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The saturated non-singular terminal switching function (SNTSF) for sliding mode control with speed error limitation and finite-time error convergence is proposed. The sliding-mode dynamics and the boundary layer dynamics of the SNTSF are analyzed. It is also shown that the non-singular terminal switching function does not have a higher boundary layer position tracking precision than the linear switching function, contrary to some previous claims in the literature. An SNTSF sliding mode controller with speed error limitation and finite-time convergence is proposed and tested both simulatively and experimentally on a laboratory DC motor system.

Abstract To analyze the relationship between macro and meso parameters of the gas hydrate bearing coal (GHBC) and to calibrate the meso-parameters, the numerical tests were conducted to simulate the laboratory triaxial compression tests by PFC3D, with the parallel bond model employed as the particle contact constitutive model. First, twenty simulation tests were conducted to quantify the relationship between the macro–meso parameters. Then, nine orthogonal simulation tests were performed using four meso-mechanical parameters in a three-level to evaluate the sensitivity of the meso-mechanical parameters. Furthermore, the calibration method of the meso-parameters were then proposed. Finally, the contact force chain, the contact force and the contact number were examined to investigate the saturation effect on the meso-mechanical behavior of GHBC. The results show that: (1) The elastic modulus linearly increases with the bonding stiffness ratio and the friction coefficient while exponentially increasing with the normal bonding strength and the bonding radius coefficient. The failure strength increases exponentially with the increase of the friction coefficient, the normal bonding strength and the bonding radius coefficient, and remains constant with the increase of bond stiffness ratio; (2) The friction coefficient and the bond radius coefficient are most sensitive to the elastic modulus and the failure strength; (3) The number of the force chains, the contact force, and the bond strength between particles will increase with the increase of the hydrate saturation, which leads to the larger failure strength.

Predischarge pulse oximetry screening (POS) is recommended to pick up critical congenital heart diseases in apparently well neonates. However, it is possible that cases may be missed during the early POS in the presence of delayed closure of the ductus arteriosus. Repeat POS in the second week of life was found to be helpful and feasible for early detection of pathological states causing hypoxemia in seemingly well neonates. Studies with larger sample size are recommended to establish the role of an additional POS in the second week for enhanced CCHD detection. [ABSTRACT FROM AUTHOR]

Hydrocarbon reservoir characterization using well log in part of Niger Delta, Nigeria was done in order to examine the potentiality and productivity of the reservoir. A suite of well log data consisting of gamma ray, density, resistivity and neutron logs obtained from two wells within the area of study were used for this research. Gamma ray log was used for lithology identification and differentiation, resistivity log was used to identify the type of fluid present in the reservoir, density log was used to detect gas bearing zones in the reservoir while neutron log was used to distinguish gas from oil in sandstone and shale reservoirs. The results of this study showed sand bodies were delineated and correlated across the wells and were inferred as potential hydrocarbon reservoirs. The result also showed that there is an increase in both porosity and permeability, evaluated petrophysical parameters showed that porosity values range between 0.0391 - 0.3019, water saturation values range from 0.1660 - 1.6740 while hydrocarbon saturation values range from 0.0013 - 0.7296 and net to gross values range from 0.5332 - 0.9674. [ABSTRACT FROM AUTHOR]

For normal alfalfa growth and development, a high supply of moisture is of great importance. The most stable fodder productivity is obtained on irrigated and floodplain lands. Though, water excess can also have a negative effect, especially on seed productivity. Alfalfa seeds can absorb large amounts of water, no less than their dry matter weight. Under a soil moisture shortage, low soil temperature and deep seeding, sprout emergence slows down. The main purpose of the current work was to analyze the effect of sucrose solutions of various saturations on seed germination and determine the desired saturation, which would be best used to estimate the relative drought resistance of alfalfa varieties under conditions of osmotic stress. The work was carried out at the “Ershovskaya ESIA, the branch of the FSBSI FARC of the South-East” in 2021–2022. There has been conducted trials to consider the effect of different solution saturations on the germination of alfalfa seeds of the varieties ‘Artemida’, ‘Yuzen’, ‘Virineya’, ‘Natali’ and ‘Sirena’. As a result of the study, there was shown that, depending on the varieties and saturation of the solution, seed germination varied from 4 to 100 %. The variety ‘Yuzen’ showed maximum seed germination of 75.2 % and a minimal decrease in germination with increasing osmotic pressure relative to other varieties. At the highest sucrose solution saturation (16.6 %), the best figures were produced by the varieties ‘Artemida’ and ‘Virineya’. Our trial has identified that to determine the relative drought resistance of alfalfa varieties, it was most effective to use sucrose solutions with a concentration of 7.4 and 16.6% for a more reliable result.

The attitude tracking control problem of an overdriven quadrotor aircraft experimental platform is studied. The platform has unknown input disturbances and angular velocity cannot be measured, and the motor also has dead zone and saturation nonlinear characteristics. First, a linear perturbed double-integral model of the platform is established. Afterwards, an attitude-tracking robust controller including a proportional-integral-derivative nominal controller and an adaptive extended state observer (AESO) is designed. Among them, the nominal controller is used to ensure the asymptotic stability of the nominal closed-loop system, and AESO is used to estimate the angular velocity and disturbance information of the experimental platform to solve the problem of no velocity measurement and disturbance suppression. Moreover, the overdrive control allocation problem is solved by using the pseudo-inverse matrix method. In addition, an auxiliary system is constructed to weaken the influence of the motor’s dead zone and saturated nonlinear characteristics. Finally, the simulation and experiments verify that the proposed control strategy can effectively solve the problems caused by the dead zone and saturation characteristics of the motor, and can simultaneously take into account the transient overshoot and steady-state error performance of the closed-loop system.

This work considers the isothermal process of incompressible viscous fluid filtration in an oil-saturated, fractured-porous reservoir. A study of the pressure and water saturation distribution process is carried out for a case in which a production well is put into operation. For this problem, i.e., a mathematical model in a two-dimensional formulation, a numerical method and a parallel algorithm are proposed. The mathematical model of two-phase filtration is written in accordance with the classical laws of continuum mechanics and Darcy’s law and also includes a function of fluid exchange between low-permeability pores and high-permeability natural fractures within the framework of the Warren–Root model. The numerical solution is based on the finite-difference method and a splitting scheme of physical processes and spatial coordinates. For a split system with respect to piezoconductivity, an implicit finite-difference scheme with fixed saturations is constructed, and with respect to saturation transfer, explicit and implicit difference schemes are constructed. For parallel implementation of the developed numerical approach, a method based on geometric parallelism is selected. Testing of the developed method is performed using the example of calculating liquid mass transfer for a wide range of parameters. To verify the model, the obtained calculated pressure curves are compared with field data recorded by a deep-well measuring device. The results allow for estimation of the distribution of reservoir pressure and water saturation depending on the permeability of the fracture set and the pore part. The obtained results allow for monitoring of well operations, reducing unexpected accident risks and optimizing the development system in order to increase oil production in fractured-porous reservoirs. Computational experiments confirm the efficiency of the developed numerical algorithm and its parallel implementation.

In this paper, a data processing approach was developed to accurately extract the ring-down time and amplitude of the saturated cavity ring-down (CRD) signal; both were utilized to determine simultaneously the high reflectance and residual transmittance of highly reflective (HR) mirrors with a dual-channel CRD configuration. The influence of saturation was eliminated by deleting the beginning saturated data points of the saturated CRD signal and fitting the remaining non-saturated CRD signal to a single-exponential function. By comparing the reflectance/transmittance measurement results of HR samples obtained via data processing of saturated CRD signals and via single-exponentially fitting non-saturated CRD signals with utilization of neutral density filter(s) to eliminate saturation, it was found that the reflectances obtained with both methods were in excellent agreement, while the residual transmittance obtained with the saturated CRD signal was more accurate than that obtained with the neutral-density-filter-attenuated non-saturated CRD signal. The proposed data processing method eliminated the need to use the neutral density filters, therefore avoiding the adding of the optical density error to the uncertainty of residual transmittance measurement and improving the measurement accuracy. The proposed data processing method also extended the dynamic range of the dual-channel CRD scheme for simultaneous measurement of reflectance, transmittance and optical loss.

Gillnets are widely used in research and commercial fishery activities. As passive gear, gillnets can be selective and dependent on the diel migration of fish. In areas with limited littoral extent, inshore–offshore migration may cause bias in the gillnet catch. Our hypothesis was that some factors, such as gillnet saturation, fish depletion, or chemical cues, could be the cause of the bias. We used a total of 66 CEN gillnets deployed at Římov Reservoir parallel to the shore at different positions of littoral-pelagic gradient. Individual fish direction was recorded from inshore, offshore, or unknown direction (i.e., entangled fish). A total of 5791 fishes from nine different species were caught. For most fish, it was possible to determine their directivity, and most fish were captured in littoral or first pelagic gillnets. Shallower and deeper benthic gillnets differed in their bleak (Alburnus alburnus) catch. No significant differences were found between fish directions. At the species level, only asp (Leuciscus aspius) and ruffe (Gymnocephalus cernua) showed differences between the captured directions in one case. The results support the assumption that gillnet capture is a random process that to a great extent is connected to random local movements. This is good news for fish monitoring projects. Sampling catch is likely to reflect true changes in the fish community, and not the effects of the deployment of the sampling gear. The experiment also showed that fish directivity statistics can be used for investigation of fish behavior and gear performance.

In response to the fairness issue arising from the unequal delay of vehicles in different phases at intersections and considering the actual situation of small and variable delays for vehicles in low-saturation intersection phases, this paper proposes the concept of “sacrificing efficiency for fairness”. Firstly, the universality of unfair delay phenomena at intersection phases is explained, especially at low-saturation intersections where the fluctuation in phase delays is 1.87 times higher than at other intersections. Then, a fairness evaluation index is constructed using information entropy, and the feasibility of the proposed approach is demonstrated. Subsequently, a signal optimization model that balances efficiency and fairness is proposed. Finally, the proposed model is validated through case studies, showing that it not only simultaneously considers efficiency and fairness but also has minimal impact on efficiency. Moreover, the changes to timing schemes in the efficiency model are much smaller compared to the model that only considers fairness. Sensitivity analysis reveals that the model performs better under low-saturation intersection conditions.

This paper introduces an FPGA-based implementation of a smart switch designed to avoid inrush currents occurring during the connection of single-phase transformers utilized in grid-connected photovoltaic (PV) systems. The magnitude of inrush currents is notably impacted by the residual flux within the transformer core and the precise moment of energization relative to the wave cycle. Alternative methods frequently hinge on intricate procedures to estimate residual flux. This challenge is adeptly circumvented by the innovative smart control system proposed herein, rendering it a cost-effective solution for grid-connected PV systems. The proposed solution for mitigating inrush current remains effective, even in the face of challenges with current and voltage sensors. This resilience arises from the system's ability to learn and adapt by leveraging information acquired from the network. [ABSTRACT FROM AUTHOR]

The movement of dissolved salt in melting snow is considered based on the equations of non-isothermal two-phase filtration. The thermal conductivity of snow and the dependence of the water freezing point on salinity were verified using available experimental data. The influence of the presence of dissolved salt on the phase transition was evaluated by numerical experiments. [ABSTRACT FROM AUTHOR]

The concept of saturation in qualitative research is a widely debated topic. Saturation refers to the point at which no new data or themes are emerging from the data set, which indicates that the data have been fully explored. It is considered an important concept as it helps to ensure that the findings are robust and that the data are being used to their full potential to achieve the research aim. Saturation, or the point at which further observation of data will not lead to the discovery of more information related to the research questions, is an important aspect of qualitative research. However, there is some mystification and semantic debate surrounding the term saturation, and it is not always clear how many rounds of research are needed to reach saturation or what criteria are used to make that determination during the thematic analysis process. This paper focuses on the actualisation of saturation in the context of thematic analysis and develops a systematic approach to using data to justify the contribution of research. Consequently, we introduce a distinct model to help researchers reach saturation through refining or expanding existing quotations, codes, themes and concepts as necessary. [ABSTRACT FROM AUTHOR]

This study investigated the effects of color presence and saturation on the affective judgment of real-life images, as functions of the image's affective valence. In the first two experiments, participants observed and rated original color photos and their grayscale versions, presented in an interleaved order across two separate experimental sessions. Color photos were rated as more pleasant than grayscale photos when image valence was positive, and more unpleasant when image valence was negative. The third experiment consisted of the same original images and their versions with saturation reduced by 50%. Original photos were rated as more pleasant than saturation-reduced photos when image valence was positive, yet less unpleasant when image valence was negative, implying potentially separable mechanisms for processing color presence and saturation. Significant interactions were found between color or saturation mode and valence on affective judgment in all three experiments. The effects persisted after controlling for colorfulness and luminance between the color and grayscale (or de-saturated) conditions. [ABSTRACT FROM AUTHOR]

Background: In antibiotic naïve populations, there is a strong association between the use of an antimicrobial and resistance to this antimicrobial. Less evidence is available as to whether this relationship is weakened in populations highly exposed to antimicrobials. Individuals taking HIV preexposure prophylaxis (PrEP) have a high intake of antimicrobials. We previously found that there was no difference in the prevalence of pheno- and genotypic antimicrobial resistance between two groups of PrEP clients who had, and had not, taken antimicrobials in the prior 6 months. Both groups did, however, have a higher prevalence of resistance than a sample of the general population. Methods: In the current study, we used zero-inflated negative binomial regression models to evaluate if there was an individual level association between the consumption of antimicrobials and 1. the minimum inhibitory susceptibilities of oral Neisseria subflava and 2. the abundance of antimicrobial resistance genes in the oropharynges of these individuals. Results: We found no evidence of an association between the consumption of antimicrobials and the minimum inhibitory susceptibilities of oral Neisseria subflava or the abundance of antimicrobial resistance genes in these individuals. Conclusions: We conclude that in high-antimicrobial-consumption populations, the association between antimicrobial consumption and resistance may be attenuated. This conclusion would not apply to lower-consumption populations. [ABSTRACT FROM AUTHOR]

Porous materials have emerged as one of the most widely employed sound-absorbing materials in practical applications, owing to their excellent sound absorption properties and lightweight nature. Unsaturated porous materials have the potential to achieve superior sound absorption effects and significantly reduce mass. However, current research on the sound absorption performance of unsaturated porous materials is limited. This paper used a modified transfer matrix method (MTMM), which relies on matrix dimensionality reduction, to analyze the sound absorption characteristics of unsaturated porous materials under various boundary conditions. The study also examines the impact of different parameters, such as material thickness and saturation, on sound absorption performance and compares the results. The findings indicate that when a solid elastic plate is attached to an unsaturated porous elastic plate, the absorption coefficient decreases while the transmission loss increases. Additionally, reducing the thickness of the plate and increasing its porosity and saturation levels lead to an increase in the absorption coefficient and a decrease in the transmission loss. [ABSTRACT FROM AUTHOR]

Studying the changes in electrical resistivity of sandstones under various frequencies and saturation levels is important for addressing many geological problems through electrical prospecting. In this study, we investigated the effect of different frequencies (500 Hz-200 kHz) and saturation levels (0%-100%) on the resistivity of sandstone in the Ordos region. Our research indicates that when the saturation level is low (<40%), the resistivity of the sandstone decreases rapidly. With the increase of saturation level, pore water gradually becomes another major factor affecting resistivity in addition to induced polarization effect. When the saturation level is high (>80%), the resistivity tends to stabilize. Additionally, the resistivity of sandstone decreases with the increase of saturation. Furthermore, with an increase in frequency, the rate of reduction in resistivity gradually slows down, and the resistivity of sandstone decreases under the influence of saturation. This study provides a valuable reference for the practical application of sandstone resistivity in geological prospecting. [ABSTRACT FROM AUTHOR]

To analyze the relationship between macro and meso parameters of the gas hydrate bearing coal (GHBC) and to calibrate the meso-parameters, the numerical tests were conducted to simulate the laboratory triaxial compression tests by PFC3D, with the parallel bond model employed as the particle contact constitutive model. First, twenty simulation tests were conducted to quantify the relationship between the macro–meso parameters. Then, nine orthogonal simulation tests were performed using four meso-mechanical parameters in a three-level to evaluate the sensitivity of the meso-mechanical parameters. Furthermore, the calibration method of the meso-parameters were then proposed. Finally, the contact force chain, the contact force and the contact number were examined to investigate the saturation effect on the meso-mechanical behavior of GHBC. The results show that: (1) The elastic modulus linearly increases with the bonding stiffness ratio and the friction coefficient while exponentially increasing with the normal bonding strength and the bonding radius coefficient. The failure strength increases exponentially with the increase of the friction coefficient, the normal bonding strength and the bonding radius coefficient, and remains constant with the increase of bond stiffness ratio; (2) The friction coefficient and the bond radius coefficient are most sensitive to the elastic modulus and the failure strength; (3) The number of the force chains, the contact force, and the bond strength between particles will increase with the increase of the hydrate saturation, which leads to the larger failure strength. [ABSTRACT FROM AUTHOR]

Background: Despite the high number of synthetic androgenic–anabolic steroids, testosterone is still misused for doping in amateur and professional sports. However, only few studies investigated the dose–response effects of testosterone beyond its physiological concentrations and in over 90 years of research, no saturation dosage has been experimentally described for exogenous testosterone administration. Objectives: We want to elucidate the physiological and pathophysiological effects of supra‐physiological testosterone application and close this gap in testosterone dose–response data. Materials and methods: Male orchiectomized rats were treated with different testosterone doses ranging from 0.1 to 50 mg/kg body weight for 3 weeks. Several physiological endpoints (e.g., body weight, organ and muscle weight, muscle strength, muscle fiber size) were examined during and after the termination of the treatment with an adjusted Hershberger assay, open‐field‐test, and (immuno‐)histologic. Results: The wet weights of androgen responsive organs (penis, prostate, seminal vesicle) showed a significant increase in a dose‐dependent manner. Histological evaluation of the prostate showed a significant higher percentage of KI67 positive prostate nuclei in the highest dosage group and an increasing hyperplasia with increasing testosterone administered. A significant anabolic effect was only observed in Levator ani wet weight, and to minor degree for the cardiac muscle. Regarding other skeletal muscles (Musculus soleus and Musculus gastrognemicus), no significant testosterone effects were observed. We showed a significant increasing dosage–response effect for testosterone in androgen responsive organs with saturation at the two highest concentration of 10 and 50 mg/kg body weight. Discussion and conclusion: The dose‐dependent androgenic effects of testosterone were well observable and the anabolic effects on muscle tissue were visible although to a lesser degree, without the support of aerobic exercise and a protein rich diet. Future studies should investigate a combinatorial effect of testosterone and training. Nevertheless, with the chosen range of applied testosterone, we showed a saturation of testosterone effects in prostate, seminal vesicle, penis, and Levator ani. [ABSTRACT FROM AUTHOR]

A solution of the nonlinear problem on the driving of the oil from an oil-bearing stratum of finite length by the filtrate of a drilling agent (flushing water) has been constructed with the use of the asymptotic method. On the basis of this solution, the saturation field of the stratum in the zone of penetration of the flushing water into it was investigated with regard for the process of opening of the stratum by drilling. The indicated solution defines the movement, along the thickness of the stratum, of the boundary, corresponding to the position of a drill bit, above which the saturation of the stratum with the filtrate of the flushing water and the velocity of filtering of this water are prescribed, and, below this boundary, the velocity of the water filtration flow and the stratum saturation are assumed to be equal to zero. It is shown that, within large times, the solution obtained conforms with the known Buckley–Leverett expression. On the basis of the computational experiments, spatial and time distributions of the stratum saturation in the zone of penetration of the flushing water into it have been constructed with regard for the process of opening of the stratum. [ABSTRACT FROM AUTHOR]

The main method for estimating the level of arterial blood oxygenation is pulse oximetry, which has the advantages of being fast, simple, reliable, and non-invasive. However, in well-known pulse oximeters, oxygen saturation is determined only by hemoglobin functional fractions, which reduces the device accuracy and is unacceptable in certain clinical cases. The known pulse oximeter improvement that considers the dysfunctional fraction concentration, especially carboxyhemoglobin, when measuring the level of blood oxygenation is an actual scientific and technical task. The research subjects. Mathematical, algorithmic, and technical support of a pulse oximeter that measures blood oxygenation levels considering the carboxyhemoglobin concentration. Objective. To expand the pulse oximeter functionality to consider the concentration of carboxyhemoglobin in arterial blood. Methods. Methods of computer simulation for developing a model and estimating the pulse oximeter accuracy that measures the blood oxygenation level considering the carboxyhemoglobin concentration. Results. The theoretical statements of measuring the level of blood oxygenation considering the carboxyhemoglobin concentration and the simplest pulse oximeter structural diagram for measuring are developed. An additional LED used in the pulse oximeter is proposed, and the wavelength choice is justified on the condition of maximizing the carboxyhemoglobin contribution to the optical density of the biological object. Computer models of a traditional pulse oximeter and a pulse oximeter with an additional LED were developed, simulation research was conducted using the developed models, and the device accuracy for measuring the level of blood oxygenation was estimated considering the carboxyhemoglobin concentration. Conclusions. Simulation studies based on the developed models show that the proposed pulse oximeter, compared with the known one, allows determining and estimating a decrease in blood oxygenation caused by the carboxyhemoglobin concentration increasing in the patient's blood. Considering that light is also absorbed by the third derivative of hemoglobin, carboxyhemoglobin, increases the accuracy of the proposed pulse oximeter in measuring functional saturation. [ABSTRACT FROM AUTHOR]

Purpose: Saturated lights appear brighter than white lights of the same luminance. This is the Helmholtz--Kohlrausch (H--K) effect, and the phenomenon can be estimated by modeling achromatic luminance and saturation to total brightness. Current H--K effect models are different between women and men and are also more variable in women, which may be due to hormonal changes across the menstrual cycle (MC). Methods: Total brightness (B) and achromatic luminance (L) were measured across blue, green, yellow-green, yellow, and red hues. These data were measured along with salivary hormone levels for nine cycling women and seven oral contraceptive (OC) users at points representing the menstrual, peri-ovulation, and luteal phases. Results: Simple brightness/luminance (B/L) ratio estimates of the H--K effect did not differ by OC use or MC phase, but B/L ratios were higher for the red stimulus in cycling women than OC users during the luteal phase. Estrogen, progesterone, and their interaction predicted 18% of the variation in brightness for cycling women. For OC users, only estrogen could be fit to brightness models where it accounted for 5% of brightness variance. Conclusion: These findings first provide clear support for separating cycling women from OC users, particularly when examining long-wavelength mechanisms. Next, the interaction of OC use and MC phase on B/L ratios for the red stimulus adds to a rich history of longwavelength mechanisms. Lastly, the current result amends previous brightness models with multiple hormone terms for cycling women but not OC users. [ABSTRACT FROM AUTHOR]

The objects we encounter in everyday settings are composed of multicolored surfaces. To utilize the color information of these surfaces, it is necessary to efficiently summarize the color distribution of object surfaces. Studies examining such summarization (averaging) processes have shown that the three attributes of color -- hue, saturation, and brightness -- are averaged in different manners. Hue can be averaged accurately and approximated by the arithmetic mean on the uniform chromaticity scale diagram. Averaging of saturation exhibits a bias, with the average tending to shift towards a more saturated direction than the colorimetric mean. Furthermore, this bias becomes more pronounced when there is greater variability (noise) in the color distribution. While there is also a bias observed in the averaging of brightness, the underlying processing strategy seems to be adaptively adjusted depending on the task at hand. These summarizing strategies are believed to be acquired to enhance the reliability and certainty of sensory information in noisy natural environments. Identifying the factors that determine these processing strategies remains a challenge for future research. [ABSTRACT FROM AUTHOR]

Background: Semi-structured interviews allow progressive interview refinements to gain an in-depth understanding of a research question, but interview refinements affect the stopping point. This paper aims to describe a method that provides transparency in interview refinements and helps researchers decide on a stopping point. Methods: We established systematic and practical methods to document interview refinements and visualize novel and duplicate interview codes. We illustrated the methods using a case study called the Mass Atrial Fibrillation Screening Study, a real-world clinical trial. Interviews were audio recorded and transcribed progressively. Two researchers established the initial coding into a predefined framework with reference to the Medical Research Council Guidance of Process Evaluation. Final codes were reached by discussion and consensus. NVivo v12 software was utilized to manage the qualitative data. Results: We developed an open-access software package for the 'R' statistical programming language called 'novelqualcodes' and a video demonstrating the application. Our package converts NVivo coding matrices into graphs of the trends of novel and duplicate codes. Our package also enables users to document interview refinements as fieldnotes, providing a visual guide to help researchers decide on a stopping point. In the case study, one researcher (KCW) conducted 48 one-to-one in-depth semi-structured interviews with participants from September 2021 to July 2022. Interview refinements were identified and reported to provide transparency to the readers. The novel code graphs and examination of the code sufficiency in the predefined framework demonstrated the stopping point at which we were satisfied with the richness and insights of the interviews in answering our research question. Conclusions: We illustrated a new paradigm of systematic and practical methods and shared an open-access software package and a video to describe, document and visualize the path to the stopping point. This approach can be applied in other qualitative research using different predefined frameworks. [ABSTRACT FROM AUTHOR]

Geometric heterogeneities in tight reservoir rocks saturated with a fluid mixture may exhibit different scale distribution characteristics. Conventional models of rock physics based on poroelasticity, which usually consider single‐scale pore structure and fluid patches, are inadequate for describing elastic wave responses. A major challenge is to establish the relationship between the wave response at different spatial scales and frequencies. To address this problem, three sets of observational data over a wide frequency range were obtained from a tight oil reservoir in the Ordos Basin, China. Ultrasonic measurements were made on eight sandstone samples at partial oil‐water saturation at 0.55 MHz. Data from six borehole measurements and seismic profiles were acquired and analyzed at about 10 kHz and 30 Hz, respectively. Analysis of the cast thin sections shows that dissolution pores and microcracks generally develop, with fractal dimensions of the pores ranging from 2.45 to 2.67 for the samples with porosities between 5.1% and 10.2%. Compressional wave velocity and attenuation were estimated from the observed data. The results show that the velocity dispersion from seismic to ultrasonic frequencies is 10.02%, mostly occurring between sonic and ultrasonic frequencies. The attenuation is stronger at higher oil saturation. The relationships between velocity, attenuation, and wavelength were established and can be used for further forward modeling and seismic interpretation studies. A partial saturation model has been derived based on effective differential medium theory and a double double‐porosity model, assuming that the medium contains fractal cracks and fluid patches. The effects of scale and saturation on wave responses are prevalent. Modeling results consistent with observed data show that the radii of cracks and fluid patches range from 0.1 μm to 2.8 mm, affecting ultrasonic, acoustic, and seismic attenuation. The multiscale data and proposed model quantify the relationship between fracture and fluid distributions and attenuation and could be useful for upscaling to the reservoir scale. The study helps improve the understanding of seismic wave propagation in partially saturated rocks, which has potential applications in seismic exploration, hydrocarbon production in reservoirs, and CO2 sequestration in aquifers. Plain Language Summary: The physical properties of the rock and fluid can be inferred from the measured elastic wave responses and energy dissipation characteristics. However, the effects of heterogeneities of different sizes and at different frequencies can hinder studies to quantify wave responses in a partially saturated porous medium, which are usually based on laboratory measurements. A major problem is the difference between observed frequencies and scales: megahertz in the laboratory, 10 of kilohertz in the borehole scale, and hertz in the seismic exploration scale. In this work, the frequency‐ and saturation‐dependent compressional velocity and attenuation are investigated using three geophysical data sets from the same tight reservoirs. A strong velocity dispersion over the measured frequency range is observed. The stronger attenuation at partial saturation may be caused by the multiscale heterogeneities of the pore structure and fluid patch distribution. A fractal poroelasticity model is developed by gradually inserting inclusions of different sizes with compliant pores and liquid patches into a homogeneous host skeleton. The wave responses are significantly affected by scale distribution and saturation. The proposed model, verified by the measured data, can be useful in interpreting the anelasticity of tight heterogeneous reservoirs in a broadband range. Key Points: We investigate how fluid saturation affects wave attenuation and dispersion over a wide frequency range in tight sandstone layersA partial saturation model describes the fractal properties of the layersThe size of the cracks and fluid patches are determined by applying the fractal model to the multiscale data [ABSTRACT FROM AUTHOR]

The freezing and thawing processes in sandstones under unsaturated conditions are methodically explored via the low-field nuclear magnetic resonance (NMR) technique. To precisely monitor the water content and distribution during the freezing and thawing processes, a special Carr–Purcell–Meiboom–Gill (CPMG) pulse sequence is proposed, leading pulse-induced temperature perturbations to be minimized. The results exhibit totally dissimilar water distributions in the two processes even under the same saturation: the freezing process retains more water in large pores, while the thawing process contains less water in large pores. This observation is primarily attributed to the ink-bottle effect occurring during the freezing: large pores with narrow entrances do not freeze until the entrance freezes. In addition, phase transition duration depends on the initial water saturation, for instance, the duration of the thawing process increases from 7 to 12 min as the initial water saturation varies from 40% to 80%. Through NMR observation, this phenomenon is associated with the variation of surface-to-volume ratio: high saturation is associated with the presence of water in large pores; the latter owns a small surface-to-volume ratio and accordingly involves a longer phase transition duration. After the assessment of surface-to-volume ratio, the intrinsic kinetic rate coefficient is further estimated to be 4.6 × 10–12 mol cm−2 s−1 ℃−1 for the ice thawing process in the studied rock. This value is five orders of magnitude lower than that found in the literature for the thawing process in bulk condition, i.e., 7.5 × 10–7 mol cm−2 s−1 ℃−1. We suggest that the small intrinsic kinetic rate coefficient addressed in the present work could be related to the constrained effect in rocks. Highlights: A special pulse sequence with minimized temperature perturbation is developed to perform the freezing/thawing experiment. The difference in water distribution is attributed to the effect of ink-bottle pores in the freezing and thawing processes. Phase transition time increases with initial water saturation, which is lucidly explained by the nuclear magnetic resonance measurement that directly gives rise to information about the surface-to-volume ratio. The intrinsic kinetic rate coefficient for ice melting within sandstones is estimated. [ABSTRACT FROM AUTHOR]

The present work details the development of a compositional model to replicate the heavy hydrocarbon flow in porous reservoir systems under non-isothermal conditions. The mathematical model considers mass and energy conservation equations describing the reactive of natural variables distributed in a multiphase hydrocarbon system. Such natural variable based compositional models better suit fully implicit numerical schemes with inexpensive Jacobian matrix computations. Further, the model accommodates a switch of primary variables for the disappearance and reappearance of a phase. The resulting nonlinear conservation equations are numerically discretized using a block-centered finite-difference scheme and solved with a quasi-Newton based implicit iterative solver. The present model is validated with the thermal profiles presented in the literature for the multiphase flow during the combustion of heavy crude oil in petroleum reservoir system with performance coefficient (R2), mean absolute error (MBE), and maximum absolute percentage error (MAPE) of about 0.954, 0.37, and 0.01 respectively. The developed compositional model projected 26 and 72 % of light and heavy oil recoveries respectively in about 160 days with a maximum or peak temperature of about 798 K. Further, the thermal and production profiles projected by the sensitivity analysis on various operating parameters are presented. It is noteworthy that the present works aid in providing an economical numerical based tool in evaluating the flow and transport during underground or in-situ combustion process for efficient energy exploration. [ABSTRACT FROM AUTHOR]

The research aimed to investigate the effect of oxygen saturation on students before and after physical basketball training. This research employed an experimental method with a one-group pretest-posttest research design. A total of 40 students, comprising 21 female students aged 18-20 years and 19 male students aged 18-20 years, participated in the research. Respondents were given treatment in the form of a 5 vs. 5 basketball game for 20 minutes. The saturation value was measured using a pulse oximetry device. Oxygen saturation was measured before exercise and after exercise. The statistical analysis technique used the t-dependent sample test with a significance level of 5%. The results of this study showed that the average oxygen saturation of male students at the pre-test was 96.47% and 95.47% at the post-test. For female students, the average pre-test oxygen saturation was 96.29% and 95.10%. Overall, the average oxygen saturation value before exercise was 96.38% and decreased after exercise to 95.28%. Based on the results of statistical calculations, there was no notable change in oxygen saturation values after basketball physical training (t-observation 2.157 < t-table 2.44). There was no notable change in oxygen saturation after physical exercise or a decrease in oxygen saturation, indicating that basketball training did not necessitate an increased oxygen uptake by the tissue. During the period, the peripheral appeared to function normally with no observed rise in oxygen uptake. Based on the research results, a physical exercise carried out for 20 minutes did not affect oxygen saturation. [ABSTRACT FROM AUTHOR]

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The authors have proposed a modified intensity–duration (I-D) method that incorporates field measurements of tensiometer to improve the accuracy of predicting the risk of slope failure. This method uses an indicator that considers the relationship of the duration from the time point at which the saturated zone is assumed to have formed to the average rainfall intensity during that period. The usefulness of this method has been verified, but its applicability to different slopes has not yet been investigated. Here, the authors collected long-term observations on a natural slope in Minamiashigara City, Kanagawa Prefecture, and examined the Modified I-D method using data on slope failures in the surrounding area. The authors also compared the results with plots of previous rainfall index (soil water index–accumulated rainfall in 60 min, effective rainfall amount with a half-life of 72 h–effective rainfall amount with a half-life of 1.5 h, and accumulated rainfall–accumulated rainfall in 60 min). The snake curves for rainfall events during slope failure and non-failure were clearly separated. The accuracy was high, confirming the applicability of the modified I-D method. [ABSTRACT FROM AUTHOR]

Copyright of Aero Weaponry is the property of Aero Weaponry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Given q-uniform hypergraphs (q-graphs) F, G and H, where G is a spanning subgraph of F, G is called weaklyH-saturated in F if the edges in E (F) \ E (G) admit an ordering e 1 , ... , e k so that for all i ∈ [ k ] the hypergraph G ∪ { e 1 , ... , e i } contains an isomorphic copy of H which in turn contains the edge e i . The weak saturation number of H in F is the smallest size of an H-weakly saturated subgraph of F. Weak saturation was introduced by Bollobás in 1968, but despite decades of study our understanding of it is still limited. The main difficulty lies in proving lower bounds on weak saturation numbers, which typically withstands combinatorial methods and requires arguments of algebraic or geometrical nature. In our main contribution in this paper we determine exactly the weak saturation number of complete multipartite q-graphs in the directed setting, for any choice of parameters. This generalizes a theorem of Alon from 1985. Our proof combines the exterior algebra approach from the works of Kalai with the use of the colorful exterior algebra motivated by the recent work of Bulavka, Goodarzi and Tancer on the colorful fractional Helly theorem. In our second contribution answering a question of Kronenberg, Martins and Morrison, we establish a link between weak saturation numbers of bipartite graphs in the clique versus in a complete bipartite host graph. In a similar fashion we asymptotically determine the weak saturation number of any complete q-partite q-graph in the clique, generalizing another result of Kronenberg et al. [ABSTRACT FROM AUTHOR]

A family F on ground set [ n ] : = { 1 , 2 , ... , n } is maximalk-wise intersecting if every collection of at most k sets in F has non-empty intersection, and no other set can be added to F while maintaining this property. In 1974, Erdős and Kleitman asked for the minimum size of a maximal k-wise intersecting family. We answer their question for k = 3 and sufficiently large n. We show that the unique minimum family is obtained by partitioning the ground set [n] into two sets A and B with almost equal sizes and taking the family consisting of all the proper supersets of A and of B. [ABSTRACT FROM AUTHOR]

The key benefits of qualitative research are rich insights and thick data. However, some argue these come at the cost of small sample sizes and low generalisability of findings. With traditional FGDs (FGDs), this could be addressed by conducting multiple groups. However, this requires significant investment of time and manpower. We explored methods to gather thick data quickly, aiming to increase the number of respondents without increasing manpower or lengthening fieldwork while maintaining data quality. In this paper, we detail our experience running a pilot study of a 1.5 hour online discussion with N=100 respondents, to capture in-depth responses at scale. Using pre-programmed questions and artificial intelligence (AI) to provide instant visual analyses of responses and additional probes to respondents live, we ran a full qualitative study with a bigger sample in the same duration required for a typical FGD. The discussion was text-based, with respondents being able to view and give their agreement or disagreement to what others may have said without interaction between them. The data was compared to data collected from a previous study with a similar topic and analysed from an operational aspect of conducting research and gathering insights from both methodologies. While this methodology does not replace traditional FGD, it has proven effective in scaling up qualitative research by gathering large amounts of qualitative data within a short duration, in real-time. The methodology has its limitations, primarily the inability to further nuance responses. Despite this, the pilot study appears to be a successful attempt conceptually, as the AI generated valuable instant insights while the study was ongoing, particularly from open-ended (OE) responses. It may add value to specific use cases such as quick sensing which require both breadth and scalability.

Background: Extracorporeal membrane oxygenation (ECMO) is a cardiopulmonary bypass device that provides life-saving complete respiratory and cardiac support in patients with cardiorespiratory failure. The majority of drugs prescribed to patients on ECMO lack a dosing strategy optimized for ECMO patients. Several studies demonstrated that dosing is different in this population because the ECMO circuit components can adsorb drugs and affect drug exposure substantially. Saturation of ECMO circuit components by drug disposition has been posited but has not been proven. In this study, we have attempted to determine if propofol adsorption is saturable in ex vivo ECMO circuits. Methods: We injected ex vivo ECMO circuits with propofol, a drug that is highly adsorbed to the ECMO circuit components. Propofol was injected as a bolus dose (50 μg/mL) and a continuous infusion dose (6 mg/h) to investigate the saturation of the ECMO circuit. Results: After the bolus dose, only 27% of propofol was recovered after 30 minutes which is as expected. However, >80% propofol was recovered after the infusion dose which persisted even when the infusion dose was discontinued. Conclusion: Our results suggest that if ECMO circuits are dosed directly with propofol, drug adsorption can be eliminated as a cause for altered drug exposure. Field of Research: Artificial Lung/ECMO

Abstract Background The perception of the quality of care provided by the medical institution to patients is directly affected by the job satisfaction of nurses. The feeling of job satisfaction is caused besides other things by the subjective expectations of employees about what their work should provide them with in return. The aim of the study is to evaluate and compare job satisfaction of hospital nurses in the Czech Republic in 2011 and 2021 by identifying differences between their personal preferences and perceived saturation. Methods The respondents are hospital nurses in the Czech Republic in 2011 and 2021. A developed questionnaire was used to determine the job satisfaction factors. The order of factors of personal preferences, perceived saturation and differences between them was compiled. For evaluation was used the Euclidean distance model that enables to capture the order and determine the significance given by the distance in which the factors are located. Results At the top of personal preferences of hospital nurses, the factors salary and patient care are in the first two places with a similar distance. The salary factor is the most preferred by hospital nurses in both evaluated periods, and at the same time there is the greatest discrepancy between personal preferences and perceived saturation. By contrast, image of profession and working conditions were sufficiently saturated by the employer in both periods, but nurses do not significantly prefer these factors. Conclusions The salary and patient care (i.e. the mission of the nurse’s work itself) are at the top of personal preferences of hospital nurses, with an exclusive position among other factors. We consider it important that the hospital management emphasizes them in the management of hospital nurses. At the same time, the patient care is perceived by the hospital nurses as one of the most saturated factors - in contrast to salary, which is located at the complete opposite pole as the least saturated factor and therefore emerges from the mutual comparison as the factor with the greatest degree of divergence. The stated conclusions are valid for both compared periods. New method of data evaluation was successfully tested.

There are hesitations about the use of surgical face masks, which are the main tools in protection from the COVID-19 pandemic, one of the biggest disasters of our age, in chronic airway diseases. The purpose of the study was to examine how stable patients with chronic obstructive pulmonary disease (COPD) responded to short-term surgical mask use in terms of in-mask air quality, oxygen saturation, and pulmonary function. Forty-one patients with stable COPD, by clinical presentation and pulmonary function tests (PFTs), were included in a quasi-experimental study. Stable COPD patients' PFTs, in-mask air quality, and pollution measures were collected before and after wearing surgical masks for two hours at rest. The findings of simultaneous tests of peripheral-blood-oxygen saturation were also recorded. The mean age of participants was 67.1 years and 87.8% were male. The pre- and post-mask PFTs parameters for GOLD (A+B) group were FEV1 (ml), FEV1 (%), FVC (ml), FVC (%), FEV1/FVC (%) and DLCO (%) (p=0.067, p=0. 065, p=0.062, p=0.083, p=0.083, p=0.269, p=0.956, respectively), whereas in GOLD (C+D) group (p=0.340, p=0.538, p=0.728, p=0.044, p=0.105, p=0.054, respectively). In post-mask measurements, the respiratory function was not impaired in GOLD-2022 (A-B-C-D) COPD subgroups. Oxygen and carbon-monoxide concentrations in exhaled air and oxygen saturation decreased after surgical mask use. The difference was statistically significant, but the difference was unimportant in terms of clinical implications. Surgical masks don't appear to have a negative effect on pulmonary function and clinical parameters in stable COPD. This study may help provide evidence-based data to overcome hesitations in use of surgical masks in chronic airway diseases. [Med-Science 2023; 12(3.000): 865-71]

Water content is one of the critical factors affecting frost damage to rock masses in alpine regions. A dynamic disturbance load further complicates the issue. In this study, the effects of saturation and impact loading on the dynamic behavior of the frozen red sandstone were investigated using a low-temperature split Hopkinson pressure bar (LT-SHPB) experimental system. By combining low-field nuclear magnetic resonance (NMR) and scanning electron microscopy (SEM), the dynamic evolution of the microstructure of the frozen sandstone due to changes in saturation was investigated. The experimental results show that the increase in saturation reshapes the pore structure of the frozen sandstone and promotes the expansion of pores of different sizes during freezing, while the frozen samples at complete saturation are mainly developed with mesopore and macropore. The dynamic strength, elastic modulus and brittleness index of the frozen sandstone under impact loading, which are limited by the critical saturation Src, tend to increase and then decrease with saturation increase. In contrast, the ultimate deformation capacity of the frozen sandstone showed an opposite trend with saturation. With increasing impact loading, the dynamic strength, elastic modulus, and peak strain of the frozen sandstone gradually increase, showing an obvious strain-rate enhancement effect; while the brittleness index decreases by 8.1% at full saturation when the impact velocity increases from 4 m/s to 6 m/s, indicating that the dynamic damage mode develops from brittle to ductile. Moreover, the frozen samples changed from tensile damage to composite damage with increasing saturation and impact loading; the distribution of crushing masses remained closely related to their dynamic strength. Based on the experimental results, the mechanism of the effects of saturation variation on the dynamic mechanical behavior of frozen sandstone is discussed.

Abstract In the petroleum sector, spectral-induced polarization (SIP) can detect low-frequency electrical characteristics in rocks without causing any damage. Measurements from 1 mHz to 100 kHz were conducted at ambient temperature for synthetic shale sand combinations from Gabel El-Galala, Cairo, Egypt. Because of an increase in the relative conductor (shale) concentration despite a reduction in the relative insulator (sand) concentration, and the effect of increasing saturation, this is the first study to explain the electrical impact of shale sand combination. We will also look into its saturation and frequency to further model and analyze shale with electrical characteristics. Both conductivity and impedance decrease regarding sand's presence. The dielectric constant increases with increasing shale level and saturation below the percolation threshold but drops beyond it. Material rich in shale has lower impedance than material rich in sand. Concentrating and saturating the shale in the synthetic sand enhanced its electrical conductivity. Ionized liquid and the conductive minerals present in shale also contribute to this improvement. The mixture's electrical characteristics improved significantly as the frequency rose. Low-frequency analysis shows that the samples have high conductive and dielectric constants. These investigations could improve oil and gas recovery by illuminating the electrical characteristics of the reservoir rock.

A family $\mathcal{F}$ of subsets of $\{1,\dots,n\}$ is called $k$-wise intersecting if any $k$ members of $\mathcal{F}$ have non-empty intersection, and it is called maximal $k$-wise intersecting if no family strictly containing $\mathcal{F}$ satisfies this condition. We show that for each $k\geq 2$ there is a maximal $k$-wise intersecting family of size $O(2^{n/(k-1)})$. Up to a constant factor, this matches the best known lower bound, and answers an old question of Erdős and Kleitman, recently studied by Hendrey, Lund, Tompkins, and Tran.Mathematics Subject Classifications: 05D05Keywords: Intersecting family, saturation, set system

Forest biomass estimation is undoubtedly one of the most pressing research subjects at present. Combining multi-source remote sensing information can give full play to the advantages of different remote sensing technologies, providing more comprehensive and rich information for aboveground biomass (AGB) estimation research. Based on Landsat 8, Sentinel-2A, and ALOS2 PALSAR data, this paper takes the artificial coniferous forests in the Saihanba Forest of Hebei Province as the object of study, fully explores and establishes remote sensing factors and information related to forest structure, gives full play to the advantages of spectral signals in detecting the horizontal structure and multi-dimensional synthetic aperture radar (SAR) data in detecting the vertical structure, and combines environmental factors to carry out multivariate synergistic methods of estimating the AGB. This paper uses three variable selection methods (Pearson correlation coefficient, random forest significance, and the least absolute shrinkage and selection operator (LASSO)) to establish the variable sets, combining them with three typical non-parametric models to estimate AGB, namely, random forest (RF), support vector regression (SVR), and artificial neural network (ANN), to analyze the effect of forest structure on biomass estimation, explore the suitable AGB of artificial coniferous forests estimation of machine learning models, and develop the method of quantifying saturation value of the combined variables. The results show that the horizontal structure is more capable of explaining the AGB compared to the vertical structure information, and that combining the multi-structure information can improve the model results and the saturation value to a great extent. In this study, different sets of variables can produce relatively superior results in different models. The variable set selected using LASSO gives the best results in the SVR model, with an R2 values of 0.9998 and 0.8792 for the training and the test set, respectively, and the highest saturation value obtained is 185.73 t/ha, which is beyond the range of the measured data. The problem of saturation in biomass estimation in boreal medium- and high-density forests was overcome to a certain extent, and the AGB of the Saihanba area was better estimated.