fit to few-body observables only. The empirical saturation density and energy are well reproduced within statistical and systematic uncertainties. We have also derived the symmetry energy as a function of the density, finding good agreement with available experimentally derived constraints at saturation and twice saturation density. We find that the corresponding pressure is also in excellent agreement with recent constraints extracted from gravitational waves of the neutron-star merger GW170817 by the LIGO-Virgo detection.

The Saturation properties of Nuclear Matter Using Different Three-Body Force at zero and finite temperature

We have used the three-body force (3BF) to modify the two body forces to achieve the empirical saturation points as well as study the ground state properties for symmetric nuclear matter using the Brueckner-Hartree-Fock approximation (BHF) with the Argonne AV18 potential at zero and finite temperature. Besides the energy per nucleon (E/A) as a function of nuclear density ρ is calculated. Further, the correction of the two-body dependent potential (correction 1) is added to shift and improve the saturation properties of the nuclear matter from ρ_o=0.265 〖fm〗^(-3) to ρ_o=0.149 〖fm〗^(-3) at E/A = -16.142 MeV towards to the empirical saturation point ρ_o=0.16 〖fm〗^(-3). In addition, the pressure p for symmetric nuclear matter for zero-temperature T=0 as a function of density ρ/ρ_o using the Argonne AV18 potential is calculated revealing good agreement between our calculations and the experimental data. On other hand, more calculations for the pressure are added at different energies T= 4, 8, 12, 18 and 20 MeV. Also, the level-density parameter as a function of density ρ is calculated for the BHF approach. Moreover, the internal energy F for the symmetric nuclear matter as a function of density ρ using the Argonne AV18 potential for continuous choice at T= 4, 8, 12, 18 and 20 MeV for the BHF with and without 3BF is calculated.

Probing chiral interactions up to next-to-next-to-next-to-leading order in medium-mass nuclei

We study ground-state energies and charge radii of closed-shell medium-mass nuclei based on novel chiral nucleon-nucleon (NN) and three-nucleon (3N) interactions, with a focus on exploring the connections between finite nuclei and nuclear matter. To this end, we perform in-medium similarity renormalization group (IM-SRG) calculations based on chiral interactions at next-to-leading order (NLO), N$^2$LO, and N$^3$LO, where the 3N interactions at N$^2$LO and N$^3$LO are fit to the empirical saturation point of nuclear matter and to the triton binding energy. Our results for energies and radii at N$^2$LO and N$^3$LO overlap within uncertainties, and the cutoff variation of the interactions is within the EFT uncertainty band. We find underbound ground-state energies, as expected from the comparison to the empirical saturation point. The radii are systematically too large, but the agreement with experiment is better. We further explore variations of the 3N couplings to test their sensitivity in nuclei. While nuclear matter at saturation density is quite sensitive to the 3N couplings, we find a considerably weaker dependence in medium-mass nuclei. In addition, we explore a consistent momentum-space SRG evolution of these NN and 3N interactions, exhibiting improved many-body convergence. For the SRG-evolved interactions, the sensitivity to the 3N couplings is found to be stronger in medium-mass nuclei.

Quark mean-field model for nuclear matter with or without bag

We propose the new quark mean-field bag (QMFB) model by incorporating the bag confinement mechanism in the original quark mean-field model. Nuclear matter and neutron star properties are studied with the QMFB model. For the study of the bag effect, we newly fit 12 parameter sets by reproducing the empirical saturation properties of nuclear matter. Quark confinement is found to be mainly demonstrated by the bag after it is included in the model, instead of the confining potential. For nuclear matter, the bag decreases the binding energy and increases the symmetry energy. For neutron star, the bag affects significantly the radius $R$ of a $1.4M_\odot$ star, with the maximum mass only slightly modified. The bag also has a large suppression effect on the well-accepted $R$ vs $L$ dependence, with $L$ the symmetry energy slope at the saturation density.