Large Volumes Of Water Research Articles

Wetting Patterns in a Subsurface Irrigation System Using Reservoirs of Different Permeabilities: Experimental and HYDRUS-2D/3D Modeling

Precipitation in arid lands is low and often highly variable; therefore, efficient irrigation is the best approach for managing limited water supplies and irregular precipitation events for establishing seedlings. The HYDRUS-2D/3D software is a useful tool for simulating water content distribution in the design of subsurface irrigation systems, determining the proper locations of reservoir and plant, irrigation scheduling and maximizing water use efficiency. In this study, wetting patterns around the reservoirs with different permeabilities (low, medium, and high) were assessed in the field and simulated using the HYDRUS-2D/3D software. Different amounts of animal manure and wheat straw were mixed with clay fractions to produce the reservoirs with different permeabilities. The results showed that the highest soil water content was observed near the reservoir, and it decreased with distancing from the reservoir. In the high permeability treatment (with saturated hydraulic conductivity, Ks = 0.2 cm/day), a large volume of water was released for almost three days, so that more water was deep-percolated and lowered the soil water available to plant roots. In the low and medium permeability treatments (Ks = 0.08, and 0.06 cm/day, respectively), the water slowly leaked, and the maximum soil water content was observed in the 20–40 cm layer over time. The HYDRUS-2D/3D software was able to simulate water flow and soil water content during the growth period of plants, with a high correspondence between measured and simulated soil water contents (R2 = 0.90–0.95), which was higher in the lower discharges.

Exploiting Ground-Penetrating Radar Signal Enhancements by Water-Saturated Bulb Surrounding Defective Waterpipes for Leak Detection

The detection of water leakage along its transportation network has important societal impacts, such as avoiding a large volume of water wasted along the waterways or preventing water-related chemical or physical surrounding media deterioration. Among the vast domain of destructive techniques, Ground-Penetrating Radar (GPR) is a common and efficient tool used for detection in many near-surface contexts, and it is particularly efficient in civil engineering cases, such as utility detection, due to its fine resolution and the ease of data acquisition. A peculiar form of signal enhancement appears in GPR profiles recorded over spheres and cylinders where velocity contrasts exist between the body’s material and the surrounding medium. We used this enhancement to detect potential water leakages in water pipes. After exhibiting the signal enhancement effect in a laboratory sandbox experiment using a spherical glass ball, we verified the results with numerical experiments with varied sphere and cylinder sizes and dielectric properties. We then investigated field and numerical experiments of GPR transects above a “real life” water-leaking PVC pipe. Our results show that the water cylinder and water infiltration bulb produced a characteristic signal that could be used for detecting water leakages along water pipes. The largest amplitude in the GPR signal is caused by a bottom pipe reflection enhanced by the water bulb and not by the top of the pipe. We stress the risk of miscalculating the pipe’s depth during velocity estimation when amplitude enhancement conditions are met. Beyond civil-engineering impacts, knowledge on signal amplification phenomena can help GPR data interpretations in sedimentology and hydrogeology studies.

S2517 Pill Prep Problems? Erosive Gastritis and Peptic Ulcers due to Sodium Sulfate-Based Tablet Bowel Prep

Introduction: SUTAB is the second ever tablet formulation for bowel preparation. It became FDA approved in 2020 based on 2 randomized studies in which SUTAB provided noninferior bowel cleansing when compared to other commonly used FDA approved preparations. These randomized studies focused only on colonoscopies, possibly ignoring SUTAB’s effects on the upper GI tract. Endoscopists have recently been noticing significant adverse side effects from SUTAB, notably erosive gastritis and peptic ulcers in patients scheduled for same day bidirectional endoscopy. These findings were not noted by the studies used for FDA approval. SUTAB is a sodium sulfate based tablet composed of 3 main active ingredients: sodium sulfate, magnesium sulfate, and potassium chloride. SUTAB is taken as a 2-day split dose regimen of 24 tablets with large volumes of water. The most common adverse side effects published for SUTAB include nausea, abdominal distension, vomiting, and abdominal discomfort. Any mention of mucosal ulcerations focused on colonic ulcerations in patients with suspected inflammatory bowel disease or in concurrence with the use of stimulant laxatives. Case Description/Methods: 5 cases of same day bidirectional endoscopy were examined from 9/2/2021 to 11/15/2021. Indications for upper endoscopy included a history of Barrett’s esophagus and/or gastroesophageal acid reflux disease and all patients used SUTAB as the sole bowel preparation. In all cases there was no previous history of erosive gastritis or peptic ulcer disease, however, all upper endoscopies noted signs of moderate to severe erosive gastritis. Two of the cases also noted similarly appearing linear gastric ulcers with black eschars. All patients were subsequently placed on antacid therapy and follow-up endoscopies were performed to assess ulcer healing, which was noted at the time. Discussion: SUTAB is a relatively new bowel preparation on the market with very little published data on its known side effects. The convenience of a tablet formulation for a bowel preparation that achieves successful bowel cleansing attracts patients and doctors, but it comes with the cost of possible adverse side effects in the upper GI tract. The ingredients in SUTAB are corrosive agents, specifically, potassium chloride has been linked to erosions that are found in the mucosa of the GI tract with prolonged exposure. To better understand this recently noted phenomena, more research is needed to help prevent these unwanted and potentially dangerous side effects.

Policy and Kidney Community Engagement to Advance toward Greener Kidney Care.

Policy and Kidney Community Engagement to Advance toward Greener Kidney Care.

S2544 Acute Symptomatic Hyponatremia Following Single Balloon Enteroscopy With Water Immersion: Be on the Lookout

Introduction: The water immersion endoscopic method is a safe and often used endoscopic technique. We report a unique case of electrolyte abnormalities in a single balloon enteroscopy secondary to this procedure Case Description/Methods: A 70-year-old female with HTN and hypothyroidism presented for single balloon enteroscopy for removal of a retained capsule. The capsule was initially performed for the of work up of melena and iron deficiency anemia after a negative upper endoscopy and colonoscopy. Physical exam and labs prior to the procedure were normal, including a sodium level of 139. The patient underwent the planned enteroscopy with water emersion with an estimated amount of 4 L of water being used. Shortly after completion of the procedure, the patient was noted to be delirious and have an altered mental status. The patient became aphasic, began clenching her fists, and was shaking. A sodium level post-procedure was obtained and was 113. A head CT scan was performed and no central involvement was noted. The patient was managed with 3% hypertonic saline and her symptoms resolved. Over the next 2 days patient’s sodium level normalized and the patient was discharged from the hospital. Discussion: This is the first reported case of hyponatremia secondary to water immersion endoscopy. While there is an abundance of reports describing hyponatremia in urologic and gynecologic procedures those procedures generally use glycine and mannitol as their irrigate. With regards to GI procedures, hyponatremia secondary to polyethylene glycol-electrolyte preparation has infrequently been reported. Free water irrigation/immersion is generally regarded as safe during gastroenterological procedures. Our case, brings awareness to the possibility of symptomatic hyponatremia following prolonged enteroscopy with the use of large volume water irrigation/immersion. Absorption of ingested water and most solutes occur in the proximal small intestine. If a large amount of fluids are necessary then normal saline can be utilized instead of water. Limiting water to 1.5 liters and suctioning excess water can help minimize these complications. Clinicians should be aware of this serious complication when performing these procedures.

Screening of microplastics in water and sludge lines of a drinking water treatment plant in Catalonia, Spain

Microplastics (MPs) are emerging pollutants detected everywhere in the environment, with the potential to harm living organisms. The present study investigated the concentration, morphology, and composition of MPs, between 20 μm and 5 mm, in a drinking water treatment plant (DWTP) located close to Barcelona (Catalonia, NE Spain). The sampling included different units of the DWTP, from influent to effluent as well as sludge line. Sampling strategy, filtration, allows sampling of large volumes of water avoiding sample contamination, and during 8 h in order to increase the representativeness of MPs collected. The pre-treatment of the samples consisted of advanced oxidation with Fenton's reagent and hydrogen peroxide, followed by density separation of the particles with zinc chloride solution. Visual identification was performed with an optical and stereoscopic microscope with final Fourier-transform infrared spectroscopic (FTIR) confirmation. MPs were found in all DWTP samples, with concentrations from 4.23 ± 1.26 MPs/L to 0.075 ± 0.019 MPs/L in the influent and effluent of the plant, respectively. The overall removal efficiency of the plant was 98.3%. The most dominant morphology was fibers followed by fragments and films. Twenty-two different polymer types were identified and synthetic cellulose, polyester, polyamide, polypropylene, polyethylene, polyurethane, and polyacrylonitrile were the most common. Although MPs could be incorporated from the distribution network, MPs intake from drinking water from this DWTP was not an important route compared to fish and seafood ingestion.

Hematological parameters in workers of water supply facilities of petrochemical enterprises

Introduction. One of the major petrochemical complexes of the Republic of Bashkortostan is Limited liability company (LLC) «Gazprom Neftekhim Salavat». The normal operation of industrial enterprises requires the use of large volumes of water. Its water supply, water disposal, waste disposal, reclamation of sludge reservoirs, equipment repair, cleaning of oil sludge reservoirs is provided by LLC «PromVodoKanal». The main technological personnel are wastewater treatment operators, process plant operators, pumping plant operators, chemical analysis laboratory assistants, commodity operators. Their work is associated with exposure to harmful and / or dangerous production factors. Objective. Search and substantiation of laboratory markers of early health disorders in workers of water supply facilities of petrochemical enterprises. Materials and methods. Hygienic and clinical laboratory studies were carried out among workers of the main occupations of the «PromVodoKanal» station who have contact with various harmful derivative factors. A complex of hematological and biochemical research methods was used in the work. Results. A comparative analysis of the frequency of occurrence of deviations of hematological parameters from the norm in all examined (occupational) groups was carried out. A laboratory study showed that hematological parameters are characterized by an increased content of hemoglobin, erythrocytes, and hematocrit. Changes in the mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC), and thrombocytes count, were detected in every fifth worker. Over the years of work, the share of workers with high levels of glucose and cholesterol increases markedly, the correlation of which reaches from 0.90 to 0.97. Limitations. The article has limitations on the scientific study of working conditions, as periodic medical examinations are carried out by occupational pathologists. Conclusions. Red blood values are specific markers of workers’ health problems and require special attention during periodic medical examinations.

Quantifying denitrification in a field-scale bioremediation experiment

Nitrate (NO3ˉ) in mine waste rock derived from undetonated NH4NO3 can contaminate receiving waters. An in-situ bioremediation experiment was conducted at a coal mining operation in Elk Valley, British Columbia, Canada to remediate NO3ˉ from large volumes of mine water. Over the test period (201 d), 5000 to 7500 m3 d−1 of NO3ˉ-rich (mean concentration 22 mg N L−1) mine water was injected into saturated waste rock along with methanol, nutrients, and a conservative tracer (Brˉ). Complete denitrification (<0.5 mg N L−1) was recorded in monitoring wells located 38 m from the injection wells after 114 to 141 d of operation. Plots of δ15N- and δ18O-NO3ˉ versus NO3ˉ-N concentrations for monitoring wells yielded isotopic enrichment factors (ε) for δ15N- and δ18O-NO3ˉ of −25.7 and −13.2 ‰ for high C/C0 NO3ˉ concentrations (>10.5 mg N L−1) and −5.5 and −3.6 ‰ for lower C/C0 values. The fraction of NO3− denitrified (Dp) calculated using bi-linear ε values for δ15N- and δ18O reproduced the Dp determined independently using a conservative tracer indicating that stable isotope tracers of the NO3ˉ reducing processes in bioremediation are invaluable to determine Dp. Based on the success of this ongoing bioremediation experiment, the technology is being applied at other sites.

Degradation of dye in a continuous zig-zag flow pattern photocatalytic reactor using a Doehlert matrix

Rhodamine B-containing wastewater was thoroughly treated in a photocatalytic reactor operated in a continuous mode with a zig-zag type of flow pattern. The effect of operating parameters such as pH (1−9) and initial dye concentration (10–40 ppm) on Rhodamine B degradation was studied at 1 g/L of TiO2 and H2O2 in order to determine the optimal operating parameters for combined treatment schemes. At a concentration of 10 ppm and a loading of 1 g/L TiO2 and H2O2 at a pH of 3, the maximum rate of degradation was 94.02%, and 96.68% obtained and follows pseudo-first order kinetics, respectively. Further studies of the influence of initial dye concentration and solution pH were investigated using an optimized range of TiO2 and H2O2 loading based on the surface response of the Doehlert matrix design. Based on the surface response, it was observed that the lower initial concentration with a higher loading of TiO2 and H2O2 accelerates the production of hydroxyl radicals and thereby, higher degradation of pollutants was achieved. Complete degradation with 84.76% COD reduction of Rhodamine B was observed at 0.8 g/L of H2O2 and 2 pH of dye solution with a total treatment cost of US $0.009/L. Overall, the current study found that the novel photocatalytic reactor operated in a continuous mode can treat large volumes of waste water using hybrid methods with optimum catalyst loading, has high potential, and may be successfully applied for the removal of hazardous dyes from aqueous solutions with intensification benefits.

Spatial and temporal variations in anti-androgenic activity and environmental risk in a small river

The biological effects of multiple compounds have been widely investigated in aquatic environments. However, investigations of spatial and temporal variations in biological effects are rarely performed because they are time-consuming and labor-intensive. In this study, the variability of the anti-androgen, receptor-mediated activity of surface water samples was observed over 3 years using in vitro bioassays. Large-volume water samples were collected at one site upstream (Wer site) and two sites downstream (Sil and Nien sites) of a wastewater treatment plant (WWTP) outfall in the Holtemme River. Anti-AR activity was persistently present in all surface water samples over the three years. Large spatial variations in anti-androgenic activity were observed, with the lowest activity at the Wer site (mean concentration of 9.5 ± 7.2 μg flutamide equivalents/L) and the highest activity at the Sil site (mean concentration of 31.1 ± 12.0 μg flutamide equivalents/L) directly influenced by WWTP effluents. On the temporal scale, no distinct trend for anti-AR activity was observed among the seasons in all three years. The anti-androgenic activity at the upstream Wer site showed a decreasing trend from 2014 to 2016, indicating improved water quality. A novel bioanalytical-equivalent-based risk assessment method considering the frequency of risk occurrence was developed and then utilized to assess the environmental risk of anti-androgenic activity in the Holtemme River. The results revealed that the highest risk was present at the Sil site, while the risk was considerably reduced at the Nien site. The risk at the upstream Wer site was the lowest.

Synthesis and Applications of Carboxymethyl Cellulose Hydrogels.

Hydrogels are basic materials widely used in various fields, especially in biological engineering and medical imaging. Hydrogels consist of a hydrophilic three-dimensional polymer network that rapidly expands in water and can hold a large volume of water in its swelling state without dissolving. These characteristics have rendered hydrogels the material of choice in drug delivery applications. In particular, carboxymethyl cellulose (CMC) hydrogels have attracted considerable research attention for the development of safe drug delivery carriers because of their non-toxicity, good biodegradability, good biocompatibility and low immunogenicity. Aiming to inspire future research in this field, this review focuses on the current preparation methods and applications of CMC gels and highlights future lines of research for the further development of diverse applications.

Integrated electro-coagulation and gravity driven ceramic membrane bioreactor for roofing rainwater purification: Flux improvement and extreme operating case

The collected roofing rainwater with high water quality and large water volume, can alleviate the crisis of water resources and fit the Low-Impact Development (LID) concept. In this work, a novel water purification technology, Electro-Coagulation coupled with Gravity-Driven Ceramic Membrane Bio-Reactor (EC-GDCMBR) was developed for the roofing rainwater purification under long-term operation (136 days). EC-GDCMBR system not only exhibited the better effluent quality, but also obtained the greater flux (~32 LMH). The reason contributed to the high permeability of ceramic membrane and large porosity of biofilm formed by floc growth (~36 μm) during the EC process, which was also proved by SEM image. The coagulation, adsorption, biodegradation, and coprecipitation of EC-GDCMBR was able to synergistically remove the particulate matter, ammonia nitrogen (NH3-N), Total Phosphorus (TP), organic substances, and heavy metal (i.e., Cr, Zn, and Cu). In particular, via the analysis of bacterial abundance, Extracellular Polymeric Substances (EPS), Assimilable Organic Carbon (AOC), Adenosine Tri-Phosphate (ATP) and Confocal Laser Scanning Microscopy (CLSM), EC could sweep most free bacteria on the ceramic membrane surface, enhancing the biological purification efficiency. Furthermore, a large amount of Pseudomonas (12.4 %-66.7 %) and Nitrospira (1.46 %-3.16 %) in the aggregates formed the biofilms, improved the NH3-N removal. During the long-term operation, there are some unavoidable problems, such as the thick and ripened biofilm of EC-GDCMBR would crack and fall off. Based on this, the current work also studied the reliability of GDCMBR under “extreme operating case”, and the results showed that neither the biofilm detachment nor the biofilm breakup had a significant impact on the effluent quality. Overall, the findings of this study suggest the reliability of EC-GDCMBR for the sustainable operation of roofing rainwater purification and improve the application value of decentralized rainwater harvest device.

Well Pattern and Well Spacing Optimization of Large Volume Water Injection in a Low-Permeability Reservoir with Pressure Sensitivity

Even with the fractured wells, the primary oil recovery of low-permeability reservoirs is still poor in Block X of Shengli Oilfield. To further enhance the oil recovery, water is injected into the reservoir. Different from the conventional injection scheme, the maximum daily injection rate of the proposed scheme by Shengli Oilfield reaches 2000 m3, and the average daily injection rate is around 1500 m3. Thus, the conventional well spacing of certain well pattern is not suitable for the novel injection scheme. In the paper, the optimal well pattern and well spacing for the large volume water injection scheme to develop a pressure-sensitive low-permeability reservoir is investigated. Firstly, the CMG is employed to build the basic reservoir model developed by fractured vertical wells. To finely depict the pressure sensitivity, the dilation-recompaction geomechanical model is introduced to couple with the basic reservoir model. Based on the established coupled model, the optimal well spacing for the inverted 5-spot well pattern and the inverted 9-spot well pattern is investigated with a total of 80 sets of numerical experiments. The numerical experiments indicate that the optimal well spacing for the inverted 5-spot well pattern is 850 m/350 m and the optimal well spacing for the inverted 9-spot well pattern is 550 m/450 m. To further screen the well pattern, the normalized index of oil production per unit area of each well pattern is proposed. And it is found that the oil production per unit area of the inverted 5-spot well pattern is higher than the inverted 9-spot well pattern. For the reservoir developed with fractured vertical wells coupled with large volume water injection, compared with the inverted 9-spot well pattern, the inverted 5-spot well pattern is better, and the corresponding optimal well spacing is 850 m/350 m. The paper proposes an efficient simulation and optimization workflow for the development of pressure-sensitive low-permeability reservoirs with fractured vertical wells coupled with large volume water injection, providing practical guidance for the efficient and sustainable development of pressure-sensitive low-permeability reservoirs.

Improved oil recovery techniques and their role in energy efficiency and reducing CO2 footprint of oil production

Production of mature oil fields emits significant amount of CO2 related to circulation and handling of large volumes of gas and water. This can be reduced either by (1) using a low-carbon energy source and/or (2) reducing the volumes of the non-hydrocarbon produced/injected fluids. This paper describes how improved oil recovery techniques can be designed to reduce CO2 intensity (kgCO2/bbl oil) of oil production by efficient use of the injectants. It is shown that CO2 emissions associated with injection of chemicals is strongly influenced by water cut at the start of the project, extent of the water cut reduction, and chemical utilization factor defined as the volume of produced oil per mass or volume of the injectant. As an example, for the oil field considered in this study, 3–8% reduction in water cut can result in 50–80% reduction in its CO2 intensity. In addition to the incremental oil production with lower CO2 intensity, the earlier implementation of enhanced oil recovery methods can extend the lifetime of the mature fields if carbon emission cut-offs are applied. In case of CO2 enhanced oil recovery (EOR), the large storage potential for CO2 can significantly reduce the overall CO2 emissions of oil, albeit at a large energetic cost. For CO2 EOR using CO2 captured from gas power plants, improving the utilization factor from 2 bbl/tCO2 to 4 bbl/tCO2 can reduce the CO2 intensity of the produced oil from 120 kgCO2/bbl to 80 kgCO2/bbl (33% reduction).

Tailings dams: Assessing the long-term erosional stability of valley fill designs

Tailings is a generic term for waste material from the extraction and processing of minerals and frequently contain mineral and chemical residues. They are usually highly erodible and transportable via fluvial processes. Tailings are commonly stored in ‘tailings dams’ and such dams are a feature of many mine sites. As they impound water and sediment, tailings dams can be at risk from both catastrophic and gradual failure, especially if unmanaged. A fundamental question for their management is, can tailings dams ever be walk-away structures? Catastrophic failure occurs when there is a large scale rapid structural failure of the dam wall suddenly releasing large volumes of water and sediment. However, over time, there will the increased risk of gradual failure by the slow infilling of the dam and the erosion of the dam wall. Failure can occur where water overtops the dam wall and then incises through the wall due to a loss of freeboard in the dam, a situation which is more likely in legacy tailings dams where they have been filled, vegetated and abandoned. Here, firstly, a computer based landscape evolution model (CAESAR-Lisflood) is employed to assess a hypothetical tailings dam failure by erosion. Secondly, using an idealised example, it is demonstrated that given average climate conditions a dam can be sufficiently robust to last centuries. Thirdly, and longer term it is demonstrated that the tailings can be contained if (a) maintenance is conducted to increase the dam wall height over time or (b) a more robust dam wall is constructed to manage extreme events. However, erosion and infill will continue to reduce the integrity of any structure over time. Therefore, it is highly likely that tailings dams will require continued monitoring and maintenance. The method outlined provides a new tool for assessing any tailings facility for its erosional stability.

Leakage control of urban water supply network and mathematical analysis and location of leakage points based on machine learning

Abstract In order to solve the common problems of high leakage rate of urban water supply network and controlling water supply enterprises, a multi index system of leakage evaluation is proposed. The first step in leakage assessment is to recommend non profitable water volume, rather than just based on the percentage of leakage rate (the calculation mode of percentage is easily disturbed by the change of water volume); Advanced indicators also need to consider factors such as pipe network conditions, pressure and the number of user connections; If possible, it is recommended to calculate the leakage index (ILI) of water supply network in line with international standards, and through this index, determine the leakage classification of water supply system according to the target matrix provided by the world bank, so as to formulate corresponding leakage control countermeasures, and finally form a set of leakage performance evaluation system of urban water supply system combined with the actual situation of our country. Experiments have proved that among users with large caliber and large water volume, the promotion of electromagnetic remote transmission water meter should be strengthened to improve the metering capacity of water meter. Since 2014, non household meters above Dn40 in the company's new household installation project have adopted electromagnetic remote transmission water meters. At the same time, strengthen the remote monitoring and management of large-diameter water meters. Through remote transmission, we can grasp the changes of users' water use in real time, and realize the three-level early warning of sudden change of water volume through the mining of remote transmission data.

Do pesticides degrade in surface water receiving runoff from agricultural catchments? Combining passive samplers (POCIS) and compound-specific isotope analysis

Pesticides lead to surface water pollution and ecotoxicological effects on aquatic biota. Novel strategies are required to evaluate the contribution of degradation to the overall pesticide dissipation in surface waters. Here, we combined polar organic chemical integrative samplers (POCIS) with compound-specific isotope analysis (CSIA) to trace in situ pesticide degradation in artificial ponds and agricultural streams. The application of pesticide CSIA to surface waters is currently restricted due to environmental concentrations in the low μg.L−1 range, requiring processing of large water volumes. A series of laboratory experiments showed that POCIS enables preconcentration and accurate recording of the carbon isotope signatures (δ13C) of common pesticides under simulated surface water conditions and for various scenarios. Commercial and in-house POCIS did not significantly (Δδ13C < 1 %) change the δ13C of pesticides during uptake, extraction, and δ13C measurements of pesticides, independently of the pesticide concentrations (1–10 μg.L−1) or the flow speeds (6 or 14 cm.s−1). However, simulated rainfall events of pesticide runoff affected the δ13C of pesticides in POCIS. In-house POCIS coupled with CSIA of pesticides were also tested under different field conditions, including three flow-through and off-stream ponds and one stream receiving pesticides from agricultural catchments. The POCIS-CSIA method enabled to determine whether degradation of S-metolachlor and dimethomorph mainly occurred in agricultural soil or surface waters. Comparison of δ13C of S-metolachlor in POCIS deployed in a stream with δ13C of S-metolachlor in commercial formulations suggested runoff of fresh S-metolachlor in the midstream sampling site, which was not recorded in grab samples. Altogether, our study highlights that the POCIS-CSIA approach represents a unique opportunity to evaluate the contribution of degradation to the overall dissipation of pesticides in surface waters.

Evolution of ice sheets on early Mars with subglacial river systems

Geological observations have revealed that early Martian terrains were carved with by numerous networks of valleys, which provides evidence that prolonged water activity sculpted the ancient surface of Mars during the late Noachian and the early Hesperian ages. Although such geological records would in theory require a large volume of liquid water under a long-term stable “warm and wet” climate, several model studies have indicated a contrasting “cold and icy” climate in early Mars, such that the formation of large-scale ice sheets on highlands would provide a vast reservoir of meltwater. In this study, we developed a global ice sheet model, named ALICE (Accumulation and ablation of Large-scale ICE-sheets with dynamics and thermodynamics) to perform the first simulation of the evolution of ice sheets coupled with a paleo-Mars global climate model. We began our calculations of glacial formation from the initial state with the ocean water amount corresponding to a 500 m global equivalent layer (GEL) for “cool and wet” atmospheric conditions with a surface pressure of 2 bar, H2 mixing ratios of 0% and 3%, and obliquities of 20°, 40°, and 60°.Our results show that all the water of the ocean and lakes were transferred to ice sheets within ~105 Mars years, and extensive ice sheets (thousands of meters in thickness) were formed in the southern low to middle latitudes. When geothermal heat flux was suitably high and the atmosphere contained 3% of H2, continuous subglacial melting supplied enough water due to widespread temperate-based ice sheets, forming runoff systems in the southern highlands where most valley networks are observed. With an obliquity of 40°, meltwater carved early Martian terrains within a relatively brief geological timescale (~105 Mars years). We also revealed that CO2 only atmosphere (H2 mixing ratio of 0%) could not reproduce temperate-based ice sheets and subglacial erosions even with assumed higher geothermal heat fluxes. There is still a possibility that several valleys were produced by short-lived climatic warming events, such as volcanism and meteorite impacts, which could produce the vast amount of meltwater required to sculpt valley systems.

Generation of Intense Pulsed Electric Fields in a Large Volume of Water Verified Using Kerr Effect Diagnostics

A pulsed power system for generating intense pulsed electric fields (PEFs) in a very large volume of water was designed, manufactured, and tested as a first step toward the proof-of-principle demonstration of a novel noninvasive prepacked food processing operation. The MV-class system described in this article is based on the Tesla transformer technology and is capable of producing PEFs of 100 kV/cm in water, in a volume approaching 1 L. The electric field distribution in the processing water tank was obtained using an electrostatic solver, benchmarked using a Kerr effect arrangement. This article presents the most important experimental data, followed by a detailed electric field analysis and suggestions for the way ahead.

Substantial Biogeochemical and Biomolecular Processing of Dissolved Organic Matter in an Anticyclonic Eddy in the Northern South China Sea Down to Bathypelagic Depths

Solid-phase extracted dissolved organic matter (SPE-DOM) was isolated from two depth profiles at the core and at the edge of an anticyclonic eddy (ACE) in the northern South China Sea. Non-target nuclear magnetic resonance (NMR) spectroscopy and Fourier transform ion cyclotron mass spectrometry (FTICR/MS) of SPE-DOM revealed a higher uniformity of DOM molecules within the ACE than at the edge of the ACE. Small-scale upwelling of external nutrients may have contributed to higher productivity and production of fresher DOM, with higher proportions of CHNO and CHNOS compounds and low molecular weight species at the edge of the eddy. Common SPE-DOM molecules of supposedly biological origin such as carbohydrates and olefins were most abundant in the chlorophyll maximum layer in both stations. An unusual suite of ~10 abundant and ~35 less abundant tert-butyl benzene derivatives with potential to act as endocrine disruptors within a marine food chain and ~two dozen ketones of putative bacterial origin was recognized at meso- and bathypelagic depths in single-digit micromolar concentrations, with a distinct maximum at 1000 m depth at the edge of ACE. Downwelling might bring temporary large volumes of productive marine waters into deep waters, with micromolar concentration of abundant, microbial food web-specific metabolites (e.g. 2,4-di-tert-butylphenol et al.). In our study, these eventually added up to one quarter of common background biogeochemical marine organic matter even at bathypelagic depths and beneath and are significant food and energy sources for marine biota. Mesoscale chemical heterogeneity of marine water columns might extend to larger depths than currently anticipated and may create activity hotspots influencing biota, processing of DOM, and cycling of nutrients and trace elements.