Fluid Pairs Research Articles

Precision Medicine in Alzheimer’s Disease: Phenotype Investigation, Medication Effects and Variant Analysis in Cell Type Specific Subgroups

AbstractBackgroundAlzheimer’s disease (AD) is characterized by cognitive decline and dementia and has few clinically approved treatments. The clinical and neuropathological heterogeneity of AD suggests the existence of AD subgroups with unique mechanisms and implies the need for cell‐type specific subtyping and treatments. The goal of this project was to investigate the differential effects of medications on cognitive tests in eight previously defined brain cell type‐based polygenic risk scores (PRS).MethodMedication usage information, imputed genotypes, phenotypic data and cognitive test scores were collected for 487,409 participants from the UK Biobank to use in the analysis of the different PRS groups. We determined the characteristics of the PRS used by comparing 16 phenotypes in high and low risk subjects. Association between four cognitive test scores (fluid intelligence, reaction time, prospective memory, and pairs matching) and medication status (treated vs. untreated) was determined using logistic regression. Cognitive scores were rank‐transformed for the analysis, and the logistic regression was performed separately for high‐risk and low‐risk genetic groups. Genome‐wide association studies (GWAS) were used to detect genetic variants linked to medication usage. This analysis was repeated for all, high risk and low risk samples, using only medications that demonstrated a significant association with improved cognitive function during follow up examination.ResultPhenotypic variation was wide among different PRS groups. Genetically different PRS groups shared phenotypic characteristics, suggesting that different underlying mechanisms lead to similar outcomes. Six medications were significantly associated (P<0.05) with improved cognitive function during follow‐up examination. Atenolol, a high blood pressure medication, was associated with the largest gain, with an improvement on the effect of cognitive function by 67% in the high‐risk compared to the low‐risk subjects from an astrocyte genetic subtype (Ast‐M9). The atenolol GWAS focused on the Ast‐M9 high risk group identified two genome wide significant variants at the same locus. These were previously shown to be associated with phenotypes related to blood pressure and were known eQTLs.ConclusionOur findings suggest potential novel implications for genetic subtype‐driven treatment options for AD. Further research is needed to validate these associations that may explain differential effects of medications in AD‐subtypes.

Development and selection of working fluid pairs for cascade high-temperature heat pump based on computer-aided molecular design and group contribution method

Development and selection of working fluid pairs for cascade high-temperature heat pump based on computer-aided molecular design and group contribution method

Simulation and performance research of absorption heat pump unit based on R134a-DMF working fluid pair

R134a-DMF absorption heat pump unit is an energy-saving heat pump unit that can utilize renewable energy, and has great potential in the refrigeration and heating fields of urban and rural areas. The purpose of this article is to conduct in-depth research on the dynamic characteristics of absorption heat pump units based on R134a-DMF, a new working fluid pair. A mathematical model of the thermophysical properties of the R134a-DMF working fluid pair and the mathematical models of various components of the heat pump unit are constructed. This paper constructs a simulation program, and uses the Control variates to study the change trend of the Coefficient of performance of R134a-DMF absorption heat pump unit affected by the generator outlet concentrated solution temperature, condenser air volume and temperature rise, and chilled water outlet temperature. The results indicate that the established mathematical model for thermophysical properties and the unit model are both accurate models, which can provide guidance for the actual operation and optimization of R134a-DMF absorption heat pump units. Through simulation, it can be concluded that for the three combined forms of R134a DMF (3:2), R134a DMF (1:1), and R134a DMF (2:3), the average increase in COP and refrigeration capacity is 0.85 %, 0.39 %, and 0.42 % for each 1 °C increase in the outlet concentrated solution temperature of the generator, respectively, and the growth rate is relatively slow. The larger the proportion of refrigerant in the binary solution, the greater the COP of the unit under the same operating conditions.

The effects of initial water saturation on retrograde condensation in natural porous media: An in situ experimental investigation of three-phase displacements

In this study, state-of-the-art imaging technology is integrated with a miniature core-flooding system to map pore-scale fluid occupancy during the retrograde condensation process in the presence of brine and in a natural porous medium. Two depletion experiments were performed using a three-component synthetic gas condensate mixture in a Fontainebleau sandstone core sample and after establishing different levels of initial water saturations. The results are analyzed to investigate the impact of water saturation on condensate formation, accumulation, and mobilization and to shed light on the relevant three-phase flow dynamics. The results provide the first direct pore-scale observation of gas, condensate, and brine residing in the pore space. The micro-scale fluid occupancy maps illustrated that the presence of water in the pores delays the pressure at which condensate nuclei form, slows down the initial growth of nuclei, and partially impedes the accumulation of condensate. The higher the water saturation is, the lower the amount of condensate will be accumulated. As the pore pressure decreases, the condensate clusters develop significantly in the pore space triggering chains of displacement events between various pairs of fluids. The key mechanisms include gas-to-brine/condensate and condensate-to-gas/brine. The displacement events eventually reduce the brine saturation and increase the gas and condensate saturations in the pore space. The condensate saturation increases monotonically as the pore pressure reduces and reaches a maximum value. Quantitative pore fluid occupancy data also reconfirm the visual observations and demonstrate that condensate accumulation is associated with displacing gas and brine from small- and medium-sized pore elements.

Performance enhancement of absorption refrigeration systems: An overview

The introduction of absorption refrigeration technology addressed several significant con-cerns in the domain of energy crisis, rising cost of fossil fuel, and ecological challenges aris-ing due to the excess use of traditional compression refrigeration systems. ARS (absorption refrigeration system) is gaining popularity as a result of benefits such as the use of low-grade heat sources and environmentally acceptable low-cost working fluid pairs. However, two sig-nificant hurdles to commercial success for this technology are the often too big size of the refrigeration system and the poor performance of the system. Numerous studies have been conducted in an attempt to discover methods for improving the COP (coefficient of perfor-mance) of ARS in order to get these systems more competitive in comparison to the conven-tional compression refrigeration systems. The goal of this article is to perform a review of the literature on different methods used to enhance the COP of ARSs based on cycle layout mod-ification and working pair selection as they are the promising solutions for the enhancement of the performance of ARSs. The futuristic aspect of this technology includes the introduction of new working pairs with no corrosion to the system components, including nanoparticles to increase heat transfer rate while reducing the cost of the system. Heat recovery methods should be introduced and the efficient design of various components especially the generator and absorber are to be addressed. This technology could be combined with other refrigeration technologies while utilizing the waste heat to further improve the efficiency of ARSs.

Transient modeling of a chemisorption heat pump using ammonia with expanded graphite – NaBr

Numerical and experimental studies of a chemisorption heat pump driven by a low-temperature heat source were conducted. A transient model of a heat exchanger and reactor was developed. Equations of mass, momentum, energy and chemical reaction were considered and modeled. One of the important parameters related to the chemical reaction is the non-equilibrium curve of the working fluid and adsorbent pair. An experiment was conducted to obtain the non-equilibrium curve for NH3 and expanded graphite – NaBr under a low-temperature condition. The correlation for the non-equilibrium curve was suggested and applied to the transient model. A transient analysis of the reactor was then carried out. By comparing the simulation results to the experimental results, it was confirmed that the model of the reactor is valid. An experiment and simulation of the entire system were conducted. The transient features of the chemisorption heat pump when operated three times in an alternating manner were analyzed based on the simulation and experimental results. The simulation and experimental results showed similar values and tendencies of the temperature and pressure. Hence, the simulation model for the entire system was validated. Based on the proposed model, performance analysis according to the reactor fin tube design conditions was performed. Depending on the fin tube design, the average cooling capacity differed 2.13 times from 70.2 to 149.2 W. Depending on the fin tube design, the COP differed 2.2 times from 0.15 to 0.33. Based on the results of this study, the design condition of fin tube to achieve the optimal cooling capacity or COP was confirmed.

Water speciation and hydrogen isotopes in hydrous stishovite: implications for the deep Earth water cycle

Stishovite is a key mineral for understanding the deep Earth water cycle because of its potential as a main carrier for water into the transition zone and lower mantle. During subduction-related metamorphism of basaltic oceanic crust, stishovite stabilizes at 8–9 GPa and comprises 10–25 vol% of the bulk mineralogy, with some experimental studies indicating that stishovite can accommodate 3.5 wt% H2O or more in the transition zone and upper lower mantle. This large water solubility has been explained by a hydrogarnet substitution mechanism (1Si4+ ↔ 4H+) and/or the incorporation of interstitial molecular water. To investigate water speciation and hydrogen isotope behavior, we synthesized partially deuterated hydrous stishovite at 9 GPa and 450 °C in a multi-anvil press (MA). The hydrous stishovite contains on average 1.69 ± 0.05 wt% water, which is consistent with earlier MA studies but is significantly lower than the 3.5 wt% reported from in situ diamond anvil cell (DAC) studies made at higher pressures and temperatures. 1H MAS NMR spinning sideband characteristics suggest a high abundance of interstitial molecular water in hydrous stishovite, while the presence of a hydrogarnet defect cannot be ruled out. Unit-cell volumes and deuterium enrichment in the quenched hydrous stishovite indicate that ~ 45% of the water is lost from the stishovite upon quenching and decompression of the experiment, consistent with a higher solubility. This implies that the pristine water contents of a P–T–fO2 equilibrated hydrous stishovite cannot be quenched to 1 atm and room temperature from classical MA experiments. We further present a capillary-based recovery method for fluid from experimental capsules, allowing direct determination of the D/H ratio of the experimental fluid and indirect determination of the hydrous stishovite. Using Rayleigh modeling to account for the quench-related water loss, we find that, at 450 °C and 9 GPa, deuterium is 3.5–4.5 times enriched in hydrous stishovite relative to coexisting aqueous fluid. This is opposite of what is commonly observed for mineral–fluid pairs above 300 °C, rendering hydrous stishovite a potential sink for deuterium and decreasing the D/H ratio of coexisting aqueous fluids. Partial decomposition (30–60%) of hydrous stishovite during mantle upwelling and production of primary basaltic melts could be accompanied by high-temperature D/H fractionation, decreasing the hydrogen isotope composition of such melts towards “mantle-like” δD values between −75 and −220‰.

Resting‐state dynamic functional network connectivity predicts cognition in 37,784 participants of UK Biobank

AbstractBackgroundAge‐related cognitive decline after 65 is a well‐known phenomenon, but little is known about how brain functional changes are related to cognitive decline. To this end, previous studies explored the link between functional network connectivity (FNC) estimated from resting‐state functional MRI (rs‐fMRI) and cognitive scores in healthy adults. FNC is often assumed to be static over time. However, this assumption runs contrary to the dynamic nature of brain FNC, and dynamic FNC (dFNC) has been recently introduced to overcome this limitation. The current study investigated the relationship between dFNC estimated from 36,263 individuals from UK Biobank and cognition.MethodWe used the resting‐state fMRI (duration: 5min) data of 37,784 (20,157 females) adults’ brains, demographic information (age:64.06± 7.51), and cognitive scores from the UK Biobank in which the cognitive scores include fluid intelligence (FI), reaction time (RT), and pairs matching (Pairs). We adapted group independent component analysis to extract 53 data‐driven components for the whole brain using a fully automated approach (Fig.1: Step1). Next, we used the sliding window and Pearson correlation to estimate the dFNC among 53 components (Fig.1: Step2). We used k‐means clustering to put dFNCs of all individuals into three separated states and calculated individual state vectors (Fig.1: Step3). Then, we estimated 32 dFNC features based on three estimated states and state vectors (Fig.1: Step4). Finally, we trained a two‐fold cross‐validation support vector regression to predict the cognitive scores (Fig.1: Step5).ResultThe estimated dFNC feature predicted FI score with high accuracy (the correlation between measure and predicted score is R = 0.043, p = 6.6e−17, Fig.2A), mean time to correctly identify match in RT task (R = 0.065, p = 1.9−34, Fig.2B), and time to complete Pairs task (R = 0.049, p = 1.3e−20, Fig.2C).ConclusionHere we explored the link between dFNC features and cognition in the most extensive dFNC study and found that estimated dFNC features can successfully predict cognitive scores in the UK Biobank dataset. Even though the correlation values are very low, the results are still very significant due to large N. Future study is needed to explore the difference between the subgroup with high versus low prediction accuracy.

Association of sleep duration with cognitive performance and structural brain differences: A large population‐based cross‐sectional study

AbstractBackgroundSleep duration has been linked to dementia risk; however, its association with cognitive functioning in specific domains and the underlying mechanisms remain unclear. We aimed to examine the association of sleep duration with cognitive performance and structural brain differences using magnetic resonance imaging (MRI).MethodsWithin the UK Biobank, 43,255 dementia‐free participants (aged ≥44, 52.0% female) were included. Self‐reported sleep duration (hours/day) was recorded following a structured questionnaire and trichotomized as short (≤5), normal (6‐8), and long (≥9) sleep. Cognitive functioning (including fluid intelligence, pairs matching, reaction time, and numeric memory) was evaluated using a touchscreen test battery. MRI scans were performed, and total and regional brain volumes (including white matter, gray matter, and hippocampus), and white matter hyperintensities (WMH) were measured. Data on lifestyle factors and medical conditions were collected. Data were analyzed using linear regression.ResultsOf all participants, 2092 (4.8%) had short, 38,041 (87.9%) had normal, and 3122 (7.2%) had long sleep. In multi‐adjusted linear regression, compared with normal sleep duration, both short (β: ‐0.14, 95%, CI: ‐0.19 to ‐0.10) and long (β: ‐0.06, 95% CI: ‐0.10 to ‐0.03) sleep were related to poorer performance in fluid intelligence. Long sleep was also associated with poorer numeric memory (β: ‐0.06, 95% CI: ‐0.10 to ‐0.01). In MRI data analyses, compared with normal sleep duration, short sleep was related to a smaller hippocampus volume (β: ‐0.05, 95% CI: ‐0.09 to ‐0.01), while long sleep was associated with smaller total brain (β: ‐4.51, 95% CI: ‐6.82 to ‐2.21), gray matter (β: ‐3.32 95% CI: ‐4.70 to ‐1.94), and hippocampus (β: ‐0.06, 95% CI ‐0.09 to ‐0.02) volumes, but greater WMH (β: 0.05, 95% CI: 0.01 to 0.08), after adjusting for confounders.ConclusionsShort and long sleep durations are associated with poorer cognitive performance in different domains. Short sleep may indicate neurodegeneration, and long sleep may implicate both neurodegenerative and vascular changes in the brain.

Exergoeconomic and Exergetic Sustainability Analysis of a Combined Dual-Pressure Organic Rankine Cycle and Vapor Compression Refrigeration Cycle

In this paper, an exergoeconomic and exergetic sustainability analysis of a dual-pressure organic Rankine cycle (ORC) and vapor compression refrigeration cycle (VCRC) driven by waste heat is performed for power generation and cooling production. In addition, the most suitable fluid couple among the thirty-five different fluid pairs was investigated for the proposed combined system. The results indicate that the highest energy utilization factor, exergy efficiency, the system coefficient of performance, and net power are calculated for the R123-R141b fluid pair. In terms of exergetic sustainability indicators, the best performance results are obtained for the R123-R141b fluid combination. The minimum unit electricity generation cost and the shortest payback period are calculated as 0.0664 $/kWh and 2.5 years, respectively, for the R123-R290 fluid pair. The system component with the highest exergy destruction is the boiler, with 21.67%. The result of the parametric analysis showed that the thermodynamic performance parameters increase with the increment of the ORC’s boiling temperature. In addition, with the increasing boiling temperature, the environmental effect factor of the system decreases, while the exergetic sustainability index increases. Additionally, as the boiling temperature increases, the total system cost increases, while the unit electricity production cost and payback period decrease. It is suggested to use a R123-R141b fluid couple among fluid pairs created as a result of thermodynamic, exergoeconomic and sustainability analysis.

Emergence of transient reverse fingers during radial displacement of a shear-thickening fluid

A highly sheared dense aqueous suspension of granular cornstarch particles displays rich nonlinear rheology. We had previously demonstrated the growth and onset of interfacial instabilities when shear-thinning cornstarch suspensions were displaced by a Newtonian fluid, and had suggested methods to maximise displacement efficiency [Palak, R. Sathayanath, S. K. Kalpathy and R. Bandyopadhyay, Colloids Surf. A Physicochem. Eng. Asp., 629 (2021) 127405]. In the present work, we explore the miscible displacement of a dense aqueous cornstarch suspension in its discontinuous shear-thickening regime in a quasi-two-dimensional radial Hele-Shaw cell. We systematically study the growth kinetics of the inner interface between water and the cornstarch suspension, and also of the outer interface between the suspension and air. In addition to the growth of interfacial instabilities at the inner interface, we observe a transient withdrawal of the suspension and the formation of fingering instabilities at the outer interface. We demonstrate that these `reverse fingering' instabilities are extremely sensitive to the injection flow rate of water, the gap of the Hele-Shaw cell and the concentration of the displaced cornstarch suspension, {and emerge irrespective of immiscibility between the fluid pair. We believe that as the cornstarch suspension dilates due to the high shear rate imposed by the displacing fluid, the outer suspension-air interface responds with a restoring force, resulting in the penetration of air into the suspension and the formation of reverse fingers. We note that the growth of reverse fingers significantly reduces the displacement efficiency of the suspension. Finally, we demonstrate a correlation in the growth of inner and outer interfacial patterns by computing the velocity with which stresses propagate in the confined dense suspension. Our findings are useful in understanding the flow of granular materials through constrained geometries and can be extended to study stress propagation in shear-thickening materials due to a sudden imposition of high shear rate, such as in impact behaviour.

Development of a novel experimental technique for the measurement of residual wall layer thickness in water-oil displacement flows

The effective removal and displacement of fluids is important in many industrial and environmental applications, such as for operation and cleaning of process equipment, fluid injection in porous media for oil recovery or aquifer remediation, or for achieving subsurface zonal isolation in new or abandoned wells. The accurate measurement of the residual fluid wall film left behind after displacement by a cleaning fluid is a long-standing challenge, particularly so for very thin fluid films where the thickness can be of the order of micrometer. We focus on the characterization of oil films left on the wall of a horizontal pipe after the pipe has been displaced by water, and develop a novel, non-intrusive analytical technique that allows the use of relevant pipe materials. The oil that originally occupies the pipe is stained by a hydrophobic dye Nile red, and an intermediate organic solvent is used to collect the residual oil volume that remains after displacing the pipe with a known volume of water. Finally, ultraviolet-visible spectroscopy is used to measure the Nile red concentration in the collected fluid, which is proportional to the residual volume of oil in the pipe. We demonstrate the methodology by conducting experiments where the displacing fluid is injected at two different imposed velocities, and where the injected fluid volume is varied. As expected, we find a gradual thinning of the oil film with increasing injected fluid volume. We compare the measured film thicknesses to a displacement model based on the steady velocity profile in a pipe, and find that experiments consistently produce smaller film thicknesses. This developed technique allows quantification of displacement and cleaning mechanisms involved in immiscible displacements at laminar, transitional and turbulent regimes, for different non-Newtonian fluid pairs, and for different realistic pipe materials and surface roughnesses.

Ultrasound resonance in coflowing immiscible liquids in a microchannel.

We study ultrasonic resonance in a coflow system comprising a pair of immiscible liquids in a microchannel exposed to bulk acoustic waves. We show using an analytical model that there are two resonating frequencies corresponding to each of the coflowing liquids, which depend on the speed of sound and stream width of the liquid. We perform a frequency domain analysis using numerical simulations to reveal that resonance can be achieved by actuating both liquids at a single resonating frequency that depends on the speeds of sound, densities, and widths of the liquids. In a coflow system with equal speeds of sound and densities of the pair of fluids, the resonating frequency is found to be independent of the relative width of the two streams. In coflow systems with unequal speeds of sound or densities, even with matching characteristic acoustic impedances, the resonating frequency depends on the stream width ratio, and the value increases with an increase in the stream width of the liquid with a higher speed of sound. We show that a pressure nodal plane can be realized at the channel center by operating at a half-wave resonating frequency when the speeds of sound and densities are equal. However, the pressure nodal plane is found to shift away from the center of the microchannel when the speeds of sound and densities of the two liquids are unequal. The results of the model and simulations are verified experimentally via acoustic focusing of microparticles suggesting the formation of a pressure nodal plane and hence a resonance condition. Our study will find relevance in acoustomicrofluidics involving immiscible coflow systems.

Performance of a CO2-mixture cycled energy storage system: Thermodynamic and economic analysis

Liquid state storage is one of the most features for CO2 energy storage. How to effectively liquefy the gaseous CO2 after generating the power severely restricts its further development. In this paper, the refrigerants are employed as the additives to the CO2 working fluid and utilizing the temperature glide of zeotropic mixtures the two-tank cold energy storage can be designed to complete the condensation and evaporation processes of the gaseous working fluid. The numerical simulations for the system are completed by using an in-house code with the built mathematical models. The round trip efficiency and the economic indicators including levelized cost of storage, net present value, dynamic payback period and savings to investment ratio are analyzed in detail. The results demonstrate that increasing the mass fraction of refrigerants is negative to the system efficiency. The efficiency of the system with working fluid CO2/R32 is obviously insensitive to the additive mass fraction, with just a 3.5% change ratio when mass fraction of R32 is varied from 0.05 to 0.5. There is always an optimized mass fraction to reach the best economic performance for each additive. The mixtures CO2/R32 and CO2/R161 are firstly recommended as the working fluid pairs of the designed system with the suggested mass compositions of about 0.65/0.35 and 0.85/0.15, respectively. The charge pressure is advocated at 15 MPa and the discharge pressure is suggested at 13–16 MPa. Furthermore, the proposed energy storage system is favorable to adapt the surrounding temperatures.

Investigating the performance of heat exchangers in absorption heat pump systems using both numerical and experimental methods

To achieve better heating efficiency and lower CO2 emission, this study has proposed an air source absorption heat pump system with a tube-finned evaporator, a vertical falling film absorber, and a generator. To analyzeboth heat and mass transfer performances and optimize the sizes of both the absorber and the generator, a distributed parameter model and a two-dimensional numerical model have been adopted, both validated. To develop an environmentally efficient working fluid pair for absorption heating for cold climate, a calculation method adopting fugacity and activity models was developed. The defrosting control strategy of this system was developed based on a spatial and temporal frost development model, which determines the characteristics of frost distribution, frost growth, and frost inhomogeneity. To evaluate the functionality of this system, a test rig was constructed, with a heating capacity of 36.88 kW, a coefficient of performance of 1.54 under evaporation temperature and supply water temperature of −9.2 °C and 38.4 °C, respectively. Validation results showed a 1.5 % higher prediction accuracy for the two-dimensional model with correction, comparing to the distributed parameter model. R134a-DMF and R161-DMF were recommended at an ambient temperature of −2 °C. This is because with ambient temperature of −7 °C and supply water temperature of 41 °C, the predicted coefficient of performance was 1.04 and 1.06 for R134a-DMF and R161-DMF, respectively. The frost prediction indicated that at the time of 3,600 s, the thickness of the frost layer in the heavy frost area was 0.94 mm, with a total frost mass of 3,995 g. Compared with the initial stage, the sensible and latent heat transfer rates decreased by 22.1 % and 24.2 %, respectively.

Multi-objective optimisation of a novel organic Rankine-Goswami cycle operating with different refrigerants in the organic Rankine cycle

This paper tackles the multi-objective design optimisation and comparative investigation of a cascade organic Rankine-Goswami cycle (ORC-GW) operating with various refrigerants, namely R600, R236ea, and R245fa, in the organic Rankine cycle (ORC). The solution of the multi-objective optimisation problem is achieved by applying the African vultures optimisation algorithm (AVA). The results show that the ORC-GW operating ammonia-water/R600 working fluid pair has increased total cost and second law efficiency compared to its competitors, respectively 24.575 M€ and 0.440.

Experimental study of electrical complex resistivity in a 2D multiphase porous medium under non‐isothermal conditions: Application to soil remediation monitoring

AbstractIn this decade, electro‐geophysical methods are widely used in different environmental subjects. Studies on soil remediation when polluted by dense non‐aqueous phase liquids (DNAPLs) has become a certain need for all countries. Geoelectrical methods have shown their potential to facilitate evaluating decontamination processes. Our challenge in this study was to understand how coupled temperature and saturation changes affect electro‐geophysical parameters in a contaminated 2D sample. The primary objective was to evaluate the efficiency and potential of spectral‐induced polarization (SIP) for monitoring the recovery of DNAPLs in contaminated porous media. A set of 2D tank experiments investigated the impacts of temperature and saturation changes on the electrical complex resistivity of a saturated porous medium under non‐isothermal conditions. The measurements were made with a coal‐tar and water fluid pair in a porous medium that has been simulated by 1 mm glass beads. Hot water was circulated around the tank and an immersion heater used to heat the porous medium in the tank at different stages. The SIP technique (also called complex resistivity) was used to measure the complex electrical resistivity of a medium in the frequency domain. The experimental results for a simple drainage case were validated using numerical modelling. The complex electrical resistivity was used to obtain the saturation field before and after imbibition. For this purpose, the generalized Archie's law obtained for the same fluid pair with 1D cells (with a vertical flow) was used. Our results from electrical resistivity measurements for saturation fields are in accordance with 2D tank images and can illustrate the saturation change with pointwise resistivity measurements. The results show that saturation change has the primary role in electrical resistivity variation compared to temperature (5%–7%). We also studied the effects of temperature change on the Cole–Cole parameters, and the results confirm our previous findings with the same variation trend in these parameters. The results from varying electrical complex resistivity from the 2D tank (with vertical and horizontal flow) in the laboratory conditions will help us to understand the coupled temperature and saturation effects on complex resistivity in a real polluted site case.

Hippocampal volume mediates the association between depression and cognitive function differently by sex

AbstractBackgroundSex differences are prominent features of both depression and Alzheimer’s disease, with women showing an increased lifetime risk relative to men. However, the neural mechanisms that explain sex differences in the relationship between depression and cognition are poorly understood. The goal of this study was to evaluate whether smaller brain volumes mediate the relationship between higher depression symptom severity and poorer cognition, and whether this association differed by sex.MethodUK Biobank participants were included in the sample based on availability of demographic variables, mental health assessments, structural MRI scans, and four cognitive measures (Fluid Intelligence, Numeric Function, Pairs Matching, and Symbol Digit Substitution). Depression symptom severity was evaluated using the Patient Health Questionnaire (PHQ‐9). The indirect effect of depression symptom severity on cognition via hippocampal volumes was evaluated using causal mediation analyses. Models were adjusted for age, sex, APOE‐e4 status, and Townsend Deprivation Index, a measure of material deprivation (Fig.1). A priori sex‐stratified models evaluated sex differences. Exploratory analyses assessed the indirect effect of depressive symptom severity on cognition with amygdalar and total brain volumes as separate mediators. The significance of indirect effects was evaluated using bootstrapping procedures.ResultThe study sample consisted of 39,692 middle‐aged and older adults (53% women, mean age±SD = 64.1±7.6 years, 28% APOE‐e4 carriers). Hippocampal and amygdalar volumes mediated the effect of depression symptom severity on cognition, for Fluid Intelligence, Numeric Function, and Symbol Digit Substitution, but not Pairs Matching. Total brain volume mediated the effect of depression symptom severity on Symbol Digit Substitution performance (Fig.1, Table1). In sex‐stratified analyses, the effect of depression symptom severity on Fluid Intelligence, Numeric Function, and Symbol Digit Substitution was mediated by hippocampal and amygdalar volumes in women. In men, the effect of depression symptom severity on Symbol Digit Substitution was mediated by total brain volume (Table2).ConclusionDepression symptom severity influences cognition via hippocampal and amygdalar volumes in women, while in men, total brain volume mediated the relationship with cognition. These data suggest sex‐specific neural pathways for the relationship between depression and cognition.

Wettability Evaluation by Spontaneous Imbibition Measurement

The propensity of one fluid in a fluid pair to coat the surface voluntarily is known as wettability. Fluid distribution and flow behavior in porous rocks mainly controlled by wettability. Oil recovery by water flooding depend mainly on the wettability of the reservoir rock. Many methods used for wettability measurement. These methods are qualitative and quantitative. Spontaneous imbibition is one of widely used methods for quantitative wettability measurement. Direct measurement and weighing technique are two known methods for spontaneous imbibition measurement. This work presents comparison between the two aforementioned methods. Experimental measurement of spontaneous imbibition achieved on core samples from the same source. Results approved that the samples are water wet but having different tendencies, the imbibition rate related to time have variable trend in addition, ultimate water saturation in weighing method experiment are higher than that in volume measurement method. The weighing method is better than the volume measurement method.

Turbulent droplet breakage probability: Analysis of fitting parameters for two commonly used models

Droplet breakage in liquid–liquid systems is an important physical process in manufacturing operations throughout the chemical, food, and pharmaceutical industries. Although several mathematical models have been developed to describe droplet breakage in agitated liquid emulsions, the utility of these models is limited by the fact that they incorporate multiple fitting parameters that must be determined empirically for specified fluid pairs and flow conditions. In this work, analytical expressions that can be evaluated without need to perform droplet breakage experiments have been developed for parameters associated with droplet breakage probability in two commonly used breakage models. These expressions were derived by applying dimensional analysis and by using a hypothesis regarding breakage probability that is based upon competition between disruptive and restorative stresses on droplets. Data used for validation of the proposed equations for the breakage probability parameters were obtained from previously published reports of droplet breakage in heterogeneous flow devices, as well as from experiments performed in a von Kármán box designed to produce homogeneous turbulence. Comparison of the droplet breakage probability predictions using the derived expressions for the breakage parameters show generally good agreement with experimental data.