Evaluating Soil Water Matric Pressure and Sorptivity Relationship as Affected by some Properties of a Clay Soil

Sorptivity (S) is the fundamental variable controlling the early infiltration process. Besides soil properties, soil initial water content (θi) and/or matric pressure (hi) are key factors determining extent of S. Assessment of interrelationship among S, hi and soil properties can provide a considerable insight into understanding the behaviour of dry soils to rainfall or irrigation water. This study was conducted to evaluate relationship between S and some selected soil parametric and morphometric properties within a range of hi. Sixteen undisturbed soil samples (5 cm id, 5 cm length) were taken from the topsoil (0-15 cm) of a paddy soil with clay texture. Sorptivity was measured with a mini-disc infiltrometer (MDI) on the samples equilibrated at h, ranging from -20 to -1500 kPa. A parameter (η), representing the relationship between S and hi, was introduced. Correlation analysis was conducted between η and selected soil morphometric and parametric properties. Soil structure and clay content appeared the most important soil attributes influencing S-hi relation between -200 and -1500 kPa. The results provided a fundamental understanding on S-hi-soil properties interrelations in a clay soil. The methodology developed in this study can be used to evaluate S-hi relationship across different soils and scales.

Chemical Supercritical Fluid Infiltration of Pyrocarbon with Thermal Gradients: Deposition Kinetics and Multiphysics Modeling

The chemical supercritical fluid infiltration process is a recent variation of the chemical vapor infiltration (CVI) process that allows rapid and efficient manufacturing of ceramic-matrix composites (CMCs), albeit still needing optimization. This article proposes a quantitative assessment of the process dynamics through experiments and modeling. The kinetics of carbon deposition were determined through two sets of experiments: CVD on a single filament at pressures between 10 and 50 bar and infiltration at pressures ranging between 50 and 120 bar. The CVI experiments were conducted under important thermal gradients and were interpreted using a model-based reconstitution of these gradients. We found that (i) the kinetic law has to incorporate the potential effect of the reverse reaction (i.e., etching of C by H2); (ii) the activation energy and pre-exponential factor both decrease with pressure up to 50 bar, then remain roughly constant, and (iii) although the apparent activation energy is modest, a favorable situation occurs in which an infiltration front builds up and travels from the hottest to the coldest part of the preform due to the presence of sufficient heat flux. A numerical simulation of the process, based on the solution of momentum, heat, and mass balance equations, fed with appropriate laws for the effective transfer properties of the porous medium and their evolution with infiltration progress, was performed and validated by comparing the simulated and actual infiltration profiles.

Hydrological response of hydrographic sub-basins in the Piracicaba River Basin - Southeast Region of Brazil

Use of water for several human needs, associated with climate change, indicates the need understand the response of watersheds, in order to provide adequate water resources planning and management. This study was carried out in two pairs of hydrographic watersheds, in the Piracicaba River Basin, southeast of Brazil, analyzing water response, integrating in-situ collected precipitation and flow data, natural environment attributes, and anthropic environmental data. To support the analysis, Surface Runoff Potential Charts (SRPC). The evaluation of the physical characteristics of the sub watersheds (SW(A) and SW(B)) shows that these areas present very low to low potential, indicating greater infiltration capacity. The use and coverage of the soil partially justifies the flow changes in pair 1, since SW(A) has a larger extent of agricultural areas that can use irrigation. SW(B), even with a greater variety of crops, has a smaller cultivated area and tends to demand less water. At pair 2, the low runoff potential is mainly due to the predominance of flat relief in the sub-basins. The soils that compose them present a higher fraction of silt and clay, with thicknesses > 5m in SW(C) and varying from 0.5m, reaching depths above 5m in SW(D), however, the physical properties of these soils do not provide a low flow rate, but associated with the low slope of the land, the geological characteristics and low drainage density are configured in regions where the flow flows more slowly, contributing to the evaporation and infiltration process. The use and coverage of the soil also partially justifies the flow oscillations, due to anthropic activities in SW(C) and SW(D), such as irrigation and spraying of citrus, fertirrigation of sugarcane, irrigation of seedling nurseries, directly interfering with the availability of surface water.

Rainfall Infiltration Process of a Rock Slope with Considering the Heterogeneity of Saturated Hydraulic Conductivity

In order to analyze the effects of rainfall events on the stability of an open-pit rock slope, with considering the spatial variability of saturated hydraulic conductivity, based on the unsaturated seepage theory and the random filed theory, modified functions of the unit saturation, the hydraulic conductivity (k), and the shear strength parameters are established for unsaturated slope, by using FISH and the non-intrusive stochastic method. A saturated-unsaturated seepage random field model is proposed. And then the impacts of the rainfall intensity, the rainfall duration, and the spatial variability of saturated hydraulic conductivity (ks) on the infiltration process and stability of the unsaturated rock slope are analyzed. The results show that the proposed model can estimate rainfall infiltration of rock slope accurately. Rainfall mainly affects the seepage field in the shallow layer of the slope, where a transient saturated zone can be formed. With the development of the rainfall duration, the weight of the rock mass increased, the matric suction reduced, the negative pore pressure, the degree of saturation, and the infiltration depth of the rock slope increased, and the water in the slope root connects with the initial water table gradually, the unsaturated zone shrinks, which causes the safety factor of the model decreases, but the trend of change slows down gradually. As the rainfall intensity strengthened, the infiltration depth increased and the safety factor of the slope reduced, while the changing rate increases first and then decreases. Increasing the correlation length of k can reduces the infiltration depth and safety factor of the slope. Increasing the variation coefficient of k will increase the infiltration depth, while the safety factor of the slope decreases. The infiltration depth and safety factor of the slope are most affected by rainfall duration, but its sensitivity to the variability coefficient of k will be strengthened when the rainfall intensity exceeds the infiltration capacity. This conclusion can provide reference significance for the risk estimation of slope geological hazards, which are induced by the rainfall infiltration.

Correlation between C-Reactive Protein Level and Blood Urea Nitrogen-Creatinine Ratio in COVID-19 Patients

Coronavirus Disease 2019 (COVID-19) is caused by Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2).C-Reactive Protein (CRP) is an inflammation marker that increases significantly in COVID-19 patients. SARS-CoV-2 can affectkidney function and increase the Blood Urea Nitrogen (BUN)-creatinine ratio. The previous study showed that CRP andBUN-creatinine ratios could be used as predictors of the severity and survival of COVID-19 patients. This study aimed todetermine the correlation between CRP levels and the BUN-creatinine ratio in COVID-19 patients. A retrospectivecross-sectional study was conducted on 34 COVID-19 patients who were diagnosed by PCR test at Dr. Kariadi Hospital,Semarang from March to September 2020. The Spearman correlation test was used for statistical analysis. The median CRPvalue was 4.59 (0.36-27.48) mg/L and BUN-creatinine ratio was 15.06 (5.79-37.04), while the correlation between CRP andBUN-creatinine ratio showed p=0.003 and r=0.502. There was a moderate positive correlation between CRP level andBUN-creatinine ratio. C-reactive protein plays a role in the infiltration process of inflammatory cells and increases adhesionmolecules, which can directly or indirectly damage kidney function. SARS-CoV-2 can enter the kidney directly through theACE-2 receptor and activate the renin-angiotensin-aldosterone system, which will increase water and sodium absorption inthe renal tubules, passive reabsorption of BUN, and creatinine filtration in the glomerulus resulting in increasedBUN-creatinine ratio.

Impact of Artificial Infiltration on the Removal of Nonsteroidal Anti-Inflammatory Drugs during Treatment of Surface Water

The content of pharmaceuticals in natural waters is steadily increasing. Especially nonsteroidal anti-inflammatory drugs (NSAIDs) are often detected in natural waters due to their widespread use. This group of compounds includes commonly used representatives, such as paracetamol and ketoprofen. The quality of natural waters determines the processes applied for the treatment of drinking water. The methods used in order to remove pharmaceuticals from treated water include adsorption and biologically active filtration. Both processes also occur during artificial infiltration (forced flow of intake surface water through the ground to the collecting wells) at surface water intakes. The processes, which occur in the soil, change the water quality characteristics to a great extent. The goal of the study was to evaluate the removal efficiency of paracetamol and ketoprofen in the process of artificial infiltration used as a pre-treatment of surface water. The studies were conducted at a field experimental installation located at the technical artificial infiltration intake. The experimental installation consisted of three metering wells (piezometers) which were located on the way between the bank of the infiltration pond and the collecting well. The collected water samples allowed to evaluate the change of selected NSAIDs concentrations during the passage of water through the ground. The analysis procedure included solid phase extraction (SPE) and high-performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Removal of the studied NSAIDs in the infiltration process occurred with variable effectiveness throughout the year. Paracetamol was removed with annual efficiency equal to 42%, although no significant removal of ketoprofen was observed.

Ponding time in infiltration process for different land use

Ponding time is the period from the beginning of rainfall/infiltration until the occurrence of ponding. This paper aims to determine the infiltration rate and ponding time on different land uses, such as open fields, residential, agriculture, and vegetation. This research was conducted in one of the watersheds in the Brantas River Basin, namely the Lesti River Basin, which is administratively included in the Malang Regency, East Java. The Lesti River is one of the tributaries of the Brantas River, which originates around Mount Semeru, a very intensive area for planting rice, sugar cane, and coffee. Infiltration data were collected at 35 points using a double-ring infiltrometer spread across the Lesti watershed with Andosol, Mediterranean, and Regosol soil types. At the same time, ponding time was obtained from infiltration measurements in the field using the flooding method. The physical properties of the soils were tested in the laboratory to obtain water content, porosity, and bulk density values. This study resulted in the infiltration rate and ponding time for each land use and shows how the physical properties of the soil affect the ponding time.

Carbon nanotube biocompatibility in plants is determined by their surface chemistry

Background Agriculture faces significant global challenges including climate change and an increasing food demand due to a growing population. Addressing these challenges will require the adoption of transformative innovations into biotechnology practice, such as nanotechnology. Recently, nanomaterials have emerged as unmatched tools for their use as biosensors, or as biomolecule delivery vehicles. Despite their increasingly prolific use, plant-nanomaterial interactions remain poorly characterized, drawing into question the breadth of their utility and their broader environmental compatibility. Results Herein, we characterize the response of Arabidopsis thaliana to single walled carbon nanotube (SWNT) exposure with two different surface chemistries commonly used for biosensing and nucleic acid delivery: oligonucleotide adsorbed-pristine SWNTs, and polyethyleneimine-SWNTs loaded with plasmid DNA (PEI-SWNTs), both introduced by leaf infiltration. We observed that pristine SWNTs elicit a mild stress response almost undistinguishable from the infiltration process, indicating that these nanomaterials are well-tolerated by the plant. However, PEI-SWNTs induce a much larger transcriptional reprogramming that involves stress, immunity, and senescence responses. PEI-SWNT-induced transcriptional profile is very similar to that of mutant plants displaying a constitutive immune response or treated with stress-priming agrochemicals. We selected molecular markers from our transcriptomic analysis and identified PEI as the main cause of this adverse reaction. We show that PEI-SWNT response is concentration-dependent and, when persistent over time, leads to cell death. We probed a panel of PEI variant-functionalized SWNTs across two plant species and identified biocompatible SWNT surface functionalizations. Conclusions While SWNTs themselves are well tolerated by plants, SWNTs surface-functionalized with positively charged polymers become toxic and produce cell death. We use molecular markers to identify more biocompatible SWNT formulations. Our results highlight the importance of nanoparticle surface chemistry on their biocompatibility and will facilitate the use of functionalized nanomaterials for agricultural improvement. Graphical Abstract

Effect of the Gravel Filters and Plastic Cover on Improving Water Infiltration Process and Increasing Moisture Storage of Rainwater Harvesting Systems in Sloping Lands

Rainwater harvesting is a suitable method to plant seedlings in sloping lands in arid and semi-arid regions. In this research, a combination of plastic coating and gravel filter has been used to penetrate water into the soil. In this method, water is stored in the soil during the rainy months and the plant uses these waters in the warm months of the year. For this purpose, five treatments (with three replications) including control treatment, system vegetation removal with filter, system vegetation removal without filter, semi-insulated system with filter and semi-insulated system without filter are considered. Two sensors are installed in each of the treatments at a depth of 20 cm and 60 cm of soil, which will record moisture in seven-day periods. Apricot seedlings have been planted in all treatments. The information obtained was analyzed through a completely randomized block design. The results showed that the semi-insulated treatment with gravel filter stored significant moisture in the soil rather than other treatments and stored more moisture in the warm months of the year. The results showed that semi-insulated treatment with gravel filter is a suitable solution to increase soil moisture in the warm months of the year (June, July, August and September).