Filtration Model Research Articles

A simple, accurate, and explicit form of the Green–Ampt model to estimate infiltration, sorptivity, and hydraulic conductivity

AbstractFinding an explicit solution to the widely used Green–Ampt (G–A) one‐dimensional infiltration model has been subject of efforts for more than half a century. We derived an explicit semiempirical approach that combines accuracy with simplicity, a concept that has been generally neglected in previous studies. The equation is , with F (L), Ks (L/T), S (L/T0.5) and t (T) being cumulative infiltration, saturated hydraulic conductivity, sorptivity, and time, respectively. Relative errors (ɛ) by the application of this equation generally do not exceed ±0.3% in most applied infiltration problems faced by water resources engineering today. We show both numerically and mathematically that │ɛ│> 0.3% could only occur if Kst/F > 0.904, a criterion that could apply to sand and loamy sand soils (i.e., coarse texture) and if they experience infiltration rates for over 6 h and 19 h, respectively. Hence, we also derived a simple linear adjustment in the model as Fadj ≅ 0.9796 F + 0.335 S2/Ks to address these longer infiltration rates, and to assure that ɛ remains within the expected ±0.3% range of uncertainty. A linearized regression technique was also developed to accurately estimate S and Ks when the G–A model is used. We numerically demonstrated that our fitting method could be used even when the G–A approach is less valid (diffusive soils), provided that the actual value of the capillary length (λ) is initially known. An added benefit of our approach is that by setting λ equal to 1/3 and 2/3, it can significantly limit the range of initializing, unknown, a priori values of S and Ks, as these two parameters are estimated through the inverse solution of implicit infiltration models. Due to the model's simplicity and accuracy, our solution should find application among hydrologists, natural resource scientists, and engineers who wish to easily derive accurate estimations from the G–A infiltration approach and/or estimate sorptivity and hydraulic conductivity without encountering divergence problems.

GIS and cellular automata based slope rainwater movement process model and its application

Rainfall serves as a significant factor contributing to slope stability challenges in mountainous areas, and simulating the process of slope rainwater movement is a crucial approach for analyzing the stability of slopes triggered by rainfall. By combining computer numerical simulation technology with traditional hydraulic and hydrological calculation theories, it is possible to create an efficient and precise rainwater movement model that can simulate and analyze the process of rainwater movement on slopes. Utilizing natural slopes as the focal point of our research, the cellular automaton method was applied to simulate rainfall runoff on slopes, and a Cellular Automata (CA) based model for rainwater movement process was developed. This model modified the Green-Ampt (G-A) infiltration model by adopting an elliptical water content curve and introducing a coefficient that quantifies the ratio of saturated to unsaturated depth. Additionally, we refined the rules governing runoff generation and convergence within the slope and on its surface, enabling a comprehensive simulation of the entire rainwater movement process on the slope. Furthermore, the effectiveness of the model was validated through analytical solutions derived from simplified assumptions, laboratory experiments on infiltration and runoff in the flume, and a case study of a natural slope. The results show that the infiltration calculation results of the rainwater movement model are closer to the experimental values, and their overall values are slightly higher than the measured values, which are basically consistent with the model test results; The runoff calculation results show a phenomenon of initially increasing and gradually approaching the measured values compared to the measured values. When applying the model to an actual slope, it was found that the model comprehensively accounts for the influence of slope seepage, infiltration and runoff process, has better performance compared to G-A modified model. The model can be used to describe the spatial distribution and temporal variation of infiltration and runoff processes.

Construction of new hydrophobic δ-MnO2 flower-like/kaolin/(3-aminopropyl) triethoxysilane/metal mesh membrane for oil/water separation: modeling of fouling process

A composite material consisting of δ-MnO2 flower-like/kaolin was modified with (3-aminopropyl) triethoxysilane (APTES) and utilized for separating sunflower oil from water using a metal mesh membrane. The δ-MnO2 flower-like/kaolin/APTES/metal mesh membrane was characterized using various techniques such as X-ray diffraction analysis, Fourier-transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectroscopy mapping, Brunauer–Emmett–Teller theory/Barrett–Joyner–Halenda, atomic force microscopy, and contact angle. Based on the outcomes of the conducted experiments, it was observed that the maximum porosity was associated with the δ-MnO2 flower-like/kaolin/APTES 15 (wt.%)/metal mesh (MKA(15 wt.%)M) membrane, and the porosity was calculated to be 0.58%. The blocking filtration model was employed, and a complete blocking model was obtained with a value of n = 2.15 for MKA(15 wt.%)M membrane. The response surface methodology based on Box–Behnken design was utilized to investigate the effect of parameters such as weight percentage of APTES (wt.%), mass of δ-MnO2 flower-like/kaolin/APTES (MKA) (g), volume of oil in water (mL), and temperature (°C) on the flux (L/m2·h) and rejection (%). Under optimal conditions, weight percentage of 13.32 (wt.%) of APTES, concentration of 0.2 (g) of MKA, volume of 37.10 (mL) of oil in water, and a temperature of 59.06 (°C) were obtained. These conditions resulted in a flux of 5977 (L/m2·h) and a rejection rate of 99.99% for 9 s. The kinetic studies indicated that the pseudo-second-order model had the highest correlation coefficient of 0.9991, thus displaying the most agreement with the experimental data.

Geotechnical Characterisation of Flysch-Derived Colluvial Soils from a Pre-Alpine Slope Affected by Recurrent Landslides

Heterogeneous rock masses that include rhythmic alternations of marl, shale, marly limestone, sandstone, siltstone, and argillite, such as Flysch, are particularly prone to generating colluvial deposits on gentle slopes, which are often subject to failures triggered by heavy rainfall. Flysch-derived colluvial soils are made up of highly heterogeneous sediments ranging from clayey loam to rock fragments, and they have been studied more rarely than homogeneous soils. In this work, we present a geotechnical and hydraulic characterisation performed both in situ and in the laboratory on flysch-derived colluvial soils that were involved in a channelised landslide in the pre-alpine area of the Friuli Venezia Giulia region (NE Italy). The investigated soils were characterised by the average values of the grain size composition of about 25% gravel, 20% sand, 30% silt, and 25% clay. The loamy matrix presented low-to-medium values of the liquid and plastic limits, as well as of the plasticity index (LL = 40%, PL = 23%, and PI = 17%, respectively). The values of the peak friction angle for natural intact samples were 33° < ϕ’p < 38°, whereas the residual friction angle fell to 23–24° at great depths and high vertical stresses, for a prevailing silty–clayey matrix. Variable head permeability tests were performed both in situ and in the laboratory, showing that the values of the vertical and horizontal permeability were very close and in the range 1 × 10−4–1 × 10−6 m/s. The soil permeability measured in the field was generally higher than the hydraulic conductivity calculated on laboratory samples. The proposed geotechnical and hydrological characterisation of flysch-derived colluvial soils can be of fundamental importance before the use of more thorough analyses/models aimed at forecasting the possible occurrence of slope failures and evaluating the related landslide hazard. The reported geotechnical and hydraulic parameters of flysch-derived colluvial materials can represent a useful reference for rainfall infiltration modelling and slope stability analyses of colluvial covers that are subject to intense and/or prolonged precipitation. However, when facing engineering problems involving colluvial soils, particularly those coming from flysch rock masses, the intrinsic variability in their grain size composition, consistency, and plasticity characteristics is a key feature and attention should be paid to the proper assumption of the corresponding geotechnical and hydraulic parameters.

A mathematical mould model for transient infiltration and lubrication behaviour of slag in a steel continuous casting process

The transient infiltration and lubrication behaviour of slag during continuous casting of steel is important for billet quality. A two-dimensional coupled mathematical mould model was developed to investigate these phenomena. The accuracy of the model was verified by comparing the calculated slag consumption with measurements by the plant. The results show that the liquid slag is consumed from the middle and late period of positive strip time to the next early period of positive strip time, including the entire negative strip time. The maximum downward infiltration velocity and positive pressure in the slag channel is at the middle of the negative strip time. Increasing the positive pressure of the slag channel is conducive to lubrication. The shear stresses acting on the shell surface and at the mould side were determined by the lubrication slag consumption and total slag consumption, respectively, and gradually decreased with increasing slag consumption. The negative strip time was lengthened to increase the slag consumption and prolong the time near the maximum downward shear stress, so as to be conducive to the demould.

Application of a simplified Green-Ampt model to the Maga earthfill dam under rainfall conditions: A sensitivity analysis case of an infiltration model

The present paper applies a simplified Green-Ampt (GA) infiltration model for the numerical modelling of seepage processes within the body of the Maga earth dam, located in the Far-North Cameroon, under rainfall conditions. The parametrization approach makes possible the predictions of infiltrations parameters for various textures that constitute the body of earth dam and its vicinities. The effects of soil texture, permeability coefficient, rain intensity and initial moisture on infiltration rate and cumulative depth are investigated using numerical simulations carried out by running an Excel VBA code. A proposed optimization procedure of the literature is then used to improve the GA model parameters and accuracy of predictions. A case sensitivity analysis of the infiltration model parameters has also been made. Initial and saturated water contents, rain intensity and permeability coefficient at saturation have been identified as the most influents parameters for the model predictions, with obvious interactions between inputs. The contribution of main effects and interactions of above inputs ranges between 68.8 % and 90.03 % of the total variance. Comparisons of numerical results with the experimental ones obtained from the literature on real cases of simulated rainfall on main sub-Saharan soils have been done. The results show that numerical simulations underestimated 60 % and 56.25 % of the hydrodynamics parameters respectively for one and four simulated rain-sequence with relative errors (RE) ranging between −76.22 % and 300.25 %. The most representative results were obtained for 53.13 % of the predicted hydrodynamics parameters with RE value ranging between −23.90 % and 12.75 %. The obtained results proved that, the simplified GA model exhibited an acceptable accuracy in predicting seepage processes for ferruginous and degraded vertic soils. Therefore, the present study contributes to understand the role of numerical simulations tools in modelling and predicting subsurface phenomenon as seepage, for areas with high floods risks in a context of significant climate changes.

Stability analysis of rainfall-induced landslide considering air resistance delay effect and lateral seepage

Accumulation landslides are prone to occur during the continuous infiltration of heavy rainfall, which seriously threatens the lives and property safety of local residents. In this paper, based on the Green-Ampt (GA) infiltration model, a new slope rainfall infiltration function is derived by combining the effect of air resistance and lateral seepage of saturated zone. Considering that when the soil layer continues to infiltrate after the saturation zone is formed, the air involvement cannot be discharged in time, which delays the infiltration process. Therefore, the influence of air resistance factor in soil pores is added. According to the infiltration characteristics of finite long slope, the lateral seepage of saturated zone is introduced, which makes up for the deficiency that GA model is only applicable to infinite long slope. Finally, based on the seepage characteristics of the previous analysis, the overall shear strength criterion is used to evaluate the stability of the slope. The results show that the safety factor decreases slowly with the increase of size and is inversely correlated with the slope angle and initial moisture content. The time of infiltration at the same depth increases with the increase of size and slope angle, and is inversely correlated with the initial moisture content, but is less affected by rainfall intensity. By comparing with the results of experimental data and other methods, the results of the proposed method are more consistent with the experimental results than other methods.

Retention profiles of multiparticle filtration in porous media

A one‐dimensional deep bed filtration model of a polydisperse suspension or colloid in a porous medium is considered. The model includes a quasilinear system of 2n equations for concentrations of suspended and retained particles of n types. The problem is reduced to a closed 3 × 3 system for total concentrations of suspended and retained particles and of occupied rock surface area, which allows an exact solution. The exact solution to the n‐particle problem is derived, the existence and uniqueness of the solution are proven, and the solution in the form of a traveling wave is obtained. The retention profiles (dependence of the deposit concentration on the coordinate at a fixed time) of different size particles and the total profile are studied. It is shown that the profile of large particles decreases monotonically, while the profile of small particles is nonmonotonic. Conditions for the monotonicity/nonmonotonicity of the intermediate particle profiles and the total profile are obtained. The maximum point of the small particles profile tends to infinity with unlimited growth of time, and the maximum points of nonmonotonic profiles of intermediate particles are limited. The asymptotical expansion of the maximum points of nonmonotonic profiles is constructed.

Ion‐Specific Hydrogel Microcarriers with Biomimetic Niches for Bioartifical Liver System

AbstractBioartificial livers have showcased significant value in the treatment of acute liver failure (ALF). Current efforts are directed toward overcoming challenges in the development of microcarriers, with a specific emphasis on integrating higher‐density liver cells to enhance detoxification capabilities. Here, inspired by the radial filtration model in hepatic lobules, ion‐specific silk fibroin microcarriers are proposed with biomimetic niches for cultivating functional liver cells at high density. These biomimetic microcarriers are generated by capillary microfluidic device with controllable adjustments of ion type or concentration within the aqueous phase. When cultivating human induced pluripotent stem cell ‐differentiated mature liver cells on these recrystallized microcarriers, notably enhanced cell proliferation activity, as well as increased metabolic and secretory functionality is observed. Based on these features, the microcarrier‐integrated bioreactor can effectively reduce hepatic transaminase levels and significantly improve urea, albumin production, and survival rate in rabbit ALF models is demonstrated. Thus, it is believed that the biomimetic microcarriers and their derived bioreactor may hold potential for clinical applications in managing ALF and other liver diseases.

On the behaviors of solutions of a nonlinear diffusion system with a source and nonlinear boundary conditions

We study the global solvability and unsolvability of a nonlinear diffusion system with nonlinear boundary conditions in the case of slow diffusion. We obtain the critical exponent of the Fujita type and the critical global existence exponent, which plays a significant part in analyzing the qualitative characteristics of nonlinear models of reaction-diffusion, heat transfer, filtration, and other physical, chemical, and biological processes. In the global solvability case, the key components of the asymptotic solutions are obtained. Iterative methods, which quickly converge to the exact solution while maintaining the qualitative characteristics of the nonlinear processes under study, are known to require the presence of an appropriate initial approximation. This presents a significant challenge for the numerical solution of nonlinear problems. A successful selection of initial approximations allows for the resolution of this challenge, which depends on the value of the numerical parameters of the equation, which are primarily in the computations recommended using an asymptotic formula. Using the asymptotics of self-similar solutions as the initial approximation for the iterative process, numerical calculations and analysis of the results are carried out. The outcomes of numerical experiments demonstrate that the results are in excellent accord with the physics of the process under consideration of the nonlinear diffusion system.

Abstract 864: Pan-cancer analysis of lactic acid metabolism landscape across the Cancer Genome Atlas

Abstract Introduction: Metabolic reprogramming plays an important role in tumor occurrence and progression. Our studies confirmed the survival state of patients with different metabolic systems was heterogeneous and glycolytic metabolism may cause tumor progression. Based on these findings, lactic acid metabolism in glycolysis aroused our interest. This study evaluated the potential association between lactate metabolism gene and tumor clinical process in hepatocellular carcinoma, and proved that it can be used as an effective tool for survival prediction and treatment guidance of 32 kinds of tumor patients by establishing lactate score prognosis model. Methods: We used the expression profile, proteomics and epigenetics of HCC lactate gene set in the Cancer Genome Atlas Database to systematically describe the changes of lactate related genes. The differentially expressed genes were then verified in 32 clinical tumor data sets. A prognostic model of tumor lactic acid infiltration was constructed to evaluate its correlation with the prognosis of patients. Finally, we analyzed the effects of lame score, immunotherapy and drug response on the clinical process of tumor. Results: Firstly, we analyzed the differential expression of lactate metabolism genes in HCC and found that the prognosis of patients with high lactate infiltration was significantly lower than that of mild infiltration. AF angiogenesis factor and EMT factor in high infiltration may be the main reason for their differential expression. We constructed a tumor lactic acid prognosis model through six significantly different lactic acid genes, and found that lame score can be used as a predictor of immunotherapy. In addition, we proved the role of lame score in Pan cancer. PGA was positively correlated with lame score in most tumors. The prognosis of 16 tumors with high lame score group was significantly lower than that of low lame score group. There were significant differences in lame score between metastatic and non metastatic cancer groups of Cesc, kirc and kirp. The high and low risk groups of some tumors showed different dryness indices and dampness. At the same time, methylation gene modification has a significant impact on the Lame score of pan cancer, and the Lame score is used to link the drug tolerance and specific pathway enrichment of pan cancer tumor cell lines, confirming the targeted effect of Lame score on tumor treatment. Finally, we used the clinical characteristics and immunohistochemical analysis of a cohort study of real patients with breast cancer endocrine therapy (Tamoxifen) and hepatocellular carcinoma targeted therapy (Lenvartinib) to verify the clinical treatment prediction ability of lame score. Conclusions: Our study provides a comprehensive analysis of lactate metabolic across cancers and highlights the potential treatment of lactate targeted therapies for cancers. Citation Format: Xiaolin Wei, Lei Cai, Qian He. Pan-cancer analysis of lactic acid metabolism landscape across the Cancer Genome Atlas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 864.

Abstract 6784: Cancer cell heterospheroids with stromal component used as drug testing and immune cell infiltration models

Abstract 3D cancer cell cultures have enabled new opportunities for replacing compound testing in experimental animals. However, driven by increased understanding of the need for more complex cancer cell models that consider drug resistance and penetration, hypoxia, and immuno-oncology applications, we have developed multicellular tumor heterospheroids composed of cancer cell lines, fibroblasts and immune cells. We have studied heterospheroids of cancer cell lines, HT29, MCF7, PANC1 and SW480 co-cultured with fibroblasts and 1) explored the architectural organization, 2) performed whole transcriptome analysis (WTA) of mono and co-cultures and 3) tested their capacity of immune cell infiltration. The architectural organization was studied in embedded heterospheroids. HT29 and MCF7 cells developed spheroids with the cancer cells surrounding the fibroblasts, whereas PANC1 cells mingled with the fibroblasts and SW480 cells were surrounded by fibroblasts. The fibroblasts expressed FAP-α mRNA as determined by ISH as well as collagen-1 as determined by immunohistochemistry. The hypoxia marker, Ca-IX, and the apoptosis marker, cleaved-Caspase-3, were dominating in the central core of the spheroids but the Ca-IX and Caspase-3 expression was not coordinated. In addition, WTA performed on day-7 heterospheroids, showed upregulated LOX, indicating that hypoxia-related markers known from genuine cancers are upregulated also in heterospheroids. WTA of day-7 mono-cell cultured and hetero-cultured spheroids, showed abundant ECM-, EMT-, and fibrosis-related expression in heterospheroids, thus reflecting a representative tumor-like microenvironment in heterospheroids compared to mono-culture spheroids. In particular, PANC1 spheroids showed a strong EMT profile with abundant FOXC2, TGF-β and TWIST expression. Genes related to Akt/mTOR and EGF pathways were consistently expressed in the tested heterospheroids. Evaluation of the cytotoxicity of anti-cancer compounds was performed using both cell viability and apoptosis assays. Exposure of the NCI drug library composed of 166 cytotoxic compounds to the heterospheroids, interestingly, revealed a complex output with limited correlation between cytotoxic and apoptotic effects. A subset of drug candidates is currently being further examined. PBMC-derived immune cells infiltrate heterospheroids and their infiltration is strongly enhanced after activation. The T cells' ability to infiltrate heterospheroids of different cancer types may serve as models of cold and hot tumors. We conclude that the cancer cell lines determine the architectural structure of heterospheroids, that ECM development is a prevalent part of the heterospheroids, and that the different heterospheroids possess varying ability of immune cell infiltration. Citation Format: Boye Schnack Nielsen, Natasha H. Madsen, Jesper Larsen, Monika Gad, Kim Holmstrøm. Cancer cell heterospheroids with stromal component used as drug testing and immune cell infiltration models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6784.

Prediction model of soil water infiltration under moistube irrigation

AbstractAs a new type of underground water‐saving irrigation method, moistube irrigation has great potential for promotion and development. However, the multi‐factor interaction influence and water infiltration prediction model of soil water infiltration under moistube irrigation need to be improved. This paper aims to obtain soil water infiltration data for different bulk densities (1.2, 1.3 and 1.4 g/cm3) and textures (loam, sandy loam and clay loam) under different pressure heads (1, 1.5 and 2 m) through an indoor moistube irrigation soil water infiltration test. By analysing multiple factors affecting soil water infiltration under moistube irrigation, the calculation method was determined with the initial soil moisture content, pressure head, bulk density and texture as the input variables and the Kostiakov model parameters as the output variables. Finally, the method of optimizing the back propagation (BP) neural network by a genetic algorithm (GA) was used to establish the Kostiakov prediction model of soil moisture in moistube irrigation, and the model was verified with analytics. The results showed that the Kostiakov prediction model based on GA‐BP had high accuracy and good consistency. The research results provide more practical proofs and perfect theoretical supplements for the study of soil water infiltration under moistube irrigation.

Role of plasma process gas on permeate flux augmentation of cellulose nitrate membrane for mud water treatment

A comparative study between Nitrogen (N2) and Argon (Ar) plasma is carried out to investigate its effect on surface morphology, hydrophilicity, permeate flux and ageing of cellulose nitrate polymeric membranes in the present work. Langmuir probe and Optical Emission Spectroscopy are used to characterize the plasma. The SEM analysis reveals the noticeable macro-void creations and pore enlargement for both N2 and Ar plasma. The AFM analysis shows a higher surface roughness for Ar plasma treatment as compared to N2 plasma treatment. XPS analysis confirms the changes in the polymer matrix along with the incorporation of various functional groups on the membrane surface as a result of the plasma treatment. A better hydrophilic nature with prolonged plasma treatment is observed for Ar plasma as compared to N2 plasma treatment. The present results show a higher permeate flux with a high rejection rate for Ar plasma treatment in comparison to N2 plasma, which might be due to the pore size and pore area enlargement of the membrane. The hydrophobic recovery for both the plasma-treated membranes is found significant for the initial ageing period of 7 days and found almost stable in nature after 7 days. A diffusion-based theoretical model is developed to study the hydrophobic recovery of plasma-treated membranes. A strong alignment between experimental and theoretical results is observed in the present work. The Cake Filtration model, derived from the Hermia model, is identified as the most suitable model for describing the fouling mechanisms for the present work.

Evaluation of Recovery of Tight Sandstone Gas Reservoirs Based on a Seepage Steady-State Model

As an important indicator for measuring the effectiveness and level of oil and gas field development, recovery rate has always been a focus in the research of oil and gas fields. Reservoirs of tight sandstone gas formations have significant characteristics of low porosity, high permeability, and high water content, which leads to greater difficulty in their development and makes it challenging to evaluate the recovery rate. Newtonian mechanics, as an important component of the mechanical system, is an innovative application of classical mechanics in the field of seepage mechanics when applied to the two-phase flow of gas and water. Firstly, starting from the perspective of mechanics analysis, we derive a steady-state model for gas–water two-phase infiltration and obtain the productivity equation based on this model. Then, according to the steady-state model, we establish a method to calculate the effective control radius of gas reservoirs under different production conditions and reservoir physical properties. Finally, using Matlab 2018a programming based on the productivity equation, we calculate the gas recovery under different conditions during constant pressure drop production and constant production rate production. The results indicate that the effective control radius of the reservoir decreases with an increase in the economic ultimate daily gas production, increases with an increase in production pressure difference, slightly decreases with an increase in startup pressure gradient, and correspondingly increases with an increase in microtube radius and quantity. Regardless of whether it is production with a fixed pressure drop or production with a fixed production rate, the gas recovery decreases as the production pressure drop and bottomhole abandonment pressure increase, but it increases as the proportion of the single-well control radius increases. In production with a fixed pressure drop, the gas recovery remains consistent across different reservoir quality indices. However, in production with a fixed production rate, the gas recovery initially increases rapidly and then gradually slows down as the reservoir quality index increases, and there is an obvious critical permeability (0.1 mD). The research findings are based on the mechanical analysis of porous media, delving into the laws governing fluid flow during infiltration. The derived infiltration model can be used to calculate the effective control radius and evaluate recovery rates, providing practical guidance for reservoir development.

Integrated Filtration and Washing Modeling: Optimization of Impurity Rejection for Filtration and Washing of Active Pharmaceutical Ingredients.

A digital design tool that can transfer material property information between unit operations to predict the product attributes in integrated purification processes has been developed to facilitate end-to-end integrated pharmaceutical manufacturing. This work aims to combine filtration and washing operations frequently using active pharmaceutical ingredient (API) isolation. This is achieved by coupling predicted and experimental data produced during the upstream crystallization process. To reduce impurities in the isolated cake, a mechanistic model-based workflow was used to optimize an integrated filtration and washing process model. The Carman-Kozeny filtration model has been combined with a custom washing model that incorporates diffusion and axial dispersion mechanisms. The developed model and approach were applied to two systems, namely, mefenamic acid and paracetamol, which are representative compounds, and various crystallization and wash solvents and related impurities were used. The custom washing model provides a detailed evolution of species concentration during washing, simulating the washing curve with the three stages of the wash curve: constant rate, intermediate stage, and diffusion stage. A model validation approach was used to estimate cake properties (e.g., specific cake resistance, cake volume, cake composition after washing, and washing curve). A global systems analysis was conducted by using the calibrated model to explore the design space and aid in the setup of the optimization decision variables. Qualitative optimization was performed in order to reduce the concentration of impurities in the final cake after washing. The findings of this work were translated into a final model to simulate the optimal isolation conditions.

Infiltration and Leaching Characteristics of Soils with Different Salinity under Fertilizer Irrigation

Salt and nutrient transport and transformations during water infiltration directly influence saline soil improvement and the efficient use of water and fertilizer resources. The effects of soil initial salinity (18.3 g/kg, 25.5 g/kg, 42.2 g/kg, 79.94 g/kg, and 165 g/kg, respectively, labeled S1 to S5) on the infiltration and leaching characteristics of water, salt, and nitrogen were analyzed via a one-dimensional vertical fertilizer infiltration experiment. Meanwhile, the estimation models of cumulative infiltration and wetting front, including the effect of soil initial salinity, were established. The results showed that, with the increase in soil initial salinity, the cumulative infiltration within the same time decreased, and the migration time of wet front to 45 cm was longer. The time required for S5 to reach the preset cumulative infiltration was more than six times that of S1, and, for the wet front migration to 45 cm, the time requirement for S5 was about four times that of S1. In the established Kostiakov model and wetting front model, the coefficients all decreased with the increase in soil initial salinity, and the test index R2 values both reached 0.999. In the Kostiakov model, coefficient K had a linear relationship with the natural logarithm of initial soil salt content, while index a had a direct linear relationship with initial soil salt content. The cumulative leachate volume decreased with the increase in soil initial salinity, and the corresponding data of S3 and S5 were reduced by 37% and 57.3%, respectively, compared with S1. The electrical conductivity values of S1, S3, and S5 were 15.4, 209.8, and 205.6 ms/cm, respectively, being affected by the initial content in soil, soil moisture transport rate, and exogenous potassium nitrate (KNO3) addition. The NO3−-N concentrations in the leachates of S1, S3, and S5 at the end of leaching were 55.26, 16.17, and 3.2 mg/L, respectively. Based on the results of this study, for soil with high initial salinity, the conventional irrigation amount (2250 m3/ha) of the general soil in the study area could not meet the requirements of leaching salt. These results can provide a reference for the formulation of irrigation and fertilization strategies for soils with different salinity and contribute to the sustainable development of saline soil agriculture and the ecological environment.

Comparison of infiltration model performance based on basic infiltration rate for small watersheds in Papua region, Indonesia

Research on soil water infiltration in equatorial climates like Indonesia is limited. Despite Papua accounting for 29% of Indonesia’s surface water, there’s a shortage of hydrological data. This study aimed to identify the best infiltration model tailored to the characteristics of basic infiltration rates in Papua’s small watersheds. Observations were made at 95 points across 11 small watersheds in Papua. Based on equatorial basic infiltration rate theories, analysis classified infiltration values against observation time. The performance of four infiltration models — Horton, Philip, Kostiakov, and Green Ampt — were compared. The results indicated the Philip model as superior, with average scores of 0.901 (R), 0.814 (NSE), and 0.424 (RSR), followed by the Horton and Green Ampt models. These three models showed excellent performance. However, the Kostiakov model was found lacking and needs modification. Further research on rapid and very rapid classifications is vital for enhancing infiltration rate predictions in small equatorial watersheds.

Forecasting oil displacement in clay-rich reservoirs using water injection with varying mineral compositions

On the basis of a two-phase four-component fluid filtration model, mathematical modeling of a clay oil-bearing reservoir has been performed, which allows taking into account all physico-chemical processes occurring when exposed to water of various mineral composition, and on its basis to assess the possibility of restoring the reduced permeability of the reservoir due to the injection of water with low mineralization on the basis of treatment with a clay stabilizer. It has been established that the treatment of the layer with the optimal amount of clay stabilizer provides a significant intensification of oil production.

Treatment of food processing industries wastewaters using a new clay-based inorganic membrane: Performance evaluation and fouling analysis

BackgroundCeramic membranes are intensely extending their applicability in wastewater treatment due to their excellent resistance to corrosive environment, anti-fouling nature, and longer lifetime. To further widen the usage of ceramic membranes despite of their high cost, development of inexpensive ceramic membranes is highly anticipated. MethodA novel inexpensive Fuller's earth clay ceramic membrane's performance was evaluated in treating the wastewater obtained from two food processing industries, namely the dairy industry and palm oil industry, by varying the applied pressure from 0.35 – 2 bar. Furthermore, the fouling mechanism concerning the microfiltration of wastewater was identified with the help of Hermia's pore blocking models. Significant FindingsThe prepared novel Fuller's earth clay ceramic membrane significantly reduced COD content below the permissible discharge limit (< 200 mg/L) for dairy and palm oil industry wastewaters at a pressure of 0.35 bar. Notably, 98 – 99 % removal of turbidity and suspended solids was achieved. Also, the total phosphorus content was brought down below the permissible discharge limit of 5 mg/L. From fouling analysis, it was inferred that the cake filtration model appropriately fits the obtained experimental results, confirming the anti-fouling nature of the fabricated clay membrane in treating food process industries' wastewater.