Electrical Conductivity Values Research Articles

Investigation of numerical transport models in protein-based molecular junctions with cofactors of diverse chemical natures

The cofactors of proteins dictate the charge transport mechanism across molecular junctions when self-assembled protein monolayers are sandwiched between two metal electrodes. Here, we summarized how the chemical coordination nature of cofactors in various proteins modulates electrical conductance by investigating electronic transport studies across different protein-based molecular junctions under various forces applied under the AFM tip. We have utilized several numerical techniques of electronic transport to analyse the experimentally obtained current–voltage measurements across various protein-based molecular junctions and depicted the origin of electronic modulation in the electrical conductance under different external stimuli. We could also find the origin of electronic conductance modulation under external stimuli at various applied forces by obtaining several analytical transport parameters such as energy barrier, coupling strength, and electrical conductance values. Utilizing density-functional-theory calculations, we further validate that the electronic density of states present in the cofactors within the proteins dominates the electronic transport behaviours across protein-based molecular junctions. Our findings reveal the limiting factor for applying various external stimuli on different proteins, which could be further valuable in bioelectronic applications. We have also found that the organic cofactor containing protein follows all the tunneling mechanism-related numerical transport models and the electronic transport across proteins with pure inorganic cofactors follows Landauer transport formalism.

Deciphering the adsorption and sensing performance of Al24N24 and B24N24 nanoclusters as a drug delivery system for nitrosourea anticancer drug: A DFT insight

Nanomaterials for drug detection are crucial in pharmaceutical research, especially in cancer therapy applications like nitrosourea. The purpose of this work was to examine the sensitivity of Al24N24 and B24N24 nanocages for the detection of nitrosourea by using density functional theory (DFT). Different analyses were performed such as adsorption energy (Eads) studies, frontier molecular orbitals (FMOs), natural bond orbitals (NBO), global indices of reactivity, UV-Vis studies, molecular electrostatic potential (MEP), non-covalent interaction (NCI), quantum theory of atoms in molecules (QTAIM) and sensor mechanism. The adsorption of nitrosourea on Al24N24 shows the highest values of adsorption energies with the value of −59.239, −55.986, and −51.019 kcal/mol for O/6m-AN, plan/6m-AN, and plan/8m-AN respectively. On the other hand, B24N24 complexes show fewer adsorption energies with the notable presence in plan/6m-BN, O/4m-BN, and plan/8m-BN that have the values of −11.064, −10.983, and −10.064 kcal/mol respectively. The energy gap of Al24N24 and B24N24 complexes decrease from 4.120 eV and 6.493 eV respectively for bare nanocage showing the potential of using these cages for nitrosourea (NUr) detection. FMOs studies reveal that among all designed complexes the lowest energy gap is present in O/4m-AN having a value of 2.913 eV. Moreover, global indices of reactivity suggest the increase in softness for Al24N24 complexes from 0.2427 eV for bare nanocage to 0.3433 eV for O/4m-AN. Similarly, the softness for B24N24 complexes also increases from 0.1540 eV for bare cage to 0.3012 eV for O/B-BN. Sensitivities for NUr in O/B-BN, O/4m-BN, plan/6m-BN and plan/8m-BN are 0.896, 0.870, 0.834 and 0.815 respectively. Moreover, the recovery time of NUr drug from BN nanocage is also very short as 7.53 × 10-12 s for O/N-BN. Topological analysis predict the non-covalent nature of interaction present between AN and BN nanocages. The electrical conductivity values are increased after the adsorption process. The highest electrical conductivity is present in AN complexes such as 4.41 × 1012 S/m for O/4m-AN due to low energy gap of 2.91 eV. The sensor mechanism reflects the high values of sensitivity for B24N24 complexes due to narrow energy gaps. Thus, B24N24 could be a fine candidate for the detection of nitrosourea and as a drug delivery vehicle for nitrosourea to treat cancer.

Mechanisms of enhancing MgO for stabilization/solidification of Pb-contaminated red clay through CO2 sequestration

Pb-contaminated soil poses significant environmental and health risks as well as soil stability issues. Research on sandy soils highlights CO2-enhanced reactive MgO as a promising solution for improving the solidification of Pb-contaminated soils. However, carbonation effects can differ markedly between soil types owing to varying soil properties. In this study, we evaluated the effects of CO2-enhanced reactive MgO on the engineering and environmental characteristics of Pb-contaminated red clay and explored its mechanism of carbonation solidification. The results showed that CO2-enhanced reactive MgO increased the strength of Pb-contaminated red clay to over 3 MPa within 1 h, which was approximately 25 times the strength of untreated soil (0.2 MPa) and significantly higher than that of reactive MgO-treated, uncarbonated soil (0.8 MPa). The pH of the carbonated soil (9–10) facilitated Pb2+ immobilization, and the increase over the initial parameter elevated the electrical conductivity value. Moreover, CO2-enhanced reactive MgO reduced the Pb2+ leaching concentration to below 0.1 mg/L, even at high Pb concentrations (10,000 mg/kg). Pb2+ transformed into lead carbonates during the carbonation process, with the hydrated magnesium carbonates forming a dense internal structure. This solidification mechanism included chemical precipitation, physical adsorption, and encapsulation. Notably, the carbonation time should be controlled within 1 h to prevent soil expansion. Together, these findings support the potential of CO2-enhanced reactive MgO for efficient and low-carbon application in the solidification of Pb-contaminated red clay.

Effect of soil conditioners based on geomimetic materials on plant growth in degraded soils: Poly(acrylic acid)/bentonite

Geomimetic materials (GEOMI) are composite materials based on polymer and clays, able to imitate structural and functional properties of soils, including their structure, cationic exchange capability (CEC), water uptake capability (WUC), pH buffering ability, immobilizing of substances, among other. Because they can be used to develop of fertilizer slow-release systems, they have been identified as a novel approach to advance toward a most sustainable agriculture. The aim of this work was to study the effect of GEOMI on the plant growth in degraded soils. For this, GEOMI-1.0 was synthesized using poly(acrylic acid) as model of humic substances and bentonite modified with trichlorovinylsilane as mineral fraction model. Materials were characterized by different techniques. GEOMI-1.0 showed a hybrid, homogeneous, and amorphous structure. In addition, it was thermally stable at below ⁓200 °C with a Tg about 49.3 °C, showed a high WUC (⁓1384 g of water per 100 g of material). Likewise, it was verified that GEOMI-1.0 can decreases the pH values and increases the CEC of degraded soils depending on the added amount of geomaterial; but also, the electric conductivity values showed no dependence on the added amount of GEOMI-1.0. By correlation analysis, an exponential dependence of CEC was observed respect to pH changes, the relative amount added of GEOMI-1.0 and the initial CEC. Finally, using Brachiaria Brizantha cv. Marandú as plant model, the increase in the biomass content of roots and leaves, and the number of germinated seeds, were observed when GEOMI-1.0 was used for restoration of in-lab degraded soils.

Low-frequency capacitor with hopping electrical conductivity of the working substance (on the example of a-Si:H)

We propose a structural and electrical schemes of a capacitor based on a 3 μm thick a-Si:H (amorphous hydrogenated silicon) layer separated from the metal plates by 0.3 μm thick dielectric layers of SiO2 (silicon dioxide). We consider room temperatures (T ≈ 300 K) when in the absence of illumination for a-Si:H the hopping mechanism of electron migration via point defects of the structure prevails. For such a capacitor, the dependencies of the capacitance on the frequency of the measuring signal ω/2π in the range from 0.1 to 300 Hz are calculated for the a-Si:H layer with stationary hopping electrical conductivity σdc ≈ 1 ∙ 10−10 (Ohm ∙ cm)−1. It is assumed that there is no end-to-end electron transfer between the a-Si:H layer, dielectric layers and capacitor plates in the small-signal mode of capacitance measurement. It is shown that the real part of the capacitance of the capacitor decreases with increasing angular frequency ω, and the imaginary part is negative and depends non-monotonically on ω. The decrease in the real part of the device capacitance to the geometric capacitance of the series-connected oxide layers and the a-Si:H layer with increasing ω is due to a decrease in the electrical resistance of the capacitor. As a result, with increasing ω, the imaginary part of the capacitance is shunted by the hopping electrical conductivity of the capacitor. The phase shift for a sinusoidal electrical signal supplied to the capacitor is determined depending on the frequency ω/2π in the range of 0.1–300 Hz for the values of electrical conductivities of the hydrogenated amorphous silicon layer σdc ≈ 1 ∙ 10−11, 1 ∙ 10−10, and 1 ∙ 10−9 (Ohm ∙ cm)−1 at the temperature 300 K. With an increase in the electrical conductivity σdc of the a-Si:H layer, the minimum absolute value of the phase shift angle (≈65°) shifts to the high- frequency region (from 1 to 100 Hz). The proposed low-frequency capacitor can find application in electrical circuits for detecting low-frequency electrical signals for the purposes of biomedicine.

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.

Wedge-shape Al and Mg co-doped zinc oxide thin films: A Facile Route to achieve high thermoelectric power factor

Thin film thermoelectric technology has immense potential to become a next-generation power source for small-scale electronics. However, the rapid development of thin film thermoelectric still lacks a controllable structural design to improve the performance of thermoelectric devices for required temperature applications. This work presented a controlled thermoelectric design of ZnO-based thin films by Al and Mg co-doping using ALD. Herein, the Mg-doped ZnO sample exhibits the highest Seebeck coefficient of −311.83 μVK−1 at 500oC, while the maximum thermoelectric power factor of 3.68 μWcm−1K−2 is obtained at 300oC, which drops for higher temperatures. This decrease in power factor resulted from the reduction in electrical conductivity above 300oC. Similarly, the Al and Mg co-doped ZnO sample (Mg/Al ≈2 at%) exhibits a high thermoelectric power factor of 3.85 μWcm−1K−2 for ZnO based material due to its moderate electrical conductivity and Seebeck coefficient value at 325oC and behave monotonically for elevated temperatures. Scanning electron microscope (SEM) images show the formation of wedge-shaped structures for Al-incorporated samples, which helps to boost the overall thermoelectric performance. Additionally, we performed XRD, UV–Vis, Hall, and AFM analysis to get a deep insight into structural, optical, electrical, and surface features of the grown thin films and their linkage with the thermoelectric properties.

Elucidating the role of Ag+, Cu2+, and Fe3+ in tuning the electrical characteristics of polyaniline prepared through post-doping method

Abstract Conducting polymers possess inherent electrical conductivity, attracting significant attention in engineering applications, including dye-sensitized solar cells, gas sensors, and energy storage electrodes. Of various conducting polymers, Polyaniline has gained much attention due to its low cost of monomer, ease of bulk synthesis, high flexibility, and good environmental stability. Nevertheless, the conductivity of polyaniline is rather low when it is prepared under an un-doped state. Despite that, there is no clear information regarding how the valency of a metal dopant and its concentration can affect the electrical characteristics and other physicochemical properties of doped polyaniline. This study aims to fill this research gap by elucidating the changes in the electrical characteristics of polyaniline through metal doping. Polyaniline was synthesized through chemical oxidative polymerization in an HCl medium, followed by a post-doping to produce metal-codoped polyaniline. Three dopant materials, namely AgNO3, Cu(NO3)2, and Fe(NO3)3, were used in this synthesis, representing mono-, di-, and tri-valent metal ions, respectively. Results showed that bare PANI (which was doped with HCl only) exhibited a higher electrical conductance value of 8.44 x 10-7 S, while 1 M of Ag-codoped polyaniline, 1 M of Cu-codoped polyaniline, and 1 M of Fe-codoped polyaniline exhibited electrical conductance values of 1.73 x 10-7 S, 4.27 x 10-8 S, and 2.33 x 10-6 S, respectively. Apparently, the trivalent metal dopant was able to improve the conductivity of polyaniline; however, a detrimental effect resulted when the concentration of Fe3+ was increased to 1.5 M (overdose), resulting in a drop in electrical conductance to 4.66 x 10-8 S. In terms of morphological property, Ag-doped polyaniline exhibited a mixture of plate-like and globule-like structures, while both Cu-doped polyaniline and Fe-doped polyaniline predominantly displayed tiny globule-like structures, likely attributed to the stronger acidity of the Cu(NO3)2 and Fe(NO3)3 solutions. Meanwhile, the presence of several common bands of polyaniline such as N-H, C=N, C-H aromatic, quinoid and benzoid units are detected in the produced samples. The project outcomes are expected to guide tailored development of metal-doped polyaniline for specific electrical applications.

Insights into the Optoelectronic and Thermoelectric Properties of Defect Chalcopyrites XAl2Se4 (X = Zn, Cd, and Hg): A Density Functional Theory Approach

In the current study, we employed the full-potential linearized augmented plane wave plus local orbitals (FP-LAPW + lo) approach within the density functional theory (DFT) to investigate the physical properties of Defect Chalcopyrites XAl2Se4 (X = Zn, Cd, and Hg). Calculations yield precise structural and electronic parameters in good agreement with experimental data, revealing all three compounds as direct wide-bandgap semiconductors. The modified Becke-Johan potential (TB-mBJ) method accurately estimates energy gaps, which increase with decreasing lattice constants. The calculated values are 3.34 eV, 3.12 eV, and 2.30 eV for ZnAl2Se4, CdAl2Se4, and HgAl2Se4, respectively. The optical properties, including dielectric function and absorption coefficient, indicate potential applications in visible and ultraviolet optoelectronic devices. The high anisotropy of these materials further enhances their suitability for a range of linear and nonlinear optical applications. Moreover, ZnAl2Se4 exhibits the highest Seebeck coefficient at room temperature. The positive Seebeck coefficient confirmed the p-type behavior of the studied compounds. The highest observed power factor demonstrates optimal thermoelectric performance for these materials. High electrical conductivity values suggest their suitability as effective electrical conductors, especially at elevated temperatures. This study encourages further research into defect chalcopyrites for applications in optoelectronics and thermoelectric energy conversion.

CHARACTERISTICS OF EFFLUENTS FROM AQUACULTURE FARMS IN KANO STATE AND SUITABILITY AS IRRIGATION WATER

This work assessed the physicochemical characteristics of aquaculture effluents generated in aquaculture farms in Kano State to establish their suitability as irrigation water. Samples were collected from different aquaculture farms in the urban and peri-urban areas where the farms are clustered, and the physicochemical parameters, including the concentrations of nutrients, heavy metals, electrical conductivity (EC), and sodium adsorption ratio (SAR) were evaluated. The physicochemical characteristics of the effluents vary across the farms and the differences in the mean values were statistically significant at the 0.05 confidence interval. However, post hoc analysis based on the Fisher LSD test showed that the concentrations of certain individual parameters were not statistically different at the 0.05 interval. The concentrations of heavy metals were mostly within the standard limits. The EC values of the samples ranged from 0.85 dS/m to 2.4 dS/m, which are classified as having ‘slight to moderate restriction’ based on the FAO guidelines. Based on the combined EC and SAR analysis, some effluents fall under the “none” degree of restriction and are, therefore, suitable for irrigation. However, for some samples, such as that obtained from Farm No. 8 with SAR of 4.48 and a corresponding EC of 104 dS/m, the effluents are classified as having “slight to moderate” degrees of restriction, and should therefore be used with caution. The results show that although aquaculture effluents can be used as irrigation water, high SAR and EC may pose challenges. Thus, it is necessary to evaluate the suitability of the effluents before using them

Statistical Evaluation and Quality Analysis of Water Resources Around Quarry Site in Abuja Suburban Nigeria

Water resources occupy a vital position regarding the source of human hope for longevity and significant shortfalls on the strive towards sustainable development globally. Host communities to quarry companies without a water treatment plant are greatly affected by use of untreated water. This research highlights statistical evaluation and quality analysis of water resources around a quarry site in FCT Nigeria. The study engaged biological assay, physiological and chemical analysis to quantify contamination levels in the water resources and obtained data were subjected statistically using Pearson’s Correlation, descriptive statistics, Levene’s test for homogeneity and one–way analysis. The physiochemical analysis revealed the water resources to have high turbidity value in 58.3% of sampled population while nitrate concentration and electrical conductivity value were very low. The bioassay revealed presence of coliform bacteria in 100% of sampled population while thermotolerance count discovered disease-causing-pathogens in 41.7% of sampled population. Chemical analysis revealed that Pb, Cr, Ni and As were 91.7%, 83.3% 100% and 100% above recommended permissible limits for sampled population. These results suggests that water resources in this study is unsafe and holds a health-treat with regards to the contaminations inherent in them. Statistical evaluation revealed average positive linear relationship between heavy metal concentration suggesting close relationship of contamination source. Observed strong positive linear relationship between lead and copper, nickel and chromium as well as nickel and arsenic in the scatterplot depicts same source of contamination.

Statistical Evaluation and Quality Analysis of Water Resources Around Quarry Site in Abuja Suburban Nigeria

Water resources occupy a vital position regarding the source of human hope for longevity and significant shortfalls on the strive towards sustainable development globally. Host communities to quarry companies without a water treatment plant are greatly affected by use of untreated water. This research highlights statistical evaluation and quality analysis of water resources around a quarry site in FCT Nigeria. The study engaged biological assay, physiological and chemical analysis to quantify contamination levels in the water resources and obtained data were subjected statistically using Pearson’s Correlation, descriptive statistics, Levene’s test for homogeneity and one–way analysis. The physiochemical analysis revealed the water resources to have high turbidity value in 58.3% of sampled population while nitrate concentration and electrical conductivity value were very low. The bioassay revealed presence of coliform bacteria in 100% of sampled population while thermotolerance count discovered disease-causing-pathogens in 41.7% of sampled population. Chemical analysis revealed that Pb, Cr, Ni and As were 91.7%, 83.3% 100% and 100% above recommended permissible limits for sampled population. These results suggests that water resources in this study is unsafe and holds a health-treat with regards to the contaminations inherent in them. Statistical evaluation revealed average positive linear relationship between heavy metal concentration suggesting close relationship of contamination source. Observed strong positive linear relationship between lead and copper, nickel and chromium as well as nickel and arsenic in the scatterplot depicts same source of contamination.

Numerical Verification of Groundwater Suitability for Irrigation Around the Subsurface Dam Area of Miyako Island, Japan

The sustainable management of water resources is essential for agricultural productivity, especially in areas with scarce water availability. This study focused on assessing groundwater quality for irrigation near the subsurface dam area of Miyako Island, Japan. Water samples from three observation points were tested for various parameters, including electrical conductivity (EC), sodium adsorption ratio (SAR), soluble sodium percentage (SSP), residual sodium bicarbonate (RSBC), permeability index (PI), Kelley's ratio (KR), and magnesium adsorption ratio (MAR). EC values ranged from 270 to 800 µS/cm, suggesting water quality ranging from doubtful to good. SAR values between 0.23 and 1.49 suggested excellent quality. SSP ranged from 7.90% to 31.71%, mostly indicating good to excellent quality. RSBC values fluctuated between -1.57 to 1.45 epm, largely within safe limits. PI values varied from 40.34 to 75.83, indicating good permeability. Total hardness (TH) ranged from 105.50 to 326.45 ppm, classifying the water as hard to very hard. MAR values were below 50, suggesting potential soil issues. A numerical model confirmed observed Ca²⁺ concentrations, showing an increasing trend due to enhanced CO₂ emissions and lower pH. The data analysis revealed strong positive relationships between SSP and KR (r = 0.984), SAR and SSP (r = 0.951), and SAR and KR (r = 0.960). Despite generally acceptable values, continuous monitoring is recommended, especially for hardness, to ensure sustainable crop production. This study underscores the need for regular assessment and management of groundwater quality in subsurface dam areas to mitigate potential adverse effects on soil and agricultural productivity.

Subsurface flow pathway and hydrochemistry of a geographically isolated depression wetland in the Serra Geral Diabase Formation, São Paulo State, Brazil

Connectivity among water bodies is crucial for hydrological and ecological processes and fundamental for water management. Hydrochemistry and potentiometric studies on an isolated wetland allow to assess landscape influence, flow pathways, and subsurface connection. This study focuses on an isolated wetland over diabase on a topographic depression, with no visible river connection, and aims to determine the influence of rainfall and landscape on water composition and investigate subsurface flow toward the Santa Gertrudes stream. Water levels were monitored, and samples were collected from four wells during wet and dry seasons. Physical and chemical water parameters were measured, and ion concentrations determined. Pearson’s correlations highlighted codependence between physical and chemical parameters and ions and Piper’s diagram classified water composition. Six potentiometric maps were generated using interpolated hydraulic loads from monitoring campaigns. The findings show fluctuations in water level (0.11 to 0.93 m during wet periods and 1.25 to 1.79 m during dry periods), indicating rainwater directly affects water availability. Water composition was categorized as Sodium Bicarbonate and electrical conductivity values (greater than 100 µS/cm) may indicate that upstream wells are retaining salts from the surrounding crops. Strong positive correlation between sodium, bicarbonate and carbonate, and sulfate with electrical conductivity suggests simultaneous release of ions due to rock and soil mineral alteration. Potentiometric data reinforce the hypothesis of a subsurface connection between the studied area and the Santa Gertrudes stream. Future studies could benefit from expanding the monitoring network to include more GIWs and applying additional methods, such as isotope tracers.

Effects of black bean cell wall pectin by exogenous calcium ions: Insight into the metabolomics, physicochemical properties and anti-digestive capacity

In this work, the metabolomics, physicochemical and in vitro digestion properties of black beans influenced by different calcium ion solutions (0, 0.5 %, 1 %, and 2 %) were explored. The addition of calcium ions had a significant effect on the metabolic processing of black beans, including 16 differential metabolites and 4 metabolic pathways related to the cell wall. From the results of FT-IR and ICP-OES, it was confirmed that calcium ions can interact with COO− in non-methylated galacturonic acid in pectin to form calcium carboxylate strengthening the middle lamellae of the cell wall. Based on this mechanism, the soaked beans with an intact and dense cell structure were verified by the analyses of SEM and CLSM. Compared with other soaked beans, BB-2 exhibited lower cell permeability with electrical conductivity value decreased to 0.60 μs·cm−1. Additionally, BB-2 demonstrated slower digestion properties with digestion rate coefficient at 0.0020 min−1 and digestion extent only at 30.83 %, which is attributed to its increasingly compact cell wall and densely cellular matrix. This study illustrates the effect of calcium ions on the cellular structure of black beans, providing an effective process method for low glycemic index diets.

IoT-based fertigation system for agriculture

Fertigation system has been widely used by farmers to automate some processes of crops productions. A conventional system requires workers to prepare a fertilizer mixture, before transferring it into a main storage tank to be mixed with water. Then, electrical conductivity (EC) of the mixture will be measured. The existing fertigation system still relies heavily on workers and is manually operated and prone to human error. Therefore, internet of things (IoT) based fertigation system has been developed to deliver the fertilizer mixture with consistent EC value automatically to the plants. The main system controller is designed using ESP32 development module. The operation of the system can be monitored using an IoT dashboard and farmers can also control the system remotely. Alert will be given to the farmers if the condition of the system or plant does not meet the predefined settings. The values of EC together with temperature and humidity sensors are recorded for further analysis. A testbed is set up to provide fertigation to 120 polybags eggplants. Using the proposed fertigation system, the eggplants have been harvested earlier, therefore reducing the fertilizer usage. The cost of this IoT based fertigation system is lower compared to existing commercial products.

Pigmentos fotossintéticos, crescimento, e produção de tomate cereja sob estresse salino e peróxido de hidrogênio

ABSTRACT Excess of salts in water and/or soil stands out as one of the stresses that compromise the development of crops, including cherry tomato, requiring the use of strategies that reduce salt stress effects, such as foliar application of hydrogen peroxide. Thus, the objective of this study was to evaluate the effect of foliar application of H2O2 on the contents of photosynthetic pigments, growth, and production of cherry tomato under irrigation water salinity. The design used was randomized blocks, in a 5 × 5 factorial scheme, with five values of electrical conductivity of water - ECw (0.3, 1.0, 1.7, 2.4, and 3.1 dS m-1) and five concentrations of hydrogen peroxide - H2O2 (0, 15, 30, 45, and 60 μM). Application of hydrogen peroxide at concentration of 60 μM attenuated the deleterious effects of salt stress on the growth and number of leaves of cherry tomato up to ECw of 3.1 dS m-1. Hydrogen peroxide concentration of 45 μM increased root dry mass, synthesis of chlorophyll b and total chlorophyll under electrical conductivity of water of 0.3 dS m-1 and synthesis of chlorophyll a up to ECw of 0.8 dS m-1. Foliar application of 30 μM reduced the effects of salt stress on leaf, shoot and total dry mass accumulation up to ECw of 3.1 dS m-1. Electrical conductivity of water from 1.41 dS m-1 reduced the production of cherry tomato.

Thermal and chemical expansion of layered oxygen-deficient double perovskites

Layered oxygen-deficient double perovskites (ODP) based on the rare-earth elements (REE), barium and 3d-metals (Fe, Co, Cu etc.) are characterized by high values of electrical conductivity and high electrochemical activity in oxygen reduction reaction, and are considered as prospective cathode materials for intermediate-temperature solid oxide fuel cells (SOFC) on the base of proton- and oxygen-ion conducting solid electrolytes (SE). Effective cathode materials should be thermomechanically compatible with materials of SE, which tаkes place when the values of their thermal expansion coefficients (TEC) are close to each other. Due to this the study of thermal expansion of ODP as well as the isotation of different contributions in it (thermal, chemical, spin etc.), is of considerable interest. In this work using dilatometric method the thermal expansion of NdBa1–xSrxFeCo0,5Cu0,5O6−δ (0.0 ≤ х ≤ 1.0) (NBSFCC) ODP was studied using dilatometric method. It was established that the values of average linear thermal expansion coefficient (LTEC) (α) of the samples sharply increased from (15.1–16.2) · 10–6 K–1 at Т &lt; 630–920 K to (18.9–23.5) 10–6 K–1 at Т &gt; 630–920 K due to the evolution of weaklybonded oxygen from the samples. Values of α in the low-temperature region increase with increasing of values of their oxygen nonstoichiometry index (δ), and in the high-temperature one increase with the x increasing due to the increment of chemical contribution in the samples expansion. Based of the results of dilatometry, thermogravimetry, and iodometry, the thermal and chemical contributions in the expansion оn NBSFCC were isolated, and the effect of crystal structure, cationic and anionic composition of NBSFCC ODP on the values of their thermal and linear chemical expansion coefficient (LCEC, αδ ) was investigated. It was found, that LCEC values of the samples sharply increased from (8.6–11.8) · 10–3 at (х &lt; 0.5) to (12.6–15.8) · 10–3 at (х &gt; 0.5) when transition from ordered tetragonal (х &lt; 0.5) to disordered cubic (х &gt; 0.5) phase took place. It was shown, that dependences of LTEC and LCEC of NBSFCC phases on their crystal structure and chemical compositions obtained in this work are in good accordance with the analogous dependences determined earlier for the ODP of other types.

Probing the electronic structure, optical, and transport nature of lanthanide-based ternary materials: A First-principles perspective

High thermal stability and adjustable optoelectronic properties are the unique characteristics of lanthanide-based materials. The complex interplay between unique electronic, optical, and thermoelectric characteristics of lanthanide-based ternary chalcogenides is investigated by first principles modeling. The cohesive energy values were anticipated to be −4.54 eV/atom for PrSF and −4.87 eV/atom for PrSBr suggesting PrSBr to have the greatest bonding properties and is the most stable material. The computed formation energies range from −1.3 to −3.0 (eV/f. u), demonstrating their stability. The inclusion of bromine, a more electronegative element than fluorine, produces unique hybridization patterns and spin polarization effects. Compared to PrSBr, PrSF bonding employs more effective orbital hybridization, resulting in a greater band gap. PrSF has a higher frequency dielectric constant compared to PrSBr. The absorption edges in the ε2(ω) result from optical transitions between the Pr-f, S-p, F-p, and Br-p states. As the temperature rises, the Seeback coefficients for PrSF and PrSBr decrease exponentially. The thermal conductivity spectra of PrSF and PrSBr materials exhibit a linear increase across the temperature range. As temperature rises, the concentration of carriers and mobility increases, resulting in increased electrical conductivity values.

Effect of Mechanical Alloying Time on Microstructure, Hardness and Electrical Conductivity Properties of Cu-B4C Composites

This study aims to investigate the effect of mechanical alloying time on the microstructure, hardness, and electrical conductivity properties of copper (Cu) matrix boron carbide (B4C) reinforced composites. Cu-B4C composites with 2% B4C by volume were subjected to mechanical alloying processes for 0, 1, 5, 10, and 20 hours. The microstructure and phase formation of the composites were examined using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Hardness measurements of the composites were conducted using the microhardness measurement method, and density values were determined using the Archimedes principle. The electrical conductivity values of the samples were measured in terms of the international annealed copper standard (%IACS) based on the eddy current principle. SEM images revealed a more homogeneous distribution of B4C particles in the Cu matrix as the mechanical alloying time increased. Hardness values showed significant increases with the increasing mechanical alloying time, reaching the highest value in the 20 h milled sample with a 90.86 value. The effect on electrical conductivity values was noteworthy, with a measurement of 63% IACS at 0 hours and 25% IACS at 20 hours of mechanical alloying.