Resistivity Research Articles

Biochar and straw amendments drive microbial regulation of phosphorus dynamics in saline-irrigated cotton fields

Saline water drip irrigation is a potential solution for addressing freshwater scarcity in arid regions. However, prolonged use can accumulate soil salinity and reduce phosphorus (P) availability. Biochar and straw amendments have been shown to alleviate these effects, but their mechanisms in regulating microbial genes involved in P transformation under long-term saline irrigation remain unclear. This study aimed to evaluate the impact of biochar and straw incorporation on soil microbial community structure and P availability in saline-irrigated cotton fields. Based on a 14-year field trial, three treatments were developed: saline water irrigation alone (CK), saline water irrigation with biochar (BC), and saline water irrigation with straw (ST). Results indicated that both amendments significantly enhanced soil water content, organic carbon, total P, available P, and inorganic P fractions (Ca10-P, Al-P, Fe-P, and O-P) while reducing soil electrical conductivity and Ca2-P and Ca8-P fractions. Biochar increased the relative abundance of Chloroflexi, Gemmatimonadetes, and Verrucomicrobia, while straw promoted Proteobacteria and Planctomycetota. Both treatments decreased the abundance of several P mineralization genes (e.g., phoD, phoA) and increased genes associated with P solubilization (e.g., gcd). Microbial populations and P cycling genes were shown to be tightly associated with soil characteristics, with Ca2-P and Al-P serving as important mediators, according to correlation studies. Generally, under long-term salty irrigation, biochar, and straw amendments reduced soil salinity, raised soil P availability, decreased the expression of phosphorus cycling-related microbial genes, and improved soil characteristics. These results made them excellent techniques for sustainable soil management.

Polyethersulfone/fish-shrimp chitosan-based mixed matrix membrane for industrial wastewater treatment.

In this study, chitosan (CH) was synthesized by processing of fish-shrimp solid waste (shell). It was utilized in the preparation of polyethersulfone (PES)-based mixed matrix membrane (Mx/CHy) through the film casting method. The hydrophilicity of the membrane was modified by increasing the concentration of CH. The degree of deacetylation (DD%) of CH, analyzed using the acid-base titration method, was found to be 78%. The molecular weight cutoff (MWCO) of the membrane was analyzed using the polyethylene glycol rejection method. The surface properties such as mean pore size and hydrophilicity of the membrane were analyzed using a scanning electron microscope (SEM) micrograph and water contact angle meter. The membrane (M18/CH1.0) mean pore size and MWCO were 7.0nm and 1.8kDa, respectively, which is in the nanofiltration (NF) range. After cross-linking of CH with PES/PVP, hydrophilicity and porosity of the M18/CH1.0 increased. The feasibility of the membrane was tested for the treatment of industrial wastewater (iron and steel, distillery, and paper and pulp industry) by varying the feed pressure. The collected permeate through the M18/CH1.0 for all industrial wastewater was transparent. The M18/CH1.0 showed the removal efficiency as follows: turbidity, 65%; total dissolved solids (TDS), 86.6%; total suspended solids (TSS), 60.5%; chemical oxygen demand (COD), 99.5%; biochemical oxygen demand (BOD), 99.5%; and electrical conductivity (EC), 63.2% of distillery industry wastewater. In the case of steel and iron wastewater, it showed the removal efficiency for TDS, 48.3%; TSS, 65.3%; and EC, 42.2%. However, M18/CH1.0 removed the turbidity, 94.5%; TDS, 65.7%; TSS, 97.6%; and EC, 85.5% from the pulp and paper industry wastewater feed. The strong removal efficiency and resistance towards the fouling of the M18/CH1.0 make it a potential candidate for the application in the treatment of industrial wastewater.

Phenol formaldehyde‐flax fabric (PF‐F) hybrid composites reinforced with cellulose nanofiber (CNF)—mechanical, morphology, electrical conductivity, electronic structure, optoelectronic, and charge transfer properties

AbstractFor developing an eco‐friendly world, a sustainable solution has encouraged to use natural fibers. Among the various options, lignocellulose fiber‐reinforced composites have captured the interest of material experts and engineers. These remarkable materials offer plentiful supply, inherent sustainability, easily degradability, and affordability, making them an attractive choice for a multitude of uses. Herein, we prepared a series of hybrid cellulose nanofiber (CNF)‐reinforced phenolic composites. Flax fabric was coated with CNF followed by phenolic resin coating was made in this work to check the mechanical, morphological behavior, electrical conductivity, electronic structure, opto‐electronic, and charge transfer properties. We found that 0.5 CNF showed better tensile properties, greater AC conductivity, dielectric constant, and dielectric loss compared with other composites. The electronic structure, opto‐electronic, and charge transfer properties of the PF‐resin/nanocellulose polymer nanocomposite have been systematically examined using density functional theory (DFT). The findings indicate that the PF‐resin/cellulose nanocomposite undergoes intramolecular charge transfer (CT) in response to an external electric field. The negative binding energy exhibited between the DFT optimized PF‐resin/cellulose nanocomposite shows the complex is stable and energy‐favorable.Highlights The impact of CNF on the properties PF‐F hybrid composites was investigated. The mechanical performance has been improved by the addition of CNF. The incorporation of CNF improved the fracture toughness of the composites. The fabricated composite has negative binding energy from DFT studies. A promising high‐performance electroactive polymer and structural material.

Enhancing the Thermoelectric Performance of Bi2O2Se Ceramics via Multi-Element Doping

Bi2O2Se, as the n-type counterpart of p-type BiCuSeO, has garnered considerable attention. The lower carrier concentration leads to reduced electrical conductivity, prompting extensive research efforts aimed at enhancing its electrical performance. This study prepared Bi2−3x(CeTiSn)xO2Se (x = 0, 0.02, 0.03, and 0.04) ceramics using a combination of high-energy ball milling and cold isostatic pressing techniques. Results demonstrated that the incorporation of multiple elements led to an increase in the carrier concentration within the Bi2O2Se system, thereby improving electrical conductivity. The electrical conductivity increased from 5.1 S/cm for Bi2O2Se to 154.1 S/cm for Bi1.88(CeTiSn)0.04O2Se at 323 K. Furthermore, the maximum power factor value of Bi1.88(CeTiSn)0.04O2Se was 112 μW m−1 K−2 at 763 K. Doping led to a slight increase in thermal conductivity. The figure of merit ZTmax value of Bi1.88(CeTiSn)0.04O2Se was ~0.16, marking a significant enhancement of about 1.45 times compared to that of the pure sample (~0.11).

Investigation on the Anisotropic Electrothermal Performance of Wood‐Based Graphene Electric Heating Composites

The unique material structure and pronounced anisotropy of wood bestow it with an array of remarkable properties, creating opportunities for designing functional materials. This study investigates the application of wood's anisotropic structure in temperature‐controlled intelligent electric heating materials by preparing wood‐based graphene electric heating composites (GNPs@EW). Graphene nanosheets (GNPs) are incorporated into a birch matrix (EW) to enhance the electrical and thermal conductivity of insulating wood. The integration of graphene with wood is confirmed through Fourier transform infrared spectrometer (FTIR) and X‐ray diffractometer (XRD) analysis. The optimal composite (GNPs@EW1) is prepared with graphene‐to‐anhydrous ethanol mass ratio of 1:1. The results demonstrate the influence of wood's anisotropy on the electrical and thermal conductivity of the composites, revealing superior performance in the axial direction compared to the tangential direction. The resistivity of GNPs@EW1 along the axial direction decreases by 2.1–2.9 times relative to the tangential direction, and the temperature rise after energization at 6 V is 22–29 °C higher in the axial direction. Furthermore, GNPs@EW1 exhibits thermal stability, enhanced axial mechanical properties, and temperature uniformity, establishing these superior axial properties as a foundation for the development of wood‐based heating materials and innovative smart heating applications.

Post-Annealing-Induced Enhancement of Structural, Optical and Electrical Properties in Copper Tin Sulphide (CTS) Thin Films

Abstract This study investigates the impact of post-annealing on the enhancement of structural, optical and electrical properties of Copper Tin Sulfide (CTS) thin films. The CTS thin films were synthesized using the successive Ionic Layer Adsorption and Reaction (SILAR) method, then annealed at temperatures of 100°C, 200°C, and 300°C and characterized using XRD, SEM, FTIR, UV-Vis-NIR, and EDAX. The results show improved crystallinity, optical transmittance and electrical conductivity with increasing annealing temperature. The films show high bandgap energies (3.68-3.90 eV) and strong UV absorption. The transmittance curves reveal low transmittance in the UV region and high transmittance in the visible region. Post-annealing resulted in a decrease in film thickness, suggesting improved uniformity and density. An inverse relationship between crystallite size and bandgap energy was observed. These findings introduce a new paradigm for tailoring the bandgap energy and optical transmittance of CTS thin films through controlled post-annealing, enabling their application in high-performance optoelectronic devices.

Boosting Fiber Properties via Selective Sorting and Wet spinning of High Aspect Ratio Carbon Nanotubes

Abstract The development of high-performance fibers using carbon nanotubes (CNTs) has gained significant attention due to their extraordinary mechanical, electrical, and thermal properties. In this study, we focus on the selective sorting and wet spinning of high aspect ratio CNTs to enhance the physical properties of the resulting fibers. By utilizing a lyotropic liquid crystal (LLC) mesophase, we effectively separated long and short CNTs. At the isotropic cloud point (ICP), long CNTs form nematic domains while short CNTs remain in the isotropic phase, enabling selective sorting based on differences in surfactant adsorption probability. After removing amorphous carbon and surfactant molecules through thermal treatment and dialysis purification, continuous CNT fibers were produced via wet spinning process. The CNT fibers, composed primarily of long CNTs, demonstrated outstanding mechanical strength (1.76 GPa) and electrical conductivity (3.89 MS m-1), surpassing fibers made from short or as-synthesized CNTs. This strategy provides a promising approach to boost the physical properties of CNT fibers, utilizing commercially available CNTs to broaden their applications in flexible electronics and energy transportation.

Self-optimizing Cobalt Tungsten Oxide Electrocatalysts toward Enhanced Oxygen Evolution in Alkaline Media.

Self-optimizing mixed metal oxides represent a novel class of electrocatalysts for the advanced oxygen evolution reaction (OER). Here, we report self-assembled cobalt tungsten oxide nanostructures on a lab-synthesized copper oxide substrate through a single-step deposition approach. The resulting composite exhibits remarkable self-optimization behavior, shown by significantly reduced overpotentials and enhanced current densities, accompanied with substantial increase in OER kinetics, electrocatalytically active surface area, surface wettability, and electrical conductivity. Under operating conditions, interfacial restructuring of the electrocatalyst reveals the in situ formation of oxidized cobalt species as the true active site. Complementary density functional theory (DFT) calculations further demonstrate the formation of *OOH intermediate as the rate-determining step of OER, and highlight the adaptive binding of oxygen intermediates, which transitions from tungsten to cobalt sites during OER process. Our study provides a fundamental understanding of the self-optimization mechanism and advances the knowledge-driven design of efficient water-splitting electrocatalysts.

Effect of Enriched Coconut Shell Biochar on Soil Properties and Soybean (Glycine max L.) Yield in Acidic Soils of Eastern Dry Zone of Karnataka, India

A two-season field study was conducted at ICAR-KVK, Hadonahalli, which is located in the Eastern Dry Zone of Karnataka, to evaluate the influence of phosphorus-solubilizing bacteria (PSB) and zinc-enriched coconut shell biochar on soil biological properties, nutrient bioavailability and soybean (Glycine max L.) yield in acidic soils. 13 treatments, including a control, package of practice and various combinations of PSB and zinc-enriched biochar were assessed in randomised complete block design at P=0.05 level of significance. The biochar was characterized for its physical properties, including bulk density (0.38 Mg m-3), water holding capacity (76.27%) and chemical properties including pH (9.52), electrical conductivity (1.12 dS m-1) and nutrient composition. Results indicated significant improvements in soil dehydrogenase activity, phosphatase activity and major nutrient bioavailability (N, P, K and Zn) in treatments receiving 100% NPK, PSB enriched FYM at 3.125 t ha-1 and different doses of zinc enriched Biochar at 5 t ha-1 compared to the control and package of practice. Soybean yield was maximized under treatments combining PSB-enriched FYM and zinc-enriched biochar, with the highest yield observed in T6 (23.61 q ha-1). The enhanced yield was attributed to improved soil health and nutrient dynamics by PSB and biochar. These findings underscore the potential of PSB and zinc-enriched biochar as sustainable amendments for enhancing soil fertility, crop productivity, and nutrient use efficiency in acidic soils.

Effect of 90 MeV oxygen and carbon ion irradiation on structural, optical and dielectric properties of ZnO embedded in PVA matrix

Abstract ZnO nanoparticles embedded in polyvinyl alcohol (PVA) matrix have been synthesized by solution casting method. The samples were irradiated with 90 MeV O7+ and C6+ ions to different fluences. The structural characterization indicated the semicrystalline nature of PVA along with the formation of ZnO/PVA nanocomposite. The reduction in the peak intensity of the sample upon ion irradiation is due to the chain scissions as well as creation of free-radicals. The crystallite size of the sample increased from ~5.57 to 6.47 nm with increasing fluence. The morphological study reveals the uniform distribution of the ZnO nanoparticles inside the PVA matrix upon ion irradiation. UV-Visible absorption study indicated the presence of both direct and indirect band gap transitions in the sample. Although, the direct band gap of the sample decreased slightly at the initial ion fluence, but the same increased from ~2.95 to 3.82 eV and ~2.95 to 3.73 eV with increasing ion fluence from 0 to 1×1012 ion cm-2, for 90 MeV O7+ and C6+ ion irradiation, respectively. Similar features have also evidenced for the indirect band gap transition. This could possibly be due to the chain scission or cross linking of polymer. The reduction in both real part and imaginary part of impedance with the progress of frequency along with the shifting of impedance peak upon ion irradiation demonstrates the presence of a relaxation process in ZnO/PVA nanocomposite. Both the ion irradiation led to the alteration in dielectric constant and loss, electric modulus, impedance and AC electrical conductivity of the sample. The increase of electrical conductivity of the ZnO/PVA nanocomposite at certain ion fluences of irradiation could be due to uniform dispersion of ZnO inside the PVA matrix as well as the increase of free radicals, unsaturation, loss volatile fragments, etc. due to breaking of chemical bonds.

Delineation and mapping of groundwater quality in Salem district: A comprehensive assessment of contaminant sources

A comprehensive study was conducted at block level in Salem District, Tamil Nadu, India, to evaluate the major ionic chemistry and to assess the suitability of ground water for irrigation purpose. A total of 200 groundwater samples were systematically collected through grid survey and analyzed for major ionic constituents and irrigation water quality parameters. The resulting water quality parameters were interpreted based on established hydrochemical guidelines. The classification of groundwater samples under various quality categories based on pH, electrical conductivity (EC), residual sodium carbonate (RSC) and sodium adsorption ratio (SAR) indicates that many blocks (70 %) in the study area exhibit good-quality groundwater suitable for irrigation. However, exceptions (30 %) were observed in the blocks of Omalur, Mecheri, Kolathur and Pethanaickenpalayam having been observed with saline and alkali water quality. This might be due to the underlying metamorphic and crystalline rocks carrying the element calcium and sodium rich minerals are responsible for the development of saline/alkali groundwater. It was observed that mushrooming of industrial complexes in these blocks might also be the reasons for the development of saline or alkali groundwater. The need for this work is to evaluate groundwater quality for irrigation in Salem District and identify areas affected by saline and alkali contamination due to natural and industrial influences.

Self‐optimizing Cobalt Tungsten Oxide Electrocatalysts toward Enhanced Oxygen Evolution in Alkaline Media

Self‐optimizing mixed metal oxides represent a novel class of electrocatalysts for the advanced oxygen evolution reaction (OER). Here, we report self‐assembled cobalt tungsten oxide nanostructures on a lab‐synthesized copper oxide substrate through a single‐step deposition approach. The resulting composite exhibits remarkable self‐optimization behavior, shown by significantly reduced overpotentials and enhanced current densities, accompanied with substantial increase in OER kinetics, electrocatalytically active surface area, surface wettability, and electrical conductivity. Under operating conditions, interfacial restructuring of the electrocatalyst reveals the in situ formation of oxidized cobalt species as the true active site. Complementary density functional theory (DFT) calculations further demonstrate the formation of *OOH intermediate as the rate‐determining step of OER, and highlight the adaptive binding of oxygen intermediates, which transitions from tungsten to cobalt sites during OER process. Our study provides a fundamental understanding of the self‐optimization mechanism and advances the knowledge‐driven design of efficient water‐splitting electrocatalysts.

Distribution and dynamics for the ecological assessment of Asan Wetland through periphyton -a water quality indicator

The Asan Wetland is an important freshwater wetland in Uttarakhand’s Dehradun district. It is known for its diverse flora and fauna and as a stopover for migratory birds. Periphyton, an essential biological component of aquatic ecosystems, serves as a bioindicator of water quality and ecosystem integrity. This study fills a gap in our knowledge of the Asan Wetland’s ecological health by analyzing periphyton populations and a number of physicochemical characteristics across three selected sites from November 2021 to October 2023. Selected sites named as Site 1(S1), Site 2(S2), Site 3 (S3). Monthly variations in parameters such as water temperature, pH, turbidity, transparency, total dissolved solids (TDS), electrical conductivity, dissolved oxygen (DO), total hardness, alkalinity, biological oxygen demand (BOD), chemical oxygen demand (COD), and nutrients were collected, identified and assessed using Ms-excel and Past software. Phosphorus levels in the Asan Wetland indicated a moderate to high nutrient load, peaking in August (1.20–1.25 mg/L) across all three sites and dropping to their lowest in January (0.35–0.65 mg/L). Nitrate levels were moderate, with the highest concentrations in December (1.40–1.55 mg/L) and the lowest in July (0.25–0.35 mg/L), showing similar seasonal patterns across sites. The periphyton was represented in this study by 18 different periphytic taxa that belong to three different classes. These classes include Bacillariophyceae (Cymbella, Navicula, Nitzschia, Fragilaria Meridion, Synedra, Gomphonema, Tabellaria, and Diatoma), members of the Chlorophyceae Ulothrix, Spirogyra, Cosmarium, Microspora, Chlorella, Oedogomium, Zygnema, and Cladophora are, while Phormidium is a member of the Cyanophyceae. The peak periphytic density (individuals/cm2) recorded was 322.67 ± 89.08 × 103 in January, with all three classes exhibiting maximum values at S3, the minimum periphytic density (individuals/cm2) recorded was 18 ± 5.57 × 10³ in August. The annual percentage composition of periphytic flora in the Asan wetland over 2 years indicates that Bacillariophyceae constituted the predominant group (89%–90%), succeeded by Chlorophyceae (7%–9%) and Cyanophyceae or Myxophyceae (1%–4%) across three sites. The canonical correspondence analysis (CCA) of periphyton among different sites during both years of the study suggested that S3 was more diverse, followed by S1 and S2, represented 64.93%, 35.07% of the variance with eigenvalues of 0.01794, 0.00968 respectively. PCA suggested that PC1 and PC2 were represented by 93.98% and 6.015% of the variance with eigenvalues 279.149 and 17.8675, respectively The multivariate cluster analysis showed the similarity of periphyton at three different sites during the 2-year study. The findings of this study emphasize the need for targeted management strategies to maintain the ecological health of the Asan Wetland.

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.

Physicochemical parameters, microbiological quality, and antibacterial activity of honey from the Bucovina region of Romania

In this study, the physicochemical properties (electrical conductivity (EC), pH, free acidity, moisture content, DPPH radical scavenging activity, total polyphenols content (TPC), flavonoids content (FC), individual polyphenols, carbohydrates, and organic acids), microbiological quality, and antibacterial activity of honey (raspberry, rosehip, alfalfa, hawthorn, and honeydew honey) from Bucovina were evaluated. Along with melissopalynological analysis, the physicochemical parameters were determined for the honey samples to characterize the samples and to assess their applicability in classifying honey based on its botanical origin. Another objective of the study was the evaluation of the microbiological quality and antibacterial activity of honey samples. The antibacterial activity was examined against the growth of four pathogenic bacterial strains (Staphylococcus aureus ATCC 29213, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, and Salmonella enterica serovar Typhimurium ATCC 14028) by the diffusion test in the agar well and by determining the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC). The analyzed honey samples were within the safe limits, except for three samples in which Bacillus cereus was detected and two other samples that had values above the acceptable limit for yeasts. Thus, 40.46% of all honey samples had bactericidal activity that was superior or at least comparable to manuka honey MGO550 against Staphylococcus aureus, 57.69% against Salmonella enterica serovar Typhimurium, 74.15% against Pseudomonas aeruginosa, and 75% against Escherichia coli. Of all types of honey analyzed in this study, honeydew honey had the highest bactericidal activity, followed by polyfloral honey.

3D laser structuring of supermetalphobic microstructures inside elastomer for multilayer high-density interconnect soft electronics

Abstract High-density interconnect (HDI) soft electronics that can integrate multiple individual functions into one miniaturized monolithic system is promising for applications related to smart healthcare, soft robotics, and human-machine interactions. However, despite the recent advances, the development of three-dimensional (3D) soft electronics with both high resolution and high integration is still challenging because of the lack of efficient manufacturing methods to guarantee interlayer alignment of the high-density vias and reliable interlayer electrical conductivity. Here, an advanced 3D laser printing pathway, based on femtosecond laser direct writing (FLDW), is demonstrated for preparing liquid metal (LM)-based any layer HDI soft electronics. FLDW technology, with the characteristics of high spatial resolution and high precision, allows the maskless fabrication of high-resolution embedded LM microchannels and high-density vertical interconnect accesses for 3D integrated circuits. High-aspect-ratio blind/through LM microstructures are formed inside the elastomer due to the supermetalphobicity induced during laser ablation. The LM-based HDI circuit featuring high resolution (∼1.5 μm) and high integration (10-layer electrical interconnection) is achieved for customized soft electronics, including various customized multilayer passive electric components, soft multilayer circuit, and cross-scale multimode sensors. The 3D laser printing method provides a versatile approach for developing chip-level soft electronics.

Properties of Soils of Medak District in Telangana State, India

For the management of soil and plant growth the physicochemical study of parameters are crucial.The objective of this study is to do the physical and chemical analysis of soil samples collected from agricultural fields of Medak district and to provide information to the farmers. Soil samples collected from twenty mandals at three samples per mandal from 0-15 cm depth. Soil parameters like soil texture, pH, EC, organic carbon available nitrogen, phosphorus, potassium and Sulphur tested and recorded. Results shows texture varies from sandy clay loam to sandy loam. pH shows slightly acidic, neutral to slightly alkaline. Electric conductivity remains within the safe limits. The organic carbon recorded maximum low to medium in content, low in nitrogen content, medium to high range in phosphorous, potassium. The available sulphur recorded deficient to sufficient values. The findings suggest that farmers should adopt appropriate soil management techniques, such as crop rotation and conservation tillage which will add to maintain the soil physical characteristics to ensure the sustainability of agricultural practices and the long-term health of the soil.

Enhanced Conductivity of Multilayer Copper–Carbon Nanofilms via Plasma Immersion Deposition

Although room-temperature superconductivity is still difficult to achieve, researching materials with electrical conductivity significantly higher than that of copper will be of great importance in improving energy efficiency, reducing costs, lightening equipment weight, and enhancing overall performance. Herein, this study presents a novel copper-carbon nanofilm composite with enhanced conductivity which has great applications in the electronic devices and electrical equipment. Multilayer copper-carbon nanofilms and interfaces with superior electronic structures are formed based on copper materials using plasma immersion nanocarbon layer deposition technology, effectively enhancing conductivity. Experimental results show that for a five-layer copper-carbon nanofilm composite, the conductivity improves significantly when the thickness of the carbon nanofilm increases. When the carbon nanofilm accounts for 16% of the total thickness, the overall conductivity increases up to 30.20% compared to pure copper. The mechanism of the enhanced conductivity is analyzed including roles of copper atom adsorption sites and electron migration pathways by applying effective medium theory, first-principles calculations and density of states analysis. Under an applied electric field, the high-density electrons in the copper film can migrate into the nanocarbon film, forming highly efficient electron transport channels, which significantly enhance the material's conductivity. Finally, large-area electrode coating equipment is developed based on this study, providing the novel and robust strategy to enhance the conductivity of copper materials, which enables industrial application of copper-carbon nanocomposite films in the field of high conductivity materials.

Metabolomic profiling of paper board sludge biochar for agricultural use.

The pulp and paperboard industries are the major industrial sector that consumes significant amounts of fresh water and generates large volumes of wastewater. The treatment of this wastewater resulted in the production of a substantial amount of sludge, which posed serious environmental challenges. This study explored a sustainable solution by converting PBS into biochar through slow pyrolysis of temperatures up to ≤ 500°C, offering an alternative approach to waste management and resource conservation. The physicochemical parameters of paper board sludge biochar (PBSB) exhibited a neutral pH of 7.49, electrical conductivity of 0.09 dS m-1, organic carbon of 38.12% and CaCO3 of 24.5%. Proximate analysis of PBSB revealed an increased fixed carbon of 76.43%, total organic carbon (TOC) of 7.13%, and reduced volatile matter and moisture levels. The TGA analysis of the dried paperboard sludge sample showed a 20% mass reduction when heated to 350°C. During this process, more than 90% of the volatile components were removed.. The micro nutrients viz., Fe 5.06mg L-1, Mn 419.3mg L-1, Cu 26.3mg L-1, and Zn 66.1mg L-1 contents were observed in PBSB. FT-IR analysis identified the presence of various carbon-containing functional groups, including C-Cl, C-N, C-C, H-C = O, C-H, and -C≡C-H, indicating substantial chemical transformations during pyrolysis. SEM-EDX analysis revealed that PBSB has fine particle size and a coarse fluffy spongy porous structure ideal for water adsorption. Elemental analysis (XRD) showed high carbon and oxygen content with significant amounts of aluminosilicates, carbonates, and nutrients like phosphorus and potassium, suggesting PBSB as a potential slow-release fertilizer. This research highlights the potential of biochar derived from paperboard waste as a sustainable solution for waste management and resource recovery.

Fe3O4 modified graphene epoxy composite materials via polyether amine reduction with enhanced microwave absorption performance

Abstract The increasing complexity of electromagnetic environments demands the development of advanced absorbers with superior performance. In this study, a novel magnetic Fe3O4-modified graphene-based absorber (FARGO) is synthesized via an in-situ reduction process using polyether amine. The resulting FARGO composite exhibits excellent microwave absorption properties. When the filling content of FARGO is 5 wt% in epoxy resin, the optimal reflection loss is -23.12 dB with a thickness of 4 mm and a broad absorption bandwidth of 5.6 GHz can be achieved as the thickness changes to 2 mm. Polyether amine efficiently reduces GO to rGO, significantly improving electrical conductivity. Simultaneously, it grafts amine groups onto the graphene surface, enhancing dispersion and reactivity within the epoxy resin matrix. These synergistic effects make it a promising candidate for high-performance microwave absorbing materials.