Properties Of Water Research Articles

Towards Portable Kits for On-Site Colorimetric Detection of Aqueous Hydrazine Using Piperidine-Thiophene-Barbituric Acid Push-Pull Probe.

Owing to the carcinogenicity and environmental risks as well as the wide industrial use of hydrazine, we report herein a colorimetric probe for its ratiometric detection in pure water. The developed probe possesses push-pull architecture with 2-(piperidyn-1-yl) thiophene as the donor, N,N'-dibutylbarbituric as the acceptor, and butadiene as the spacer. In contrast to weak solvatochromic behavior in organic solvents, the probe showed distinct optical photophysical properties in water resulting from the formation of nanoscopic aggregates. The probe underwent pronounced spectral changes upon the addition of hydrazine including an 11.5-fold decrease in absorbance and ~2.4-fold fluorescence quenching. The mechanistic investigation revealed the rapid formation of hydrazone upon the interaction of the probe with hydrazine via retro-Knoevenagel reaction as confirmed experimentally and corroborated with DFT calculations. The induced colorimetric and fluorometric changes were utilized in hydrazine sensing with excellent selectivity over other biologically relevant analytes with a detection limit of 0.76 μM in aqueous media. The practical utility of the probe was assessed in real-life natural water samples, while we have also developed a cost-effective portable kit for the on-site hydrazine detection both in the solution and vapor phases.

The Evolution of Underwater Microelectronic Encapsulation: An Universal Marine Wearable Hydrogel

AbstractLong‐term access to undersea information is of critical importance for undersea sensing. However, the paramount challenge in marine wearable technology lies in achieving durable and stable adhesion, coupled with biocompatibility, for devices submerged in the saline conditions of the ocean. Here, a self‐healing, seawater‐resistant hydrogel is reported that exhibits robust adhesion to diverse biotic and abiotic surfaces. Remarkably, the presented hydrogel is augmented with octopus sucker‐inspired microstructures, a feature that markedly improves its capability of organism adhesion underwater. The hydrogel exhibits robust mechanical properties in water, with over 20‐fold elongation in a fully swollen state, and a mechanical healing efficiency exceeding 90% after healing for 30 min. The hydrogel is applied toward several representative undersea scenes. Specifically, the hydrogels equipped with flexible pressure sensors are reliably affixed to fish and turtles for sensing hydraulic pressure for more than 20 days, while the hydrogels featuring a compact camera are mounted on corals and crabs for constant monitoring of surroundings. Furthermore, the hydrogel is molded into a mesh structure for integrating multiple sensors, functioning as multi‐node marine wearable platforms. The underwater hydrogel, with its broad applicability, introduces an approach to real‐time undersea monitoring and non‐invasive marine life internet construction.

Mesoscale dynamics and its interaction with coastal upwelling in the northern Gulf of Guinea

Mesoscale dynamics is essential to understanding the physical and biological processes of the coastal ocean regions due to its ability to modulate water properties. However, on the shelf, interactions between eddies, coastal currents, and topography involve complex processes whose observation, understanding, and accurate simulation still pose a major challenge. The purpose of our work is to quantify the mesoscale eddies in the northern Gulf of Guinea, off West Africa (10°W–10°E, 2°N–7°N), and their dynamical interaction with the near-surface ocean particularly in the coastal upwelling that occurs in summer between 2°W and 2°E. We used a regional NEMO model simulation at 1/36° resolution over the 2007–2017 period with daily outputs. A total of 38 cyclonic and 35 anticyclonic eddy trajectories were detected over the 2007–2017 period in July–August–September (JAS), with a mean radius along their trajectories of 95 km and 125 km, respectively. The mean lifetime for cyclones and anticyclones is approximately 1 month with an associated sea-level amplitude between 1 and 2 cm. We then focused on the JAS upwelling period of the year 2016 and found a 73 km radius cyclonic eddy east of Cape Three Points (Ghana) with a lifetime of 1 month which interacted with the coastal upwelling. Indeed, the quasi-stationary eddy dwelled within the coastal upwelling region from mid-July to mid-August 2016. A Lagrangian study shows that the eddy waters come from the coastal upwelling, then mix with warmer offshore waters, and later are transported eastward by the Guinea Current. Using a heat budget analysis, we show that this eddy–coastal upwelling interaction has an impact on sea surface temperature (SST) with a double effect: i) the eddy expands offshore the cold and salty waters (23°C and 35.6) of the coastal upwelling from 14 to 26 July; and ii) from 27 July until its dissipation, the eddy weakens this upwelling by an easterly inflow of warm offshore waters. This study highlights how the eddy–upwelling interaction can modulate the coastal upwelling in the northern Gulf of Guinea.

Research on Wildfire and Soil Water: A Bibliometric Analysis from 1990 to 2023

In the context of climate change, wildfires occur more frequently and significantly impact the vegetation–soil–water continuum. Soil water is a critical factor for understanding wildfire occurrence and predicting wildfire hazards. However, there is a lack of specific bibliometric analysis of the research on the mechanisms by which soil water influences wildfire occurrence. Therefore, this study conducted a bibliometric analysis of wildfire and soil water, aiming to understand their relationship, research characteristics, and future development trends. We used the Bibliometrix software package in R 4.4.0, which provides different methods for analyzing bibliometric data. A total of 1585 publications were analyzed from 1990 to 2023. The results of the study showed that the number of publications showed an overall growth trend during the period, with an average annual increase rate of 4.4%. The average annual citations per paper exhibited a pattern of rapid increase, followed by slow growth, and then rapid decrease. Ten highly productive authors in the field contributed 12.2% of the total publications during this period. Over the past 30 years, the University of Aveiro has consistently ranked first in terms of paper quantity. Most of the top ten productive institutions are in the United States, Australia, and several European countries. Fifty-eight countries engage in research related to wildfires and soil water, with close collaboration observed between the United States, Canada, and Spain. The four most frequently used keywords are “wildfire”, “fire”, “water repellency”, and “runoff” (with a total frequency of 1385). Water properties relevant to soil characteristics in the word cloud primarily include hydrophobicity, runoff, erosion, and infiltration. Erosion, wildfires, and runoff are crucial in the field but have yet to receive substantial development. The correlation of post-wildfire soil water properties with infiltration, runoff, and erosion processes is most likely to be addressed in future research. The findings will help researchers assess the post-wildfire disaster chain and its impact on the ecological environment, with clear trends, gaps, and research directions in the areas.

Tuning Water at the Solid–Liquid Interface for Durable Electrocatalysis

The solid–liquid interface is one of the oldest and most fundamental concepts in electrochemistry. However, the interface consists of various elements — such as electrode, solvent, cation, anion, reactant, product, etc. — and its microscopic structure remains elusive and a great challenge. Here, we show that the ionomer can selectively control the water properties at the electrode-electrolyte interface, which directly or indirectly affects electrocatalytic performance. Advanced online spectroscopic studies revealed that the change in water properties due to introduction of the ionomer layer led to superior stability of the carbon-supported catalyst with alleviated carbon corrosion. Overall, in this work, we elucidate that interfacial water is one of the key factors for electrocatalytic performance and consider the introduction of an ionomer layer as an appropriate methodology to selectively control it at the solid-liquid interface.

(Invited) Organic Molecule and Polymer Nanoparticles in Biohybrid Photocatalysis

Organic molecule and polymer nanoparticles have found extensive application in photocatalysis for solar fuel production, owing to their excellent dispersion in water and customizable optical properties [1]. These nanoparticles, characterized by their small size and modifiable surface charge through different surfactants, present a unique opportunity for integration with bio-systems. While organic nanoparticles have been traditionally employed as fluorescent probes and phototherapy reagents [2], their exploration within bio-systems for solar fuel production remains underexplored. In our recent research, we present innovative approaches utilizing organic particle-based bio-hybrid systems for solar fuel production.In one study, we successfully integrated polymer particles (Pdots) with FeFe hydrogenase, as evidenced by Cryo-EM and electrophoresis revealing a visually detectable interaction between Pdots and hydrogenase [3]. The Pdots-hydrogenase system demonstrated remarkable performance in light-driven hydrogen production.In another investigation, we immobilized Pdots onto the membrane of Ralstonia eutropha H16 (RH16) bacteria and employed natural redox shuttle, utilizing natural red as a mediator between Pdots and RH16 bacteria to facilitate the transport of protons and electrons [4]. The resulting Pdots-RH16 bio-hybrid system exhibited a threefold increase in the yield of poly(3-hydroxybutyric acid) compared to the original RH16.Furthermore, I will provide insights into the progress of our work within the EU Photo2Fuel project, specifically focusing on the development of biohybrid systems for CO2 fixation.

Photoelectrochemical Properties of Water Splitting Reactions Using NiO/InGaN Photoanodes with Different InGaN Thicknesses and Characteristics in Gas-Phase CO2 Reduction Reactions

To improve the durability of water splitting reaction, we have developed a NiO/AlGaN photoanode in which highly crystalline AlGaN grown on a GaN substrate is covered with a protective layer of NiO [1]. InGaN, a mixed crystal of GaN and InN, has a narrower band gap than AlGaN or GaN, and it has been reported that InGaN photoanodes have higher solar-to-hydrogen conversion efficiencies compared with ones made from those materials [2]. To improve their efficiency further, it is necessary to increase the photocurrent by increasing the thickness of InGaN with the aim of maximally absorbing the light transmitted into it. However, increasing the thickness may increase dislocations that occur when growing the InGaN layer. In this study, to investigate the effect of the thickness of the InGaN layer on photoelectrochemical properties, we measured the photocurrent in a water splitting reaction using NiO/InGaN photoanodes with different InGaN thicknesses. In addition, we measured the CO2 reduction products after 350 h of continuous light irradiation using the best-performing photoanode (NiO/InGaN on GaN substance) in gas-phase CO2 reduction reaction system. In0.02Ga0.98N (thickness: 100, 200, 300, 400, 500, 600, and 700 nm)/n-GaN heterostructures were grown by metal organic chemical vapor deposition on a sapphire substrate. The InGaN layer had a composition gradient in which the In composition increased from the InGaN/n-GaN interface toward the InGaN surface [2]. The thickness of In0.02Ga0.98N was evaluated by secondary ion mass spectroscopy. The light transmittance was measured with a spectrophotometer, and the arithmetic average roughness (R a) of the In0.02Ga0.98N surface was evaluated with atomic force microscopy. Ni thin film was fabricated on the In0.02Ga0.98N surface by vacuum evaporation. The sample was then heat-treated at 563 K for 60 min in air to form the NiO layer [1]. NiO/In0.02Ga0.98N/n-GaN as the photoanode and Pt wire as the cathode were immersed in 1 mol/L NaOH and the water splitting reaction proceeded. The photocurrent was measured with a potentio-galvanostat under application of 1.7 V and irradiation with a Xe lamp adjusted to the same intensity as AM1.5G (λ ≤ 374 nm). Next, to quantify the CO2 reduction products, NiO/In0.02Ga0.98N (thickness: 500 nm)/n-GaN on GaN substrate was prepared as the photoanode. Thermocompression was used to prepare a composite sheet using gold fiber as a cathode and NafionTM as an electrolyte membrane [3]. The sheet was set so as to separate the oxidation and reduction chambers. 0.5 mol/L CsOH was used in the oxidation chamber and CO2 was directly supplied at 45 sccm to the cathode in the reduction chamber. The photocurrent was measured under similar conditions as the water splitting reaction. The produced gas was determined every 10 h with gas chromatography, and the produced liquid after 350 h was determined with high-performance liquid chromatography. The photocurrent density measured 1 min after the light irradiation ceased increased with thickness from 100 to 500 nm, while it decreased for thicknesses more than 500 nm. The maximum photocurrent density was 0.81 mA/cm2. It was considered that the light absorption ability of the In0.02Ga0.98N layer increased with its thickness. Moreover, since R a increased, it was thought that the crystallinity of the In0.02Ga0.98N decreased as its thickness increased. These results indicate that increasing the In0.02Ga0.98N thickness increases the number of generated electron-hole pairs because of the increased light absorption. On the other hand, these also indicate that the decrease in crystallinity increases the recombination probability of electron-hole pairs. Here, it was assumed that the photocurrent density reached its maximum when the thickness was 500 nm. The results of measuring the CO2 reduction products using the NiO/In0.02Ga0.98N (thickness: 500 nm)/n-GaN on the GaN substrate photoanode and the composite sheet are shown in Fig. 1. CO and HCOOH were detected, with the cumulative amounts of product per photoanode area being 3237 and 263 µmol/cm2, respectively, after 350 h. The average Faradaic efficiencies of CO and HCOOH during 350 h were 83 and 6%, respectively. The cumulative amount of O2 was 1865 µmol/cm2, and the average Faradaic efficiency during 350 h was 96%. Therefore, the NiO/In0.02Ga0.98N (thickness: 500 nm)/n-GaN on GaN substrate was found to be an effective photoanode for a gas-phase CO2 reduction reaction system with high efficiency and durability.[1] Y. Uzumaki et al., PRiME 2020, L04-3054 (2020).[2] K. Ohkawa, ECS Transactions 66 (1), 135-138 (2015).[3] S. Sato et al., 2023 ECSJ Fall Meeting, S2-1-09 (2023) (in Japanese).Fig. 1. Amount of CO, HCOOH, H2, and O2 measured using NiO/In0.02Ga0.98N (thickness: 500 nm)/n-GaN on GaN substrate photoanode versus irradiation time. Figure 1

Numerical simulation of pendant droplet behavior on plain and patterned surfaces using Surface Evolver: Applications to condensation heat transfer

In this work, pendant water droplet behavior on a plain surface was simulated using the Surface Evolver (SE) finite element program to study the three-dimensional shape of the droplet on the surface. The critical droplet volume (CDV) before detachment from the surface was measured and compared against experimental data for different plain surfaces. These computational predictions were shown to agree well with experimental data. Next, patterned surfaces were studied which consisted of a central wetting region 2 mm to 5 mm wide sandwiched between two outer non-wetting superhydrophobic stripes. These superhydrophobic stripes served as “bumpers” to confine the droplet to the wetting region during its simulated growth. For these simulations, the primary inputs to the program were the droplet volume V, stripe width w, and surface static contact angle θ which was varied from 30° to 150°. Water droplet contact angle measurements on the plain surfaces used for initial benchmarking were also reported which included polished aluminum, mill finish aluminum, glass, plastic (acrylic), stainless steel, and copper. The idea of this study was to see if the superhydrophobic borders could be used to effectively “pinch off” a droplet in the wetting region, thereby reducing the critical droplet volume needed for detachment and drainage. The motivation for this work was condensation heat transfer which is common to many HVAC&R applications. In these systems, increasing the droplet shedding frequency is often associated with increased heat transfer and improved system efficiency.Therefore, the baseline surface adopted in this study was aluminum with and without the use of superhydrophobic stripes. For these simulations, properties of water at 20 °C were used, and the droplet volume was gradually increased until the critical condition was reached and detachment was detected. Typically, more than 1000 iterations were performed before the droplet geometry converged and was ready for measurement. Grid refinement was also performed to make sure that the results were grid independent. According to Surface Evolver, the lowest predicted critical droplet volume on the plain surfaces was <5 μL for θ1 = 150°, whereas the highest CDV was >295 μL for θ1 = 30°. For θ1 = 90° which is typical of aluminum, the CDV on the plain surface was 74 μL for the fine mesh and 83 μL for the rough mesh. When a 3-mm wide θ1 = 90° wetting region was used, however, bordered by two superhydrophobic stripes with θ2 = 150°, this CDV was reduced to 71 μL for the rough mesh, and when a 2-mm wide wetting region was used, the CDV was reduced even further to 55 μL. This shows both the promise of the idea and the possibility of using a striped / patterned tube to reduce the critical droplet volume needed for droplet shedding in a condensation environment.

Molecular Hydrophobicity Signature in Charged Bidimensional Clay Materials.

The unraveling of the hydrophobicity/hydrophilicity molecular signature of nanometric bidimensional confined systems represents a challenging task with repercussions in environmental transport processes. Swelling clay minerals represent an ideal model system, as hydrophobicity can be modified during material synthesis by substituting hydroxyls by fluorine in the structure, without additional surface treatment. This following work presents a combined approach, integrating experimental inelastic neutron scattering spectroscopy and ab initio molecular dynamics simulations, with the objective of advancing our understanding of the role of surface hydroxylation/fluorination and the extent of confinement on water properties. From computed structures, the analysis of molecular hydrophobicity/hydrophilicity signature was investigated in detail through water-cation-surface interactions. The results elucidate the influence of fluorination on interlayer species, thereby tracing the impact of the surface on the diminished number of water molecules in such a sample. It is notable that the strong cation-water interaction can overcome the disruptive influence of fluorine, thereby maintaining comparable water hydration shells around cations and resulting in an almost identical bidimensional confinement geometry for both hydroxylated and fluorinated specimens. The analysis of the hydrogen-bond network revealed a significant reorganization of the water molecules due to fluorination. Our results suggest that a quantitative molecular signature of hydrophobicity/hydrophilicity can be derived from the analysis of the formation of cavities in the confined fluid. This new finding represents a robust approach for generalizing the hydrophobicity/hydrophilicity character for a wide variety of bidimensional systems while proposing a framework for the design of new materials with controlled water properties.

The Dynamic Diversity and Invariance of Ab Initio Water.

Comprehending water dynamics is crucial in various fields, such as water desalination, ion separation, electrocatalysis, and biochemical processes. While ab initio molecular dynamics (AIMD) accurately portray water's structure, computing its dynamic properties over nanosecond time scales proves cost-prohibitive. This study employs machine learning potentials (MLPs) to accurately determine the dynamic properties of liquid water with ab initio accuracy. Our findings reveal diversity in the calculated diffusion coefficient (D) and viscosity of water (η) across different methodologies. Specifically, while the GGA, meta-GGA, and hybrid functional methods struggle to predict dynamic properties under ambient conditions, methods on the higher level of Jacob's ladder of DFT approximation perform significantly better. Intriguingly, we discovered that both D and η adhere to the established Stokes-Einstein (SE) relation for all of the ab initio water. The diversity observed across different methods can be attributed to distinct structural entropy, affirming the applicability of excess entropy scaling relations across all functionals. The correlation between D and η provides valuable insights for identifying the ideal temperature to accurately replicate the dynamic properties of liquid water. Furthermore, our findings can validate the rationale behind employing artificially high temperatures in the simulation of water via AIMD. These outcomes not only pave the path to designing better functionals for water but also underscore the significance of water's many-body characteristics.

Water motifs in zirconium metal-organic frameworks induced by nanoconfinement and hydrophilic adsorption sites

The intricate hydrogen-bonded network of water gives rise to various structures with anomalous properties at different thermodynamic conditions. Nanoconfinement can further modify the water structure and properties, and induce specific water motifs, which are instrumental for technological applications such as atmospheric water harvesting. However, so far, a causal relationship between nanoconfinement and the presence of specific hydrophilic adsorption sites is lacking, hampering the further design of nanostructured materials for water templating. Therefore, this work investigates the organisation of water in zirconium-based metal-organic frameworks (MOFs) with varying topologies, pore sizes, and chemical composition, to extract design rules to shape water. The highly tuneable pores and hydrophilicity of MOFs makes them ideally suited for this purpose. We find that small nanopores favour orderly water clusters that nucleate at hydrophilic adsorption sites. Favourably positioning the secondary adsorption sites, hydrogen-bonded to the primary adsorption sites, allows larger clusters to form at moderate adsorption conditions. To disentangle the importance of nanoconfinement and hydrophilic nucleation sites in this process, we introduce an analytical model with precise control of the adsorption sites. This sheds a new light on design parameters to induce specific water clusters and hydrogen-bonded networks, thus rationalising the application space of water in nanoconfinement.

Geological substantiation of studies on hydrogeochemical analysis and utilisation of associated waters in fields under long-term development (On the example of Karachukhurskoe field)

The presented article is devoted to the solution of the problem of cleaning of mining territories, sea from oil and oil products pollution. Treatment of produced water is one of the most important tasks facing the oil and gas industry. Formation water is a complex mixture of minerals and organic compounds that, if not treated properly, can cause serious damage to the environment. The problem of discharging this water to the Earth’s surface is relevant for all oil and gas production facilities, as the aggressive properties of formation water can lead to corrosion of industrial equipment, significant pollution of natural water bodies and topsoil. The results of the studies show that the oil-water emulsion formed by mixing well water at the Karachukhur field with liquid in the sumps forms large-sized masses in the sumps. This also makes it difficult to collect, transport well product and separate formation water from oil, treat and dispose of it. The use of mathematical techniques such as cluster analysis and hierarchical classification can be seen as a tool to optimise the operation and disposal process. To improve the efficiency and economic viability of operations, it is important to use modern methods to analyse and optimise well production and disposal processes. Such studies can help to create a more sustainable and environmentally friendly oil industry in the future. It is advisable to conduct similar studies on other fields in Azerbaijan that are under long-term development.

Changes in microbial communities across the whole A2/O wastewater treatment process and their drivers—Reduced community diversity but increased proportion of certain pathogens

Microorganisms play a crucial role in pollutant removal and water quality stabilizing. However, limited research exists on the microbial variability and the factors driving it at different stages of wastewater treatment. In this study, the physicochemical properties of water and the composition of bacterial communities were thoroughly investigated across the entire A2/O wastewater treatment process, encompassing 3 stages (12 steps). The results revealed a significant reduction in alpha diversity, whereas the beta diversity remained largely unchanged across stages. Alpha diversity was primarily influenced by dissolved oxygen (DO) and pH, with DO having the most notable influence, while beta diversity was mainly constrained by nutrient conditions such as COD, BOD5, NH4-N, TN, and TP. Additionally, analyses of relative abundance, LEfSe, variance, and functional prediction indicated a significant increase in the relative abundance of certain pathogenic bacteria (e.g., Legionella, Leptospira), exhibiting different removal characteristics compared to Escherichia coli across various treatment steps. Even after UV disinfection, these pathogens persist, highlighting a potential pathogenic risk, which deserves more attention. In addition, this study helps explore the relatively under-researched area of microbial variability at different stages (steps) of wastewater treatment, especially in terms of how microbial communities respond to operational processes and environmental conditions. This will offer valuable guidance for addressing water treatment safety challenges encountered in real-world processes.

Effect of Super Retarder on Recycled Water and Concrete Properties of Waste Slurry in Mixing Plant

A large amount of waste slurry water will be generated in the production process of concrete mixing plant, due to the complex composition of waste slurry water, if it is not handled in time when stored, serious coagulation will occur, which will accelerate the loss of equipment and reduce the utilization rate. In this paper, a super retarder suitable for waste slurry recycled water from concrete mixing plant was prepared using composite technology. The waste slurry recycled water mixed with super retarding agent was characterized by using microscopic testing means XRD, TG and DTG. The waste slurry recycled water mixed with super retarding agent was used to replace tap water in the production of concrete, and its effect on the workability and mechanical properties of concrete was investigated. It was found that the compounding of Butane 2-phospho-1,2,4-tricarboxylic acid (PBTCA) with Reclaimed water treatment agent (ACS) resulted in a setting time of 64 h for 10% concentration of recycled water, with optimal retarding effect. When PBTCA:ACS was 1:20, mixed at 1.5% of the mass of recycled water, the 1 h slump of concrete had no loss, the loss of extension was 15 mm, the 7 days compressive strength was increased by 3.5 MPa, and the 28 days compressive strength was increased by 3.0 MPa. The microscopic results showed that the use of ACS and PBTCA does not affect the type of cement hydration products, but only affects the the rate of hydration product generation.

Numerical Investigation of Increasing-Decreasing Stepped Micro Pin Fin Heat Sink Having Various Arrangements

The ongoing trend of miniaturization of electronic devices, including computer processors, high-speed servers and micro-electro-mechanical system devices, should go hand in hand with their improved performance. However, managing heat remains a major challenge for these devices. In the present study, a numerical investigation was done on a micro-channel heat sink with an open-stepped micro-pin fin heat sink with various arrangements through ANSYS software. Pin fin was varied in a fashion of increasing and decreasing. The working fluid opted for was water in a single phase. The analysis takes into account varying thermo-physical properties of water. The operating parameters, i.e. the Reynolds number was taken as 100–350 and heat flux as 500 kW/m2. Arrangements selected were staggered and inline. Observations revealed that the staggered 2 arrangement has shown better thermal performance than other arrangements within the entire investigated range of Reynolds numbers because of the effective mixing of fluids. Furthermore, the inline configuration of micro pin fin heat sink has the worst performance. It is interesting to note that a very small difference was observed in the heat transfer capability of both staggered configurations, while the pressure drop in the staggered 2 arrangement has shown an elevated value at a higher Reynold number value compared to the staggered 1 arrangement.

Study of Hydrogeochemical Properties of Surface Water (Case Study: Comparison of Two Adjacent Catchments, Cheshmeh Kileh and Shiroud, Northern Iran)

Study of Hydrogeochemical Properties of Surface Water (Case Study: Comparison of Two Adjacent Catchments, Cheshmeh Kileh and Shiroud, Northern Iran)

The Potential of Micro-Dictum Preparation in Surface Water Reclamation Subject to Strong Anthropogenic Pressure

The aim of this research was to analyze the potential of e micro-dictum preparation containing compositions of beneficial microorganisms using this product in surface water reclamation. The experiments were carried out in 2016. The scope of this research included the analysis of the physical and chemical properties of a solid preparation; tests of the microbiological parameters of micro-dictum; an analysis of the spread of microorganisms in the aquatic environment; a study of water quality with the solid preparation; and tests of the formulation in real conditions and its potential in the reclamation of surface waters. Tests on the produced formulation were carried out in the laboratory in containers and under real conditions. Laboratory tests have shown that the analyzed preparation may introduce certain amounts of nitrogen and phosphorus into the water. However, they are not important in the case of water reclamation. Analyses of the micro-dictum preparation showed that the content of lactic acid bacteria in the center of the ball is lower compared to the outer layers. The results describing an increase in the number of lactic acid bacteria correlate with a decrease in pH and oxygen dissolved in the water with the preparation. The tests showed no negative impact on changes in the physical and chemical properties of water at the site of application. Changes in physical parameters were recorded, in particular dissolved oxygen and pH at the bottom, where the greatest microbiological activity occurred.

Improving the thermal properties of water by adding MWCNTs, cerium oxide, and MgO hybrid nanoparticles at different temperatures and volume fraction of nanoparticles: Experimental investigation

This study aimed to investigate the thermal conductivity (TC) of various nanofluid compositions, including water/MWCNT-MgO-cerium oxide ternary hybrid nanofluids (THNFs) with solid volume fractions (SVFs) ranging from 0.1 % to 0.6 %. Additionally, the thermal conductivity of water/MWCNT-cerium oxide, water/MWCNT-MgO, and water/MgO-cerium oxide hybrid nanofluids (HNFs), as well as water/MWCNT, water/cerium oxide, and water/MgO mono nanofluids (MNFs), was measured at SVF=0.1 % and 0.3 %. The experimental temperature was varied between 20, 30, 40, and 50 °C for all samples. The MWCNT, MgO, and cerium oxide nanoparticles (NPs) were suspended in the water base fluid (BF) to create the nanofluids (NFs) in a two-step process. MWCNT NPs are 20–30 nm in size, MgO NPs are 20 nm, and cerium oxide NPs are 10–30 nm in size. DLS and zeta potential experiments, which demonstrate the correct stability of NFs, were used to evaluate the stability of NFs. The KD2-Pro instrument was used to test the samples' TC after making sure they were stable. The data obtained demonstrate a rise in TC with rising SVF and rising temperature. The MWCNT/water MNF exhibits the largest rise in TC in SVF=0.3 %, with a TC increase of 19.16 % at T = 40 °C. It should be noted that the largest increase in TC is 26.09 % compared to the BF for water/MWCNT-MgO-cerium oxide THNF at SVF=0.5 % and T = 40 °C. Finally, a mathematical connection was shown with the comparisons done to estimate the data. The results demonstrate the postulated relationship's high degree of accuracy.

CONTRIBUIÇÕES DA FISIOTERAPIA AQUÁTICA: REABILITAÇÃO EM PACIENTES COM LESÃO MEDULAR ESPINHAL TRAUMÁTICA

Aquatic Physical Therapy (APT) has been reported as applicable in various specialties within the physiotherapy field, culminating in rehabilitation procedures, especially after Spinal Cord Injury (SCI), with beneficial results for individuals with this condition. It tends to be more effective in restoring some or all movement, initially with plegia, presenting a decrease and even absence of strength and balance post-trauma in the vertebral column region, leading to spinal cord injury. The aquatic environment provides the patient with a bombardment of sensory-motor stimuli, further activating neuroplasticity in rehabilitation, as well as reducing pain, providing relaxation of all muscles, and increasing blood supply to the muscles. In addition to being a therapy in a safe environment, an important factor is the reduction of joint impact and improvement in venous return, making it possible to recover movements. Objective: To understand the contributions of aquatic physiotherapy in functional rehabilitation in (SCI). Methodology: Based on bibliographic research, using the electronic databases Bireme, PubMed, and Scielo, with articles published from 2000 onwards. Conclusion: Aquatic physiotherapy and its benefits in health recovery, achieved through the physical properties of water, have been studied since the time of Hippocrates, which, combined with physiotherapy treatment protocols, promote better functional rehabilitation for patients with (SCI).

Enabling the photochromism of 4′-aminoflavylium compounds in water by host-guest interaction with β-cyclodextrin

Aminoflavylium compounds are known to display poor photochemical properties in water precluding their application in aqueous medium. In this work, we show that the host-guest encapsulation with β-cyclodextrin (β-CD) significantly improves the photochemical performance of 4′-aminoflavylium enabling their operation in aqueous solution. The pH-dependent thermodynamics and kinetics of two aminoflavylium compounds 4’-(N,N-dimethylamino)-7-hydroxylflavylium (4′NMe27OH) and 4’-(N,N-diethylamino)-7-hydroxylflavylium (4′NEt27OH) were studied in water in the absence and presence of β-CD. The association constants follow the order trans-chalcone > quinoidal base > flavylium cation, resulting in β-CD lowering both pKa and pK'a. All species in the 4′NEt27OH multistate system interact more strongly than those in 4′NMe27OH. The pH-dependent kinetics toward the equilibrium follows a bell-shaped curve at moderately acidic pH and increases in the presence of β-CD in both compounds. At highly acidic pH, protonation of trans-chalcone accelerates the kinetics, particularly for 4′NEt27OH due to the easier protonation of the trans-chalcone. In the presence of β-CD this effect is reduced, because protonation of trans-chalcone becomes more difficult.Upon irradiation of trans-chalcone in both compounds in the presence of β-CD, the pale yellow trans-chalcones convert into a purple, less-bound mixture of the flavylium cation and quinoidal base, with a quantum yield of ∼0.01.