Electrical Conductivity Values Research Articles

Source identification and characterization of water-insoluble single particulate matter in rainfall sequences

ABSTRACT Analysis of atmospheric pollutants in rainwater provides valuable information on the environmental impacts of both natural and anthropogenic pollution sources. Air pollution studies often show that particulate matter (PM) collection on filters is used for subsequent analysis. However, this approach can result in significant particle accumulation on filters and complicate their characterization by semi-quantitative analytical techniques. In this study, insoluble PM in sequentially collected rainwater samples was analyzed for particle size, morphology, and chemical composition. Scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectrometry (EDS) and a particle size analyzer were used for these analyses. By combining SEM–EDS data with particle size distribution analyses, chemical composition findings, and upper atmosphere back-orbit modeling, specific sources of insoluble particles in rainwater were identified. In addition, rainwater samples were analyzed for pH, electrical conductivity, and major anions and cations. The pH values varied from 6.19 to 7.04, while the electrical conductivity values varied from 5.35 to 83.53 μS/cm. Among the major ions, relatively high concentrations of Ca2+, SO42−, and NO3− were detected, while F−, Mg2+, Na+, and Cl− were observed in lower concentrations. The contributions of sea salt were evidenced by the presence of Cl− and Na+ ions.

Long-term impact of different prevalent cropping systems on soil physico-chemical characteristics under subtropical climate conditions of Punjab, Pakistan

Lack of site-specific nutrients information for different cropping systems has been a major challenge in addressing declining soil fertility levels and enhance crop productivity in Punjab, Pakistan. Therefore, the study was designed to assess and quantify soil physico-chemical characteristics, crop yield and economic feasibility of different cropping systems (CS), including groundnut-wheat (G-W), rice-wheat (R-W), fallow-gram/wheat (F-G/W), mix cropping (Mix C) and cotton-wheat (C-W). A total of 470 georeferenced soil samples were collected using a random survey approach, and the samples were analyzed for soil texture, pH, electrical conductivity (EC), organic matter percentage (OM), total nitrogen percentage (TN), accessible phosphorus (AvP) (mg kg−1) and extractable potassium (ExK) (mg kg−1). For crop yield and economic feasibility, the data collected for each crop were summed up and mean data for every cropping system were compared. Cotton-wheat cropping system had the highest mean value of EC (1.57 dS/m), while mix cropping showed the maximum level of OM (0.53%), TN (0.028%), AvP (5.16 mg kg−1), yield (10.09 t ha−1), gross revenue (PK Rs. 87,883) and benefit cost ratio (2.2). The R-W cropping system had the highest pH (8.37), ExK (127.39 mg kg−1) and total cost (PK Rs. 46,882.25). Curiously, the fallow-gram/wheat cropping system had lower value of OM, TN, AvP, ExK, yield, GR and BCR, highlighted its poor performance compared to mix cropping system. Deficiencies in OM were widespread across all cropping systems, with only 3.1% of samples under mix cropping system being in the medium range. Similarly, TN %, AvP and ExK were deficient in varying degrees across all cropping systems, particularly in the fallow-gram/wheat cropping system. Spatial variability maps showed that nutrient deficiencies were more pronounced from the southern to northern side of study area. Our findings indicate that mixed cropping can improve soil health and enhance crop productivity, supporting the need for targeted nutrient management in Punjab agriculture systems.

Thermoelectrics in alkaline earth metal tellurides of ATe2 type - A first-principles study

Abstract We report an extensive study on the structural and thermoelectric performance of the novel semiconducting binary type ATe2 (A=Mg,Be,Ca,Sr,Ba) earth abundant materials using Density Functional Theory (DFT) and semi-classical Boltzmann transport theory. The PBE-GGA exchange correlation potential method was used for electronic structure calculations within the framework of density functional theory. The structural stability of the materials was confirmed by ground state energy, formation energy and mechanical responses. The calculated lattice constants, energy band structures and density of states explain the nature of the materials and are agreed with previous experimental and theoretical works. According to our calculated results, we revealed a high figure of merit materials are CaTe2 and SrTe2 due to high Seebeck and electrical conductivity and low thermal conductivity values. Additionally, Slack's equation was utilized to obtain low lattice thermal conductivity values. Our findings will serve as theoretical guidelines for future experimental and industrial applications both in cooling and heating

The Use of Non-Conventional Sensors to Monitor and Evaluate the Quality of Coal During the Cleaning Process

Coal is one of the most important sources for energy generation. In order to reach buyer or legislation requirements, and prevent environmental pollution, coal must be washed by processes such as froth flotation to remove mineral matter and to increase the coal quality. Different techniques such as X-ray diffraction and artificial vision are employed to monitor coal flows during the washing process; nevertheless, these techniques require high-cost equipment and qualified personnel to perform the analysis; also, data interpretation is a time-consuming task. The use of non-conventional sensors, such as a solid–liquid electrical conductivity sensor, to forecast the quality of coal offers an easy to employ method to monitor the process in real time, take corrective actions and improve the resulting coal grade, reduce the loss of valuable material and reduce pollution, increasing the sustainability of the process. For this research, coal samples from Región Carbonífera in Coahuila, Mexico were analyzed to obtain their intrinsic characteristics and their electrical conductivity. It was found that the electrical conductivity value is directly proportional to the calorific value and inversely proportional to the ash content. A conductivity value increase from 25 to 30 µS/cm was obtained when using a surfactant modified coal pulp.

Preserving soil properties and enhancing cauliflower yield with black plastic mulch in Bangladesh

<p>Poor soil health and inefficient farming practices significantly challenge sustainable agriculture and crop productivity in Bangladesh. This study evaluated the impact of various mulching techniques on soil properties, cauliflower yield, and carbon sequestration in Bangladesh to identify the optimal mulching strategy for sustainable cauliflower production and carbon sequestration. A field experiment in the Bogura district evaluated the effects of various mulching materials—newspaper, rice husk, rice straw, black plastic, craft paper, and no mulch—on soil physicochemical properties and cauliflower production. Data measurement and monitoring assessed soil properties, mulch degradation rates, and cauliflower quality, with organic carbon determined using Walkley and Black's method. Results showed significant impacts of mulching on soil parameters and cauliflower yield. Black plastic mulch increased soil temperature by approximately 6°C and conserved soil moisture by 13.2% compared to the no-mulch (control). Organic mulches, especially rice husk, were superior in conserving soil carbon (21.3 g Kg<sup>-1</sup>) and increasing available nitrogen (22.4 mg Kg<sup>-1</sup>), phosphorus (36.5 mg Kg<sup>-1</sup>), and soil pH (7.4). Although all treatments increased electrical conductivity (EC), the control showed the highest EC value (405.5 µS cm <sup>-1</sup>). Among organic mulches, craft paper had the highest degradation rate followed by newspaper and rice straw mulches. Cauliflower yield varied with mulch type, with black plastic producing the highest yield (1162.0 g), followed by rice straw (1050.0 g), rice husk (983.0 g), craft paper (821.0 g), and newspaper (752.0 g). These findings suggested black plastic mulch for maximizing cauliflower production in Bangladesh and similar conditions.</p>

Predicting the spatial distribution of salt-affected soil using Sentinel-2 in coastal area of Demak Regency

Abstract The distribution of salt-affected soil in Indonesia is difficult to locate because there are no main characteristics such as soil parent material, climate type, and evaporation rate. This study aimed to assess the spatial distribution of salt-affected soil in coastal area of Demak Regency using several salinity indices of Sentinel-2. Salt-affected soil distribution was identified by regressing electrical conductivity of soil samples with normalized difference salinity index (NDSI), normalized difference index (NDI), and salinity index (SI). A total of 30 soil samples taken from the coastal area of Demak Regency was examined for their electrical conductivity values to be used as training samples. The result showed that NDSI was more sensitive in mapping salt-affected soil with coefficient of determination of 0.23, standard error of estimate of 1.47 dS/m, and RMSE of 1.42 dS/m. The salt-affected soil distribution map indicated that electrical conductivity values in coastal area were higher compared to inland area with electrical conductivity ranged from 0 to 7.98 dS/m.

Structure-directing effect of terephthalate in bridging Zn(II)- and Cd(II)-based coordination polymers towards application in the detection of trace quantities of Pd2+ in aqueous media and their electrical conductivities.

Energy crisis and environmental pollution are two central themes of contemporary research towards achieving sustainable development goals (SDGs). Material chemistry is the chief discipline that can resolve glitches in these areas through the appropriate design of chemical compounds with multifunctional properties. In this regard, two stable coordination polymers (CPs) were synthesised in this work using Zn(II) (3d10) and Cd(II) (d10) metal nodes with 1,4-benzenedicarboxylate (bdc2-) as the bridging ligand and monodentate pyridyl-N coordinated 9H-fluoren-2-yl-pyridin-4-ylmethylene-amine (flpy) as the fluorogenic partner. The structures of the polymers [Zn2(bdc)4(flpy)2]n (CP1) and [Cd(bdc)2(flpy)2(H2O)]n·(flpy) (CP2) were confirmed via single-crystal X-ray diffraction measurements. In CP1, the paddle-wheel coordination unit [Zn2(bdc)4] was propagated to constitute a 2D polymer, while in CP2, the capped octahedron motif CdN2O5 generated a 1D chain. Both CP1 and CP2 were strongly emissive, and the emission could be quenched selectively by Pd2+ in aqueous solutions in the presence of as many as twenty other metal ions. Pd(II) is the most toxic in its three oxidation states of 0, II, and IV, and the limit of detection of Pd2+(aq) was 79.1 nM (CP1) and 89.2 nM (CP2), which were much below the toxicity limit of Pd2+ recommended by WHO (the tolerance limit of Pd2+ in water is 3.97-46.98 μM). Based on the Tauc plots of the ITO/(CP1 or CP2)/Al thin films, the bandgaps were determined as 3.63 eV for CP1 (theoretical value = 3.28 eV) and 3.55 eV for CP2 (theoretical value = 3.21 eV). Moreover, the electrical conductivity values of the Schottky semiconducting devices fabricated using these polymers at ambient conditions were 1.285 × 10-4 (CP1) and 2.399 × 10-4 S m-1 (CP2). Therefore, the application of these two CPs can accomplish sustainability goals for future generations.

Estimating soil salinity level by pedotransfer functions

Abstract In this study, the electrical conductivity (EC) of cultivated fields were predicted by pedotransfer functions (PTFs) using basic soil properties as variables in stepwise analyses. Before using PTFs, 207 soil samples were divided into development and validation datasets. This division was done 10 times to assess the accuracy and reliability of the PTFs. According to the principal component analysis (PCA), the EC values had higher load in PC1 and PC2 with clay, exchangeable Na, Ca, Mg and K contents. The EC values had significant positive correlations with pH, clay, exchangeable Ca, Mg, K, Na content, and negative correlations with silt and sand content. According to the stepwise analyses, 10 PTFs or linear multiple regression models were obtained using development data sets. The accuracy in development data sets and reliability in the validation data sets for these PTF models were assessed with R2 and RMSE values. The higher mean R2 and the lower mean RMSE values were obtained in the development data set when compared to the validation data set. The PTF-7 including clay, exchangeable Na, Mg and Ca was suggested to predict soil EC values of cultivated fields. It was determined that clay and exchangeable Na, Mg and Ca content were the most effective soil properties on predicting the EC values of cultivated fields. Keywords: Salt, EC, exchangeable cations, soil texture

Assessing the Relationship Between Electrical Conductivity and Total Dissolved Solids of Different Water Resources in a Large-scale Irrigation Scheme in the Eastern Mediterranean Basin of Turkiye

Climate change and the growth of the population have led to changes in both the quantity and the quality of water resources. In Turkiye, a Mediterranean country, over 75% of its surface water is used for irrigation. Given the average annual precipitation (574 mm) of Turkiye, except for the Black Sea Region, all arable land in the country relies on irrigation to maintain sustainable food production. Agriculture constitutes 6% of Turkiye’s gross domestic product (GDP), with exports including crops such as cotton, corn, cereals, pulses, oilseeds, nuts, citrus orchards, and various fruits. As a result, the water provided for irrigation in any irrigation system must meet acceptable water quality standards to ensure sustainability of irrigation and food security. This study aims to a) investigate two essential irrigation water parameters: Electrical Conductivity (EC) and Total Dissolved Solids (TDS), and b) evaluate their empirical relationship using samples collected from various water sources within a large-scale irrigation district, covering an area of 9495 ha in the Eastern Mediterranean Region of Turkiye. Water samples were collected over one year, from October 2022 to September 2023. A total of thirteen locations were considered: a) Seven agricultural drainage channels, b) Four irrigation water sources (Seyhan River, Ceyhan River, one spring, and one groundwater well), c) Two outlets - the existing research catchment outlet and the other downstream. EC values of water samples were determined by using a benchtop type EC meter in the laboratory and TDS was determined by gravimetric method. Research results showed that there was a statistically significant correlation (r≥0.98) between EC and TDS across all water samples. The proportionality constant (K) ranged predominantly between 400-800 and was consistent with literature indicating the linear relationship between EC and TDS. Research findings suggest that the quality of different water supplies is suitable for the irrigation of all kinds of crops grown in the Lower Seyhan Plain of Turkiye. The overall characteristics of the average EC and TDS values throughout the year are reflected in the proposed equations for each water body. However, in future research, we suggest that the water sample volume should be at least 100 ml in order to provide more accurate results for water quality assessment.

Effect of different land use types on selected soil characteristics in Erode district, Tamil Nadu

An experiment was conducted with thirty cropping systems from six land use types (agriculture, horticulture, silviculture, pastoral, horticulture + agriculture and silviculture + horticulture) to observe the effect of various land use systems on soil properties. The results showed that land use type had a substantial impact on measured soil organic matter (SOM), soil organic carbon (SOC), available nitrogen, phosphorous, potassium, electrical conductivity (EC) and soil reaction (pH). Results showed that agriculture/horticulture based land use systems had considerably higher pH (on an average: 8.30) and EC (0.93 dS m-1) values than did other land use systems. The SOM and SOC in tree-based land use systems were found to be higher than cultivated agri and horti soils. The findings indicated that periodical cultivation of land with agricultural/horticultural crops reduced the soil organic matter, available nitrogen, phosphorous, and potassium while dramatically raising pH and EC. Therefore, for sustainable agricultural productivity, it is necessary to create integrated land management strategies that could aid in restoring soil fertility and limiting soil deterioration.

The Effect of Slope Chamfer on Hydroponic NFT (Nutrient Film Technique) System For Cultivitation Of Japan Spinach (Spinacia Oleracea L.)

NFT is a hydroponic cultivation system by putting the roots of plants in a thin layer of water where the plants get nutrients from the nutrient solution that flows through the gutters, the flow of nutrient on NFT hydroponic circulated continuously so that the plant's nutritional needs can be fulfilled. NFT hydroponic vegetables is suitable to be cultivated for leafy vegetables, like a Japanese spinach plant (Spinacia Oleracea L.). The purpose of these research was to test the design of NFT Hydroponic with slope 3%. In the testing performance of hydroponic NFT consist of three parameters. These parameters include the testing of irrigation efficiency, pH values ​​and Electrical Conductivity (EC) solution and the uniformity of crop productivity. Data obtained from this study were analyzed based on its design to determine the effect of each parameter on plant growth. The average irrigation efficiency value is 92.00%, the value of uniformity electrical conductivity (EC) reached 92.10% and the uniformity of solution pH value reaches 99.51%. For the final harvest that obtained from its various agronomical aspects result obtained is the uniformity of the result obtained in plan weight gained is the smallest weight 13 grams and the heaviest 70 grams. From 32 plants produced, uniformity values obtained of plant weight at 67.788% (chamfer 1), 68,388% (chamfer 2) and 68,388% (chamfer 3).

Artisanal and small-scale limestone mining affects soil parameters in Sohra (Meghalaya), India.

In this study, we assessed the changes in the physical and chemical characteristics of the soil samples collected from the artisanal and small-scale limestone mining site in Sohra (Cherrapunjee), Meghalaya, by comparing them with the non-mining site. Eleven distinct soil parameters, namely pH, electrical conductivity (EC), texture (ST), moisture content (MC), bulk density (BD), total porosity (TP), water holding capacity (WHC), organic carbon (OC), total nitrogen (TN), available phosphorus (AP), and exchangeable potassium (EK), were evaluated seasonally (winter, pre-monsoon, and post-monsoon) for 2years. The results showed that limestone mining has significantly affected the soil quality. The effect is evident by the substantial increases in EC values, sand content, and alkaline soils coupled with noticeably low concentrations of OC and TN. In addition, prominent changes were perceived in the soil MC and EK content, as well as in WHC, BD, and TP percent. Results from ANOVA revealed significant differences (p < 0.05) in mean values at different sampling seasons and sites. The multivariate statistical analysis results showed that the computed correlation coefficient (r) matrix data ranged from - 1.00 to 0.974. A strong positive correlation was highest between OC and TN (0.974), followed by OC with EK (0.828). Principal component (PC) analysis revealed two major components, PC 1 and PC 2, having eigenvalues of 6.276 and 1.747, respectively. Cumulatively, these two components explained 80.23% of the total variance. The loading factor in PC 1 is high and is attributed to OC (.974), TN (.970), and EK (.903). However, in PC 2, the loading factor is positively pooled by MC (0.894) and TP (0.765). The present study concludes that artisanal and small-scale limestone mining altered the soil's physical and chemical properties, and these changes are likely to have a subsequent deteriorating impact on the area's biodiversity, landscape, and natural ecosystem. Therefore, to minimize the impact and ensure sustainable soil management in the area, approaches for effective mitigation and remediation measures, including formulating steps for the conservation and enhancement of the soil's environmental quality, are recommended.

DFT-based computational investigation of the structural, electronic, and thermoelectric properties oftransition-metal hydride VH2.

Vanadium hydride is of significant interest because of its potential applications in thermoelectric materials and hydrogen storage technologies. Understanding its structural, electronic, and thermoelectric properties is crucial for optimizing its performance in these applications. This study investigates these properties via density functional theory (DFT), revealing key insights into its stability and efficiency as a thermoelectric material. In this work, the structural, electronic, and thermoelectric properties of cubic VH2 were investigated using the GGA approach within the framework of DFT. The band structure and density of states demonstrate the metallic nature of these compounds. Using the semi-empirical Boltzmann's approach implemented in the BoltzTraP code, transport parameters, such as the Seebeck coefficient, electrical conductivity, thermal conductivity, and figure of merit as a function of the chemical potential, are computed at a temperature gradient of 500K. For the VH2 compound, the thermal and electrical conductivities and Seebeck coefficient are greater for p-type doping and n-type doping. The moderate values of the figure of merit obtained for these materials indicate that these materials have applicability where small values of thermoelectric efficiency are required, and higher values can harm the process. The maximum values of the Seebeck coefficient for VH2 against chemical potential values ranging between 0.095 and - 0.095eV in the p-type region and n-type region are 2.28µV/K and - 2.27µV/K, respectively. The highest value of electrical conductivity per relaxation time in the chemical potential range between - 0.07 and 0.07eV in the p-type region is 5.3 × 10201/Ωms, and that in the n-type region is 1.97 × 10201/Ωms. The maximum dimensionless figure of merit value for VH2 is 0.020.

Расчет удельной электропроводности расплавов смесей LiF+NaF

The calculation of the specific electrical conductivity of lithium and sodium fluorides mixtures melts is presented. The Iinterest in the LiF–NaF system melts is determined by their practical significance. Melts of LiF+NaF mixtures are used in heat-storing compositions and in metallurgy. They are part of various multicomponent systems. The specific electrical conductivity calculation by isoconcentration, isothermal and interpolation methods is given for LiF+NaF mixtures melts of various compositions using known reference data for the temperature range 1020...1340 K. A calculation has been performed for the eutectic composition. The resulting analytical equations have been used to describe and calculate the specific electrical conductivity of the eutectic mixture for temperatures 5°, 10°, 50°, 75°, 100° above the liquidus. The specific electrical conductivity of the eutectic mixture melt is calculated on isotherms by interpolation for the isoconcentration dependences of hypoeutectic and hypereutectic mixtures. Isotherms of electrical conductivity (1020...1340 K) of melts depending on the content of LiF and NaF components are described by a third-degree polynomial. Depending on the temperature, the coefficients in the resulting equation change linearly. A comparison has been made of the values of specific electrical conductivity ϰ(LiF+NaF), calculated from the obtained equations. The description of ϰ(LiF+NaF) by isoconcentration and isothermal methods has showed satisfactory convergence of calculation results and makes it possible to calculate the specific electrical conductivity of LiF+NaF mixtures melts of any given composition, including eutectic.

Thermal stability and electrophysical properties of oxide tungsten bronzes produced by electrolysis of melts

Oxide tungsten bronzes (OTB) of cubic, tetragonal and hexagonal structure were electrodeposited under galvanostatic conditions. Electrolysis of polytungstate melts 0.8Na2WO4–0.2WO3, 0.25Na2WO4–0.25K2WO4–0.5WO3 and 0.1K2WO4–0.55Li2WO4–0.35WO3 was performed at a temperature of 973 K and a cathode current density of 25 mA cm–2 for 20 min. The synthesized OTB powders were studied by X-ray diffraction analysis, laser diffraction, and scanning electron microscopy coupled with energy dispersive spectroscopy. To determine the upper limit of the thermal stability range, the phase composition of OTB powders with an average particle size of 40–50 μm was studied after isothermal annealing at 373–1173 K for 2 h in an air or argon atmosphere. OTB powders with a tetragonal structure were additionally studied by synchronous thermal analysis. The electrical resistance of the samples sintered at 473 K was measured in air using direct and alternating current. It has been established that the most stable are the hexagonal OTBs isostructural to K0.3WO3, since their phase composition does not change up to 773 K during heat treatment in air and remains constant over the entire studied temperature range in an inert atmosphere. Tetragonal OTB powders isostructural to K0.475WO3 and Na0.28WO3 are stable up to 1073 K in argon and partially oxidize in air above 673 K to form OTBs with lower alkali metal content, WO3 and Na2W2O7. The phase composition of cubic OTB isostructural to Na0.74WO3, is stable up to 673 K in air and up to 873 K in argon. Conductivity studies of all samples indicate mixed ion-electron conductivity with a predominance of the electronic component. Аt 298–573 K, the specific electrical conductivity values vary within the range of 0.035–0.051, 0.012–0.030 and 0.005–0.019 (Ohm⋅cm)–1 for the OTB samples of tetragonal, cubic and hexagonal structures, respectively.

Evaluation of the Physico-Chemical Parameters of the Sediments of the Tsieme River in Brazzaville (Republic of Congo)

Population growth, accompanied by rapid urbanization, is the cause of many disturbances in natural environments. The presence of physical and/or chemical contaminants in sediments causes toxic effects in aquatic environments. This work aims to determine the physicochemical parameters of the sediments of the Tsiémé River in Brazzaville during the dry and rainy seasons. Four (04) sediment samples were taken per season and analyzed by potentiometric, X-ray diffractometric and Robinson methods. The results obtained show that quartz is the only mineral species detected. The particle size distribution of the sediments shows particles of different sizes in the order of coarse sand &amp;gt; fine sand &amp;gt; coarse silt &amp;gt; fine silt. The sediments of the Tsiémé River are moderately acidic with pH values varying between 5.75 and 6.69 in the dry season and between 6.38 and 7.13 in the rainy season. The low values of electrical conductivity ranging from 18 to 173 μs/cm in the dry season and from 13 to 86 μs/cm in the rainy season characterize the low mineralization of the sediments. The percentage of total nitrogen varies from 0.004 to 0.006% in the dry season and from 0.00 to 0.005% in the rainy season. Similarly, the total phosphorus rate fluctuates between 0.007 and 0.07% and from 0.06 to 0.1% in the dry and rainy seasons. The organic matter contents vary between 0.248 to 3,549% and 0.038 to 0.114% in the dry and rainy season. These results indicate the absence of mineral and organic pollution of the sediments. Thus, the sediments of the Tsiémé River do not present imminent risks from a physicochemical point of view.

Exploring optimal soil conditions for high-functional Oenanthe javanica (water dropwort) production.

Oenanthe javanica (Blume) DC., also known as water dropwort, is an aquatic plant species native to various regions across Asia. Despite its numerous health-promoting effects, research on improving its quality remains limited. The present study aimed to identify the optimal soil conditions required for high-quality water dropwort production. Fifty crop and soil samples from South Korean farms were analyzed for their functional content, soil chemical properties and plant tissue components. The results indicated that crop samples with lower functional components had higher soil pH, electrical conductivity (EC) and exchangeable cations than those with higher functional components. High-quality crop samples exhibited neutral soil pH and low EC values, suggesting better nutrient availability for crop growth and reduced salt stress as a result of mineral accumulation in soil. These findings suggest that soils affected by excessive salinity may create suboptimal soil conditions for water dropwort cultivation, potentially compromising crop quality. © 2024 Society of Chemical Industry.

Electronic Nature and Thermoelectric Characteristics of Cubic LaPb3 LaIn3 and LaTl3 Compounds: B3PW91 Approach

In this paper the structural, electronic and transport properties of the strongly correlated intermetallics LaX3 (X=Pb, In and Tl) in the space group Pm-3m (221) have been investigated using B3PW91 hybrid functional within the framework of density functional theory. These compounds have 4f orbitals and hence strong electron-electron correlation effect is expected, therefore, the electronic properties are also calculated with the B3PW91 hybrid functional and the effect of B3PW91 hybrid functional on the density of states is discussed in details. The band structure and density of states, demonstrate the metallic nature of these compounds. Using the semi-empirical Boltzmann’s approach implemented in the BoltzTraP code, the transport parameters, such as the Seebeck coefficient, electrical conductivity, thermal conductivity and figure of merit as a function of the chemical potential are computed at a temperature gradient of 500 K. For all materials the thermal and electrical conductivities, and Seebeck coefficient has higher values for n-type doping in comparison with p-type doping. The moderate values of figure of merit obtained for these materials indicate that these materials have applicability where small values of thermoelectric efficiency are required and higher values can harm the process but need experimental verification. LaIn3 has the highest value of electrical conductivity per relaxation time and thermal conductivity per relaxation time are 9.43 x 1020 1/Ωms and 107.65 x 1014 W/mKs respectively. LaTl3 has the highest figure of merit among these materials.

Regulation of the physicochemical properties of nutrient solution in hydroponic system based on the CatBoost model

Too high or low nutrient solution concentrations adversely affect hydroponic vegetables’ growth and yield performance. In addition, the temperature of the solution and the dissolved oxygen (DO) content of the water are critical factors. A real-time regulation model for nutrient solutions based on the CatBoost model was developed to address the issues of low automation and accuracy of nutrient solution configuration and management. The pH, electric conductivity (EC) and DO of the nutrient solution, and the corresponding water temperature of 96 groups of hydroponic lettuce nutrient solutions (KNO3, MgSO4, Ca(NO3)2, KH2PO4, NH4H2PO4, and microfertilizer) were measured using a gradient combination test designed according to the formula of hydroponic lettuce nutrient solution. A prediction model of the nutrient solution index was constructed using a gradient-enhanced decision tree algorithm and the accuracies of the random forest, XGBoost, and CatBoost algorithms were compared. The results show that the root mean square error (RMSE), mean absolute error (MAE) and coefficient of determination (R2) of the simulated and measured values of the EC prediction model established by the CatBoost model were 248.28 µS/cm, 203.19 µS/cm and 0.946, respectively. At the same time, it was found that the hydroponic variable fertilization control system, composed of four modules–data acquisition, data decision, field control, and manual control–could predict the EC and pH value changes of the nutrient solution and timely add compounds for control. The application of nutrients based on the developed system was good and the weight of the cream lettuce (Flandria RZ) grown using the system was more than 200 g, which meets the requirement for high-quality cream lettuce production. Therefore, the CatBoost model system can be used to improve the hydroponic production system of vegetables by managing nutrients effectively.

Evaluating the Impact of Agrivoltaic Systems on Microclimate and Andrographis paniculata Growth

Abstract Agrivoltaic systems (AVS) integrate photovoltaic (PV) systems with agricultural production, presenting a dual strategy that optimize both energy and crop yields. This study aims to evaluate the effects of AVS on microclimate and growth performance of Andrographis paniculata, a medicinal herbaceous. The experiment consists of three treatments; Mono-Photovoltaic (MPV), Monocrop (MC), and AVS system (where the crops are grown under solar panels). Parameters like air temperature, humidity, and light intensity of the microclimate, and soil data such as soil temperature, moisture content, and electrical conductivity values are taken using sensors connected to a datalogger. Next, parameters such as plant height, stem diameter, number of leaves and SPAD value are measured and analyzed. The results show that AVS not only provide shade, but also produce a 6% cooler and 8.9% humid microclimate compared to MC, that benefits the growth of Andrographis paniculata and potentially improve the efficiency of PV. Furthermore, growing media under the AVS recorded higher moisture content, suggesting good water retention, which possibly reduce the irrigation water requirement. The study concludes that AVS system can be a practicable method to improve both productions in Malaysia. Thus, suggesting further research on other crops, irrigation management, and large-scale implementation of AVS.