Electrical Resistivity Values Research Articles

Development of knitted reinforced structures with self-diagnostic function for composite applications

The research aims the development of knitted reinforcement structures for inducing self-diagnostic properties into knitted reinforced composites for structural health monitoring. Conductive carbon fiber was used in knitted inlaid structures as inlay yarns, and l × 1 Rib knitted base fabric of polyester filament yarn was used for knitting. The reinforcement’s conductive nature induced self-diagnostic properties into composites using correlation of mechanical damages and changes in electrical resistance values. Single and double stimuli layers and inlay patterns of 3 × 1, 6 × 1 and 9 × 1 was used to check their impact on self-diagnostic properties. Mechanical testing and real-time electrical resistance monitoring proved knitted structures as a solution to induce self-diagnostic properties into composite materials. Composites having double stimuli (conductive) layers exhibited better self-diagnostic properties than single stimuli layer composites, and the self-diagnostic properties also improved as the inlay pattern of reinforcement moved from 9 × 1 to 6 × 1 and 3 × 1 inlay. Such knitted reinforced self-diagnostic composites could be practically used in structural health monitoring applications, e.g., complicated structures of large buildings infrastructures and machinery which require record of each minor happening with structures to keep smooth and successful running of the system.

Assessment for utilization of tobacco stem ash as a potential supplementary cementitious material in cement-based composites

Present study investigates the effectiveness of utilizing tobacco stem ash (TSA) as the partial replacement of Portland cement (PC) on the properties of cement pastes and mortars. Cement pastes and mortars were fabricated by replacing cement with TSA at four replacement levels i.e., 3.75, 7.5, 11.25, and 15 wt% relative to cement. Setting time, consistency, and hydration activity tests were performed on TSA-based cement pastes. Moreover, water absorption, porosity, compressive strength, ultrasonic pulse velocity (UPV), and electrical resistivity (ER) testing were performed on TSA-based mortars. The pozzolanic behavior of TSA was assessed via Frattini test and strength activity index. Analytical characterizations such as x-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), thermogravimetric (TG), scanning electron microscopy (SEM), and energy-dispersive x-ray (EDX) analyses were also performed. The results indicate lower water absorption and apparent porosity, leading to enhanced compressive strength, UPV, and ER values for TSA-based mortars. The analytical characterizations show that TSA promotes the hydration reaction and formation of a greater amount of cement hydrates. The strength activity index and Frattini test results showed that TSA possesses moderate pozzolanic activity at a higher replacement level. While, for low replacement levels of TSA in cement composites, the hydration reaction is governed by rapid precipitation of portlandite due to higher hydration activity.

Deoxynivalenol exposure inhibits biosynthesis of milk fat and protein by impairing tight junction in bovine mammary epithelial cells

Deoxynivalenol (DON) is one of the most common feed contaminants, and it poses a serious threat to the health of dairy cows. The existing studies of biological toxicity of DON mainly focus on the proliferation, oxidative stress, and inflammation in bovine mammary epithelial cells, while its toxicity on the biosynthesis of milk components has not been well documented. Hence, we investigated the toxic effects and the underlying mechanism of DON on the bovine mammary alveolar cells (MAC-T). Our results showed that exposure to various concentrations of DON significantly inhibited cell proliferation, induced apoptosis, and altered the cell morphology which was manifested by cell distortion and shrinkage. Moreover, the transepithelial electrical resistance (TEER) values of MAC-T cells exposed to DON were gradually decreased in a time- and concentration- dependent manner, but lactate dehydrogenase (LDH) leakage was significantly increased with the maximum increase of 2.4-fold, indicating the cell membrane and tight junctions were damaged by DON. Importantly, DON significantly reduced the synthesis of β-casein and lipid droplets, along with the significantly decreases of phospho-mTOR, phospho-4EBP1, phospho-JAK2, and phospho-STAT5. Gene expression profiles showed that the expressions of several genes related to lipid synthesis and metabolism were changed, including acyl-CoA synthetase short-chain family member 2 (ACSS2), fatty acid binding protein 3 (FABP3), 3-hydroxy-3-methylglutaryl-CoA synthase 1 (HMGCS1), and insulin-induced gene 1 (INSIG1). GO and KEGG enrichment analyses revealed that the differentially expressed genes (DEGs) were significantly enriched in ribosome, glutathione metabolism, and lipid biosynthetic process, which play important roles in the toxicological process induced by DON. Taken together, DON affects the proliferation and functional differentiation of MAC-T cells, which might be related to the cell junction disruption and morphological alteration. Our data provide new insights into functional differentiation and transcriptomic alterations of MAC-T cells after DON exposure, which contributes to a comprehensive understanding of DON-induced toxicity mechanism.

Effects of Various Mineral Admixtures and Fibrillated Polypropylene Fibers on the Properties of Engineered Cementitious Composite (ECC) Based Mortars

This study investigates the mechanical and durability properties of fly ash-based engineered cementitious composites (ECC). The effect of various mineral additions, such as wheat husk ash (WHA), rice husk ash (RHA), glass powder (GP), and fibrillated polypropylene (PP) fibers, on mechanical performance, water absorption, and porosity was investigated. Furthermore, the durability of ECC specimens was assessed in terms of sorptivity, acid/sulfate attacks, electric resistivity (ER), rapid chloride penetration (RCPT), and ultrasonic pulse velocity (UPV). The results revealed higher mechanical strength, UPV, and ER values for RHA-based ECC. After 180 days of immersion in acid and sulfate solutions, RHA-based ECC showed a lower loss in compressive strength (23.21% and 1.07% in HCl and Na2SO4, respectively) relative to the control mix (44% and 7% in HCl and Na2SO4, respectively). Moreover, analytical characterizations such as X-ray diffraction (XRD), Fourier transform infrared (FTIR), Scanning Electron Microscopy (SEM), and Energy dispersive X-ray (EDX) analyses were also carried out to corroborate the mechanical and durability properties of ECC.

New insights into arsenic and cadmium distribution and origin in paddy soils using electrical resistivity tomography

In-situ geophysical techniques based on electrical resistivity tomography were performed to determine the spatial and temporal distribution of heavy metals. This paper aimed to pursue a novel methodology consisting in combining electrical resistivity tomography measurements, soil chemical data, and statistical analysis to predict As and Cd distribution in paddy soils. The resistivity surveys were performed at 2 m depth in nine locations of Tolima district in Colombia. Chemical concentrations of both As and Cd were introduced in a standardization procedure to estimate their electrical resistivity values. Soil and fertilizers information were acquired to determine As and Cd input in the studied area. The laboratory standardization showed a direct linear regression for Cd and an inverse one for As. A high positive Spearman correlation between electrical resistivity and As / Cd content was determined, with 0.98 and 0.99 values, respectively. Results showed that As-like compounds were distributed mainly in shallower soil layers (0.45 m) and were characterized by lower electrical resistivity values (181–2318 Ω.m). On the contrary, Cd-like compounds were observed in a deeper profile (0.80 m) with higher electrical resistivity values (559–4879 Ω.m). This work underlies the utility of the combined geophysical techniques, soil chemical parameters and statistical analysis to improve the understanding of As and Cd dynamics and origin in topsoil, supporting the need of an agricultural management of paddy soils.

Alternating electric field-based ionic control and layer-by-layer assembly of anion exchange membranes for enhancing target anion selectivity

Separation and recovery of target anions from wastewater is a sustainable method for chemical production industry. In this study, the novel anion exchange membranes with high antifouling and target ion selectivity performance were designed by the layer-by-layer (LbL) assembly of dopamine, positive and negative polyelectrolytes under the alternating current electric field and ionic control (AC[ion]) process. The resulting membranes were fabricated with different LbL assembled multilayers to evaluate the target ion selectivity. Besides, the different LbL assembled methods, including the electrostatic deposition self-assembly (EDS), AC[Cl−] assembly and AC[NO3−] assembly methods were carried out to evaluate the ion effect in membrane assembly process on final target ion permeation rate, respectively. With the initial concentration of 50 mM of NaCl, NaNO3 and Na2SO4 in mixed solution and the constant current density of 5.00 mA cm−2 of electrodialysis, the permselectivity of resulting membrane could be enhanced by the increased multilayers. Besides, the ion control in the alternating current electric field assembly process could enhance the relevant target ion permeation rate. The increased values of membrane surface electrical resistance fouled by organic pollutants were used to evaluate the antifouling property of membranes in electrodialysis, and the resulting membranes showed a high antifouling performance. This work provided a promising membrane separation technology in target anion recovery from wastewater for sustainable development.

Electrical Resistivity Measurements for Nondestructive Evaluation of Chloride-Induced Deterioration of Reinforced Concrete-A Review.

The objective of this study is to review, evaluate, and compare the existing research and practices on electrical resistivity as a nondestructive technique in evaluating chloride-induced deterioration of reinforced concrete elements in buildings and civil infrastructure systems. First, this paper summarizes the different measurement techniques for gathering electrical resistivity (ER) values on concrete. Second, comparison analyses are performed to review the correlation of ER to different parameters representing corrosive environment and activity of steel corrosion in concrete, such as degree of water saturation, chloride penetration and diffusivity, and corrosion rate. In addition, this research enumerates and individually discusses the different environmental and interference factors that are not related to the electrochemical process of steel corrosion in concrete but directly affect the ER measurements, including temperature, the presence of steel reinforcement, cracks and delamination defects, specimen geometry, and concrete composition. Lastly and most importantly, discussions are made to determine the current gap of knowledge, to improve the utilization of this method in field and laboratory measurements, and future research.

Characterization and electrical analysis of carbon-based solid lubricant coatings

• Electrophoretic deposition of different carbon nanoparticles on copper substrate. • Nanoparticle coatings protect substrate, reduce wear, and lubricate contacts. • Hierarchy in electrical contact resistance values established among nanoparticles. • Carbon nanotubes and nanohorns show promising results as electrical contact coating. The use of electrical devices has skyrocketed over the past decades, increasing the demand for electrical connectors worldwide. Therefore, it is of utmost importance to produce more reliable, energy and material efficient, and durable electrical contact material systems; particularly in low-redundancy systems, such as in passenger vehicles. This work analyzes the potential use of carbon nanoparticle coatings applied via electrophoretic deposition over copper substrates to reduce wear, require lower insertion forces, and to protect the connectors from atmospheric conditions, while reducing the gain on the overall resistance of the system. Four carbon nanoparticles were considered due to their well-known solid-lubricating capabilities, namely: graphite flakes, graphene oxide, carbon nanotubes, and carbon nanohorns. Through a comprehensive characterization of the coatings, aspects like coating topography, compactness, thickness, elasticity, and electrical contact resistance were analyzed. Carbon nanotubes and nanohorns proved to have the highest potential. In addition to their previously documented outstanding solid-lubricity and environmental protection - after chemical modification of the coatings’ surfaces - these nanoparticles showed low resistance values for loads above 4 N, i.e., below 400 mΩ. Moreover, the coatings produced were thin and homogeneous, with adequate mechanical stability, and elastic behavior.

Nanoscale Electrical Investigation of Transparent Conductive Electrodes Based on Silver Nanowire Network

AbstractPresently, metallic nanowires (NWs) are the most promising materials to fabricate flexible transparent electrodes as an alternative to indium tin oxide. Here, the high performance of transparent conductive electrodes (TCEs) based on silver nanowires (AgNWs) percolation networks is reported. With optimized experimental conditions for the deposition, the AgNWs result in low sheet resistance of 10 Ω sq−1 combined with a high optical transmittance of 92.6% at λ = 550 nm. This leads to a valuable figure of merit as compared to other TCEs. In this study, the nanoscale electrical properties of the AgNWs are measured via conductive atomic force microscopy to characterize the percolation network. The electrical resistivity value calculated for a single AgNW is found to be about 12.35 µΩ cm, while a nanoscale conductivity map over an AgNW network bridging two electrodes has revealed high levels of current within the network over a distance of more than 1000 µm. The favorable determined conductivity results along with the high optical properties of the AgNWs network strongly suggest that thin‐film electrodes based on AgNWs will be a potential approach for future flexible electronic devices.

Application of Fucoidan in Caco-2 Model Establishment.

The Caco-2 model is a common cell model for material intestinal absorption in vitro, which usually takes 21 days to establish. Although some studies have shown that adding puromycin (PM) can shorten the model establishment period to 7 days, this still requires a long modeling time. Therefore, exploring a shorter modeling method can reduce the experimental costs and promote the development and application of the model. Fucoidan is an acidic polysaccharide with various biological activities. Our study showed that the transepithelial electrical resistance (TEER) value could reach 600 Ω·cm2 on the fourth day after the addition of fucoidan and puromycin, which met the applicable standards of the model (>500 Ω). Moreover, the alkaline phosphatase (AKP) activity, fluorescein sodium transmittance, and cell morphology of this model all met the requirements of model establishment. Fucoidan did not affect the absorption of macromolecular proteins and drugs. The results indicate that fucoidan can be applied to establish the Caco-2 model and can shorten the model establishment period to 5 days.

Experimental Comparison of Primary and hiPS-Based In Vitro Blood–Brain Barrier Models for Pharmacological Research

In vitro model systems of the blood–brain barrier (BBB) play an essential role in pharmacological research, specifically during the development and preclinical evaluation of new drug candidates. Within the past decade, the trend in research and further development has moved away from models based on primary cells of animal origin towards differentiated models derived from human induced pluripotent stem cells (hiPSs). However, this logical progression towards human model systems from renewable cell sources opens up questions about the transferability of results generated in the primary cell models. In this study, we have evaluated both models with identical experimental parameters and achieved a directly comparable characterisation showing no significant differences in protein expression or permeability even though the achieved transendothelial electrical resistance (TEER) values showed significant differences. In the course of this investigation, we also determined a significant deviation of both model systems from the in vivo BBB circumstances, specifically concerning the presence or absence of serum proteins in the culture media. Thus, we have further evaluated both systems when confronted with an in vivo-like distribution of serum and found a notable improvement in the differential permeability of hydrophilic and lipophilic compounds in the hiPS-derived BBB model. We then transferred this model into a microfluidic setup while maintaining the differential serum distribution and evaluated the permeability coefficients, which showed good comparability with values in the literature. Therefore, we have developed a microfluidic hiPS-based BBB model with characteristics comparable to the established primary cell-based model.

Efficacy of antioxidant in the therapy of subclinical mastitis in buffaloes

This study was conducted to assess the therapeutic efficiency of antioxidant in subclinical mastitis. Therapeutic trials were conducted in twelve buffaloes affected with subclinical mastitis and were randomly divided into two groups. The buffaloes of Group 1 were treated with intramuscular injection of Inj. Mofoi 5 mg/kg body weight, while Group 2 buffaloes were treated with intramuscular administration of Inj. Mofoi 5 mg/kg body weight along with antioxidant powder orally. The therapeutic efficacy was assessed based on bacteriological cure and the pre and post therapeutic values of somatic cell count, electrical resistance, pH and milk yield. The use of antioxidant along with Moxifloxacin was found to be superior than antibiotic alone by improving udder's natural defence mechanism, early restoration of milk yield and quick recovery.

Establishment of Immortalized Yak Ruminal Epithelial Cell Lines by Lentivirus-Mediated SV40T and hTERT Gene Transduction.

Yak is a unique species of cattle that is adapted to the harsh natural environment of the Qinghai-Tibet Plateau. Research on the function of the yak rumen is limited to animal experiments, and the cell molecular mechanism is very limited. The high cost of isolation and culture of adult yak rumen epithelial cells (YRECs), low success rate, and limited cell life limit the scope of long-term physiological functions and nutrient absorption mechanisms of yak rumen epithelium in vitro studies. This study aimed to explore the isolation and immortal culture methods of primary YRECs and establish a new cell line model for studying cell molecular mechanisms. The human telomerase reverse transcriptase gene (hTERT) and simian virus 40 large T antigen (SV40T) were transferred into primary YDECs using mammalian gene expression lentiviral vectors. The immortalized cell line (SV40T-YREC-hTERT) retains the morphological and functional characteristics of primary cells. The epithelial cell marker protein cytokeratin 18 of the immortalized cell lines was positive, and the cell proliferation and karyotype were normal. The SV40T and hTERT genes were successfully transferred into immortalized cell lines and maintained high expression. Simultaneously, the immortalized cell lines had normal function of short-chain fatty acid (SCFA) transport and absorption, and the immortalized yak rumen epithelial cell lines were successfully established. In addition, the transepithelial electrical resistance value gradually increased with culture time, and the permeability of epithelial cells decreased by culturing epithelial cells in Transwell culture chambers. Transmission electron microscopy demonstrated the submicroscopic structure of cells in the integrity barrier model and established the YREC barrier model in vitro.

Investigation of a novel technology of stud spraying aluminum alloy on the copper surface

Stud spraying is a novel spraying technology developed from stud welding technology. It is a technology where the coating is prepared by contacting the contact surface of a resistively heated molten metal. Using the spraying voltage of 30–70 V to prepare the aluminium alloy coating on a copper plate, the optimum stud spraying parameters are identified. Electrical resistance measurements and microhardness tests show that the aluminium alloy coating has high microhardness and low electrical resistance values. The average microhardness of the coating is approximately 208 HV which is 2.5 times the microhardness of the copper plates. The surface of the coating was observed by scanning electron microscope (SEM) to have distinct crystal structures. Analysis of the coating using energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) shows that these microstructures are mainly composed of intermetallic compounds (IMCs) such as Al2Cu and Al4Cu9.

Dual effect of TAT functionalized DHAH lipid nanoparticles with neurotrophic factors in human BBB and microglia cultures

BackgroundNeurodegenerative diseases (NDs) are an accelerating global health problem. Nevertheless, the stronghold of the brain- the blood–brain barrier (BBB) prevents drug penetrance and dwindles effective treatments. Therefore, it is crucial to identify Trojan horse-like drug carriers that can effectively cross the blood–brain barrier and reach the brain tissue. We have previously developed polyunsaturated fatty acids (PUFA)-based nanostructured lipid carriers (NLC), namely DHAH-NLC. These carriers are modulated with BBB-permeating compounds such as chitosan (CS) and trans-activating transcriptional activator (TAT) from HIV-1 that can entrap neurotrophic factors (NTF) serving as nanocarriers for NDs treatment. Moreover, microglia are suggested as a key causative factor of the undergoing neuroinflammation of NDs. In this work, we used in vitro models to investigate whether DHAH-NLCs can enter the brain via the BBB and investigate the therapeutic effect of NTF-containing DHAH-NLC and DHAH-NLC itself on lipopolysaccharide-challenged microglia.MethodsWe employed human induced pluripotent stem cell-derived brain microvascular endothelial cells (BMECs) to capitalize on the in vivo-like TEER of this BBB model and quantitatively assessed the permeability of DHAH-NLCs. We also used the HMC3 microglia cell line to assess the therapeutic effect of NTF-containing DHAH-NLC upon LPS challenge.ResultsTAT-functionalized DHAH-NLCs successfully crossed the in vitro BBB model, which exhibited high transendothelial electrical resistance (TEER) values (≈3000 Ω*cm2). Specifically, the TAT-functionalized DHAH-NLCs showed a permeability of up to 0.4% of the dose. Furthermore, using human microglia (HMC3), we demonstrate that DHAH-NLCs successfully counteracted the inflammatory response in our cultures after LPS challenge. Moreover, the encapsulation of glial cell-derived neurotrophic factor (GNDF)-containing DHAH-NLCs (DHAH-NLC-GNDF) activated the Nrf2/HO-1 pathway, suggesting the triggering of the endogenous anti-oxidative system present in microglia.ConclusionsOverall, this work shows that the TAT-functionalized DHAH-NLCs can cross the BBB, modulate immune responses, and serve as cargo carriers for growth factors; thus, constituting an attractive and promising novel drug delivery approach for the transport of therapeutics through the BBB into the brain.

The Measurement Uncertainty in Determining of Electrical Resistance Value by Applying Direct-Comparison Method

This paper considers the unknown electrical resistance (measurand) as the numerical result of the measurement that was carried out by means of the well-known direct comparison measurement method using an appropriate standard resistor and voltmeter. In the literature, this measurement method is also referred to as a series comparison method. This method of measurement is one of the indirect methods and is suitable for measuring low resistance. This paper presents two approaches for evaluating the unknown electrical resistance and its associated combined standard uncertainty. The entire process of evaluating the combined standard uncertainty that is associated with the measurand and the standard uncertainties that are associated with the analyzed input quantities has been entirely performed in accordance with the applicable international recommendations and guidelines for the uncertainty of measurement. The analyzed approaches for evaluating the combined standard uncertainty are designed to be universal and valid both for the mutually non-correlated input quantities and for the mutually correlated input quantities, which can be obtained from a single observation, or repeated observations or by other means. This paper can substantially contribute to the measurements in electrical engineering and education.

Fabrication of AZO and FAZO films using low-cost spin-coating method

This paper proposes a spin coating method to investigate the use of Al-doped ZnO (AZO) and F, Al co-doped ZnO (FAZO) films using zinc acetate as a zinc source and aluminum nitrate and ammonia fluoride as the dopant. Different processing temperatures have been conducted in-depth research on the AZO and FAZO thin film structures, morphology and photoelectric properties. The results show that for the AZO film, the intensity of the (002) diffraction peak (DP) first increases and then decreases with temperature, while the intensity of the (002) DP of the FAZO film gradually increases with temperature, effectively improving the thermal stability of the prepared AZO film. With the incorporation of F, the optimum growth of ZnO films along the c-axis perpendicular to the substrate surface is promoted, and the grain size on the film surface increases. Meanwhile, the introduction of F inhibits the generation of interstitial Zn atoms, O vacancy, and Zn vacancy; reduces the adsorption of –CO3, H2O, OH−, and O2 on the surface; and significantly improves the film stability. The optimum electrical resistivity (ρ) values of FAZO and AZO films prepared at 450 °C are 3.32 × 10−3 Ωcm and 5.66 × 10−3 Ωcm, respectively, and the average transmittance (TA) within the range of 380–1600 nm is 92.84% and 88.65%, respectively.

Action of the Nrf2/ARE signaling pathway on oxidative stress in choroid plexus epithelial cells following lanthanum chloride treatment

Lanthanum (La) can damage the blood brain barrier when it enters the brain tissue, causing learning and memory dysfunction. Currently, few studies have focused on La-induced oxidative stress in choroid plexus epithelial cells, which can severely impair the normal function of the blood-cerebrospinal fluid barrier (BCSFB) and ultimately cause central nervous system dysfunction. The nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element(ARE) signaling pathway is one of the major antioxidant systems and is vital in protecting cells against oxidative injury in rodents. In this study, Z310 cells were employed to construct BCSFB in vitro and treated with lanthanum chloride (LaCl3); meanwhile, 40 μmol/L tert-butylhydroquinone and the corresponding concentration of LaCl3 was used as the intervention groups. The results showed that LaCl3 treatment markedly decreased Z310 cell viability, increased the necrosis rate, and then reduced the transepithelial electrical resistance value of BCSFB in vitro; reactive oxygen species levels gradually increased, catalase and glutathione peroxidase activities decreased; furthermore, Nrf2 was significantly downregulated, and the expression of Nrf2 downstream genes such as heme oxygenase1, NADP(H): dehydrogenase quinone1, glutathione thiotransferase etc. noticeably decreased; in addition, interleukin-1β and tumour necrosis factor-α associated with Nrf2 activation noticeably increased. However, tert-butylhydroquinone could activate the Nrf2/AER signaling pathway and attenuate the Z310 cell oxidative damage induced by LaCl3. Thus, the Nrf2/ARE signaling pathway is probably involved in weakening the BCSFB in vitro that is created by La-induced oxidative stress. Tert-butylhydroquinone can activate this pathway to reverse severe oxidative damage, which significantly strengthen the function of BCSFB.

Computation of the Electrical Resistance of a Low Current Multi-Spot Contact.

In high complexity electrical systems such as those used in the automotive industries, electric connectors play an important role. The automotive industry is gradually shifting its attention to electric cars, which means more electrical connectors for sensors and data collection. A fault in connectors for sensors used in a vehicle can cause drastic damage to capital equipment and, in the worst case, the loss of life. The studies of faults or degradation of electrical contacts are essential for safety in vehicles and various industries. Although such faults can be due to numerous factors (such as dust, humidity, mechanical vibration, etc.) and some yet to be discovered, high contact resistance is the main factor causing erratic behavior of electrical contacts. This paper presents a study on the computation of electrical contact resistance of two metal conductors (in the form of a disk) with analytical relations and a numerical computation model based on the finite element method (FEM) in COMSOL Multiphysics. The contact spots were considered to have a higher electrical resistivity value (ρcs) than those of the two metal conductors (ρCu). Studies such as the one in view that is carried out on a microscopic level are often difficult to investigate experimentally. Therefore, with the help of a simplified numerical model, the consequences of the degradation of electrical contacts are investigated. To validate the FEM model, the numerical results were compared to those obtained from analytical models.

Machine learning-based self-sensing of the stiffness of shape memory coil actuator.

Self-sensing actuation (SSA) assists in sensing the vital property of the shape memory coil which can be used to monitor and control the actuation in smart equipment as well as robotics. The stiffness characteristic of the shape memory coil (SMC) is sensed during actuation which plays a significant role in development of intelligent robotics in defense systems. The electrical property of SMC such as electrical resistance changes due to martensitic phase transformation which is further used to sense the mechanical properties such as strain, stress, temperature, length, and force of the equipment. Nowadays electrical properties are used to sense the stiffness of the shape memory coil. As of now, there is no well-established analytical model to predict the stiffness of SMC during actuation accurately. Therefore, a soft model based on machine learning is proposed in this paper for autosensing of the stiffness in SMC. The experimental facility has been developed for the collection of data with respect to diverse Joule heating currents. To determine the experimental data values of stiffness and electrical resistance of SMC is a cumbersome task. Hence, we have proposed an automated method to predict the stiffness of the SMC using soft computing-based methods. The Classical Polynomial and Bayesian optimization-based Feedforward Neural Network (FFNN) models are developed for analyzing the stiffness of the SMC. It is found that the hybrid FFNN model outperforms the other ML-based model by attaining 95.2650% accuracy. The FFNN model is also able to explain almost all the predicted stiffness values which are experimentally recorded.