Electrical Conductivity Measurements Research Articles

Salinity Measurement with a Plasmonic Sensor Based on Doubly Deposited Tapered Optical Fibers

Salinity is a very important parameter from an environmental perspective, and therefore, efficient and accurate systems are required for marine environmental monitoring and productive industries. A plasmonic sensor based on doubly deposited tapered optical fibers (DLUWTs—double-layer uniform-waist tapers) for the measurement of salinity is presented. The physical principle of the sensor, as well as its structure, is discussed, and its performance is experimentally demonstrated, obtaining very good sensitivities. The possibility of shifting towards higher wavelength measuring ranges associated with DLUWTs is also exploited. At the same time, we have considered the necessity of an extensive characterization of the behavior of the refractive index of salty water, both with variations in temperature and the composition of the salts dissolved. This is important due to the somehow changing reality of salinity measurements and the possibility of establishing new approaches for the determination of absolute salinity as opposed to practical salinity based on electrical conductivity measurements. The results obtained, which show high sensitivity and a good performance in general without the need for the use of semi-empirical algorithms, permit, in our opinion, an advance in the tendency towards refractometric determination of salinity with optical sensors apt for in situ, real-time, accurate measurements in realistic measuring conditions.

Forecasting Oligochaeta Abundance using the Apparent Electrical Conductivity of Irrigated Soils with Reclaimed Wastewater: Evidence from Corso, Algeria

Background: The main objective of this paper is to study the possibility of using the measurement of apparent electrical conductivity (ECa) to estimate Oligochaeta (earthworm) density in irrigated soils treated with reclaimed wastewater. Additionally, the study sought to analyze the impact of using reclaimed wastewater for irrigation on earthworm density in the study area. Methods: Earthworm sampling was carried out at thirty emplacements within the study area during two measurement campaigns. Soil ECa was measured by (EM38). Result: The results showed that irrigation with reclaimed wastewater promotes the abundance of earthworms (earthworm density). Indeed, sites irrigated with reclaimed wastewater have higher earthworm densities compared to sites irrigated with conventional water. The results also show a strong correlation between ECa and earthworm density (R2 greater than 0.7). The Wilcoxon test indicates a non-significant difference between measured earthworm densities and those predicted by ECa (p greater than 0.5). This result confirms the effectiveness of the EMI technique as a tool to evaluate the spatial variability of soil biological parameters. These results collectively suggest that ECa represents a real possibility of reducing the number of earthworm samplings, whil ensuring the reliability of the estimates of real values of earthworm density and their surface spatial distribution. ECa could therefore be a useful tool to spatialize and predict the presence of earthworms in soil irrigated by reclaimed wastewater.

Tracking microstructural evolution and hardening in Al–Zn–Mg–Cu alloys aged artificially via electrical conductivity measurements

Precipitation hardening, a crucial mechanism for strengthening aluminum alloys, involves stages like Guinier–Preston (GP) zone formation, precipitation, peak aging, and precipitate coarsening. This study focuses on the aluminum 7050 alloy, proposing a method to gauge artificial aging through electrical conductivity measurement. The evolving microstructure and time to peak hardness during aging are vital for creating high-strength alloys. The electrical conductivity variation over time is utilized to analyze the diffusion process governing the clustering and growth of specific phases (η′, η, and S) during artificial aging. The paper demonstrates the impact of GP zones, precipitate formation, and grain growth on electrical conductivity, correlating these factors with hardness, microstructure, and tensile strength to determine the hardening stage. Differential electrical conductivity plots, highlighting aging stages, assist in identifying the hardening phase. Tensile strength and hardness plots differentiate the precipitation phases. The Johnson–Mehl–Avrami–Kolmogorov equation models particle growth kinetics, determining growth rates for AA 7050 alloy. The overall activation energy for precipitate growth is 40.77 kJ/mol, with a growth constant ( m) of ∼4, indicating S phase nucleation during η′ and η growth.

Groundwater salinity modeling and mapping using machine learning approaches: a case study in Sidi Okba region, Algeria.

The groundwater salinization process complexity and the lack of data on its controlling factors are the main challenges for accurate predictions and mapping of aquifer salinity. For this purpose, effective machine learning (ML) methodologies are employed for effective modeling and mapping of groundwater salinity (GWS) in the Mio-Pliocene aquifer in the Sidi Okba region, Algeria, based on limited dataset of electrical conductivity (EC) measurements and readily available digital elevation model (DEM) derivatives. The dataset was randomly split into training (70%) and testing (30%) sets, and three wrapper selection methods, recursive feature elimination (RFE), forward feature selection (FFS), and backward feature selection (BFS) are applied to train the data. The resulting combinations are used as inputs for five ML models, namely random forest (RF), hybrid neuro-fuzzy inference system (HyFIS), K-nearest neighbors (KNN), cubist regression model (CRM), and support vector machine (SVM). The best-performing model is identified and applied to predict and map GWS across the entire study area. It is highlighted that the applied methods yield input variation combinations as critical factors that are often overlocked by many researchers, which substantially impacts the models' accuracy. Among different alternatives the RF model emerged as the most effective for predicting and mapping GWS in the study area, which led to the high performance in both the training (RMSE = 1.016, R = 0.854, and MAE = 0.759) and testing (RMSE = 1.069, R = 0.831, and MAE = 0.921) phases. The generated digital map highlighted the alarming situation regarding excessive GWS levels in the study area, particularly in zones of low elevations and far from the Foum Elgherza dam and Elbiraz wadi. Overall, this study represents a significant advancement over previous approaches, offering enhanced predictive performance for GWS with the minimum number of input variables.

Antioxidant, Antibacterial and Anti-cancer Properties of Bio -fabricated Copper-silver-zinc Nanocomposites: An Ecofriendly Approach

Recent advancements in nanotechnology have led to the development of bio-fabricated copper-silver-zinc nanocomposites, which exhibit multifunctional properties suitable for various applications. This study investigates their antioxidant, antibacterial, anti-cancer, and conductive properties through an eco-friendly synthesis approach. The nanocomposites were synthesized using Allium sativum extracts as reducing agents, ensuring minimal environmental impact and promoting sustainability. Antioxidant activities were evaluated using DPPH and ABTS, FRAP, Phosphomolybdenum and superoxide assays, demonstrating significant scavenging capabilities comparable to standard antioxidants. Antibacterial efficacy was assessed against Gram-negative bacteria, E. coli revealing potent inhibitory effects attributed to the synergistic action of copper, silver, and zinc nanocomposites (Cu-Ag-Zn-NC). Furthermore, the nanocomposites exhibited promising anticancer activity against breast cancer cells MCF-7, highlighting their potential as therapeutic agents. Electrical conductivity measurements confirmed their suitability for use in electronic applications, underscoring their versatility. This study underscores the eco-friendly synthesis of bio-fabricated copper-silver-zinc nanocomposites and their multifaceted properties, positioning them as promising candidates for biomedical, environmental, and technological applications.

Hyposense: An Integrated Sensor Device for Hydroponics Farm Monitoring

In recent years, the monitoring of hydroponics farms has undergone a significant transformation due to the integration of sensors. However, the conventional method of manually observing measurements from multiple sensors has proven to be excessively time-consuming and costly. Additionally, the lack of automatic data recording options in most sensors has been a limiting factor. To address these challenges, we conducted an experimental study to introduce a novel integrated sensor device named “HypoSense”, designed to monitor essential parameters such as temperature, humidity, pH, light intensity, Total Dissolved Solids (TDS), and Electrical Conductivity (EC) in hydroponic systems. HypoSense consists of three microcontroller units (MCUs) incorporated with two controlling circuits based on the Arduino platform: the Arduino UNO, ESP32, and the ESP8266 (NodeMCU) microcontrollers. The device is designed using high-precision sensors, including the DHT11 for temperature and humidity monitoring, an Analog pH sensor kit for pH measurement, BH1750 for light intensity, and an Analog TDS sensor kit for TDS and electrical conductivity measurements. These sensors were chosen for their reliability, accuracy, and compatibility with the Arduino platform, ensuring that HypoSense delivers precise and consistent readings. HypoSense is a cost-effective, portable sensor device specially designed for monitoring growth parameters simultaneously in hydroponic farming, saving growers time and effort. The evaluation was carried out in two phases. Firstly, field sensors were employed to calibrate HypoSense device sensors. Next, a secondary evaluation was conducted to confirm the practicality and user-friendliness of the HypoSense device. To facilitate the evaluation of HypoSense, we set up an indoor hydroponic system for growing tomatoes and lettuce. The results of these evaluations, focusing on the performance and applicability of the HypoSense device, will provide valuable insights for hydroponic growers and future researchers in precision agriculture.

Hyposense: An Integrated Sensor Device for Hydroponics Farm Monitoring

In recent years, the monitoring of hydroponics farms has undergone a significant transformation due to the integration of sensors. However, the conventional method of manually observing measurements from multiple sensors has proven to be excessively time-consuming and costly. Additionally, the lack of automatic data recording options in most sensors has been a limiting factor. To address these challenges, we conducted an experimental study to introduce a novel integrated sensor device named “HypoSense”, designed to monitor essential parameters such as temperature, humidity, pH, light intensity, Total Dissolved Solids (TDS), and Electrical Conductivity (EC) in hydroponic systems. HypoSense consists of three microcontroller units (MCUs) incorporated with two controlling circuits based on the Arduino platform: the Arduino UNO, ESP32, and the ESP8266 (NodeMCU) microcontrollers. The device is designed using high-precision sensors, including the DHT11 for temperature and humidity monitoring, an Analog pH sensor kit for pH measurement, BH1750 for light intensity, and an Analog TDS sensor kit for TDS and electrical conductivity measurements. These sensors were chosen for their reliability, accuracy, and compatibility with the Arduino platform, ensuring that HypoSense delivers precise and consistent readings. HypoSense is a cost-effective, portable sensor device specially designed for monitoring growth parameters simultaneously in hydroponic farming, saving growers time and effort. The evaluation was carried out in two phases. Firstly, field sensors were employed to calibrate HypoSense device sensors. Next, a secondary evaluation was conducted to confirm the practicality and user-friendliness of the HypoSense device. To facilitate the evaluation of HypoSense, we set up an indoor hydroponic system for growing tomatoes and lettuce. The results of these evaluations, focusing on the performance and applicability of the HypoSense device, will provide valuable insights for hydroponic growers and future researchers in precision agriculture.

Anisotropy of Electrical and Thermal Conductivity in High-Density Graphite Foils

Flexible graphite foils with varying thicknesses (S = 282 ± 5 μm, M = 494 ± 7 μm, L = 746 ± 8 μm) and an initial density of 0.70 g/cm3 were obtained using the nitrate method. The specific electrical and thermal conductivity of these foils were investigated. As the density increased from 0.70 g/cm3 to 1.75 g/cm3, the specific electrical conductivity increased from 69 to 192 kS/m and the thermal conductivity increased from 109 to 326 W/(m·K) due to the rolling of graphite foils. The study showed that conductivity and anisotropy depend on the shape, orientation, and contact area of thermally expanded graphite (TEG) mesoparticles (mesostructural factor), and the crystal structure of nanocrystallites (nanostructural factor). A proposed mesostructural model explained these increases, with denser foils showing elongated, narrowed TEG particles and larger contact areas, confirmed by electron microscopy results. For graphite foils 200 and 750 μm thick, increased density led to a larger coherent scattering region, likely due to the rotation of graphite mesoparticles under mechanical action, while thinner foils (<200 μm) with densities > 1.7 g/cm3 showed increased plastic deformation, indicated by a sharp reduction in the coherent scattering region size. This was also evident from the decrease in misorientation angles with increasing density. Rolling reduced nanocrystallite misorientation angles along the rolling direction compared to the transverse direction (TD) (for 1.75 g/cm3 density ΔMA = 1.2° (S), 2.6° (M), and 2.4° (L)), explaining the observed anisotropy in the electrical and mechanical properties of the rolled graphite foils. X-ray analysis confirmed the preferred nanocrystallite orientation and anisotropy coefficients (A) using Kearns parameters, which aligned well with experimental measurements (for L series foils calculated as: A0.70 = 1.05, A1.30 = 1.10, and A1.75 = 1.16). These calculated values corresponded well with the experimental measurements of specific electrical conductivity, where the anisotropy coefficient changed from 1.00 to 1.16 and mechanical properties varied from 0.98 to 1.13.

Anisotropy of Electrical and Thermal Conductivity in High-Density Graphite Foils.

Flexible graphite foils with varying thicknesses (S = 282 ± 5 μm, M = 494 ± 7 μm, L = 746 ± 8 μm) and an initial density of 0.70 g/cm3 were obtained using the nitrate method. The specific electrical and thermal conductivity of these foils were investigated. As the density increased from 0.70 g/cm3 to 1.75 g/cm3, the specific electrical conductivity increased from 69 to 192 kS/m and the thermal conductivity increased from 109 to 326 W/(m·K) due to the rolling of graphite foils. The study showed that conductivity and anisotropy depend on the shape, orientation, and contact area of thermally expanded graphite (TEG) mesoparticles (mesostructural factor), and the crystal structure of nanocrystallites (nanostructural factor). A proposed mesostructural model explained these increases, with denser foils showing elongated, narrowed TEG particles and larger contact areas, confirmed by electron microscopy results. For graphite foils 200 and 750 μm thick, increased density led to a larger coherent scattering region, likely due to the rotation of graphite mesoparticles under mechanical action, while thinner foils (<200 μm) with densities > 1.7 g/cm3 showed increased plastic deformation, indicated by a sharp reduction in the coherent scattering region size. This was also evident from the decrease in misorientation angles with increasing density. Rolling reduced nanocrystallite misorientation angles along the rolling direction compared to the transverse direction (TD) (for 1.75 g/cm3 density ΔMA = 1.2° (S), 2.6° (M), and 2.4° (L)), explaining the observed anisotropy in the electrical and mechanical properties of the rolled graphite foils. X-ray analysis confirmed the preferred nanocrystallite orientation and anisotropy coefficients (A) using Kearns parameters, which aligned well with experimental measurements (for L series foils calculated as: A0.70 = 1.05, A1.30 = 1.10, and A1.75 = 1.16). These calculated values corresponded well with the experimental measurements of specific electrical conductivity, where the anisotropy coefficient changed from 1.00 to 1.16 and mechanical properties varied from 0.98 to 1.13.

Electrochemical polymer synthesis using thiophene and pyrrole/carbazole: Their electrochemical behaviours and capacitor performance

In this study, carbazole-derived monomers were synthesized on ITO-coated PET via electrochemical reactions and conductivity measurements of the resulting polymeric films were performed by UV, FT-IR, NMR, TG-DTG, SEM and AFM analyses. Their spectroelectrochemical properties were investigated. The carbazole (C) based thiophene (Th) polymer abbreviated as pThC and its copolymer with pyrrole (Py), named as pThC-Py were obtained by electrochemical polymerization method. The surface stability of the resulting polymer films was good depending on time. The contact angle (CA) between the water and theco- polymer surface was determined by dropping 6.09 μL of pure water and CA average was calculated as 68.19° < 90°. According to the thermal analysis data of the polymers, the thermal stability of the pThC-Py was better than pThC as it had higher thermal decomposition temperature. Comparisons of electrical conductivity measurements of the polymer films were made depending on the temperature (25, 50 and 90 °C). Due to increasing temperature, the electrical conductivity of pThC-Py film was read as 29.3 S/cm at 90 °C, and also the electrical conductivity values of the pThC-Py were determined as 1.92 × 10−2 S/cm at 25 °C and 14.2 S/cm at 50 °C. Because of the high electrical conductivity of the pThC-Py, its capacitor performance was tried to be determined from cyclic voltammetric measurements. According to the voltammetric results, the power density (P) and the energy density (E) values of the synthesized substance were calculated as 290.532 W/g and 9.684 Wh/g, respectively. This indicates that the amount of energy the material storable is relatively high. Moreover, it is possible to say that it can be included in the classical capacitor class and in the supercapacitor category by improving its features. Moreover, since the electrical conductivity of pThC-Py is quite good, it is thought that it may be suitable for use in electronic devices.

Thermodynamic characteristics and aggregation behavior of surface active ionic liquids in presence of vitamin B7 (biotin)

Abstract This study investigated the influence of vitamin B7 (biotin) at different concentrations (0.1, 0.3 and 0.5) mM on the micellisation behaviour of three different ionic liquids with different cationic headgroups, namely N-methylmorpholinium bromide [Mor1,12][Br], N-dodecyl-N-methylpyrrolidinium bromide [Pyrr1,12][Br], and 1-dodecyl-3-methylimidazolium bromide [C12mim][Br], at four different temperatures (298.15, 303.15, 308.15, and 313.15) K using electrical conductivity and surface tension measurements. The evaluated CMC values for the studied system were used to obtain information about the colloidal behavior of the ionic liquids in the presence of biotin. The different thermodynamic parameters were studied. Tensiometry was used to determine the interfacial properties. The parameters obtained were used to study the different types of interactions for micelle formation. The main objective of studying these interactions is to further utilize this type of mixture in pharmaceutical industry, medicinal chemistry, and bio industry.

Effects of a landslide on the geochemistry of dissolved major and trace elements in a granite-gneiss forest catchment of Southeast Brazil

This study investigated the hydrogeochemical variations in a scenario following a landslide event in the Soberbo pristine rainforest small catchment (13 km2). The selected catchment is underlain by granite gneiss and located at the Serra dos Órgãos a mountainous region in the Rio de Janeiro, Brazil, that faces frequent high-intensity rainfall events. Stream water sampling, water discharge, and pH and electrical conductivity measurements were conducted monthly from May 2018 to October 2019. In January 2019, a landslide occurred upstream. Concentrations of dissolved organic carbon (DOC), HCO3−, major elements (Ca, K, Mg, Na, and Si), and trace elements (Al, Ba, Ce, Fe, Mn, Nd, Sr, Rb, La, Pr and Sm) were determined. The Spearman correlation and the multivariate analysis (PCA) indicated that during baseflow, rock weathering hydrolysis reactions are the main source of Si, Na, Mg, Ba and Sr. On the other hand, the forest plays a significant role during the rainy months by remobilizing colloidal litter material (represented by the DOC concentration) closely associated with colloidal Al. The landslide promoted a change in local redox conditions, resulting in the early release of Mn-scavenged elements, and about a month later, Fe and LREE, following a deepening in reduced conditions. The Ce/La molar ratio appeared to be a reliable hydrogeochemical redox proxy. The landslide effects persisted for at least nine months. In this case, the traceability of natural geochemical impacts of landslides was achieved through the river hydrogeochemistry in a mountainous small catchment model area.

High operational functionality nanofluids from choline chloride, ethylene glycol, and multi-walled carbon nanotubes – Economical substitutes for ionanofluids

Deep eutectic solvents (DESs) are an emerging class of green, easy-to-synthesize, and inexpensive solvents with designable properties widely used in nanotechnology applications. The optimization of such working fluids for energy transfer purposes requires the simultaneous maximization of their thermal/electrical conductivities and thermal/shelf-life stabilities, as well as minimization of their viscosity and overall material/maintenance costs. In this work, there is provided a comprehensive analysis of physicochemical properties, including, first-ever measurements of electrical conductivity and refractive index, of new highly-concentrated DES-based nanofluids composed of choline chloride/ethylene glycol (ChCl/EG) with molar ratios of 1:15, 1:5, 1:3, and 0.25–1 wt% of originally 860-µm-long multi-walled carbon nanotubes (MWCNTs), cut upon sonication to 14.0–16.9 µm. The study deepens the understanding of the mechanisms occurring at the molecular level during heat and electricity transfer in DES-based nanofluids and provides new empirical transport-property correlations. The analyzed nanodispersions are highly viscous (150–840 mPa·s at 25 °C, 9.3 s–‍1) non-Newtonian fluids (flow behavior index 0.49 ≤ m ≤ 0.66), though their viscosity can be notably reduced by elevated temperature and shear rate (28.3–120 mPa·s at 40 °C, 186 s−1). Importantly, DES-based nanofluids exhibit significant improvement in thermal conductivity (λ = 0.307 W·m−1·K−1), AC electrical conductivity (σ = 42.6 mS·cm−1), and decomposition temperature (T50%=255 °C) for ChCl/EG 1:3 + 1 wt% MWCNTs at 25 °C, thus, they can potentially become an interesting alternative to ionanofluids with up to 83 times lower raw material costs and at least 30-month shelf-life stability.

La-based perovskites for autothermal reforming: In-situ electrical conductivity measurements and catalytic study

La-based perovskites for autothermal reforming: In-situ electrical conductivity measurements and catalytic study

Electrocatalytic Properties of Quasi-2D Oxides LaSrMn0.5M0.5O4 (M = Co, Ni, Cu, and Zn) for Hydrogen and Oxygen Evolution Reactions.

Designing cost-effective and highly efficient electrocatalysts for water splitting is a significant challenge. We have systematically investigated a series of quasi-2D oxides, LaSrMn0.5M0.5O4 (M = Co, Ni, Cu, Zn), to enhance the electrocatalytic properties of the two half-reactions of water-splitting, namely oxygen and hydrogen evolution reactions (OER and HER). The four materials are isostructural, as confirmed by Rietveld refinements with X-ray diffraction. The oxygen contents and metal valence states were determined by iodometric titrations and X-ray photoelectron spectroscopy. Electrical conductivity measurements in a wide range of temperatures revealed semiconducting behavior for all four materials. Electrocatalytic properties were studied for both half-reactions of water-splitting, namely, oxygen-evolution and hydrogen-evolution reactions (OER and HER). For the four materials, the trends in both OER and HER were the same, which also matched the trend in electrical conductivities. Among them, LaSrMn0.5Co0.5O4 showed the best bifunctional electrocatalytic activity for both OER and HER, which may be attributed to its higher electrical conductivity and favorable electron configuration.

Dynamics of micro and macronutrients in a hydroponic nutrient film technique system under lettuce cultivation

While hydroponics is considered an efficient vegetable production system, there is a compelling need to investigate the efficiency of the current generic nutrient dosing recommendation primarily based on electrical conductivity (EC) measurements. Such information is critical to fine-tune and optimize the current hydroponic management practices for improved nutrient uptake efficiency. This study investigated the dynamics of some micro and macronutrients (N, P, Ca, Mg, K, Fe, and Mn) in a recirculating nutrient film technique (NFT) hydroponic system under lettuce cultivation. The research was conducted in an indoor controlled environment growth chamber with lettuce grown in different EC levels (1.2 and 1.6 dS m−1). Each treatment had four hydroponic cultivation units, each one with 24 plants. Nutrient solution and tissue samples were collected two to three times per week. Nutrient dynamics, including nutrient uptake efficiencies and environmental losses, were calculated using a mass balance approach. The effects of EC level on fresh and dry lettuce biomass and nutrient uptake were insignificant. Observed variations in nutrient solution composition during lettuce cultivation included the almost complete removal of ammonia nitrogen, nitrate decreases towards the end of the experiment, consistent increases in aqueous Ca concentration, and corresponding decreases in K and Mn. Average N losses ranged between 27 and 40 %, presumably through denitrification, while 10–14 % of N was assimilated into the plant biomass. The remaining N in the recirculating nutrient solution was estimated to be between 50 and 59 %. The average P loss was 11–35 %, likely due to precipitation, while 52–77 % remained in the nutrient solution. Nutrient uptake efficiencies averaged 19–31 % K, 12–21 % P, 9–16 % Mn, 4–6 % Ca, 3–4 % Mg, and 2–4 % Fe. These results suggest that elevated nutrient concentrations in recirculating nutrient solutions led to losses and underutilization. Findings from this study provide a comprehensive dataset critical to improving hydroponic nutrient management beyond N and P. Hydroponic nutrient management should target providing essential nutrients needed by plants at the correct proportions considering the plant growth stage.

Development of a soil electrical conductivity measurement system in paddy fields

This study aims to develop a data collection system for measuring soil electrical conductivity (EC) in Paddy Fields using the Wenner measurement principle, with one electrode configuration based on the Veris 3100 measuring machine, and a second electrode configuration with fixed electrodes. The result is a system that measures soil EC using the fixed electrode configuration for more stable results compared to the coulter electrode configuration on the Veris 3100. This system comprises three main components: a 7-inch industrial touchscreen monitor used for real-time monitoring and storing collected data on external memory, a controller that provides reverse direct current (DC) power supply to the electrodes and measures voltage and current parameters on the electrodes, two mechanical configurations including six electrodes in contact with the soil. The system is developed to operate best after soil preparation and before seed sowing. The collected data is processed and compared to actual measurements using an artificial neural network (ANN), resulting in an R2=0.7449, equivalent to linear regression. The system has been successfully installed and operated on a handheld tractor and tested in Paddy Fields on the outskirts of Can Tho City, Vietnam.

Interaction of anionic dye ethyl orange and cationic CnTAC surfactants: A multi technique investigation

This research presents the application of electrical conductivity measurements to ascertain the critical micelle concentration (CMC) values for N-alkyltrimethylammonium chloride surfactants (CnTAC; with alkyl chain lengths of n = 12, 14, 16, and 18). Complementary spectrophotometric analysis was conducted to probe the interactions between CnTAC series and Ethyl Orange (ETO), an anionic dye. Applying the Benesi-Hildebrand and Scott equations, we evaluated the binding constant (Kb) of the cationic micelles’ interaction with ETO, which in turn facilitated calculations of Gibb’s free energy (ΔG°) changes. These calculations provided insight into the binding affinity of ETO to the micelles. Our findings suggest that the interaction between ETO and CnTAC is contingent on the surfactant concentration, with higher concentrations leading to a disassociation of the ETO-CnTAC complex and a reduction in ETO adsorption. Notably, the alkyl chain length within CnTAC molecules critically affects various properties, including ΔG°, CMC, and other thermodynamic parameters that determine the surfactant’s energetic behavior. The study underscores the importance of the alkyl chain length in dictating the interaction dynamics and properties of CnTAC surfactants. A trend was observed where longer alkyl chains lead to increased Kb values and reductions in both CMC and ΔG°, enhancing dye solubilization and interaction spontaneity. The affinity sequence of ETO to the micelles, influenced by alkyl chain length, was found to be C12TAC < C14TAC < C16TAC < C18TAC.

Geo-spatial sensing of physical properties a leeway to agricultural soil assessment

The demand for economical means of evaluating soil nutrients’ unpredictability triggered the use of physical factors against the costlier, laborious, and time-consuming chemical approach. This drive led to resolving its capability in evaluating intricate soil properties as a productivity checker. This study aimed at assessing the physical parameters as a useful alternative to the conventional chemical examination of nutrient inconsistency. A petrographic examination was conducted on four rock samples for their classifications. Apparent Electrical Conductivity (ECa) measurements were seasonally executed in the wet (912-station) and dry (906-station). Ten cored soil samples were subjected to a permeability test. Twenty soil samples were examined for pH, Electrical Conductivity (EC), available phosphorus, acidity, Na, Mg, K, and Ca using standard soil science procedures. The mineralogical composition of six samples was determined with X-ray diffraction. The rock is biotite granite gneiss containing plagioclase (22%), microcline (24%), orthoclase (4%), quartz (25%), biotite (7%), and others (18%). The soils ECa were 10-344 µS/cm; categorised as low (1-49 µS/cm), moderate (50-99 µS/cm), and high (&gt;100 µS/cm). The ECa distribution varied from moderate (61%) to high (64%) suggesting a heterogeneous pattern of soil attributes. The infiltration rate was slow in high ECa (5.56x10-5-1.67x10-4 cm/s) signifying good retention capability whereas the low and moderate ECa (moderate-moderately rapid) sections promote nutrient leaching. The cation exchangeable capacity was low (2.99 cmol/kg) in the low ECa and moderate (3.30-4.85 cmol/kg) in the moderate and high ECa; with varying basic cation saturation in the high (81.38%), moderate (73.34%) and low (71.89%) ECa regions and high ECa had higher fertility status. The high ECa had low quartz (41.3%) and microcline (15.7%), but high kaolinite (31.1%) had an affinity to ads orb more cations compared to other ECa regions. ECa variability is practicable in predicting the spatial distribution of soil properties and delineating the management zones. Key words: Granite gneiss, electrical conductivity, permeability, soil composition, mineral assemblages

Predicting leachate impact on groundwater using electrical conductivity and oxidation–reduction potential measurements: An empirical and theoretical approach

This study developed innovative predictive models of groundwater pollution using in situ electrical conductivity (EC) and oxidation–reduction potential (ORP) measurements at livestock carcass burial sites. Combined electrode analysis (EC and ORP) and machine learning techniques efficiently and accurately distinguished between leachate and background groundwater. Two models—empirical and theoretical—were constructed based on a supervised classification framework. The empirical model constructs a classifier with high accuracy, sensitivity, and specificity, utilizing the comprehensive in situ EC and ORP measurements. The theoretical model with only two end members achieves comparable performance by simulating the leachate–groundwater interactions using a geochemical mixing model. Besides enhancing the early detection capabilities, our approach considerably reduces the reliance on extensive hydrochemical analyses, thus streamlining the monitoring process. Moreover, the use of field parameters was found to proactively identify potential pollution incidents, enhancing the efficiency of groundwater monitoring strategies. Our approach is applicable to various waste disposal sites, indicating its extensive potential for environmental monitoring and management.