Resistance Values Research Articles

Utilizing of Geophysical Methods for Geothermal Exploration at Guru Kinayan Village, Tanah Karo Regency

Guru Kinayan, located at the foothills of mount Sinabung in Karo regency, is characterized by several geothermal manifestations, highlighting the necessity of studying its geothermal potential. This research aims to assess the geothermal prospects of the area through 2-D electrical resistivity, geomagnetic surveys, and (XRD) methods. To acquire 2-D resistivity data, a Wenner Schlumberger array with a 5-meter electrode spacing was utilized, and the data were processed using Res2Dinv. Geomagnetic surveys were conducted using a PPM, with the results analyzed using Mag2dc and Surfer 13 to determine susceptibility results. The analysis of rock composition was performed using XRD. The 2-D resistivity results indicated resistivity values ranging from 1 to 1250 Ωm. Values between 1 and 20 Ωm indicated as alluvium, indicating a reservoir for geothermal, while resistivity values >1000 indicates as limestone, which indicated as a heat conductor. The magnetic residual map shows geomagnetic values (20 to 380 nT), suggesting a geothermal source, and the susceptibility values ranging (0.0013 x 10³ to 0.0088 x 10³) indicates the presence of igneous rocks, specifically andesite lava and pyroclastic rocks. The XRD results show arsenopirit and quartz in the geothermal area. Based on the integrated results, the study area has significant geothermal potential.

Impact of Implementing Female Genomic Selection and the Use of Sex-Selected Semen Technology on Genetic Gain in a Dairy Herd in New Zealand

Genomic selection (GS) has changed cattle breeding, but its use so far has been in selecting superior bulls for breeding. However, its farm-level impact, particularly on female selection, remains less explored. This study aimed to investigate the impact of implementing GS to identify superior cows and using artificial mating of those cows with sex-selected semen in a New Zealand Holstein-Friesian (HF) dairy herd (n = 1800 cows). Heifers (n = 2061) born over four consecutive years between 2021 and 2024 were genotyped and their genomic breeding values (GBVs) were estimated. These heifers were ranked based on the Balanced Performance Index (BPI; DataGene, Dairy Australia) Lower-performing cows producing less than 15 L/day (or 20 L/day for older cows) and those with severe mastitis were culled. Cows were mated with HF genetics based on production and udder breeding values, while lower-performing cows were mated to beef genetics. Milking adult cows were mated to bulls with similar BPI value. Annual genetic change was measured using Australian breeding values (ABVg) for milk fat production (FAT), protein production (PROT), fertility (FER), Mastitis Resistance (MAS), and BPI. The genetic merits of the heifers improved annually, with BPI increasing from 136 to 184 between 2021 and 2023, corresponding to a financial gain of NZD 17.53 per animal per year. The predicted BPI gain from 2023 to 2026 is expected to rise from 184 to 384, resulting in a financial gain of NZD 72.96 per animal per year. Using sex-selected semen on the top 50% of BPI-rated heifers in 2024 further accelerated genetic gain. Predicted BPI values for progeny born in 2025 and 2026 are 320 and 384, respectively. These findings revealed that the female GS, combined with sex-selected semen from genomically selected bulls, significantly accelerates genetic gain by improving the intensity and accuracy of selection. The approach achieves genetic progress equivalent to what traditionally would have required eight years of breeding without female GS, and has potential to improve dairy herd performance and profitability.

Enhancing the performance of polyfarnesene-based bio-rubbers with surface-modified cellulose nanocrystals and nanofibers

As the rubber industry seeks sustainable alternatives to mitigate its environmental impact, this study introduces a biobased approach using polyfarnesene rubber reinforced with plasma-modified cellulose nanocrystals (MCNC) and nanofibers (MCNF). The nanocellulose was modified by plasma-induced polymerization using trans-β-farnesene and was characterized by FTIR, XPS, XRD, TGA, and SEM to confirm the grafting of farnesene-derived polymer chains onto the cellulose surface, demonstrating the successful modification and integration of the nanoparticles. Polyfarnesene bio-based rubbers were synthesized through two different polymerization techniques: solution-based coordination polymerization (PFA1) and emulsion-based free radical polymerization (PFA2). The modified nanoparticles were incorporated into these rubber matrices at 2–12 wt% and vulcanized by incorporation of sulfur. The performance of bio-rubbers reinforced with cellulose nanoparticles was analyzed by tensile test and dynamic mechanical analysis (DMA). Mechanical tests focused on tensile strength, Young’s modulus, and elongation at break showed that incorporation of 12 wt% modified MCNF into the PFA1 and PFA2 increased tensile strength by 56% and 22%, and Young’s modulus by 27% and 58%, respectively (compared to the neat rubber matrix), while elongation at break decreased with increasing MCNF content. The addition of MCNC into PFA1 and PFA2 improved the deformation resistance values of 205% for PFA1-MCNC12% and 49% for PFA2-MCNC12%. Dynamic mechanical analysis showed an increase in storage modulus and a shift towards higher glass transition temperatures, indicating stronger filler-matrix interactions. The results demonstrate that plasma-modified cellulose nanoparticles effectively enhance the mechanical properties of polyfarnesene bio-rubbers, offering a sustainable alternative with performance competitive to synthetic rubbers.

Development and Optimization of a Cost-Effective Electrochemical Immunosensor for Rapid COVID-19 Diagnosis

The coronavirus disease (COVID-19) pandemic has created an urgent need for rapid, accurate, and cost-effective diagnostic tools. In this study, an economical electrochemical immunosensor for the rapid diagnosis of COVID-19 was developed and optimized based on charge transfer resistance (Rct) values obtained by electrochemical impedance spectroscopy (EIS) from the interaction between antibodies (anti-SARS-CoV-2) immobilized as a bioreceptor and the virus (SARS-CoV-2). The sensor uses modified pencil graphite electrodes (PGE) coated with poly(4-hydroxybenzoic acid), anti-SARS-CoV-2, and silver nanoparticles. The immobilization of anti-SARS-CoV-2 antibodies was optimized at a concentration of 1:250 for 30 min, followed by blocking the surface with 0.01% bovine serum albumin for 10 min. The optimal conditions for virus detection in clinical samples were a 1:10 dilution with a response time of 20 min. The immunosensor responded linearly in the range of 0.2–2.5 × 106 particles/μL. From the relationship between the obtained signal and the concentration of the analyzed sample, the limit of detection (LOD) and limit of quantification (LOQ) obtained were 1.21 × 106 and 4.04 × 106 particles/μL, respectively. The device did not cross-react with other viruses, including Influenza A and B, HIV, and Vaccinia virus. The relative standard deviation (RSD) of the six immunosensors prepared using the shared-pool sample was 3.87. Decreases of 22.3% and 12.4% were observed in the response values of the ten immunosensors stored at 25 °C and 4.0 °C, respectively. The sensor provides timely and accurate results with high sensitivity and specificity, offering a cost-effective alternative to the existing diagnostic methods.

Using roof borehole electrical resistivity tomography to monitor roof water infiltration in a mine work face

Roof water inrush in coal mining is a significant type of water-related disaster that usually results from the interconnection of water-bearing geological formations formed by cracks during and after work face mining. Therefore, monitoring roof water infiltration is of paramount importance in preventing or mitigating water inrush in the mine work face. This study employed the roof borehole electrical resistivity tomography method to conduct physical experiments for monitoring water seepage in roof cracks generated during coal model mining. Additionally, roof water infiltration monitoring was performed in the 7130 work face of the Qidong Coal Mine. The results of both physical experiments and field tests demonstrate that roof borehole electrical resistivity tomography (ERT) is well suited for monitoring roof water infiltration in mine work faces, enabling the determination of the temporal and spatial distributions of water seepage. By analyzing the variation patterns of low-resistivity anomalies in the resistivity profile, the water-conducting channels and water outflow points can be identified. Experiments and field tests suggest that the resistivity and its changes are related to the amount of water inflow and water channel. With the increase of water inflow, the relatively low resistivity anomalies region increases, the resistivity value decreases and the water channel appears and expands. With the amount of water inflow decreasing, the relatively low resistivity area becomes smaller, the resistivity value increases, and the water channel narrows or even disappears.Furthermore, by combining the areas of low-resistivity anomalies, a qualitative assessment of the water content can be achieved. Finally, The results of the periodic weighting analysis of the field tests indicate that roof water infiltration is related to periodic weighting. The greater the periodic weighting is, the more severe the roof water infiltration.

Adipose-derived stem cells promote the recovery of intestinal barrier function by inhibiting the p38 MAPK signaling pathway.

Intestinal barrier damage causes an imbalance in the intestinal flora and microbial environment, promoting a variety of gastrointestinal diseases. This study aimed to explore the mechanism by which adipose-derived stem cells (ADSCs) repair intestinal barrier damage. The human colon adenocarcinoma cell line Caco-2 and rats were treated with lipopolysaccharide (LPS) to establish in vitro and in vivo models, respectively, of intestinal barrier damage. The expression of inflammatory cytokines (TNF-α, HMGB1, IL-1β and IL-6), antioxidant enzymes (iNOS, SOD and CAT), and oxidative products (MDA and 8-iso-PGF2α) was detected using ELISA kits and related reagent kits. Apoptosis-related proteins (Bcl-2, Bax, Caspase-3 and Caspase-9), tight junction proteins (ZO-1, Occludin, E-cadherin, and Claudin-1) and p38 MAPK pathway-associated protein were detected by Western blotting. In addition, cell viability and apoptosis was determined by a CCK-8 kit and flow cytometry, respectively. Cell permeability was assayed by the transepithelial electrical resistance value and FITC-dextran concentration. The homing effect of ADSCs was detected by fluorescence labeling, and intestinal barrier tissue was observed by HE staining. After ADSC treatment, the level of phosphorylated p38 MAPK protein decreased, the expression of inflammatory factors, oxidative stress and cell apoptosis decreased, the expression of tight junction proteins increased, and cell permeability decreased in Caco-2 cells stimulated with LPS. In rats, ADSCs are directionally recruited to damaged intestinal tissue. ADSCs significantly decreased the levels of D-lactate, diamine oxidase (DAO) and FITC-dextran induced by LPS. ADSCs promoted tight junction proteins and inhibited oxidative stress in intestinal tissue. These effects were reversed after the use of a p38 MAPK activator. ADSCs can be directionally recruited to intestinal tissue, upregulate tight junction proteins, and reduce apoptosis and oxidative stress by inhibiting the p38MAPK signaling pathway. This study provides novel insights into the treatment of intestinal injury.

System-level modeling with temperature compensation for a CMOS-MEMS monolithic calorimetric flow sensing SoC

We present a system-level model with an on-chip temperature compensation technique for a CMOS-MEMS monolithic calorimetric flow sensing SoC. The model encompasses mechanical, thermal, and electrical domains to facilitate the co-design of a MEMS sensor and CMOS interface circuits on the EDA platform. The compensation strategy is implemented on-chip with a variable temperature difference heating circuit. Results show that the linear programming for the low-temperature drift in the SoC output is characterized by a compensation resistor Rc with a resistance value of 748.21 Ω and a temperature coefficient of resistance of 3.037 × 10−3 °C−1 at 25 °C. Experimental validation demonstrates that within an ambient temperature range of 0–50 °C and a flow range of 0–10 m/s, the temperature drift of the sensor is reduced to ±1.6%, as compared to ±8.9% observed in a counterpart with the constant temperature difference circuit. Therefore, this on-chip temperature-compensated CMOS-MEMS flow sensing SoC is promising for low-cost sensing applications such as respiratory monitoring and smart energy-efficient buildings.

The Effect of Polyethylene Fiber and Flowable Resin Composite on Fracture Resistance in the Restoration of Large MOD Cavities.

This invitro study aims to evaluate the effect of placing polyethylene fibers used in large Class II MOD (mesio-occlusion-distal) cavities into different flowable resin composites and in different positions on the fracture resistance of the restoration. Ninety healthy human molars were used in the study. No treatment was performed on 10 of these teeth and they were used as the control group. The other 80 teeth were divided into 8 groups by opening large MOD cavities (n = 10). The groups were divided into 4 main groups according to the use of fiber strips; no fiber, placed in the buccolingual direction, placed in the mesiodistal direction, and placed in an "O" shape on all walls. Each main group was divided into two subgroups according to the use of the nanofill flowable composite or flowable short fiber resin composite (SFRC) as the base material. All teeth were aged with a thermal cycler and then fractured with a universal testing machine. Fracture types were recorded in terms of fracture strength and repairability. Kruskal-Wallis, one-way ANOVA, and Tukey post hoc tests were used to compare fracture strength values (p < 0.05). The highest fracture resistance was observed in the control group (2888.67 ± 395.43 N). The control group was significantly higher than all groups except the 7th and 8th groups (p < 0.05). Among the restored groups, the highest mean fracture resistance values were observed in the 8th group (2463.92 ± 332.37 N). The 8th group was statistically significantly higher than the 1st and 2nd groups (p < 0.05). There was no statistically significant difference between any of the other restored groups (p > 0.05). The application of polyethylene fiber in the treatment of teeth with large MOD cavities in different positions did not result in a significant difference in fracture resistance.

Unveiling the Origin of the Scale-Dependent Conductivity of Ni3(HITP)2 Metal-Organic Framework Thin Films.

Conductive metal-organic frameworks (MOFs) are crystalline, intrinsically porous materials that combine remarkable electrical conductivity with exceptional structural and chemical versatility. This rare combination makes these materials highly suitable for a wide range of energy-related applications. However, the electrical conductivity in MOF-based devices is often limited by the presence of different types of structural disorder. Here, the electrical transport characteristics of high quality Ni3(HITP)2 nanometer-thin films are reported. These findings reveal a tenfold difference in conductivity between the micro- and nano-scale, attributed to poor electrical connection among a limited number of crystalline grains. Average in-plane conductivity values at the micro- (σIP,micro = 0.7 ± 0.3 Scm-1) and nano- (σIP,nano = 6 ± 3 Scm-1) scales is determined, and the value of the inter-grain resistance, Rinter-grain = 40 kΩ is found. Using a 2D resistor network model with a 40 kΩ base resistance and scattered higher resistances, surface potential maps of in-operando MOF-based electrical devices are successfully reproduced. Additionally, a structure-property relationship that links the density and spatial distribution of electrical failures in inter-grain connections to the observed micro-scale conductivity in MOF thin films is established.

Integrative analysis of the Aachen geothermal system (Germany) with an interdisciplinary conceptual model

The comprehension of geothermal systems involves the efficient integration of geological, geophysical and geochemical tools that are crucial in unraveling the distinct features inherent in geothermal reservoirs. We provide a first approach to comprehending the geologically complex geothermal system in the Aachen area, which has been known for its natural thermal spring occurrences since Roman times. Through a comprehensive analysis involving geochemical interpretation of water samples, a review of 2D seismic profiles, stress analysis, and surface geology, a dynamic model has been built, which serves as a conceptual framework providing a clearer understanding of the system. The model characterizes a non-magmatic, detachment fault-controlled convective thermal system, wherein the reservoir exhibits mixed properties of the mainly Devonian carbonate rocks. NW–SE directed fault lines play a pivotal role in fluid transport, enabling the ascent of thermal waters without the need for additional energy. We additionally conducted magnetotelluric (MT) surveys and analyzed apparent resistivity and impedance values obtained through forward modeling, along with an assessment of noise levels. These findings contribute to evaluating the potential use of MT methods in further evaluating the study area and for geothermal energy exploration in general.

A simplified computational liver perfusion model, with applications to organ preservation

Advanced liver preservation strategies could revolutionize liver transplantation by extending preservation time, thereby allowing for broader availability and better matching of transplants. However, developing new cryopreservation protocols requires exploration of a complex design space, further complicated by the scarcity of real human livers to experiment upon. We aim to create computational models of the liver to aid in the development of new cryopreservation protocols. Towards this goal, we present an approach for generating 3D models of the liver vasculature by building upon the space colonization algorithm. Additionally, we introduce the concept of a super lobule which enables a computational abstraction of biological liver lobules. User-tunable parameters allow for vasculatures of varying depth and topology to be generated. In each model, we solve for a common lumped resistance value assigned to the super lobules, allowing the overall physiological blood pressure and flow rate through the liver to be preserved. We demonstrate our approach’s ability to maintain consistency between models of varying depth. Finally, we simulate steady state machine perfusion of the generated models and demonstrate how they can be used to quickly test the effect of different boundary conditions when designing organ preservation protocols.

LFP via Nanoscale Surface Reforming with a Tiny Minimal Amount of Conductivity-Enhancing Material.

LiFePO4 (LFP) typically requires a conductive additive to improve its low ion and electron conductivity. In this study, we achieved significant enhancements in Li+ and electron mobility by applying a minimal amount of conductive material through a new coating process. The coin cell demonstrated an excellent capacity of 157.57 mA h g-1 at 0.1 C/25 °C, while the pouch cell exhibited excellent long-term cycling stability, maintaining 99.33% capacity after 150 cycles at 1 C/45 °C. Compared to pristine LFP, the rate capacities increased by 30%, reaching 130.9 mA h g-1 at 3 C. After 100 cycles, the RCT resistance value decreased by 10% compared to pristine. The uniform coating layer not only improved electronic conductivity but also enhanced the rate performance. DCIR testing of the pouch cell showed a 17.7% reduction in resistance values compared to that of pristine LFP with increasing cycles. This new coating method, using a very small amount of conductive material, forms a uniform coating layer that optimizes electrochemical performance while maintaining the economic benefits of the LFP cathode material.

Eliminating Inductive Coupling in Small-Loop TEM Through Differential Measurement with Opposing Coils

The small-loop transient electromagnetic method (TEM) refers to a system in which the coil frame length or diameter is less than 2 m. Due to the inductive effects of the multi-turn coils used for both transmission and reception, the induced electromotive force in the measuring coil increases, causing a reduction in the decay rate and an extension of the shutoff time. This results in coupling between the primary and secondary fields in early-time signals, making them difficult to separate and creating a detection blind spot in the shallow subsurface. The opposing coil TEM transmission and reception method can significantly reduce early-time signal distortion caused by coil inductance. However, this approach is constrained by the physical symmetry of the coil dimensions, which makes it challenging to achieve balance in a zero-field space. By performing both forward and reverse measurements at the same location using the opposing coil setup and calculating the difference between the signals, the inductive coupling between coils at the measurement site can theoretically be eliminated. This eliminates the induced potential of the TEM signal, enhancing the induced electromotive force from the formation. As a result, more accurate resistivity values are obtained, detection blind spots are eliminated, and the resolution in shallow TEM exploration is improved. Field experiments were conducted to validate the method on both high-resistivity and low-resistivity anomalies. The results demonstrated that this method effectively identified a high-resistivity corrugated pipe at a depth of 1.2 m and two low-resistivity gas pipelines at a depth of 2 m, thereby essentially eliminating detection blind spots in the shallow subsurface.

Effect of Mediterranean Diet in Combination with Isokinetic Exercise Therapy on Body Composition and Cytokine Profile in Patients with Metabolic Syndrome.

Metabolic syndrome (MS) is a combination of comorbidities that increase pro-inflammatory cytokines (PIC) production, with subsequent body composition (BC) abnormalities and high cardiovascular risk. Treatment with diet and exercise has been suggested as possible non-pharmacological adjuvant treatment. To determine changes in BC and PIC in patients with MS after a Mediterranean-type diet (MedDiet) and/or isokinetic exercise (IE). A controlled randomized clinical trial was conducted at a third-level hospital in Mexico City. Intervention groups: G1: MedDiet + IE; G2: IE; G3: MedDiet; G4: control. Anthropometry, BC, and PIC were collected from the baseline and at 12 weeks post-intervention. MedDiet was estimated from a 24-h recall record. IE consisted of a standard high-intensity anaerobic exercise program. Forty-two patients with MS aged 18-65 years old were included. The most frequent comorbidities were obesity, insulin resistance, and dyslipidemia. After 6 months of intervention, a significant reduction of resistin was observed within the IE group and MedDiet + IE, whereas the former group also showed an increase in adiponectin. Interventions of MedDiet and MedDiet + IE showed a decrease in IL-10. Regarding BC, all groups increased the resistance values in relation to the baseline but were lower than the control group. The results suggest that MedDiet and IE have a selective impact on pro-inflammatory mediators, while the combination of MedDiet and IE may induce only minor changes in BC.

Renal pelvis pressure and flowrate with a multi-channel ureteroscope: invoking the concept of outflow resistance.

Understanding renal pelvis pressure (PRP) during ureteroscopy (URS) has become increasingly important. High irrigation rates, desirable to maintain visualization and limit thermal dose, can increase PRP. Use of a multi-channel ureteroscope (m-ureteroscope) with a dedicated drainage channel is one strategy that may facilitate simultaneous low PRP and high flowrate. We sought to define the relationship between PRP and flowrate across a range of different outflow resistance scenarios with an m-ureteroscope versus a single-channel ureteroscope (s-ureteroscope). The m- or s-ureteroscope was placed into the pelvis of a validated silicone kidney-ureter model. Trials were conducted at irrigation pressures (50-150 cmH20) and five different outflow resistance scenarios simulated with catheters of different lengths and diameters. PRP was measured with a fiber optic pressure sensor positioned in the renal pelvis. Flowrate was determined by measuring the mass of drainage fluid over 60s. PRP was lower with the m-ureteroscope than the s-ureteroscope when equivalent flowrates were delivered (i.e. 34 vs. 82 cmH20 respectively with 15ml/min irrigation in a high outflow resistance scenario). Flowrate was higher with the m-ureteroscope than the s-ureteroscope when equivalent irrigation pressures were applied (i.e. 28 vs. 14ml/min respectively with irrigation pressure 150 cmH20 in a high outflow resistance scenario). The m-ureteroscope has improved pressure-flow dynamics imparting important clinical benefits. More importantly, this approach to framing ureteroscopy in the context of pressure-flow relationships related by resistance values allows quantification of ureteroscopy within a deterministic system, which can be used to streamline future device development and technological innovation.

Geophysical and geochemical characterization of Odogbo Dumpsite, Ijebu Ijesa, Southwestern Nigeria.

Due to incessant contamination of the groundwater system near the dumpsite in southwestern Nigeria Basement Complex, this study seeks to evaluate the impact of the Odogbo dumpsite on the local groundwater system by integrating geophysical and geochemical methodologies. Aeromagnetic data covering the study area was acquired, processed, and enhanced to delineate basement features that could potentially be passing plumes to the groundwater system. Concurrently, geoelectric methods using 2-D dipole-dipole imaging and vertical electrical sounding (VES) were utilized to characterize the vulnerability indices of the lithologies underlying the dumpsite. The resistivity data was collected with the UltraminiRES resistivity meter. Vulnerability assessment of the regolith was conducted through longitudinal conductance rating. Water samples from the vicinity of the dumpsite were analyzed using a spectra AA220 atomic absorption spectrophotometer (AAS). The results of magnetic derivatives and analytical signals filters revealed that the Odogbo dumpsite is directly situated atop lineaments trending mainly in an NE-SW direction. The 2-D resistivity model depicted the extent of the leachate plume percolation, characterized by resistivity values below 20 Ωm. The curve types identified from VES results were A, H, HK, and KQ while the geoelectric layers were identified as topsoil, weathered layer, lateritic layer, and fresh/fracture basement. The protective capacity varied across the area, from 0.02 to 0.473 mhos, signifying weak to moderate protective capacity of the overlying layer. Most elemental parameters tested fell below the World Health Organization (WHO) permissible values and some were within WHO standards except iron. All the water sampled were rated poor to unsuitable as their water quality index (WQI) ranged between 232.81357 and 1520.88776 due to high elemental iron content which could be from other sources. The study area is safe from contamination for now but there is a high tendency that the area may be contaminated in future; hence, the need to monitor the region periodically is highly recommended.

Assessing Corrosion Effects on the Electrical Performance of Wearable Photovoltaic Cells: A Comparative Analysis of Current Consistency and Resistance.

Wearable photovoltaic (PV) cells offer a sustainable and lightweight solution for energy-harvesting applications, including safety gear and protective textiles. Despite their growing adoption, the application of PV cells in marine environments is limited due to the corrosive conditions that can degrade performance. This study evaluates the impact of corrosion on commercially sourced PV cells by analyzing maximum current and electrical resistance. This study used eight samples of two types of PV panel cells and tested them in corrosion conditions, and current and electrical resistance values were recorded. A paired sample t-test was used to assess variations in current and electrical resistance, while a repeated MANOVA compared the performance of two sample types during corrosion. The results reveal that corrosion significantly reduced current values and increased electrical resistance in Sample Type (1), while Sample Type (2) remained relatively stable. The MANOVA findings show a significant decrease in current for both samples, though the magnitude of reduction is similar between types. However, when combining both sample types, corrosion has no significant effect on electrical resistance. These results highlight the need for developing more durable, corrosion-resistant PV cells suitable for marine applications, emphasizing their potential for sustainable and practical use in harsh environments.

Improved capacitance of NiO and nanoporous silicon electrodes for micro-supercapacitor application

We investigated the NiO/PS/Si and the NiO/Si electrodes to highlight the effect of the PS porous silicon on the enhancement of the electrode performance. We elaborated the PS with the stain etching method, whereas the NiO nickel oxide was synthesized using sol–gel and deposited through the spin coating technique. We showed that PS porous silicon significantly increased the active surface area and improved the electrical and electrochemical properties. Thus, we obtained promising results for NiO/PS/Si. The effective series resistance and interfacial resistances were reduced from 1.8 Ω cm2 and 42 Ω cm2 to 0.05 Ω cm2 and 0.29 Ω cm2 from NiO/Si to NiO/PS/Si, respectively. The capacitance increased from 12.34 µF cm−2 for NiO/Si to 9.64 mF cm−2 for NiO/PS/Si. We found similar capacity values from the CV cyclic voltammetry curves and IS impedance spectroscopy Nyquist plots. We obtained equivalent effective series resistance values from the charge–discharge and Nyquist plots, confirming our results. The NiO/PS/Si electrode showed good stability with only a 3% loss for 5000 galvanostatic cycles. The energy efficiency is estimated from the charge–discharge curves to be 91%.

An electrochromic alginate fiber based on a W18O49/PEDOT:PSS composite layer.

In this experiment, we studied a technique that permits the continuous fabrication of electrochromic alginate fibers because there hasn't been much research on electrochromic alginate fibers. Therefore, it's important to investigate ways to increase the application areas of alginate fibers. AgNP‑calcium alginate fibers with high electrical conductivity were prepared by Ag+ substitution method. Electrochromic alginate fibers were successfully prepared by sequentially coating the fibers with PEDOT:PSS, W18O49, and PVDF:HFP to form a W18O49/PEDOT:PSS composite color-changing layer and a PVDF:HFP stable electrolyte layer. Fifty electrochromic alginate fibers with a length of 7cm were tested, and their resistance values ranged from 2 to 12Ω, of which 78% were between 3 and 8Ω, providing excellent electrical conductivity. In the electrolyte from 0.1V to -0.7V, the color of the fiber changes from the original state to the colored state in only 5s. Ten minutes after the voltage is disconnected, the color changes to the original color of the AgNP-Calcium Alginate fibers and the color change are reversible. The solid fibers can change from light blue to dark blue and the color change is uniform in the upright and bent state. This study lays a solid research foundation for the industrial production and intelligent application of electrochromic alginate fibers.

Electrical resistivity tomography data inversion using prior information for tunnel prospecting: A case study from southwestern China

AbstractThe direct current (DC) resistivity method is extensively used to predict water‐inrush disasters in tunnel prospecting. However, during DC resistivity inversion, different initial models can significantly affect the inversion results, often resulting in convergence at a local optimum. To overcome these challenges, we propose a new method for DC data inversion that uses prior information as a reference model. First, the resistivity distribution of the surrounding rock mass was estimated based on detailed geological analysis. Next, an initial homogeneous resistivity model was constructed by averaging the observed tunnel resistivity values. Finally, the initial model was developed by incorporating borehole rock samples and water content data. The effectiveness of the method' was assessed using a series of synthetic models of typical water‐bearing structures. We then applied this approach to the Laomacao Tunnel in the Yunnan Central Water Diversion Project (southwestern China), where drilling data were used as a priori information to optimize the initial model together with the average tunnel resistivity values, successfully identifying the water‐bearing structure ahead of the tunnel face. Overall, the proposed method enhances the understanding of sudden surges, aiding in the prevention and control of water disasters in tunnels.