LCR Meter Research Articles

Selective Recognition of Acetone in Air Against Hydrogen By Impedance Measurement of Two-Terminal Electrochemical Sensors Based on Ionic Liquids

Introduction Ionic Liquids (ILs) are molten salts at room temperature and have both solvent and electrolyte properties. ILs have been actively studied for use in electrochemical gas sensors, thanks to their gas absorption property, electrochemical stability, and low evaporation loss. For example, gas sensors based on the changes in electrical double layer capacitance or in bulk impedance induced by gas dissolution in ionic liquids have been reported [1, 2]. However, there are few reports on the selective recognition of volatile organic compounds such as metabolites in human exhaled air against interfering gases. In this study, we demonstrated selective recognitions of acetone, which is a typical low-molecular-weight metabolic gas in human exhaled air, against hydrogen, which is a metabolite of enterobacteria, by electrochemical impedance measurement using ionic liquids. Method The interdigitated electrodes made of Cr/Pt shown in Fig. 1 were fabricated on a glass substrate. The 3-nm-thick chromium film acting as the adhesion layer was deposited by electron beam evaporation technique, which was followed by the pattern definition and evaporation of 100-nm-thick platinum electrode acting as the main electrical conduction layer. The droplet of 3-μL 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, a kind of ionic liquids, was casted onto the electrodes, which completed the fabrication of a two-terminal electrochemical sensor. The impedance measurements were performed under various atmospheres. The following shows the sequence of atmospheres under which the impedance responses of the fabricated sensors were measured. ⅰ) Dry air (3 min) ⅱ) (case Ⅰ) 25-ppm H2 in dry air (3 min)ⅱ) (case Ⅱ) 25-ppm CH3COCH3 in dry air (3 min) ⅲ) dry air (3 min)In the second process ii), case I or case II was chosen from two target gases; hydrogen and acetone. The gas flow rate was kept constant at 200 sccm. Impedance measurements were performed using an LCR meter (Keysight E4980A) with DC bias of 0.0 V and AC amplitude of 10 mV. The measurement frequency was varied from 300 kHz to 20 Hz. Results Fig. 2 shows the measured sensor response at (a) 200 kHz, (b) 30 Hz, and (c) 350 Hz. The sensor response is defined as impedance change ΔZ re due to target molecules normalized by the impedance in dry air Z re(Air), where Z re represents the real part of the impedance. The equation used to extract the sensor response is shown in Fig. 2. We noticed that the sensor response was strongly dependent on the measured frequency. Z re decreases at 200 kHz in both the CH3COCH3 and H2 atmospheres (Fig. 2(a)), whereas it is increased by the target molecules at 30 Hz (Fig. 2(b)). The directions of the impedance changes were the same for both the target molecules. On the other hand, at 350 Hz (Fig. 2(c)), Z re decreases in the CH3COCH3 atmosphere, although it stays constant in the H2 atmosphere. This clearly demonstrates that CH3COCH3 can be selectively detected against H2 by impedance measurement with an appropriate measurement frequency. Discussion and Conclusion We consider that the equivalent circuit of the present system includes an element related with the bulk IL resistance and one related with the electrical double layer at the electrode/IL interfaces. The measurement of the impedance phase angle reveals that the phase angle is close to 0 degrees at 200 kHz and close to -90 degrees at 30 Hz. Therefore, we consider that high-frequency (200 kHz) Z re is affected by the bulk IL resistance change induced by dissolved gaseous molecules and that low-frequency (30 Hz) Z re is influenced by the change in electrical double layer characteristics. On the other hand, at medium frequencies; namely 350 Hz in this study, the gas-induced effects both on bulk IL resistance and on the electric double layer characteristics causing Z re modulation may be compensated with each other, and no sensor response was observed under the H2 atmosphere as shown in Fig. 2(c). We will extract the equivalent circuit model for the system used in this experiment and examine how the parameters of circuit elements change in the H2 and CH3COCH3 atmospheres in comparison with the standard dry air atmosphere. By investigating the frequency dependence of the impact of each parameter change on Z re, we will clarify the mechanism of Z re constancy in the H2 atmosphere at medium frequencies.

Cell viability and electrical response of breast cancer cell treated in aqueous graphene oxide solution deposition on interdigitated electrode

Breast cancer is one of the most reported cancers that can lead to death. Despite the advances in diagnosis and treatment procedures, the possibility of cancer recurrences is still high in many cases. With that in consideration, researchers from all over the world are showing interest in the unique features of Graphene oxide (GO), such as its excellent and versatile physicochemical properties, to explore further its potential and benefits towards breast cancer cell treatment. In this study, the cell viability and electrical response of GO, in terms of resistivity and impedance towards the breast cancer cells (MCF7) and normal breast cells (MCF10a), were investigated by varying the pH and concentration of GO. Firstly, the numbers of MCF7 and MCF10a were measured after being treated with GO for 24 and 48 h. Next, the electrical responses of these cells were evaluated by using interdigitated gold electrodes (IDEs) that are connected to an LCR meter. Based on the results obtained, as the pH of GO increased from pH 5 to pH 7, the number of viable MCF7 cells decreased while the number of viable MCF10a slightly increased after the incubation period of 48 h. Similarly, the MCF7 also experienced higher cytotoxicity effects when treated with GO concentrations of more than 25 µg/mL. The findings from the electrical characterization of the cells observed that the number of viable cells has corresponded to the impedance of the cells. The electrical impedance of MCF7 decreased as the number of highly insulating viable cell membranes decreased. But in contrast, the electrical impedance of MCF10a increased as the number of highly insulating viable cell membranes increased. Hence, it can be deduced that the GO with higher pH and concentration influence the MCF7 cancer cell line and MCF10a normal breast cell.

Development of dynamic wireless power transfer coils for 3rd generation wireless in‐wheel motor

AbstractShort cruise range is a major issues in electric vehicles, and dynamic wireless power transfer (WPT) has been proposed to solve this problem. In this study, a new dynamic power transfer system is introduced, called the hird generation wireless in‐wheel motor, that integrates the drive circuit and motor. Additionally, a methodology of the transmitter and receiver coil design that can calculate inductance and resistance of the rectangular spiral coils in a fast manner is proposed. It considers the theoretical efficiency of coils, current of coils, and voltage of resonance capacitor as constraints. Inductance calculation models only use coordinates of coil edge and the distance between coil and ferrite core. The coils designed by the proposed method were manufactured and evaluated using an LCR meter. The calculation error of the self‐inductance and mutual inductance was found to be ± 9%. With the transmitter coil and receiver coil, an output and DC to DC efficiency of is 18 kW and 95.2%, respectively, were obtained by actual WPT test.

Inductive particle detection system for real-time monitoring of metals in airborne particles

A novel inductive particle detection system was developed for a real-time monitoring of metals in airborne particles which cannot be measured using current commercial portable devices. The detection system consists of particle sampling, particle sensing, oil circulation sections and signal processing circuit. Airborne particles of different sizes enter the system and are classified according to their sizes in the particle sampling section. Particles larger than 5 µm are collected on the oil surface and passed through the particle sensing section along with the oil circulating throughout the system. The particle sensing section was realized using a 3D multilayer solenoid connected to a high-precision inductance meter. The performance of each section was first evaluated, and then the overall performance of the system was evaluated. The results show that ferrous and nonferrous metals in airborne particles can be detected and differentiated using proposed system with minimum detectable size of 5–10 µm for Fe and 50–60 µm for Cu particles. In addition, the number concentration of Fe particles was converted and compared with the reference number concentrations measured by high-precision commercial instrument, under the metal particle generation condition. The comparison results of the system show good agreement at concentrations within its detectable range, up to 200 #/L. The proposed system and design concept demonstrated here can be widely used for the real-time and extensive monitoring of airborne metal particles in industrial workplaces.

Nonlinear optical properties of nematic liquid crystal matrix doped with graphene nanosheets

ABSTRACT In this research, nonlinear optical (NLO) properties of the nematic liquid crystal doped with different concentrations of the graphene nanosheets are studied. The nematic liquid crystal molecules are aligned in parallel and perpendicular to the incident light polarization and accordingly order parameters of the aligned samples are studied using the dichroism method. We show how doped graphene nanosheets increase the nonlinear birefringence and nonlinear refractive index of the graphene guest-nematic liquid crystal host. Furthermore, we use LCR meter to obtain dielectric anisotropy of the mixture at the frequency of 1 kHz with varying temperatures. Obtained experimental results demonstrate doping 1% concentration of the graphene nanosheets increases significantly NLO properties and also the dielectric response of the nematic liquid crystal by the magnitude of two orders and shifts the phase transition point by about 15°.

Synthesis of Silicon Dioxide (SiO2) from Reeds Biomass (Imperata cylindrica) and The Analysis of Electrical Properties (Study Cases: Impedance, Resistance, Capacitive Reactance, Inductive Reactance)

Silicon dioxide (SiO2) has successfully synthesized from reeds biomass (imperata cylindrical) by annealing temperature variation at 500, 600, 700 oC. The result of the synthesis has analyzed using LCR meters to calculate the electrical properties including resistance (R), reactance (X) (delta inductive reactance (XL) and capacitive reactance (XC)), impedance (Z) in the frequency range at 50 Hz to 5 MHz. The resistance (R), reactance (X) (delta inductive reactance (XL) and capacitive reactance (XC)), impedance (Z) value according to reversible electric current rules.

Alüminyum Kaplanmış Çelik Tel Muayenesinde Kullanılan Girdap Akımları Muayene Sistemi için Çevreleyici Prob Tasarımı

In this paper, an encircling probe design used in the inspection of conductive wires, which are qualified as aluminum clad steel (ACS) wire is made. The eddy current systems are widely used for the quality control of conductive materials as one of non-destructive testing methods. In these systems, it is possible to design and to use different types of probes according to the material type. Internal, encircling and surface probe types are used for the inspection of pipes, wires and plate conductive materials, respectively. The discontinuities on the conductor surfaces are detected and the changes in the inductance values of the coils of probes are analyzed with the electronic hardware and the quality control of the material is ensured. In this study, a sensitive probe design is realized to detect various defect on wire surfaces. The inductance value of the designed probe is calculated by using two and three dimensional finite element analysis (FEA) and the obtained results are compared. The inductance change of the probe was measured by an LCR meter while the probe contained sample ACS wires with different types of defects, these values are given in the table and the change graph is plotted. In addition, an impedance bridge circuit was set up with the probe and the results of the change in voltage induction on the coil are given as an oscilloscope image.

Soil-pile-structure interaction effects on seismic demands and fragility estimates of a typical Ontario highway bridge retrofitted with fiber reinforced elastomeric isolator

This study investigates the seismic performance of a seismically isolated soil-pile-structure system incorporating the effects of isolation system, soil layers of low stiffness and strength, pile inclination, pile-soil-pile interactions, and bridge-embankment interaction. A coupled three-dimensional nonlinear finite element model of an existing bridge in Ottawa, Ontario is developed as a representative of the 44% of the total bridges in Ontario that have been built prior to 1970. A seismic retrofit technique which involves isolating the bridge superstructure utilizing a novel type of elastomeric isolator called Fiber Reinforced Elastomeric Isolator (FREI) is adopted. Two bridge conditions, namely, monolithic (pre-retrofit) and isolated (retrofitted) are considered to investigate the effect of Soil-Structure Interaction (SSI) on the seismic performance of the bridge prior to and after the retrofit in its longitudinal and transverse directions, independently. Analytical fragility curves are developed for the bridge components based on the outputs of an Incremental Dynamic Analysis (IDA) using 45 synthetic ground motion records. It is shown that seismic isolation can effectively reduce the superstructure acceleration by allowing the deck to experience large lateral displacements. Therefore, the transferred shear forces to the columns and their supporting piles are decreased significantly. While seismic isolation of the bridge is found to be beneficial for bridge components, it has a detrimental effect on the extensive and collapse damage states of abutment piles in the longitudinal direction. This conclusion is limited to the conventional abutment models where the abutment backwall damage has not been taken into account. Using more complex physics-based abutment spring systems may reveal that using the seismic isolation systems can mitigate the probability of extensive damage and collapse to abutment piles by allowing the abutment to serve as a fuse and dissipate the imposed energy by its fracture mechanism.

Optical and dielectric mechanism of complex double perovskite oxides xLaAlO3 – (1-x)Ba(Mg1/2 W1/2)O3

The Optical and dielectric mechanism of complex double perovskite oxides xLaAlO3 – (1-x)Ba(Mg1/2W1/2)O3 [LA-BMW] have been characterized for different values of x (0.10, 0.25, 0.50, 0.75 and 0.90). UV–Visible absorption optical spectra show that with increase in concentration x, the band gap of the corresponding sample slowly decreases from 5.59eV to 4.75eV systematically. The dielectric data have been measured using a LCR meter (Hioki-3532-50, Japan) in the frequency range from 50 Hz to 4.8 MHz as a function of temperature varying from 300 K to 723 K. The dielectric data shows that room temperature conductivity increases with increase in the doping concentration x. A comparative study has been carried out to corelate structural variation with change in band gap which in turn effects the electrical properties of the samples.

Dynamic response and parameter analysis on the vehicle–bridge coupling of cable-stayed bridge under over-limit transportation

PurposeOver-limit transportation has the characteristics of large axle load, large number of axles and lateral distribution width. Under the action of over-limit load, the coupling vibration effect of vehicle–bridge is more obvious, and the deformation of bridge components is large. Thus, research and analysis of the vehicle–bridge coupling dynamic response of long-span bridges under over-limit transportation has practical engineering significance.Design/methodology/approachBased on the principle of invariable elastic potential energy, this paper derives dynamic model of over-limit transportation n-axis flat vehicle. The numerical simulation method is used to model and calculate a cable-stayed bridge, and the static effect of the cable-stayed bridge and the dynamic response of vehicle–bridge coupling under different parameters are compared and analyzed.FindingsThe focus is on the influence of vehicle load and vehicle velocity parameters on the stress and amplitude of different cables under over-limit transportation, and the corresponding variation law is obtained.Originality/valueThe research on the coupled dynamic response of cable-stayed bridges has attracted the attention of many scholars, but there are relatively few studies on the coupled vibration of out-limit vehicles and bridges. In this paper, based on finite element software, a vehicle–bridge coupling model under bulk transportation is established.

RAI: Rapid, Autonomous and Intelligent machine learning approach to identify fire-vulnerable bridges

Recent surveys have noted that the majority of bridges continue to serve for a prolonged period of time (+40 years) that far exceeds its intended operational lifespan. Given our limited resources to maintain and upkeep bridges, these structures become notoriously vulnerable to extreme events. Building upon the fact that bridges continue not to be specifically designed to withstand the adverse effects of fire, this study presents the development of a rapid, automated, and intelligent (RAI) approach that leverages machine learning to identify vulnerable bridges to fire hazard. This work also presents details on a comprehensive database comprising actual observations collected from 135 notable and international bridge fire incidents. This database was developed to train two machine learning techniques, deep learning and genetic algorithms, to quantify hidden patterns that govern the propensity of existing/new/historical bridges to undergo fire damage and/or fire-induced collapse via a multi-classification analysis. The proposed RAI approach also has the capability to pinpoint fire-vulnerable bridge components and to display its level of confidence in its predictions. As such, our approach can be of aid to bridge engineers and government officials (who may not be well-versed in fire design) with accuracy reaching 89.6%. This approach is implemented into a software (App) with optimized architecture and reduced computational complexity and hence is easily scalable and integratable into a user-friendly framework and handheld devices. The outcome of this study shows that the RAI approach can be deployed to arrive at an instantaneous assessment of fire vulnerable bridges.

An application of convolutional neural network for deterioration modeling of highway bridge components in the United States

This paper presents a deep learning-aided deterioration modeling approach for highway bridge components (i.e., decks, superstructures, and substructures). The method trains a set of deep learning models for the maximum likelihood estimation of parameters in a Markov chain. The likelihood function is based on observed numbers of transitions between different condition states. The deep learning is leveraged for efficient representation of various factors that influence the deterioration process. Aided by deep learning, the proposed method is suitable for deterioration modeling using large-scale and high-dimensional bridge datasets. The study demonstrates an application of this approach using the historical National Bridge Inventory database from 1993 to 2019. The Convolutional Neural Network is adopted as the deep learning model. The proposed method is validated with ten-fold cross-validation that encompasses a nationwide selection of 88,596, 101,414, and 96,244 bridge decks, superstructures, and substructures, respectively. The validation shows this approach achieved a robust and low prediction error with the maximum mean-squared-error near 0.5 in a 26-years-forecast. The proposed method is also compared with the conventional Artificial Neural Network and four selected Markov-chain based deterioration modeling approaches. The study shows this approach can be a promising data-driven tool for deterioration modeling of highway bridge components.

Development of Waste Polystyrene-Based Copper Oxide/Reduced Graphene Oxide Composites and Their Mechanical, Electrical and Thermal Properties.

The current study reports the effect of different wt. ratios of copper oxide nanoparticle (CuO-NPs) and reduced graphene oxide (rGO) as fillers on mechanical, electrical, and thermal properties of waste polystyrene (WPS) matrix. Firstly, thin sheets of WPS-rGO-CuO composites were prepared through solution casting method with different ratios, i.e., 2, 8, 10, 15 and 20 wt.% of CuO-NPs and rGO in WPS matrix. The synthesized composite sheets were characterized by Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray (EDX), X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and thermal gravimetric analysis (TGA). The electrical conductance and mechanical strength of the prepared composites were determined by using LCR meter and universal testing machine (UTM). These properties were dependent on the concentrations of CuO-NPs and rGO. Results display that the addition of both fillers, i.e., rGO and CuO-NPs, collectively led to remarkable increase in the mechanical properties of the composite. The incorporation of rGO-CuO: 15% WPS sample, i.e., WPS-rGO-CuO: 15%, has shown high mechanical strength with tensile strength of 25.282 MPa and Young modulus of 1951.0 MPa, respectively. Similarly, the electrical conductance of the same composite is also enhanced from 6.7 × 10−14 to 4 × 10−7 S/m in contrast to WPS at 2.0 106 Hz. The fabricated composites exhibited high thermal stability through TGA analysis in terms of 3.52% and 6.055% wt. loss at 250 °C as compared to WPS.

Mechanical state inversion method for structural performance evaluation of existing suspension bridges using 3D laser scanning

AbstractThe abnormal mechanicalstate will cause the structural performance degradation of a suspension bridge. This paper presents a mechanical state inversion method for suspension bridges based on the measured intersection points of main cables using 3D laser scanning. First, based on the catenary, the mathematical model between the suspender force and the measured intersection points coordinates is established, and an accurate calculation method of suspender force is proposed. Then, an accurate calculation method for the internal force of suspension bridge components with abnormal suspender force is proposed to evaluate the structural performance. Numerical experiments show that the proposed method is accurate in theory. Finally, 3D laser scanning is used to capture the shape of the main cable, and an automated algorithm is developed to calculate the intersection point of the main cables precisely. The accuracy and reliability of the proposed method have been verified on a completed suspension bridge with a span of 808 m.

Study on Feature Extraction of Cable Surface Defect Image Based on Morphology and Edge Detection Algorithm

The cable-stayed bridge has been widely used because of its excellent bearing capacity, beautiful structure and relatively low construction cost. As one of the most important mechanical components in long-span cable-stayed bridges, the safety of bridge cables is the focus of attention. the image of cable surface defect was taken as the object, and carrying out the image pretreatment. On the basis, through analysis and comparison, the image of cable crack was processed by morphological gradient operation, meanwhile the Sobel operator was selected to detect the cable surface defect image.

Probabilistic Seismic Response and Capacity Models of Piles for Statewide Bridges in California

This study develops the probabilistic seismic response and capacity models for the broad collection of standard pile designs that are routinely incorporated into bridges in California. A review of the state bridge inventory indicates considerable variations in design details for different standard pile types used across multiple eras. For each pile type, fiber-section-based pile models attached with p-y soil springs are built to incorporate nonlinear behaviors of soil materials, a wide array of heterogeneous soil profiles, full-range damage states of piles, and realistic connection details between piles and footings (i.e., pile caps). Moreover, force-displacement responses of pile-soil systems under a large number of pushover analyses are regressed as response models consisting of five parameters [termed as response five parameter (R5P) models], which can capture all essential behaviors of laterally-loaded piles. Capacity damage states and limit state models are defined for different pile types by linking pile global responses to fiber-scale material behaviors at plastic hinge locations. Procedures are further provided to expand R5P models to pile foundation models at the regional scale, taking into account the pile group effect and capacities of pile cap backfills. R5P models for all distinct pile types are further summarized in an Excel workbook to facilitate their practical implementations. In general, this study provides a comprehensive and consistent set of response and capacity models to quantify the seismic damage potential of regional pile foundations, as well as to capture their dynamic interplays with other crucial bridge components, such as columns and abutment components. The proposed pile models are expected to significantly enhance the existing modeling capability toward improved seismic risk assessment of California’s bridge infrastructure.

N‐type silk fibroin/TiO2 nanocomposite transparent films: electrical and optical properties

AbstractThis paper highlights the effect of different concentrations of titanium dioxide (TiO2) nanoparticles on the electrical and optical properties of silk fibroin (SF). TiO2 based SF nanocomposite films were prepared using the solvent casting method. Uniform dispersion and agglomeration of nanoparticles, in nanocomposite films, were observed by field emission SEM. The conductivity of pure SF and nanocomposite films was determined by a four‐point probe and the TiO2 nanoparticles were found to bring high conductivity to the nanocomposite films. Dielectric strength improved with the addition of nanoparticles to the SF matrix. Dielectric constant and capacitance of the pure SF and nanocomposite films were measured using an LCR meter, which showed a 10‐fold enhancement on the addition of nanoparticles in SF. A very unusual property, i.e. negative resistance, was observed during LCR meter analysis for the nanocomposite films for a particular range of frequency (200–550 kHz), voltage (1 V) and current (0.5–1.5 μA). TiO2 nanoparticles changed the semiconducting behavior of the SF films from p‐type to n‐type as measured by the Hall effect experiment. The optical properties of pure SF and nanocomposite films were measured using a UV–visible spectrophotometer. The increased concentration of nanoparticles in the SF has effectively enhanced the absorbing coefficient, refractive index and percentage transmittance and reduced the bandgap energy. These SF/TiO2 nanocomposite films have shown the potential to be used as dielectric and high refractive index material for optoelectronics applications. © 2021 Society of Industrial Chemistry.

Construction and Performance Monitoring of Innovative Ultra-High-Performance Concrete Bridge

The application of Ultra-High-Performance Concrete (UHPC) materials in rehabilitating bridges and constructing primary bridge components is increasing rapidly across the world because of their superior strength and durability characteristics when compared to regular concretes. However, there have been few new bridges constructed using UHPC materials with regular formworks, ready-mix trucks, and construction equipment. This paper presents a comprehensive report encompassing the design, construction, and performance monitoring of a new bridge constructed in Iowa using a unique UHPC technology that includes steel fibers of two different lengths embedded in the concrete. By using optimized lengths of steel fibers, both the tensile strength and the toughness were increased. The UHPC material was produced with local cement and aggregates in the US using typical ready-mix concrete equipment. This paper discusses the experience gained from the design and construction process including mix design, batching, delivery of steel fibers to the ready-mix concrete batch unit, and post-tensioning of precast slabs at the jobsite. For four years after construction, the joints of the bridge decks were monitored using strain sensors mounted on both sides of the deck joints. The strain values were quite similar between the two sides of each joint, indicating a good load transfer between precast bridge girders. A bridge was successfully constructed using a unique UHPC technology incorporating two different lengths of steel fibers and utilizing local cement and aggregates and a ready-mix truck, and has been performing satisfactorily with a good load transfer across post-tensioned precast girder joints.

Broadband dielectric relaxation spectroscopy and molecular dynamics simulation study of paracetamol-propylene glycol solutions

The complex permittivity ε*(ω) = ε′(ω) - ε“(ω) was studied for a series of paracetamol (PCM) – propylene glycol (PG) solutions over the broadband frequency range of 20 Hz to 20 GHz at different temperatures ranging from 293.15 K to 323.15 K. Measurements of the complex permittivity were carried out using Agilent Precision LCR meter E4980A with Agilent 16452A liquid test fixture (for 20 Hz to 2 MHz frequency region) and Anritsu Shockline Vector Network Analyser MS46322A with DAK-3.5 probe (for 200 MHz to 20 GHz frequency region). Obtained broadband frequency dependent dielectric data were analyzed to explore the interaction mechanisms and structural behavior of PCM and PG molecules in mixed state in terms of molar PCM concentration and temperature variation. Temperature dependent dc conductivity response of all solutions exhibited Arrhenius behavior from which activation energy was calculated. Microwave complex permittivity data were fitted to the Cole-Davidson model in order to determine dipolar relaxation parameters of the solutions. Dielectric constant and dielectric loss values at a spot frequency of 2.45 GHz were utilized to determine the microwave heating parameters and analyzed in view of its suitability for the microwave dielectric heating in pharmaceuticals. Molecular dynamics simulation study for selected concentrations of PCM in PG was also conducted in order to understand the actual mechanism of H-bonding interactions in the solutions and to justify the inferences derived from the experimental results.

Exploring the NH3 gas sensing efficiency of polyvinylpyrrolidone based tungsten trioxide (PVP/WO3) Nanocomposites: A recent progression in the toxic gas sensing materials

In this paper, a room temperature operable, highly reproducible, stable and selective ammonia gas sensor of PVP, WO3, and PVP/WO3 nanocomposites were investigated. Drop casting method was used to deposit the sensing materials on interdigitated copper electrode. Chemical reduction and ultrasonication methods were adopted for the preparation of WO3 and PVP/WO3 nanocomposites, respectively. The as-produced sensing materials were characterized by using FTIR, XRD, and SEM techniques. LCR meter was used to analyze the gas sensing properties of PVP, WO3 and PVP/WO3 (5–25 wt%) nanocomposites. Under same condition of temperature (300 K), humidity (40%RH), and NH3 vapors (100 ppm) the sensor based on PVP/WO3 20 wt% showed higher sensing response of 87.26 as compared to pure PVP and WO3 nanosheets sensor which was 15.36 and 3.37, respectively. The PVP/WO3 20 wt% based sensor exhibited excellent results in term of reproducibility, stability (90 days), response time (14 s), and recovery time (10 s).