Maximum Electrical Resistance Research Articles

Evaluating the Impact of Laundering on the Electrical Performance of Wearable Photovoltaic Cells: A Comparative Study of Current Consistency and Resistance

Wearable photovoltaic technology has been prominent in recent years because electronic devices need to be powered continuously without reliance on traditional methods. However, the practical adoption of wearable PV cells is hindered by the need for laundering, potentially degrading performance. This research compared PV cells’ maximum current and electrical resistance before and after laundering testing conditions. This study used eight samples of two types of PV panel cells and laundered them up to five cycles. The current and electrical resistance values were recorded before and after each laundering cycle. This study analyzed the data using a paired sample t-test and MANOVA. It was found that laundering cycles significantly affected the current values in both types of samples, with no differential impact between the types; on the other hand, laundering cycles did not significantly affect the electrical resistance values in both types of samples, with no differential impact between the types. These results are crucial for industries developing textile-based PV panels, where maintaining electrical performance after laundering is essential. These findings could pave the way for more sustainable, self-powered wearable PV technologies, ultimately transforming how users interact with electronic devices daily.

Experimental Investigation into the Mechanical and Piezoresistive Sensing Properties of Recycled Carbon-Fiber-Reinforced Polymer Composites for Self-Sensing Applications.

This study investigates the mechanical and piezoresistive sensing properties of recycled carbon-fiber-reinforced polymer composites (rCFRPs) for self-sensing applications, which were prepared from recycled carbon fibers (rCFs) with fiber lengths of 6, 12, 18, and 24 mm using a vacuum infusion method. Mechanical properties of the rCFRPs were examined using uniaxial tensile tests, while sensing characteristics were examined by monitoring the in situ electrical resistance under cyclic and low fatigue loads. Longer fibers (24 mm) showed the superior tensile strength (92.6 MPa) and modulus (8.4 GPa), with improvements of 962.1% and 1061.1%, respectively. Shorter fibers (6 mm) demonstrated enhanced sensing capabilities with the highest sensitivity under low fatigue testing (1000 cycles at 10 MPa), showing an average maximum electrical resistance change rate of 0.7315% and a gauge factor of 4.5876. All the composites displayed a stable electrical response under cyclic and low fatigue loadings. These results provide insights into optimizing rCF incorporation, balancing structural integrity with self-sensing capabilities and contributing to the development of sustainable multifunctional materials.

Development of hBN/natural fibres reinforced polymer composites using grey relation grade analysis for thermal and electrical applications

The objective of this work is to enhance the thermal conductivity and electrical properties of polymer hybrid composites through a systematic novel grey relation grade analysis (GRGA) optimization approach. This involves reinforcing the hybrid composites with hexagonal boron nitride (hBN) and various kinds of natural fibers or fillers. The development of a unique technology to produce multiphase composites using 2% of natural fibers or fillers such as coir fiber, rice husk filler, wood filler (WF), banana fiber (BF) and sugarcane fiber along with hBN (1, 3, 5 wt.%) particulates as reinforcements in epoxy matrix. The Taguchi L15 matrix array is utilized to fabricate interlaced composite samples via hand layup molding. Ultrasonic waves are used to ensure the uniform distribution of hBN filler into the matrix. Analysis of variance and GRGA reveal the significant results. It shows that the multiphase hybrid composites exhibit good thermal conductivity when higher content of hBN (5 wt.%) particulate for all the micro particulate polymer (MPP) composites. Multi-response optimization shows that the micro BF (2 wt.%) interlaces with hBN (5 wt.%) composite exhibits the higher thermal conductivity and electrical resistance compared to all other natural fiber interlaced composites. The aforementioned MPP composite has thermal conductivity of 1.03 W (m·K)−1 and electrical resistance of 279.88 Giga Ohms. Besides, the WF interlaced hBN (5 wt.%) composite shows the minimum dielectric constant compared to all other natural fiber composites. This desirable result is caused by the proper dispersion of hBN with the matrix which encourages interlocking with the fiber and the matrix. Maximum electrical resistance is observed for composite containing 5 wt.% of h-BN and 2 wt.% of BF. The developed MPP composite could be used in heat shields, electrical insulation components, and interior automotive components like dashboards, luggage compartments and interior walls.

Electrical Resistance Evolution of Graphite and Talc Geological Heterostructures under Progressive Metamorphism

The electrical properties of isolated graphene established precedents for studies of electrical superconducting materials at room temperature. After the discovery of stabilized graphene and graphite nanoplatelets in a geological context, the interest in characterizing the properties of these minerals arose. This work evaluates the electrical resistance evolution of mineral graphite and talc heterostructures under progressive metamorphism simulated in the laboratory. The experiments were conducted on an end-loaded piston-cylinder apparatus. This equipment allows for the application of equal pressure in all sample directions (lithostatic pressure) and heating, simulating geological phenomena. The behavior of two sets of mineral samples were compared: graphite and talc in billets and powder. Samples in billets were submitted to treatments at 400 °C and 4 kbar; 400 °C and 6 kbar; and 700 °C and 9 kbar. The powder samples were subjected to 700 °C and 9 kbar, with two ways of disposing the mineral powders (mixed and in adjacent contact) beyond 900 °C and 9 kbar (in adjacent contact). The results show that the samples in billets had lower electrical resistance when compared to the powder samples. The lowest electrical resistance was observed in the sample treated at 400 °C and 6 kbar, conditions that are consistent with metamorphic mineral assemblage observed in the field. Powdered samples showed better cleavage efficiency during the experiment, resulting in thinner flakes and even graphene, as pointed out by Raman spectroscopy. However, these flakes were not communicating, which resulted in high electrical resistance, due to the need for an electrical current to pass through the talc, resulting in a Joule effect. The maximum electrical resistance obtained in the experiment was obtained in the sample submitted to 900 °C, in which talc decomposed into other mineral phases that were even more electrically insulating. This work demonstrates that electrical resistance prospecting can be an efficient tool to identify potential target rocks with preserved mineral nanometric heterostructures that can form an important raw material for the nanotechnology industry.

Enhanced effects of carbon-based conductive materials on the piezoresistive characteristics of cementitious composites

In the present study, an enhanced effects of carbon-based conductive materials on the piezoresistive characteristics of cementitious composites were investigated. A polycarboxylate-based superplasticizer and silica fume were used to disperse conductive mateirals effectively into cement pastes. The dispersion of the conductive materials in the cement pastes was evaluated through electrical resistance measurement, zeta-potential test, and sedimentation test. In this study, carbon nanotube (CNT) and carbonyl iron powder (CIP) were used as conductive materials. The piezoresistive characteristics of the cementitious composites under cyclic loading conditions were explored. The effects of the incorporation of CNT and CIP on the piezoresistive performance were evaluated through the electrical resistance change and the relationship between the electrical resistance change and loads. The test results indicated that the incorporation of CIP into cementitious composites with CNT improved the piezoresistive sensing performance of the composites. The maximum electrical resistance changes of the composites with CIP were 67.49% when the CNT content was 0.5 wt%. Furthermore, the effects of various temperature conditions on the piezoresistive characteristics of cementitious composites were studied. Changes in piezoresistive characteristics of the composites exposed to elevated temperature and subjected to freeze-thaw cycles were analyzed. The electrical resistance change of the conductive network significantly changes at 200 °C.

Study the Electrical Properties of Surface Mount Device Integrated Silver Coated Vectran Yarn.

Smart textiles have attracted huge attention due to their potential applications for ease of life. Recently, smart textiles have been produced by means of incorporation of electronic components onto/into conductive metallic yarns. The development, characterizations, and electro-mechanical testing of surface mounted electronic device (SMD) integrated E-yarns is still limited. There is a vulnerability to short circuits as non-filament conductive yarns have protruding fibers. It is important to determine the best construction method and study the factors that influence the textile properties of the base yarn. This paper investigated the effects of different external factors, namely, strain, solder pad size, temperature, abrasion, and washing on the electrical resistance of SMD integrated silver-coated Vectran (SCV) yarn. For this, a Vectran E-yarn was fabricated by integrating the SMD resistor into a SCV yarn by applying a vapor phase reflow soldering method. The results showed that the conductive gauge length, strain, overlap solder pad size, temperature, abrasion, and washing had a significant effect on the electrical resistance property of the SCV E-yarn. In addition, based on the experiment, the E-yarn made from SCV conductive thread and 68 Ω SMD resistor had the maximum electrical resistance and power of 72.16 Ω and 0.29 W per 0.31 m length. Therefore, the structure of this E-yarn is also expected to bring great benefits to manufacturing wearable conductive tracks and sensors.

Coupled Flexural-Electrical Evaluation of Additively Manufactured Multifunctional Composites at Ambient Temperature

Multifunctional composites offer a higher strength to weight ratio, electrical properties, etc., thereby providing possible solutions for replacing the physical electrical wirings in aircraft. The lack of research on the coupled multifunctional characterization of 3D printed composites flexural-electrical properties is the main reason for its unsuitability in aerospace applications. The proposed method evaluates multifunctional flexural-electrical properties of 3D printed multifunctional carbon fiber composites. Traditional methods for conducting structural and electrical analyses for aircraft certification do not accommodate new technologies that are not yet proven. Such technologies are additive manufacturing (AM) techniques, multifunctional composite structures, and the certification requirements for 3D printed multifunctional carbon fiber composites for use in aircraft. In this study, the multifunctional 3D printed specimens were concurrently evaluated for flexural-electrical properties using three-point bending and electrical conductivity tests. The results showed that the multifunctional properties included the maximum flexural strength of 271 MPa and the maximum electrical resistance of 55.1 G Ohms, with the failure modes and mechanisms found to be consistent with the traditional composites. Due to its infancy, the existing AM techniques, and the use of the multifunctional carbon fiber composites manufactured using those AM technologies, are not implemented on a large commercial scale.

Alginate- and Hyaluronic Acid-Based Hydrogels as Vitreous Substitutes: An In Vitro Evaluation.

PurposeTo study alginate- and hyaluronic acid–based hydrogels in vitro as vitreous substitutes.MethodsBiopolymeric hydrogels based on high-molecular alginate (0.5% and 1.0%) and hyaluronic acid (1.0% and Healaflow) were compared with extracted human vitreous bodies and silicone oil (SIL-5000) regarding their optical properties (refractive index, transmission) and viscoelastic characteristics (storage modulus G′, loss modulus G″). The cytotoxic (metabolic activity, apoptosis) and antiproliferative profiles were determined using cultured human fibroblasts, ARPE-19, and photoreceptor cells. The hydrogel systems were applied to human fetal retinal pigment epithelial cells cultured for two months until maximum transepithelial electrical resistance (TEER) to investigate the effect of the gel matrices on tight junctions using TEER measurements and immunostainings against the tight junction protein ZO-1.ResultsTested alginate- and hyaluronic acid–based hydrogels resembled the natural refractive index of human vitreous bodies (1.3356–1.3360) in contrast to SIL-5000 (1.4034) and showed high optical transparency (>90%) within the visible light region. The biopolymeric hydrogels exhibited viscoelastic properties similar to juvenile vitreous bodies with G′>G″ adjustable via different gelation times, contrary to SIL-5000 (G′<G″). The metabolic activity, apoptosis and tight junctions of all tested ocular cells were unaffected by the alginate- and hyaluronic acid–based vitreous substitutes.ConclusionsThe present in vitro study demonstrates good optical, viscoelastic, and biocompatible properties of alginate- and hyaluronic acid–based hydrogels required for their use as vitreous substitutes.Translational RelevanceBiopolymer-based hydrogels represent a promising vitreous replacement strategy to treat vitreoretinal diseases.

Comparative Studies of Electrical Resistance in Woven and Non-Woven Jute Fabrics at Different Input Voltage

The use of jute fabrics is showing an increasing trend in textile, building and automobile sectors. Electrical properties such as conductivity, resistance, di-electric constant, insulation, etc. are the essential factor for consideration for using jute fabrics in these sectors. For this reason, a study was carried out to find out the changes in electrical properties of woven and nonwoven jute fabrics at different input voltage. The electrical resistance of jute fabrics was measured by a digital impedance meter. Effects of input voltage, gauge length, and type of fabrics on electrical resistance were studied and analyzed. Experimental results indicated that the electrical resistance of woven and needle punched nonwoven jute fabrics decreased with the increase of input voltage and increased with the increase in gauge length. The highest value of electrical resistance in woven jute fabrics was 394 Mohm/cm at 2 cm gauge length and 60 V of the input voltage. In nonwoven jute fabrics, the maximum electrical resistance was 257 M ohm/cm which was obtained at 2 cm gauge length and 60 V of electrical resistance. Woven jute fabric showed a higher value of resistance than nonwoven jute fabric for different voltages. It was also observed that the electrical resistance varied with the type of fabrics used in this study.

Novel design of integrated thermal functional garment for primary dysmenorrhea relief: The study and customizable application development of thermal conductive woven fabric

Thermal garments applied with thermal woven technology especially targeted to relieve primary dysmenorrhea (PD) can hardly be found in the current commercial market. This study had successfully designed, fabricated and studied seven types of thermal conductive woven fabrics woven with two different kinds of silver-coated conductive yarns in three structures, three weft densities and three weft conductive yarn design arrangements, thereby developing a customizable application–an integrated thermal functional garment for PD relief. Appearance, mass, thickness, air permeability, water vapour permeability, thermal conductivity, maximum heat flux, electrical resistance, heating temperature and power efficiency were evaluated to guide the development of an application prototype. On the basis of the results, an optimized design and fabrication were conducted to create a practical and customizable thermal functional garment for PD with successful relief, which can be well industrialized and fill in the commercial gap in the future.

Research on the influencing factors on the corrosion resistance of rebars in concrete

This paper aims to study the influence of NaNO2 contents, water-cement ratios, mineral admixtures (fly ash and fine mineral powder) on the corrosion resistance of rebars in concrete. Electrical resistance and the corrosion current were established in order to research the anti-corrosive performances of the steel reinforced concrete. In this study, the mixing dosages of NaNO2 are increased from 0% to 2.0% by mass ratio of the total mixtures. Moreover, water-cement ratio (w/c) applied in this research ranged from 0.3 to 0.5. Fly ash and slag powder ranged from 10% to 30%, meanwhile assembly unit of fly ash (10% ∼ 20%) and slag powder(10% ∼ 20%) were used to improve the corrosion resistance of rebars. The research results indicated that electrical resistance increased initially and then decreased with the increase of NaNO2 contents and water-cement ratios. When the dosage of NaNO2 was 1.0% and water-cement ratio was 0.4 respectively, steel reinforced concrete presented the maximum electrical resistance. Additionally, electrical resistance was increased by the addition of fly ash and slag powder. Resistances of steel reinforced concrete with assembly unit of fly ash (10% ∼ 20%) and slag powder (10% ∼ 20%) was higher than that with single unit of fly ash or slag powder. Moreover, the corrosion resistance coefficient (Rp) of steel reinforced concrete firstly increased and then decreased with the increase of NaNO2 content. However, the decreasing w/c and the increased amount of mineral admixtures led to an increase of Rp. Steel reinforced concrete with 30% fly ash manifested the highest Rp.

Influence of copper slag and metakaolin on the durability of self compacting concrete

Now-a-days, researchers are endeavoring to discover new substitute materials to elucidate the scarcity of natural aggregates in the construction industry. One such alternative is copper slag (CS) obtained as byproduct during the matte smelting process of copper metal. The present investigation is aimed to assess the durability of self compacting concrete (SCC) incorporating copper slag (CS) as fine aggregates and metakaolin (MK) as substitute to fly ash (FA). A total of seven concrete mixes were prepared. The control concrete contains 60% ordinary portland cement (OPC), 40% FA and 0% CS whereas other six mixes contains constant percentage of 60% OPC, 30% FA, 10% MK with different proportions of CS from 0% to 100%. Results revealed that fresh properties declined with inclusion of MK although escalated with increment of CS content. All SCC mixes exhibited higher compressive and splitting tensile strength in comparison to control concrete. The minimum carbonation depth was marked for 100% CS substitution with 10% MK as replacement to FA. The maximum electrical resistivity and resistance to sulfate attack were obtained for 20% CS substitution while UPV values of whole mixes were under the excellent quality of concrete beyond 7 days of curing. On full replacement of sand by CS with 10% MK, initial surface absorption and sorptivity were significantly lower than control concrete at each curing period. This study suggests that CS together with MK can be a potential substitute to natural sand in the construction sector to overcome the scarcity.

Mechanical properties and piezoresistive sensing capabilities of FRP composites incorporating CNT fibers

The present study investigates the mechanical properties and piezoresistive sensing capabilities of glass and carbon fiber-reinforced plastic (GFRP and CFRP) composites incorporating solid state spun-carbon nanotube (CNT) fibers. The FRP composite specimens were fabricated by stacking in layer-by-layer sequence in a resin matrix via vacuum infusion process. The mechanical properties were examined by tensile strength tests, while piezoresistive sensing characteristics were explored by measuring the electrical resistance change during loading. The maximum electrical resistance change rate of CNT fiber-incorporated GFRP composites was 3.15%, corresponding to a value 10 times higher than those obtained in previous studies using wet spinning method for the fabrication of CNT fibers. Moreover, continuous sensing characteristics of the CNT fiber-incorporated GFRP composite subjected to cyclic tensile loadings were verified, thereby assessing the feasibility of CNT fibers in practical applications as a piezoresistive sensor.

Percolation threshold and piezoresistive response of multi-wall carbon nanotube/cement composites

The present work aims to develop piezoresistive sensors of excellent piezoresistive response attributable to change in nanoscale structures of multi-wall carbon nanotube (MWNT) embedded in cement. MWNT was distributed in a cement matrix by means of polymer wrapping method in tandem with the ultrasonication process. DC conductivity of the prepared samples exhibited the electrical percolation behavior and therefore the dispersion method adopted in this study was deemed effective. The integrity of piezoresistive response of the sensors was assessed in terms of stability, the maximum electrical resistance change rate, and sensitivity. A composite sensor with MWNT 0.2 wt.% showed the lowest stability and sensitivity, while the maximum electrical resistance change rate exhibited by this sample was the highest (96 %) among others and even higher than those found in the literature. This observation was presumably attributed by the percolation threshold and the tunneling effect. As a result of the MWNT content (0.2 wt.%) of the sensor being near the percolation threshold (0.25 wt.%), MWNTs were close to each other to trigger tunneling in response of external loading. The sensor with MWNT 0.2 wt.% was able to maintain the repeatable sensing capability while sustaining a vehicular loading on road, demonstrating the feasibility in traffic flow sensing application.

Composite piezoelectric spinal fusion implant: Effects of stacked generators.

Spinal fusion surgeries have a high failure rate for difficult-to-fuse patients. A piezoelectric spinal fusion implant was developed to overcome the issues with other adjunct therapies. Stacked generators were used to improve power generation at low electrical load resistances. The effects of the number of layers on average maximum power and the optimal electrical load resistance were characterized. The effects of mechanical preload, load frequency, and amplitude on maximum power and optimal electrical load resistance were also characterized. Increasing the number of layers from one to nine was found to lower the optimal electrical load resistance from 1.00 GΩ to 16.78 MΩ while maintaining maximum power generation. Mechanical preload did not have a significant effect on power output or optimal electrical load resistance. Increases in mechanical loading frequency increased average maximum power, while decreasing the optimal electrical load resistance. Increases in mechanical loading amplitude increased average maximum power output without affecting the optimal electrical load resistance.

Synthesis of a quaternarized poly(vinylimidazole-co-trifluoroethylmethacrylate-co-divinylbenzene) anion-exchange membrane for nitrate removal

The effect of functional agents on the ion permselectivity between an anion exchange membrane and solutions of electrolytes containing the most dominant anions of natural waters (Cl−, NO3− and SO42−) was studied. The vinylimidazole(VI)-co-trifluoroethylmethacrylate(TFEMA)-co-divinylbenzene(DVB) copolymer was synthesized by solution polymerization. The copolymer was functionalized with compounds such as 1-bromo-2-methylpropane, 1-bromobutane, 1-bromo-3-methylbutane and 1-bromopentane. Quaternarized poly(vinylimidazole-co-trifluoroethylmethacrylate-co-divinylbenzene) (QPVTD) anion exchange membranes were prepared using the casting method. The molecular structure of the membrane was confirmed by Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy. The membrane properties, such as water uptake, ion exchange capacity, electrical resistance and ion permselectivity for nitrate, were measured. The maximum water uptake, electrical resistance and ion exchange capacity were 60.8%, 3.7Ω/cm2 and 1.25meq/g dry, respectively.

Monitoring Fatigue Cracking in Interconnects in a Ball Grid Array by Measuring Electrical Resistance

In displacement controlled mechanical fatigue of ball grid solder interconnect arrays, decrease in maximum load monitors total increase in crack area in an array while electrical resistance monitors only the area of large cracks that lead to electrical failure. Small cracks with good electrical contact between the crack surfaces have only minor effect on the resistance of the array. In this mechanical fatigue research of ball grid arrays, the fatigue damage was continually followed by simultaneously measuring maximum load and electrical resistance. Experimental details, results, and analysis of the results are given including a Paris relation fit to the data.

Detection of electric resistivity tomography and evaluation of the sapwood-heartwood demarcation in three Asia Gymnosperm species

The proportions of sapwood and heartwood of trees have significant impacts on various uses. Electric resistivity tomography (ERT) and corresponding electrical resistance (ER) value maps were examined in Japanese cedar (Cryptomeria japonica D. Don), Taiwania (Taiwania cryptomerioides Hayata), and Luanta fir (Cunninghamia konishii Hayata) trees. The position of the sapwood-heartwood demarcation was measured on incremental cores from living trees and the corresponding ER of the sapwood-heartwood boundary was acquired from the ER map. A positive significant relationship was found between the maximum ER plus minimum ER values (ERmax + ERmin) and ER of the sapwood-heartwood demarcation from the tomographic data. The position of the sapwood-heartwood demarcation was determined by corresponding ER, and the critical ER can be established by the ERmax + ERmin value of the tomographic data. The results from this study indicate that ERT technique can be used to determine the position of the sapwood-heartwood boundary and can serve as a methodology in undamaged living trees of Gymnosperm species.

Graphene nanosheets deposited on polyurethane films by self-assembly for preparing transparent, conductive films

This study prepared graphene nanosheet (GNS)-based transparent, conductive films (TCFs) by a self-assembly method. We used the water-borne polyurethane (WPU, with sulfonate functional groups) film as the substrate. Aggregation and restacking of the GNS were inhibited efficiently by attracting the octadecyl trimethyl ammonium chloride surfactant (cationic surfactant) to the surface of the GNS (GNS-O), which can in turn attract sulfonate groups to the WPU surface. The GNS-O was deposited on WPU to form TCFs. We obtained highly transparent and electrically conductive thin films after treatment with nitric acid (GNS-OA). The GNS-OA composite films showed a maximum sheet electrical resistance of 1.5 × 103 Ω □−1, with a light transmittance of up to 79% and a ratio of DC conductivity to optical conductivity of 0.88.

Glycoprotein E of varicella-zoster virus enhances cell-cell contact in polarized epithelial cells.

Varicella-zoster virus (VZV) infection involves the cell-cell spread of virions, but how viral proteins interact with the host cell membranes that comprise intercellular junctions is not known. Madin-Darby canine kidney (MDCK) cells were constructed to express the glycoproteins gE, gI, or gE/gI constitutively and were used to examine the effects of these VZV glycoproteins in polarized epithelial cells. At low cell density, VZV gE induced partial tight junction (TJ) formation under low-calcium conditions, whether expressed alone or with gI. Although most VZV gE was intracellular, gE was also shown to colocalize with the TJ protein ZO-1 with or without concomitant expression of gI. Freeze fracture electron microscopy revealed normal TJ strand morphology in gE-expressing MDCK cells. Functionally, the expression of gE was associated with a marked acceleration in the establishment of maximum transepithelial electrical resistance (TER) in MDCK-gE cells; MDCK-gI and MDCK-gE/gI cells exhibited a similar pattern of early TER compared to MDCK cells, although peak resistances were lower than those of gE alone. VZV gE expression altered F-actin organization and lipid distribution, but coexpression of gI modulated these effects. Two regions of the gE ectodomain, amino acids (aa) 278 to 355 and aa 467 to 498, although lacking Ca(2+) binding motifs, exhibit similarities with corresponding regions of the cell adhesion molecules, E-cadherin and desmocollin. These observations suggest that VZV gE and gE/gI may contribute to viral pathogenesis by facilitating epithelial cell-cell contacts.