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In this work, the consolidation of calcium carbonate (CaCO3) by polyacrylamide (PAM) of different molecular weights, charge densities, and functional groups was investigated via oscillatory rheology and unconfined compressive strength (UCS) analysis. Oscillatory rheology showed that the storage modulus G′ was approximately 10 times higher than the loss modulus G″, indicating a highly elastic CaCO3 sample upon consolidation via PAM. Both oscillatory rheology and UCS analysis exhibited similar trends, wherein the mechanical values (G′, G″, and UCS) first increased with increasing polymer dosage, until they reached a peak value (typically at 3 mgpol/gCaCO3), followed by a decrease in the mechanical values. This indicates that there is an optimum polymer dosage for the different PAM-CaCO3 colloidal systems, and that exceeding this value induces the re-stabilisation of the colloidal system, leading to a decreased degree of consolidation. Regarding the effect of the PAM molecular weight, the peak G′ and UCS values of CaCO3 consolidated by hydrolysed PAM (HPAM) of different molecular weights are very similar. This is likely due to the contour length of the HPAMs being either almost the same or longer than the average distance between two CaCO3 particles. The effect of the PAM charge density revealed that the peak G′ and UCS values decreased as the charge density of the PAM increased, while the optimum PAM dosage increased with decreasing PAM charge density. The higher likelihood of lower-charge PAM bridging between the particles contributes to higher elastic energy and mechanical strength. Finally, regarding the PAM functional group, CaCO3 consolidated by sulfonated polyacrylamide (SPAM) typically offers lower mechanical strength than that consolidated with HPAM. The bulky sulfonate side groups of SPAM interfere with the surface packing, reducing the number of polymers able to adsorb onto the surface and, eventually, reducing the degree of consolidation of CaCO3. The zeta potential of the PAM-CaCO3 samples became more negative with increasing PAM concentration due to the saturation of the particle surface. Good agreement between oscillatory rheology and UCS analysis could accelerate PAM screening for optimum CaCO3 consolidation. [ABSTRACT FROM AUTHOR]

Denitrifying woodchip bioreactors successfully remove nitrates from reverse osmosis desalinization brine. On-farm desalination plants only operate for several hours per day in batch mode, meaning bioreactors should also operate in batch cycles, although this type of bioreactor operation is relatively unstudied. This study compared two tests of three cycles of 24 h per week with two treatments each (Test 1 8 vs. 24 h, and Test 2 8 vs. 12 h). Cylindrical pilot-scale bioreactors were filled with 130 kg of citrus woodchips and an average of 322 L of brine. The results show that the treatments with longer saturation periods of 24 and 12 h exhibited higher removal rates under operational conditions (i.e., 8 h flooding based on a 24 h cycle) than the 8 h treatment. However, the nitrate removal rates of the 8 h treatment were higher under fill cycle conditions (i.e., 8 h flooding based on an 8 h cycle). Dissolved organic carbon liberated from the woodchips was greater in treatments with longer drying periods (i.e., treatments with shorter saturation periods). Batch bioreactors should be considered under applicable conditions to increase nitrate removal rates. [ABSTRACT FROM AUTHOR]

Single-well tracer technique have been well applied in many petroleum industry and environmental applications. However, these tests have not been well developed for CO2 geological storage purposes to evaluate residual CO2 saturation during the appraisal phase of site investigation, due to the challenges occurring from the complex phase behaviour. In this study, two single-well tracer tests are numerically modelled to quantify the residual gas saturation. Our study addresses the design of an alternative single well tracer test sequence, which involved a single pass of the tracer saturated water over the residually trapped zone, thereby reducing the amount of CO2 dissolution into the tracer solution. A one-dimensional numerical modelling of the tracer propagation and partitioning with homogenous properties was used for the calculations of the difference in tracer breakthrough times during water withdrawal from the tests. Model sensitivity variations were applied to analyse the impact of reservoir and treatment design parameters on the residual gas saturation. The residual gas saturations calculated reflect the input values, including the effect of hysteresis, to within 10% accuracy. It was found that changing the CO2 saturated water volume injected after CO2 made the CO2 front to travel to different distances from the well, and thus the tracer had different size of residually trapped zones to travel through when it is back produced and encounters different residual gas saturations, and therefore affected the residual gas saturation calculations. The modelling also shows that optimal injection of CO2-saturated water to prevent the dissolution of the residually trapped CO2 and establish the residually trapped zone was challenging to achieve, and therefore using the fluid withdrawal method was more robust to establish the residually trapped zone. This is because of the dependency of solubility on pressure. The numerical models may be used to design, optimise, and interpret the field tests. [ABSTRACT FROM AUTHOR]

Fractured and vuggy carbonate reservoirs present a complex storage space with irregularly distributed fractures and caves. Furthermore, these reservoirs typically feature the presence of a substantial bottom aquifer, further complicating the fluid flow dynamics. At present, most well test models for this reservoir are based on discrete media primarily address single-phase flow scenarios, typically considering caves as equipotential bodies. This approach cannot accurately represent the complexities of such reservoirs. In this paper, a three-dimensional numerical well test model for two-phase oil-water flow within fractured and vuggy carbonate reservoirs is introduced. Randomly generated natural fractures are embedded within the reservoir, and the Hagen-Poiseuille law is utilized to describe fluid flow within cave spaces, effectively coupling flow interactions across fractures, caves and the porous rock matrix. The computational domain is discretized by a perpendicular bisection grid, and the finite volume method is used to solve the model, allowing for the calculation of the pressure and saturation fields at each time step. Subsequently, well test type curves are constructed and analyzed, flow regimes are segmented, and sensitivity analysis of model parameters is conducted. The pressure buildup data from well A are interpreted, and the results demonstrate a remarkable agreement between the well test curve and actual data, confirming the capability of the model to capture reservoir characteristics and complex fluid flow phenomena. The findings lay the foundation for the development of numerical well test models tailored to fractured and vuggy carbonate reservoirs. [ABSTRACT FROM AUTHOR]

Gas-hydrate saturation and porosity are the most crucial reservoir parameters for gashydrate resource assessment. Numerous academics have put forward elastic and electrical petrophysical models for calculating the saturation and porosity of gas-hydrate. However, owing to the limitations of a single petrophysical model, the estimation of gas-hydrate saturation and porosity using single elastic or electrical measurement data appears to be inconsistent and uncertain. In this study, the sonic wave velocity, density and resistivity well log data are combined with a Bayesian linear inversion method for the simultaneous estimation of gas-hydrate saturation and porosity. The sonic wave velocity, density and resistivity data of the Shenhu area in the South China Sea are used to estimate the gas-hydrate saturation and porosity. To validate the accuracy of this method, the estimation results are compared with the saturation obtained from pore water chemistry and porosity obtained from density logs. The well log data examples show that the joint estimation method not only provides a rapid estimation of the gas-hydrate reservoir parameters but also improves the accuracy of results and determines their uncertainty. [ABSTRACT FROM AUTHOR]

In this paper, a dc–dc boost converter with continuous input is investigated. In addition to its input current, the converter offers the advantage of using a reduced number of electronic components. The objective is to design an appropriate controller for the nonlinear model taking into account the system nonlinearities, the uncertainty of the resistance load, the constrained fuel cell current, and the saturation of the control input signal (duty ratio).The point is that the converter presents a no minimum phase feature, and the duty ratio must constrain between 0 and 1. Then, a saturated nonlinear controller is elaborated. Detailed analysis and simulation show that the proposed controller meets all control objectives, namely: tight dc-bus voltage regulation and asymptotic stability of the closed-loop system. Experimental results are also given, which show the effectiveness of the controller. [ABSTRACT FROM AUTHOR]

The paper gives an analytical solution for the practically important problem of finding the magnitude of the mechanical deflection of a thin palladium plate (cantilever) during its one-sided saturation with hydrogen. A reasonably simple model is proposed, which permits us to derive and analyze a system of kinetic equations defining the concentration gradient of atomic hydrogen across the plate. We perform numerical integration and asymptotic analysis of the obtained governing equations (subject to acceptable initial and boundary conditions) and thus describe the temporal evolution of the deflection. The latter is found to be in good agreement with time dependence of a palladium cantilever bending obtained in the experimental part of the work. These results permit us to determine an important kinetic coefficient, namely, the permeation rate of hydrogen through the palladium surface. [ABSTRACT FROM AUTHOR]

The purpose of the research is to evaluate the effectiveness of the Wim Hof method on Quality of Life parameters and Saturation in patients with asthma. It used the SF-36 questionnaire and pulse oximetric method before and 2 months after the application of the Win Hof breathing method. The results showed, that Wim Hof breathing method improved some parameters of QOL and the SpO2 level. We conclude, that the use of Win Hof breathing method is one of the effective breathing techniques, that increase the level of oxygenation and Quality of Life in patients with asthma. [ABSTRACT FROM AUTHOR]

The article presents a study of the effect of the carbidization process on the properties of tungsten carbide powder. The main properties of tungsten carbide (WC) powder include structurephase composition, grain size, particle size and shape, and bound and free carbon in the content. The quality of tungsten carbide powder is mainly determined by the tungsten carbide (WC) phase, its saturation with carbon, as well as the content of free carbon. Therefore, in our experimental study, the temperature of the carbidization process was carried out by determining the structurephase composition of tungsten carbide (WC) and the amount of bound and free carbon in it. [ABSTRACT FROM AUTHOR]

A downflow hanging sponge (DHS) unit was established for treating synthetic domestic wastewater (SDW) for over 100 days of continuous feed. The DHS system was operated at a chemical oxygen demand (COD) concentration of 531.62 ± 93.6 mg/L, and different hydraulic retention times (HRTs) = 6.0–2.0 h to determine the system kinetics. The substrate removal kinetics of the DHS reactor was calculated using modified Stover–Kincannon, Monod, Grau's second-order and first-order models. The Monod model has the following decay coefficient (Kd), yield coefficient (Y), and maximum specific growth rate of bacteria (μmax) that were, respectively, 0.0025 1/d, 0.1337 gVSS/gCOD, and 0.0364 1/d. Maximum substrate utilization rate (Umax) and saturation value constant (KB) for the modified Stover–Kincannon model were determined to be, respectively, 15.46 and 14.45 g/L/d. While the kinetic coefficient for the second-order model ranged was 0.516–0.641 1/d versus 27.627 1/d for the first-order model, the constants of the Grau second-order model (a and b) were estimated as 0.0366 and 0.9215. The Grau second-order and modified Stover–Kincannon models showed an R2 value of 0.995, making them the most convenient for the experimental results. The results indicated that these models could be used to predict the DHS reactor behavior at different scales. [ABSTRACT FROM AUTHOR]

We demonstrate that absorption saturation of a mid-infrared intersubband transition can be engineered to occur at moderate light intensities of the order of 10–20 kW cm−2 and at room temperature. The structure consists of an array of metal–semiconductor–metal patches hosting a judiciously designed 253 nm thick GaAs/AlGaAs semiconductor heterostructure. At low incident intensity, the structure operates in the strong light–matter coupling regime and exhibits two absorption peaks at wavelengths close to 8.9 μm. Saturation appears as a transition to the weak coupling regime—and therefore, to a single-peaked absorption—when increasing the incident intensity. Comparison with a coupled mode theory model explains the data and permits to infer the relevant system parameters. When the pump laser is tuned at the cavity frequency, the reflectivity decreases with increasing incident intensity. When instead the laser is tuned at the polariton frequencies, the reflectivity non-linearly increases with increasing incident intensity. At those wavelengths, the system, therefore, mimics the behavior of a saturable absorption mirror in the mid-IR range, a technology that is currently missing. [ABSTRACT FROM AUTHOR]

The seismoelectric effect is a coupling phenomenon between the seismic wavefield and electromagnetic field caused by the electric double layer in a fluid-saturated porous medium. As seismoelectric signals are sensitive to porous medium properties, such as the water saturation, salinity, porosity and permeability, they have good potential for imaging the structure and estimating underground parameters. In this study, we proposed an inversion method for estimating the salinity using coseismic electric fields generated by electrokinetic effects. The method was established by waveform matching between synthetic and observed coseismic electric signals based on a horizontally layered model. We used an L1 norm measure to construct the regularization term and achieve a high-resolution layer interface. Subsequently, we applied the first-order Taylor expansion to estimate the sensitivity and used logarithm transformation to constrain the range of parameters and reduce the solution space. Finally, we used an iteratively reweighted least-squares method to solve the final Gauss–Newton-type inversion function in each iteration to obtain the model update until the inversion converged. Numerical experiments were conducted to test the resolution, anti-noise ability and stability of the inversion algorithm. These results demonstrate that the proposed method can effectively recover the salinity structure, which broadens the application of seismoelectric effects. We further applied the method to the M w 6.5 Jiuzhaigou earthquake in 2017 and used the observed coseismic electric field to estimate the salinity and conductivity beneath the station. [ABSTRACT FROM AUTHOR]

Gradient doping ensures uniform transverse gain in an edge-pumped multislab pulsed amplifier, and a 1D iterative method is developed to generate the proper doping profile. Our investigations show that uniform gain under short pump duration tp = 0.25 ms can be readily achieved, where the modulation of the gain distribution is lower than 1.05 even if the diagonal transverse gain-length product (DTGLP) increases up to 5. For tp = 1.0 ms, comparable modulation of the gain distribution is achieved for a much lower DTGLP value of 2.3. To extend the DTGLP range for long pump duration, a modified 1D iterative method with an effectively "shortened" lifetime of the active ions is developed. With the modified method, the gain uniformity for both pumping conditions is greatly improved, and specifically, the DTGLP increases from 2.3 to 3.0 for tp = 1.0 ms. In addition, degradation of the gain uniformity resulting from deviations of the doping concentration is discussed. The deviations should be at least lower than 1% and 5% for tp = 1.0 ms and tp = 0.25 ms to maintain the gain uniformity, respectively. Our investigations might provide a useful way to design the amplifier with uniform gain in the beam aperture of a high average power pulsed laser. [ABSTRACT FROM AUTHOR]

Experimental characteristics of bottom-gate-contact organic thin film field-effect transistors (OTFTs) with 70 nm thick films of solution processed non-peripherally octahexyl-substituted copper tetrabenzotriazaporphyrin (6CuTBTAP) novel asymmetric molecules as active layers on silicon substrates are analyzed by both linear and non-linear parameter extraction methods in order to examine the field-dependent mobility and contact effects. Both linear and saturation field effect mobilities of OTFTs have been computationally determined as a function of gate voltage in the presence of the contact resistances. The Poole-Frankel mechanism is found to be responsible for charge transport during the saturation regime, giving the highest mobility of 6.9 × 10−2 cm2 V−1 s−1 at the gate-source voltage (VG) of 50 V. The on-off ratio is found to be 106. The contact resistance at the interface between gold electrodes and the 6CuTBTAP active layer decreases with VG sharply from 75 MΩ corresponding to VG = 0 V to 10 MΩ once the transistor is turned on at the threshold voltage. [ABSTRACT FROM AUTHOR]

The corrosion of the nuclear-borosilicate matrix in an anaerobic environment is delayed due to the formation of an amorphous gel layer on its glassy interface. The formation of this gel occurs at the saturation of silicic acid. In addition to the in-situ formed iron corrosion products, the metamorphic forms can also delay the gel formation, accelerating the nuclear glass corrosion. Saturated and pure water experimental models with and without Ankerite were incorporated into the standard materials characterization center (MCC) leach test for radioactive waste types at 90 °C. However, a synonymous test was allocated at 25 °C and was conducted among the reaction models. All the batch experiments on International Simple Glass (ISG)were performed at an initial pH of 6.3. Various techniques for tracking the ISG corrosion rate have been employed and proven to be effective. As a result, the normalized weight loss of Na and Si were efficient trackers for all of the experimental systems/models; the higher the Si concentration, the lower the saturation, and vice versa. Furthermore, Na concentrations were proven to be an effective representation of the ISG corrosion rate, as they were able to produce sound ISG corrosion rate values across the experimental curing durations and circumstances when utilizing a particular conversion factor. Even at saturation, a higher reaction temperature was found to be an effective factor that enhances the ISG corrosion rate. [ABSTRACT FROM AUTHOR]

We analyze the temperature-dependent dark saturation current density and open-circuit voltage (Voc) for GaAs, GaInP, and AlGaInP solar cells from 25 to 400 °C. As expected, the intrinsic carrier concentration, ni, dominates the temperature dependence of the dark currents. However, at 400 °C, we measure Voc that is ~50mV higher for the GaAs solar cell and ~60–110mV lower for the GaInP and AlGaInP solar cells compared to what would be expected from commonly used solar cell models that consider only the ni2 temperature dependence. To better understand these deviations, we measure the carrier lifetimes of p-type GaAs, GaInP, and AlGaInP double heterostructures (DHs) from 25 to 400 °C using time-resolved photoluminescence. Temperature-dependent minority carrier lifetimes are analyzed to determine the relative contributions of the radiative recombination, interface recombination, Shockley-Read-Hall recombination, and thermionic emission processes. We find that radiative recombination dominates for the GaAs DHs with the effective lifetime approximately doubling as the temperature is increased from 25 °C to 400 °C. In contrast, we find that thermionic emission dominates for the GaInP and AlGaInP DHs at elevated temperatures, leading to a 3–4× reduction in the effective lifetime and ~40× increase in the surface recombination velocity as the temperature is increased from 25 °C to 400 °C. These observations suggest that optimization of the minority carrier confinement layers for the GaInP and AlGaInP solar cells could help to improve Voc and solar cell efficiency at elevated temperatures. We demonstrate Voc improvement at 200–400 °C in GaInP solar cells fabricated with modified AlGaInP window and back surface field layers. [ABSTRACT FROM AUTHOR]

The complex physiological environment and inherent self-healing function of tumors make it difficult to eliminate malignant tumors by single therapy. In order to enhance the efficacy of antitumor therapy, it is significant and challenging to realize multi-mode combination therapy by utilizing/improving the adverse factors of the tumor microenvironment (TME). In this study, a novel Fe3O4@Au/PPy nanoplatform loaded with a chemotherapy drug (DOX) and responsive to TME, near-infrared (NIR) laser and magnetic field was designed for the combination enhancement of eliminating the tumor. The Fe2+ released at the low pH in TME can react with endogenous H2O2 to induce toxic hydroxyl radicals (·OH) for chemodynamic therapy (CDT). At the same time, the generated Fe3+ could deplete overexpressed glutathione (GSH) at the tumor site to prevent reactive oxygen species (ROS) from being restored while producing Fe2+ for CDT. The designed Fe3O4@Au/PPy nanoplatform had high photothermal (PT) conversion efficiency and photodynamic therapy (PDT) performance under NIR light excitation, which can promote CDT efficiency and produce more toxic ROS. To maximize the cancer-killing efficiency, the nanoplatform can be successfully loaded with the chemotherapeutic drug DOX, which can be efficiently released under NIR excitation and induction of slight acidity at the tumor site. In addition, the nanoplatform also possessed high saturation magnetization (20 emu/g), indicating a potential magnetic targeting function. In vivo and in vitro results identified that the Fe3O4@Au/PPy-DOX nanoplatform had good biocompatibility and magnetic-targeted synergetic CDT/PDT/PTT/chemotherapy antitumor effects, which were much better than those of the corresponding mono/bi/tri-therapies. This work provides a new approach for designing intelligent TME-mediated nanoplatforms for synergistically enhancing tumor therapy. [ABSTRACT FROM AUTHOR]

[Display omitted] Glycolipids in biological membranes are ubiquitous and believed to be involved in the formation of ordered functional domains. However, our current knowledge about such glycolipid-enriched domains is limited because they are inherently difficult to characterize. We use grazing-incidence X-ray diffraction, isotherm measurements, and Brewster angle microscopy to investigate the phase behavior and miscibility in Langmuir lipid monolayers containing glycolipids. Glycolipid-enriched domains give rise to distinct diffraction patterns that allow for a systematic structural investigation and reveal a rich phenomenology, ranging from near-complete demixing to the formation of mixed domains with unique features. The phase behavior is governed by the headgroup chemistry and by the length and saturation of the tails. [ABSTRACT FROM AUTHOR]

[Display omitted] • A database is generated using 3D multiphase CFD simulations. • Six surrogate models are produced to predict the resistance and water saturation. • Every model has proven to be accurate at predicting resistance. • Ensemble models have better performance at predicting water saturation. • It is suggested that CatBoost be combined with "3D + 1D" for flooding prediction. In the simulation of proton exchange membrane fuel cells, a "3D + 1D" model combines a detailed 3D domain with a simplified 1D domain. The "3D + 1D" method accurately simulates flooding by considering the resistance to oxygen transfer and water saturation in porous media adjacent to the flow field. This study proposes an efficient model compatible with "3D + 1D." The model should be able to swiftly and accurately predict the resistance and water saturation under various flow fields, GDL porosities, and operating conditions. To this end, a multiphase 3D computational fluid dynamics model generates a data set. The data set comprises anticipated variations. A comparative investigation of six regression methods has been presented. The methods are based on Response Surface Methodology (RSM), Artificial Neural Networks (ANN), and four ensemble machine learning methods, named Random Forest (RF), XGBoost, Lightgbm, and CatBoost. Genetic algorithm optimization tunes hyperparameters. It has been found that every model has proven to be accurate at predicting resistance. With an R2 of 0.9899, CatBoost has the best performance, while RSM presents the simplest regression employed to formulate the resistance. In the context of predicting water saturation, ensemble machine-learning models have demonstrated better performance than RSM and ANN models. CatBoost performs the best with an R2 of 0.983 in predicting water saturation. It is recommended that CatBoost and the "3D + 1D" method be integrated to achieve an accurate prediction of flooding. [ABSTRACT FROM AUTHOR]

Modelling the relationships among bulk conductivity, electrolyte conductivity, porosity and fractional electrolyte‐saturation continues to be based on empirical relationships such as Archie's law or the Bruggeman correlation. Several authors have attempted to connect such empirical models to first principles. This article presents a complete first principles‐based description of conductivity in partially saturated porous media. A geometrical factor is introduced which, together with porosity and saturation, describes the conductivity of partially saturated porous media. This geometrical factor is separated into two intrinsic geometrical descriptors of the electrolyte distribution accounting for tortuosity and constriction. This tortuosity and constriction factor are obtained from integration over the electrical field lines traversing the electrolyte. Bulk and saturation‐dependent conductance descriptions are illustrated using three‐dimensional pore space models and simulated fluid distributions. Describing conductance through porosity, saturation and a geometrical factor, decomposed into separate terms accounting for tortuosity and constrictivity, permits more insightful understanding of conductance in partially saturated porous media. Use and efficacy of this full conductance description is illustrated throughout this article. [ABSTRACT FROM AUTHOR]

The seas around China contain abundant non-diagenetic gas hydrate deposits. The traditional logging and evaluation techniques based on conventional oil and gas no longer satisfy the evaluation requirements of offshore gas hydrate layers, and it remains difficult to calculate the hydrate saturation accurately, which seriously restricts the accurate evaluation of the resources. Petrophysical experiments are an important means to study gas hydrate. By simulating the hydrate formation conditions in sediments under natural conditions, the study of various petrophysical properties of gas hydrate is essential to the exploration and development of hydrates and the prediction of reservoir parameters. In this study, a tetrahydrofuran (THF) solution, montmorillonite, and natural sea sand were selected to simulate the growth of gas hydrate based on its characteristics in the study area, and in situ CT scanning experiments were carried out at different hydrate formation stages to determine the microscopic morphologies of gas hydrates within the pore space. In addition, the acoustic wave and resistivity of hydrates with different saturations were measured. Forward modeling of a differential effective medium (DEM) model was conducted for the hydrate reservoirs with different saturations, and the gas hydrate morphology was analyzed. Thereafter, the hydrate saturation predictions based on the petrophysical experiments were analyzed. The results of these analyses indicate that the microscopic morphology of hydrates in the study area is primarily pore-filling form. Based on the saturation estimations using the Archie's law, Wood equation, time-average equation and the DEM method, and under the constraint of the acoustic and electrical measurement results of the petrophysical experiments, an electric acoustic joint model was built by integrating the resistivity and acoustic waves. The estimation results indicate that the joint electro-acoustic model is the best method for calculating the saturation in the study area. [ABSTRACT FROM AUTHOR]

A pure electrical method is presented to extract emitter and base bandgaps of a bipolar junction transistor (BJT) at the locations where the minority carrier injection takes place. It is based on the simultaneous measurement of the collector and base currents as a function of the emitter-base forward bias (Gummer plot) and the corresponding current gain. From the obtained saturation currents as a function of temperature, we extract the bandgap energies. The accuracy of the method is demonstrated for InGaP-GaAs, Si, and Ge commercial devices. For InGaP-GaAs transistors, the results can be understood if the emitter-base heterojunction is not an abrupt but a gradual one. The presented method is a reliable tool that can aid in the development of new compound semiconductor based BJTs whose bandgap energies are highly sensitive to their composition. [ABSTRACT FROM AUTHOR]

We report on the photoresponse of AlGaN/GaN high electron mobility transistors to the THz radiation of low (15 mW/cm²) and high (up to 40 kW/cm²) intensities. We show that the response can be described by the Dyakonov-Shur theory in the whole range of radiation intensity. At low intensities, the photoresponse is linear in radiation intensity. Under intense laser radiation, we observe a saturation at intensities >20 kW/cm². We explain our results by the change of the channel conductivity under the influence of strong THz field. This mechanism of photoresponse saturation, which is due to the mobility decrease in high ac electric field, should exist for any type of field effect transistor detectors. [ABSTRACT FROM AUTHOR]

To investigate the saturation characteristics of silicon-based optoelectronic devices caused by short-pulse laser irradiation, an Nd:YAG laser with a wavelength of 1064 nm and two typical silicon-based photodiodes, PN and PIN, were employed to build an experimental system to measure the transient response signal of the device. The change. The experimental results demonstrate that with the increase of laser energy density, the nonlinear saturation of the two devices occurs, and the response time is significantly increased. This is a response degradation phenomenon for the response of the device and the signal after the saturation of the two devices. By analyzing the rising edge, half-height width, and bottom width of the characteristic quantity, it can be found that the broadening of the two devices is mainly due to the broadening of the falling edge of the response signal. However, the broadening of the PIN-type photodiode after laser irradiation is compared with that of PN. Type photodiodes remain more remarkable. Through the analysis of carrier dynamics, when the signal is restored, the movement of carriers is affected by a large number of photogenerated carriers after the laser irradiation ends, affecting the drift movement and space charge region during the bipolar transport of carriers. The width of the two devices attenuates the speed when the signals of the two devices are restored, leading to the saturation caused by the laser irradiation of the two devices [ABSTRACT FROM AUTHOR]

The use of rock physics modeling and petrophysical analysis has become an integral part of quantitative seismic interpretation. In the present study, the above-mentioned techniques are applied to the reservoir interval of Basal Sand of Cretaceous age widely distributed in the Lower Indus Basin of Pakistan. The data used for this purpose consists of complete suits of wireline logs from four well A, B, C and D. The primary goal of this work is to understand the trends of seismic parameters such as P-wave velocity (VP), S-wave velocity (VS), bulk modulus, bulk density as a function of fluid saturation and porosity in this sand interval. Petrophysical analysis based on well logs is used to obtain petrophysical properties such as porosity, the volume of shale, fluid saturation, P-wave velocity (VP), S-wave velocity (VS) and density at reservoir conditions. The results show that seismic parameters are very sensitive to fluid saturation, fluid types and rock forming sediments. Reservoir porosity and fluid saturation control the elastic response of Basal Sand due to which seismic velocities decrease with an increase in porosity and fluid saturation. [ABSTRACT FROM AUTHOR]

Carbon monoxide (CO) poisoning is a common cause of death, leading to morbidity and mortality worldwide. Features of the CO poisoning with low carboxyhemoglobin (COHb) levels remain to be characterized. This study collected a total of 307 CO poisoning cases from Shanghai Public Security Bureau, an official organization that handles the most complicated and life-threatening cases across Shanghai municipality in China, and regrouped these cases into three categories: group 1, 10% < COHb% < 30% (n = 58); group 2, 30% ≤ COHb% < 50% (n = 79); group 3, COHb% ≥ 50% (n = 170). Epidemiological, demographic, and forensic aspects of the CO poisoning cases, particularly those with low COHb levels, were analyzed. Our results showed that group 2 and 3 were mostly observed in younger victims (≤ 30 years), while group 1 equally distributed to all age groups (p = 0.03). All the CO poisoning from group 2 and 3 occurred in enclosed spaces, whereas cases from group 1 died additionally in outdoor spaces (p = 0.01). 81.03% of group 1 cases died in fire circumstances, while only 45.57% from group 2 and 30.59% from group 3 were fire-related (p = 0.00). Accordingly, group 1 was mostly related with fire burns, while group 2 or 3 were largely associated with gas leakage (p = 0.00). A combination with alcohol, but not other psychotropic drugs, associated with significant higher levels of blood COHb% in fire-unrelated (p = 0.021) but not fire-related cases (p = 0.23). Five extremely low COHb% (< 30%)-related poisoning deaths were negative of any cardiopulmonary pathology and psychoactive substances. In conclusion, CO poisoning with low COHb% significantly associates with fire circumstances and outdoor spaces and has no age preference. Further diagnostic markers mandates to be identified in order to avoid disputes in cases of extremely low COHb%-related poisoning. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effect of fatty acid saturation (oleic acid, linoleic acid, and linolenic acid) on water distribution, migration, and gel properties of pork salt‐soluble protein, by detected indicators that are Low field nuclear magnetic resonance (LF‐NMR), magnetic resonance imaging (MRI), water‐holding capacity (WHC), and gel strength. These results suggested that the WHC and gel strength decreased with the decrease of fatty acid saturation (p < 0.05). LF‐NMR analysis revealed that the relaxation time T21 and T22 decrease (p < 0.05) with the decrease of fatty acid saturation. Results also showed that the T21 increased and T23 decreased in linolenic acid group compared with oleic acid group. Meanwhile, the peak area ratio of P21 and P22 decreased (p < 0.05), while P23 increased (p < 0.05). Therefore, the saturation of fatty acids had a great influence on the gel properties of protein. Practical Application: It provides a theoretical basis for the production of polyunsaturated fatty acids emulsified gel meat products and promotes the development of meat processing industry. [ABSTRACT FROM AUTHOR]

Groundwater is a nearly exclusive water resource, specifically for the communities which are part of the Chicago metropolitan area. However, water shortage is predicted for many communities in this region, and demand for locating and delineating groundwater is increasing to fulfill the water supply. Shallow sand and gravel aquifers within the glacial deposits of the area specifically are high volume aquifer and less stressed compare to deeper bedrock aquifer. Yet, these aquifers are poorly understood in terms of their extent and lateral variability. This study applied the shear-wave seismic reflection method to delineate the thickness, lateral extent, and internal variability of these aquifers. We acquired horizontally polarized shear-wave (SH-waves) reflection data along five profiles of a total length of 11 km using the land streamer technology in McHenry County in northern Illinois to delineate sand and gravel aquifers. As shear waves propagate through the rock matrix and less sensitive to the presence of water, information from nearby borings and water wells aided the interpretation of the acquired SHwave seismic profiles. We delineated multiple sand and gravel units of potential aquifers of different thicknesses and lateral extent along with the seismic profiles. The relatively higher vertical and lateral resolution of the shear-waves reflection method and its insensitivity to water saturation or chemistry made it an ideal method to resolve sand and gravel units of potential aquifers within the complex geological environment if aided by water-well information. [ABSTRACT FROM AUTHOR]

Structural hydroxyl content of volcanic quartz phenocrysts was investigated with unpolarized Fouriertransform infrared spectroscopy. The phenocrysts originated from five pyroclastic fallout deposits from the Bükk Foreland Volcanic Area (BFVA), Hungary, and two from the AD1314 Kaharoa eruption (KH eruption), Okataina Volcanic Complex (Taupo Volcanic Zone), New Zealand. All investigated quartz populations contain structural hydroxyl content in a narrow range with an average of 9.3 (-1.7) wt ppm. The earlier correlated horizons in the BFVA had the same average structural hydroxyl content (within uncertainty). Thus, it can be concluded that the structural hydroxyl content does not depend on the geographical distance of outcrops of the same units or the temperature or type of the covering deposit. The rare outlier values and similar structural hydroxyl contents show that the fallout horizons cooled fast enough to retain their original structural hydroxyl content. The similarity of the structural hydroxyl contents may be the result of similar P, T, and x (most importantly H2O and the availability of other monovalent cations) conditions in the magmatic plumbing system just before eruption. Therefore, we envisage common physical-chemical conditions, which set the structural hydroxyl content in the quartz phenocrysts and, consequently, the water content of the host magma (-5.5 wt %-7 wt% H2O) in a relatively narrow range close to water saturation. [ABSTRACT FROM AUTHOR]

The drying of porous media is of major importance for civil engineering, geophysics, petrophysics, and the conservation of stone artworks and buildings. More often than not, stones contain salts that can be mobilized by water (e.g., rain) and crystallize during drying. The drying speed is strongly influenced by the crystallization of the salts, but its dynamics remains incompletely understood. Here, we report that the mechanisms of salt precipitation, specifically the primary or secondary nucleation, and the crystal growth are the key factors that determine the drying behaviour of salt contaminated porous materials and the physical weathering generated by salt crystallization. When the same amount of water is used to dissolve the salt present in a stone, depending on whether this is done by a rapid saturation with liquid water or by a slow saturation using water vapor, different evaporation kinetics and salt weathering due to different crystallization pathways are observed. [ABSTRACT FROM AUTHOR]

The effεcts of magnetocrystalline anisotropy (Ku) and magnetization saturation (Ms) on the mεchanically induced switching in nanomagnets are studied using a constraint-free phase field model, which allows explicit magneto-mεchanical coupling and strictly constant magnetization magnitude. The effεcts of Ku and Ms on the transition boundary between the coherent and incoherent switching modes are presented in terms of the nanomagnet geometry. It is found that Ms rather than Ku can affεct the transition boundary between the two switching modes. In the coherent mode, there exists a critical strain (εc) to induce a deterministic 90° switching. By using the dynamic nature and overrun behavior of the magnetization, a deterministic 180° switching can occur if the mεchanical strain is removed once the magnetization rotates to the largest achievable angle (vm1). For 90° switching, increasing Ku can enhance both εc and vm1, whereas Ms incurs no noticeable changes. For 180° switching, the switching time (ts) increases with Ms linearly, but initially dεcreases with increasing Ku and then saturates. The results for ts suggest that moderate Ku and Ms are advisable to simultaneously obtain relatively low εc, quick switching, high storage density, and high magnetization-state stability in nanomagnets. This work provides insight on tuning mεchanically assisted nanomagnet-based logic and memory devices through Ms and Ku. [ABSTRACT FROM AUTHOR]

The differential effective medium (DEM) theory studied in this paper describes elastic moduli of a fractured medium with help of differential equations, where crack density is the independent variable and fluid saturation is a parameter. The effective medium is isotropic for randomly oriented flat ellipsoidal cracks and thus fully characterized by two elastic constants. In this article we derive an analytical solution of the equation for Poisson's ratio and we transform the differential equation for Young's modulus into a non-linear algebraic equation. Fluid saturation and crack density can then be determined from measured wave propagation velocities by a simple algorithm. We also derive approximate solutions for elastic moduli as a function of crack density and saturation, which allows to quantify the uncertainty of the result due to measurement errors. The DEM theory leads to higher crack densities than the self-consistent method and to lower crack densities than the non-interacting theory for measured elastic moduli, while all three methods give similar fluid saturation fractions. As an example of application of our theoretical results, we study weathered granite in the Strengbach water catchment in the Vosges mountains in France. We have performed full waveform sonic logging measurements in an 86-m-deep borehole located at an altitude of 1130 m above sea level, which is used for hydrogeophysical and geochemical studies of a granitic aquifer. The logging data allows us to investigate P and S waves in the depth range between 40 and 80 m. The P - and S -wave propagation velocities take average values of 5.0 and 2.7 km s–1, respectively, with the highest values of 5.8 and 3.2 km s–1 at 75–80 m depth. From these velocities we obtain a water saturation of 75 ± 25 per cent. The crack density describes the degree of weathering of the granite, which generally decreases with depth, but takes high values near layers of strongly weathered granite. Crack density is on average 0.5, with the highest value of 1.0 at 65 m and the lowest value of 0.2 at 75 m depth. The analysis of the full waveform logging data by the DEM method supports results from previous geochemical and hydrological studies in the Strengbach catchment which concluded that water is stored in deeper layers of the granitic aquifer. [ABSTRACT FROM AUTHOR]

The X-ray microtomography was used to visualize and characterize the remobilization oil process inside the porous system of a carbonate rock sample. After being saturated with a brine solution, dodecane oil was injected into the porous media, initially a predominant water-wet system. After an aging process is performed, the system became mixed-wet. The remobilization was induced by the injection of two KI (Potassium Iodide) brine solutions, a high salinity solution injection (1.5 M) followed by a low one (0.3 M). The intention was to achieve, besides the immiscible displacement process, oil remobilization due to the modification of interfacial properties of fluids and wettability caused by low salinity of the injected brine. It was observed that the low salinity brine was capable of shifting the oil inside the porous medium and reduce the residual oil saturation. [ABSTRACT FROM AUTHOR]

Effect of the simultaneous hydrolysis of octacalcium phosphate (OCP) and poly (lactic-co-glycolic acid) (PLGA) was investigated on its osteoconductivity. PLGA soaked in phosphate buffered saline with 0%, 20%, and 40% OCP at 37°C for eight weeks indicated that when the OCP dose was increased, 1) the weight loss of PLGA increased, 2) the glass transition temperature of the PLGAs decreased, 3) the saturation degree in the saline moved to nearly saturated condition with respect to hydroxyapatite (HA) but was undersaturated with respect to OCP, and 4) OCP tended to convert to HA by X-ray diffraction and Fourier transform infrared spectroscopy. OCP/PLGA composites of 20% and 40% with more than 92% porosity were produced by combining OCP granules with 1,4-dioxane-solubilizing PLGA followed by lyophilization and then subjected to four- and eight-week in vivo implantation tests in 3 mm diameter rat femora defects. Microfocus X-ray computed tomography, histochemical and histomorphometric analyses showed that while bone formation was very limited with PLGA implantation, the extent of repair tended to increase with increasing OCP content in the PLGA, coupled with PLGA degradation, and bridge the defects with trabecular bone. Tartrate-resistant acid phosphatase-positive osteoclast-like cells were accumulated four weeks after implantation, while osteocalcin-positive osteoblastic cells appeared later at eight weeks, especially in 40% OCP/PLGA. These results suggest that OCP hydrolysis, with phosphate ion release, enhances PLGA hydrolysis, probably through the acid catalysis function of the protons supplied during the hydrolysis of OCP, thereby inducing PLGA biodegradation and new bone formation in the femoral defects. Octacalcium phosphate (OCP) enhances osteoblasts and osteocytes differentiations during its hydrolysis accompanying inorganic ions exchange in this material. The present study found that the advancement of OCP hydrolysis under physiological conditions had an effect on poly (lactic-co-glycolic acid) (PLGA) degradation through its chemical environmental change around OCP, which was ascertained by the decreases in weight loss and glass transition temperature of PLGA with increasing the dose of OCP co-present. Rat femur-penetrated standardized severe defects were found to repair through bridging the cortical region defect margin. PLGA degradation could be enhanced through an acid catalyst function by protons derived from inorganic phosphate (Pi) ions through OCP hydrolysis under bone forming condition, resulting in showing a prominent bone regenerative capacity in OCP/PLGA composite materials. [Display omitted] [ABSTRACT FROM AUTHOR]

Hypothesis: The α-sulfo alkyl ester, AES, surfactants are a class of anionic surfactants which have potential for improved sustainable performance in a range of applications, and an important feature is their enhanced tolerance to precipitation in the presence of multivalent counterions. It is proposed that their adsorption properties can be adjusted substantially by changing the length of the shorter alkyl chain, that of the alkanol group in the ester. Experiments: Surface tension and neutron reflectivity have been used to investigate the variation in the adsorption properties with the shorter alkyl chain length (methyl, ethyl and propyl), the impact of NaCl on the adsorption, the tendency to form surface multilayer structures in the presence of AlCl 3 , and the effects of mixing the methyl ester sulfonate with the ethyl and propyl ester sulfonates on the adsorption. Findings: The variations in the critical micelle concentration, CMC, the adsorption isotherms, the saturation adsorption values, and the impact of NaCl illustrate the subtle influence of varying the shorter alkyl chain length of the surfactant. The non-ideal mixing of pairs of AES surfactants with different alkanol group lengths of the ester show that the extent of the non-ideality changes as the difference in the alkanol length increases. The surface multilayer formation observed in the presence of AlCl 3 varies in a complex manner with the length of the short chain and for mixtures of surfactants with different chains lengths. [ABSTRACT FROM AUTHOR]

We present the results of a low‐frequency study of Mancos shale, where we first elaborate a stress–strain methodology of laboratory low‐frequency experiments to estimate the elastic moduli of shales, and then apply this methodology to investigate the influence of partial water saturation on the elastic and anelastic parameters, velocities and P‐wave anisotropy of Mancos shale. We also analyse the applicability of the anisotropic Gassmann theory for predictions of the stiffness tensor components of the water‐saturated shale with non‐expandable clay content presented in our case by illite (33%) and chamosite (9.1%) minerals. The effect of water saturation was studied using two samples drilled in vertical and parallel directions to the formation bedding. The experiments were carried out at a confining pressure of 10 MPa in the frequency range from 0.1 to 100 Hz. Prior to measurements, the samples were saturated in desiccators at six different values of relative humidity ranging from 9% to 97.5%. The results of our study demonstrate a reduction of Young's modulus and P‐wave anisotropy with saturation accompanied by a decrease in shear stiffnesses. The latter indicates the inapplicability of the anisotropic Gassmann theory to Mancos shale. Our measurements of attenuation carried out on the vertical and horizontal samples saturated at a relative humidity of 97.5% revealed prominent attenuation peaks associated with partial saturation. We showed that the measurement results of the attenuation and Young's modulus dispersion are consistent with the causality principle presented by the Kramers–Kronig relations. [ABSTRACT FROM AUTHOR]

Multidimensional numerical simulation of boron diffusion is of great relevance for the improvement of industrial n-type crystalline silicon wafer solar cells. However, surface passivation of boron diffused area is typically studied in one dimension on planar lifetime samples. This approach neglects the effects of the solar cell pyramidal texture on the boron doping process and resulting doping profile. In this work, we present a theoretical study using a two-dimensional surface morphology for pyramidally textured samples. The boron diffusivity and segregation coefficient between oxide and silicon in simulation are determined by reproducing measured one-dimensional boron depth profiles prepared using different boron diffusion recipes on planar samples. The established parameters are subsequently used to simulate the boron diffusion process on textured samples. The simulated junction depth is found to agree quantitatively well with electron beam induced current measurements. Finally, chemical passivation on planar and textured samples is compared in device simulation. Particularly, a two-dimensional approach is adopted for textured samples to evaluate chemical passivation. The intrinsic emitter saturation current density, which is only related to Auger and radiative recombination, is also simulated for both planar and textured samples. The differences between planar and textured samples are discussed. [ABSTRACT FROM AUTHOR]

We have investigated the thickness, the surface roughness, and the transport properties of oligo(1-(2-bisthienyl)benzene) (BTB) thin films grafted on evaporated Au electrodes, thanks to a diazonium-based electro-reduction process. The thickness of the organic film is tuned by varying the number of electrochemical cycles during the growth process. Atomic force microscopy measurements reveal the evolution of the thickness in the range of 2-27 nm. Its variation displays a linear dependence with the number of cycles followed by a saturation attributed to the insulating behavior of the organic films. Both ultrathin (2 nm) and thin (12 and 27 nm) large area BTB-based junctions have then been fabricated using standard CMOS processes and finally electrically characterized. The electronic responses are fully consistent with a tunneling barrier in case of ultrathin BTB film whereas a pronounced rectifying behavior is reported for thicker molecular films. [ABSTRACT FROM AUTHOR]

The structural evolution of Co40Fe22Ta8B30 glassy particles has been studied by in-situ high-energy synchrotron X-ray diffraction (XRD) upon isochronal annealing. The changes in position, intensity, and full width at half maximum (FWHM) of the first and second diffuse maxima of the XRD patterns suggest the occurrence of irreversible structural relaxation upon the first heating up to a temperature close to the glass transition temperature Tg. The variations in reduced pair correlation functions upon annealing are discussed in the frame of the topological fluctuation theory for structural relaxation. Isochronal annealing of the Co40Fe22Ta8B30 glassy particles improves their soft magnetic properties through decreasing the coercivity and increasing the magnetic susceptibility, saturation magnetization, and Curie temperature. [ABSTRACT FROM AUTHOR]

This work reports on the fabrication of 1D fringed patterns on nanostructured porous silicon (nanoPS) layers (563, 372, and 290 nm thick). The patterns are fabricated by phase-mask laser interference using single pulses of an UV excimer laser (193 nm, 20 ns pulse duration). The method is a single-step and flexible approach to produce a large variety of patterns formed by alternate regions of almost untransformed nanoPS and regions where its surface has melted and transformed into Si nanoparticles (NPs). The role of laser fluence (5–80 mJ cm-2), and pattern period (6.3–16 lm) on pattern features and surface structuring are discussed. The results show that the diameter of Si NPs increases with fluence up to a saturation value of 75 nm for a fluence ≈40mJcm-2. In addition, the percentage of transformed to non-transformed region normalized to the pattern period follows similar fluence dependence regardless the period and thus becomes an excellent control parameter. This dependence is fitted within a thermal model that allows for predicting the in-depth profile of the pattern. The model assumes that transformation occurs whenever the laser-induced temperature increase reaches the melting temperature of nanoPS that has been found to be 0.7 of that of crystalline silicon for a porosity of around 79%. The role of thermal gradients across the pattern is discussed in the light of the experimental results and the calculated temperature profiles, and shows that the contribution of lateral thermal flow to melting is not significant for pattern periods ≧ 6.3 μm. [ABSTRACT FROM AUTHOR]

The complex microstructures of drug particle/ABA star triblock copolymer in dilute solutions have been investigated by a theoretical approach which combines the self-consistent field theory and the hybrid particle-field theory. Simulation results reveal that, when the volume fraction of drug particles is smaller than the saturation concentration, the drug particle encapsulation efficiency is 100%, and micelle loading capacity increases with increasing particle volume fraction. When the volume fraction of drug particles is equal to the saturation concentration, the micelles attain the biggest size, and micelle loading capacity reaches a maximum value which is independent of the copolymer volume fraction. When the volume fraction of drug particles is more than the saturation concentration, drug particle encapsulation efficiency decreases with increasing volume fraction of drug particles. Furthermore, it is found that the saturation concentration scales linearly with the copolymer volume fraction. The above simulation results are in good agreement with experimental results. [ABSTRACT FROM AUTHOR]

Depending on rock pore compressibility, a change in effective confining pressure (ECP) can have a significant influence on supercritical CO2 (SC‐CO2) migration characteristics in natural reservoirs. In this study, a tight glutenite sample was used to conduct porosity/permeability measurements under different ECPs of 1.5, 5.5, 9.5, 13.5, 17.5 and 21.5 MPa. Then a SC‐CO2 drainage core flooding experiment, which was monitored using nuclear magnetic resonance (NMR) technique, was conducted at an ECP of 5.5 MPa. Measurement results show that the porosity and permeability of the sample were comparatively low (at an ECP of 1.5 MPa, 8.3% and 2.4 mD, respectively). With increasing ECP, the porosity/permeability decreased rapidly initially then more slowly at the larger ECP value. NMR results shows that SC‐CO2 preferentially displaced water creating flow channels inside the sample. At SC‐CO2 breakthrough, the average residual water saturation was 69.86%. Following breakthrough, SC‐CO2 continued to displace the water creating more substantial flow channels until they were sufficient to transport the SC‐CO2 at the fixed flow rate, resulting in a residual water saturation of 42.72%. A two‐dimensional computational model was then established based on these experimental results to simulate the fluid behaviors at an ECP of 5.5 MPa, and then the model was extended to different ECP values ranging from 1.5 to 21.5 MPa. Numerical simulation results show that SC‐CO2 displaced water in an inverted triangle‐like shape. Under different ECPs of 1.5, 5.5, 9.5, 13.5, 17.5 and 21.5 MPa, the simulated breakthrough times were 36.8, 44.6, 54.8, 56.4, 59.0 and 59.4 mins with an average SC‐CO2 saturation of 13.18, 16.71, 18.71, 19.72, 21.99 and 22.19%, respectively. SC‐CO2 breakthrough occurred quicker for lower ECP values resulting in a smaller SC‐CO2 saturation. Likewise, with larger ECP value, SC‐CO2 breakthrough occurred later, and a higher SC‐CO2 saturation was seen. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

It has previously been demonstrated that the ratio of the degenerate four wave mixing signal from two hot water line groups near 3231 cm–1 can be used for seedless flame temperature measurements. This paper presents an investigation of the impact of saturation effects on the measured signal intensity from each line group, as well as an estimation of the accuracy of the method. The saturation effects observed here would result in a large systematic error if they are not taken into account when using the degenerate four-wave mixing intensity of these water line groups to calculate the flame temperature. [ABSTRACT FROM AUTHOR]

Wastewater is residual water of industrial activities and domestic wastewater that is derived from daily activities of human life related to water usage, such wastewater should not be discharged into water bodies if it has not met the standards based on the regulation. Oil and grease contained in the water bodies will form a layer on the surface because the density of oil is lower than the density of water. The layer of oil and grease will block the entry of sunlight and cause the inability in the photosynthesis process of aquatic plants. The textile industry facilitates canteens within the company which operates daily at 11.00-13.00 Western Indonesian Time, resulting in the domestic wastewater from the canteen kitchen activities. The purpose of this study was to determine differences in the thickness variations of activated carbon to reduce oil and grease levels using modified grease traps on the canteen wastewater at PT. Sipatex Putri Lestari. The type of study used was categorized as a field experiment with a pretest-posttest research design. The population of the study was the entire canteen wastewater of PT. Sipatex Putri Lestari. The sampling technique used the time composite method. The univariate analysis of the study showed the average number of decreases in oil and grease levels in the treatment as 12.32, 15.98 and 23.67 mg·L-1. The bivariate data analysis used the one-way ANOVA test. The results of the experiment on the three thickness variations of activated carbon within six times repetitions resulted in a decrease of oil and grease levels, which is 49% at 10 cm, 62% at 20 cm, and 88% at 30 cm. The conclusion of the study showed differences in the thickness variations of activated carbon to reduce oil and grease levels using a modified grease trap on the canteen wastewater at PT. Sipatex Putri Lestari. Furthur suggestions for this study are to determine the saturation period of activated carbon and periodic maintenance of the tool. [ABSTRACT FROM AUTHOR]

This study highlights the influence of seawater absorption on Charpy impact properties of glass/epoxy composites. For this study, two groups of glass/epoxy composites that were produced by using the vacuum infusion method were immersed in seawater at 25°C and 70°C temperatures, and one group has immersed in any condition. Specimens were kept in water until getting saturation point. The immersed specimens reached saturation at the end of the sixth week (1000 h). Charpy impact test (having 15 J impact capacity) was conducted in three groups that are dry samples, saturated samples, and re-dried samples after saturation. From the Charpy impact test result, it was observed that impact properties degradation occurred due to hydrothermal aging. Compared to their non-immersed state, the maximum impact stress - energy of the immersed specimen has dropped seriously, regardless of temperature. Also, as temperature increased, the reduction rate of maximum impact stress - energy increased. Similar results occurred in the redried group. That is the decrease rate in aged samples at 25°C is 27.3%, whereas this rate is 30.03% in aged samples at 70°C. However, when compared to their dry state, the decrease in maximum impact stress in the re-dried group is considerably lower than in the saturated group. The decrease rate in re-dried samples aged samples at 25°C is 2.6%, whereas this rate is 7.77% in re-dried samples aged at 70°C. [ABSTRACT FROM AUTHOR]

The detailed data of the Vp/Vs ratio and porosity logs were used to detect the Oil-Water Contact Zone (OWCZ) of Nahr Umr sandstone and Mishrif limestone reservoir formations in Kumiat (Kt) and Dujaila (Du) oil fields, southeastern Iraq. The results of OWC were confirmed using P-wave, Resistivity, and Water Saturation (Sw) logs of Kt-1 and Du-1 wells. It was found that the values of the oil-water contact zone thickness in Nahr Umr sandstone and Mishrif limestone were approximately one meter and eight meters, respectively. These results suggest that the OWCZ is possibly thicker in the carbonate rock than clastic rock formations. The thickness of OWCZ in the clastic rocks changed from one part to another, depending on several factors including mineral composition, grain size, porosity, pore shape, and fluid type. [ABSTRACT FROM AUTHOR]

Investigating seismic dispersion and attenuation characteristics of loosely compacted marine sandstone is essential in reconciling different geophysical measurements (surface seismic, well logging and ultrasonic) for better characterization of a shallow marine sandstone reservoir. We have experimented with a typical high‐porosity and high‐permeability sandstone sample, extracted from the Paleogene marine depositional setting in the Gulf of Mexico, at the low‐frequency band (2–500 Hz) as well as ultrasonic point (106 Hz), to investigate the effects of varying saturation levels on a rock's elasticity. The results suggest that the Young's modulus of the measured sample with adsorbed moisture at laboratory conditions (room temperature, 60%–90% humidity) exhibits dispersive behaviours. The extensional attenuation can be as high as 0.038, and the peak frequency occurs around 60 Hz. The extensional attenuation due to moisture adsorption can be dramatically mitigated with the increase of confining pressure. For partial saturation status, extensional attenuation increases as increasing water saturation by 79% with respect to the measured frequencies. Additionally, the results show that extensional attenuation at the fully water‐saturated situation is even smaller than that at adsorbed moisture conditions. The Gassmann–Wood model can overall capture the P‐wave velocity‐saturation trend of measured data at seismic frequencies, demonstrating that the partially saturated unconsolidated sandstone at the measured seismic frequency range is prone to be in the relaxed status. Nevertheless, the ultrasonic velocities are significantly higher than the Gassmann–Wood predictions, suggesting that the rocks are in the unrelaxed status at the ultrasonic frequency range. The poroelastic modelling results based on the patchy saturation model also indicate that the characteristic frequency of the partially saturated sample is likely beyond the measured seismic frequency range. [ABSTRACT FROM AUTHOR]

The radioactive noble gas radon-222 (⁠|$\mathrm{^{222}Rn}$|⁠) produced in the uranium series is a crucial background source in many underground experiments. We have estimated the adsorption property of Rn with activated carbon fibers (ACFs) in air, argon, and xenon gas. We evaluated six ACFs, named A-7, A-10, A-15, A-20, A-25, and S-25, provided by Unitika Ltd. We measured the intrinsic radioactivity of these ACF samples, and found A-20's radioactivity of the uranium series to be |$<5.5$|   |$\mathrm{mBq/kg}$| with |$90\%$| confidence level. In air and Ar gas, we found that ACF A-15 has an adsorption efficiency of |$1/10000$| reduction at maximum before saturation of Rn adsorption, and more than |$97\%$| adsorption efficiency after the saturation. In Xe gas, we found that ACF A-20 has the best Rn adsorption ability among the tested ACFs. We also found that S-25, A-25, and A-15 have similar Rn adsorption performance. [ABSTRACT FROM AUTHOR]