Parallel-plate Method Research Articles

Development of a novel PCB electric field sensor with high-resolution

Abstract Electric field sensors with high resolution and high sensitivity have an important engineering application. Developing a compact, cost-effective Electric Field Sensor (EFS) for aerospace applications, this study introduces a novel use of PCB parallel board probes, enhancing affordability and simplicity. A uniquely designed three-stage adaptive signal amplification module quickly adjusts amplification factors, ensuring high sensitivity and resolution even in complex electric field environments. Due to the non-linear response characteristics of the PCB probes in complex electric field environments, the GTEM cells and the high voltage parallel plate method are used to simulate the complex electric field scenarios. In the weak electric field experiment, the proposed EFS achieved a high resolution of 10 mV/m. In the strong electric field experiment, the linearity of fitting between the proposed EFS and commercial NBM-550EFS reached 0.9999. Finally, based on RBFNN, the overall measurement model of EFS achieves the dynamic measurement range of 0-1 kV/m.

Review of Testing Methods on the Heat Transfer Characteristics of Mold Slag Film

Heat transfer from the solidified shell to the mold, especially in the meniscus region, significantly affects the surface quality of the strand and the stability of the continuous casting process. The mold slag film serves as the sole heat transfer medium between the shell and the mold, and its performance and structure have a substantial impact on the heat transfer efficiency. Thus, since the 1980s, various testing methods are developed to investigate the heat transfer performance of the slag film, including the pouring method, immersion method, parallel plate method, and mold experiment. In this article, the principles, characteristics, and main study results of these methods are reviewed, and the existing issues are highlighted in these methods. Furthermore, specific requirements that shall be satisfied in future research on the heat transfer of slag film are presented. The new approach for testing heat transfer in slag film necessitates ensuring consistency in the heat flux, surface temperature of the shell, interfacial thermal resistance, and thickness and cooling rate of the slag film, aligning with those observed in a mold. This consistency is crucial to ensure the comparable structure and heat transfer characteristic between the experimental and industrial slag films.

Impact of Multiple Reprocessing on Properties of Polyhydroxybutyrate and Polypropylene.

Biobased plastics have the potential to be sustainable, but to explore their circularity further, current end-of-life options need to be broadened. Mechanical recycling is one of the most accepted methods to bring back plastics into the loop. Polyhydroxybutyrates (PHBs) are biobased and biodegradable in nature with promising properties and varied applications in the market. This study focuses on their potential for mechanical recycling by multiple extrusion cycles (E1-E5) and multi-faceted characterization of the virgin (V) and reprocessed materials from E1 to E5. The behavior is compared to polypropylene (PP) as a reference with a similar property profile, which has also been reprocessed five times. The thermal properties of both series showed a stable melting point and thermal decomposition temperature from thermal analyses (differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA)). However, a steady increase in the degree of crystallinity was observed which could counterbalance the decrease in molecular weight due to repeated extrusion measured by gel permeation chromatography and resulted in similar values of tensile strength across the cycles. The strain at break was impacted after the first extrusion, but no significant change was observed thereafter; the same was observed for impact strength. Even in scanning electron microscopy (SEM) images, virgin and E5 samples appeared similar, showing the stability of morphological characteristics. Fourier transform infrared spectroscopy (FTIR) results revealed that no new groups are being formed even on repeated processing. The deviation between the PHB and PP series was more predominant in the melt mass flow rate (MFR) and rheology studies. There was a drastic drop in the MFR values in PHB from virgin to E5, whereas not much difference was observed for PP throughout the cycles. This observation was corroborated by frequency sweeps conducted with the parallel plate method. The viscosity dropped from virgin to E1 and E2, but from E3 to E5 it presented similar values. This was in contrast to PP, where all the samples from virgin to E5 had the same values of viscosity. This paper highlights the possibilities of mechanical recycling of PHB and explains why future work with the addition of virgin material and other additives is an area to be explored.

Measurement of the relative permittivity of the liquid phase of R454C with vapor quality change under two-phase condition

The capacitance-based method is an alternative method for measuring the void fraction of refrigerants. The relative permittivity of the liquid phase is an essentially required property for the capacitance-based method. Unlike pure refrigerants, the composition in the liquid phase of zeotropic refrigerants and their saturation temperature depend on the vapor quality; therefore, zeotropic refrigerants have a change in the relative permittivity of the liquid phase during the phase change process. To generally apply the capacitance-based method to zeotropic refrigerants for which relative permittivity information is relatively insufficient, it is necessary to accurately predict the relative permittivity of liquid zeotropic refrigerants during phase change based on the relative permittivity of pure refrigerants. In this study, the relative permittivity of the liquid phase of a two-phase refrigerant was measured using the parallel plate method. And the measured results were compared to that estimated by five types of mixing rules. The measurements were performed at saturation pressures of 1.04–1.72 MPa and vapor qualities of 0–0.7 for R454C refrigerant. The saturation temperature variation ranged from 18 to 44 °C. Landau and Lifshitz's mixing rule best predicts the relative permittivity with a mean percentage error (MAPE) of 1.02% as the vapor quality of R454C varies.

STUDY OF SAP WATER QUALITY BASED ON VISCOSITY AND DIELECTRIC CONSTANTS

This study aims to determine the quality of sap water by measuring its viscosity and dielectric constant. The sample used is pure sap water and sap water mixed with coconut water. The dielectric constant was measured using the parallel plate method while the viscosity was measured using the Oswald viscometer method. Based on the measurement results, the viscosity coefficient value of pure sap water is 1.558 Poise. The value of the viscosity coefficient decreases as the concentration of the sap water decreases where the viscosity coefficient value is 1.005 Poise for the sap water with a concentration of 50% and 0.753 Poise for the sap water with a concentration of 10%. In measuring the value of the dielectric constant, the dielectric constant of pure sap water is 7.38 x 105. The dielectric constant value of the sap water decreases with the addition of coconut water which is 4.90 x 105 at a concentration of 50%, and 3.39 x 105 at a concentration 10%. Pure sap water has a higher level of viscosity than coconut water which is indicated by a higher coefficient of viscosity compared to sap water which has been mixed with coconut water so that it is able to store more electrical energy, as a result the capacitance increases and the dielectric constant also increases.

Locust bean gum hydrogels are bioadhesive and improve indole-3-carbinol cutaneous permeation: influence of the polysaccharide concentration

The locust bean gum (LBG) is a polysaccharide with thickening, stabilizing and gelling properties and it has been used in the preparation of pharmaceutical formulations. Hydrogels (HGs) are obtained from natural or synthetic materials that present interesting properties for skin application. This study aimed to develop HGs from LBG using indole-3-carbinol (I3C) as an asset model for cutaneous application. HGs were prepared by dispersing LBG (2%, 3% and 4% w/v) directly in cold water. The formulations showed content close to 0.5 mg/g (HPLC) and pH ranging from 7.25 to 7.41 (potentiometry). The spreadability factor (parallel plate method) was inversely proportional to LBG concentration. The rheological evaluation (rotational viscometer) demonstrated a non-Newtonian pseudoplastic flow behavior (Ostwald De Weale model), which is interesting for cutaneous application. The HET-CAM evaluation showed the non-irritating characteristic of the formulations. The bioadhesive potential demonstrated bioadhesion in a concentration-dependent manner. Permeation in human skin using Franz cells showed that the highest LBG concentration improved the skin distribution profile with greater I3C amounts in the viable skin layers. The present study demonstrated the feasibility of preparing HGs with LBG and the formulation with the highest polymer concentration was the most promising to transport active ingredients through the skin.

Blood Coagulation on Titanium Dioxide Films with Various Crystal Structures on Titanium Implant Surfaces.

Background: Titanium (Ti) is one of the most popular implant materials, and its surface titanium dioxide (TiO2) provides good biocompatibility. The coagulation of blood on Ti implants plays a key role in wound healing and cell growth at the implant site; however, researchers have yet to fully elucidate the mechanism underlying this process on TiO2. Methods: This study examined the means by which blood coagulation was affected by the crystal structure of TiO2 thin films (thickness < 50 nm), including anatase, rutile, and mixed anatase/rutile. The films were characterized in terms of roughness using an atomic force microscope, thickness using an X-ray photoelectron spectrometer, and crystal structure using transmission electron microscopy. The surface energy and dielectric constant of the surface films were measured using a contact angle goniometer and the parallel plate method, respectively. Blood coagulation properties (including clotting time, factor XII contact activation, fibrinogen adsorption, fibrin attachment, and platelet adhesion) were then assessed on the various test specimens. Results: All of the TiO2 films were similar in terms of surface roughness, thickness, and surface energy (hydrophilicity); however, the presence of rutile structures was associated with a higher dielectric constant, which induced the activation of factor XII, the formation of fibrin network, and platelet adhesion. Conclusions: This study provides detailed information related to the effects of TiO2 crystal structures on blood coagulation properties on Ti implant surfaces.

Morphological characteristics and electrical properties analysis of silica based on river and coastal iron sand

This study aims to analyze silica's morphological characteristics and electrical properties based on the river and coastal sand. Iron samples were taken from Sompang river sand, East Lombok and Coastal Sand from Gading, Mataram City. The silica was synthesized using the sol-gel method with a sintering temperature variation of 100 to 175 ℃. Morphological characteristics samples analysis was done using SEM-EDX. The electrical properties of iron sand included measuring the dielectric constant using the parallel plate method. Furthermore, the resistivity was measured using the two-point probe method. In the silica-based on river sand sample, the resistivity value was inversely proportional to the sintering temperature. In contrast, the resistivity value of silica based on the coastal sand sample was directly proportional to the sintering temperature. Silica-based on river sand has a resistivity of about 7.1'104 Wm at a sintering temperature of 100℃ and 3.5'104 Wm at a sintering temperature of 175℃. Silica-based on river sand has a resistivity of about 1.8'104 Wm at a sintering temperature of 100℃ and 7.1'104 Wm at 175℃. This research is a preliminary study on the electrical properties of natural sand-based silica to improve understanding of the physical properties of silica to be used in technological applications, such as sensors. Furthermore, the dielectric constant value in the river sand sample was directly proportional to the sintering temperature. However, the dielectric constant in the coastal sand sample was inversely proportional to the sintering temperature. Silica-based on river sand has a dielectric constant of about 1.02'102 at a sintering temperature of 100℃ and 1.18'102 at 175℃. Silica-based on coastal sand has a dielectric constant of about 1.97'102 at a sintering temperature of 100℃ and 1.15'102 at 175℃.

DERMATOLOGIC GELS SPREADABILITY MEASURING METHODS COMPARATIVE STUDY

Objective: The main objective of our study is the comprehensive analysis and characterization of the existing spreadability evaluation strategies, the comparison of the obtained results reproducibility and convergence through the example of the 9 most widely used dermatological gels. Methods: Dolobene®, Flucinar®, Ketorol®, Contractubex®, Dr. Theiss Venen gel®, Solcoseryl®, Deep Relief®, Hepatrombin® pharmacopoeia gel samples were analyzed using parallel-plate, “slip and drag”, and viscometry methods. Analysis was performed in flow mode at 32±0.2 °C, over shear rates ranging from 0 to 350 s−1, increasing over a period of 120 s, and was maintained at the superior limit for 10 s and then decreased during the same period. At least 5 replicates of each sample were evaluated, and the upward flow curves were fitted using the Casson mathematical model. Results: Solcoseryl® and Dolobene® showed the best spreadability in the parallel-plate method (3115.66±50.00 and 3316.63±50.00, respectively); Contractubex® and Dolobene showed the best spreadability in the “slip and drag” test (73.46±0.5 and 18.32±0.5, respectively); Solcoseryl® and Contractubex® showed the best spreadability in the viscometry test (43.86±0.5 and 76.92±0.5, respectively). Conclusion: This study analyzed the existing methods for determining the spreadability using commercially available samples of the dermatological gels as examples. The viscometric and the "Slip and drag" methods use different characteristics of spreadability, giving a complex evaluation of the measured parameter in vitro. Therefore, the combination of these two methods has the greatest prospects for reliable determination of this indicator.

Modified Parallel Plate Method for Electromagnetic Characterization of Thin Films in the Microwave Range

Modified Parallel Plate Method for Electromagnetic Characterization of Thin Films in the Microwave Range

The Study of The Electrical Conductivity and Activation Energy on Conductive Polymer Materials

Conductive Polymers are one of the interesting topics to be developed in recent years. Conductive polymers can combine the properties of polymers and the electrical properties of metals. Research related to the electrical properties of conductive polymers, including electrical conductivity measurements and determination of activation energy has been carried out. This study aims to determine the effect of addition mass fraction of activated carbon into the nylon polymer on the conductive polymer material based on the electrical conductivity and activation energy. The variations of activated carbon used are 0%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% (wt/V). The conductive polymer from nylon polymer and activated carbon is made by casting solution method. The electrical conductivity measurement of the conductive polymer and the activation energy was carried out using the parallel plate method. The value of electrical conductivity increased from 5.62×10-9 ± 1.89×10-10 S/cm for the pure nylon to 2.51×10-8 ± 2.87×10-10 S/cm for the addition of mass fraction of activated carbon 8% wt/V. Meanwhile, there was a decrease in the addition of 9% wt/V and 10% wt/V of mass fraction of activated carbon, which were 2.36×10-8 ± 3.47×10-10 S/cm and 2.28×10-8 ± 4.01×10-10 S/cm. The activation energy of conductive polymer obtained decreased with increasing in the mass fraction of the activated carbon into the nylon polymer. The activation energy for the pure nylon was 0.0189 eV and 0.0127 eV for the addition of 8% wt/V mass fraction of activated carbon. Meanwhile, there was an increase in the addition of 9% wt/V and 10% wt/V mass fractions of activated carbon of 0.0145 eV and 0.0150 eV, respectively.

NaCl-based blood phantom analysis for in vitro bioimpedance measurement

Daily monitoring of blood glucose levels is vital for managing diabetes; however, invasive blood sampling is a burden on patients. To improve patients’ quality of life, bioimpedance-based noninvasive blood glucose monitoring (BI-NIBGM) that involves wearable electrodes on the wrist has been proposed. In this study, we investigated the validity of applying a simple NaCl solution to a blood phantom for in vitro evaluation of BI-NIBGM. The electrical properties of cow blood and various blood phantoms with different NaCl concentrations were measured based on the parallel-plate method at frequencies from 200 kHz to 100 MHz. The following observations were made: (1) the conductivity of blood can be mimicked accurately with simple NaCl solutions, and the optimal concentration of the phantom depends on the operating frequency and (2) it is challenging to mimic the relative permittivity of blood with simple NaCl solutions because NaCl lacks a cellular structure. Furthermore, the relationship between the bioimpedance and electrical properties of the phantom was examined using a simplified arm model. The results indicate that the relative permittivity of the blood layer has little effect on the bioimpedance and that only the conductivity determines the bioimpedance. Therefore, the NaCl concentration of the phantom can be adjusted from the viewpoint of conductivity for BI-NIBGM.

Analysis of capillary water imbibition in sandstone via a combination of nuclear magnetic resonance imaging and numerical DEM modeling

The physics of water imbibition into initially unsaturated sandstone is critical to the understanding of displacement processes and fluid transport in the vadose zone. The distribution of water within rock is important due to its significant influence on rock mechanical behavior. Here, therefore, we used nuclear magnetic resonance (NMR) technology to visualize and quantify the dynamics of water infiltration and distribution in initially unsaturated sandstone. The progression of water imbibition in sandstone specimens under the following two conditions were analyzed: (1) specimens soaked in water for different durations and (2) specimens soaked in water for the same duration and then held in this state for different durations. An analytic function was developed to estimate the sandstone moisture profile and to determine the unsaturated flow within the sandstone when the water distribution matched laboratory observations. Finally, a three-dimensional discrete element grain-based model was formulated that incorporates the local parallel-plate method, the unsaturated flow function, and the generalized effective stress principle. We used this model to effectively reproduce the process of water imbibition in the laboratory sandstone specimens. The effect of water imbibition on the mechanical properties of the studied sandstone was also evaluated. These results show that the strength of the core of the sample was reduced as water migrated from its surface to its center, resulting in a decrease in bulk sample strength as standing duration (i.e. water distribution uniformity) increased. The results of this study aid in our understanding of the influence of water imbibition on the mechanical behavior of sandstone, which is important for rock slope stability assessments following rainfall.

Effect Of TiO2 Addition On The Electrical Conductivity Of Nylon-TiO2 Hybrid Membrane

Current membrane technology has developed rapidly in industrial commercial interests. This has led to various studies, especially on membrane raw material innovation. Research on the measurement of electrical conductivity on nylon-TiO2 hybrid membranes has been carried out. This study aims to determine the addition of the right TiO2 mass fraction based on the electrical conductivity value. The variations in the concentration of TiO2 used were 0.5%, 1%, 3%, 5%, and 7% (w/v). The nylon-TiO2 hybrid membrane was prepared using the phase inversion method. The measurement of the electrical conductivity of the hybrid membrane was carried out using the parallel plate method. The measurement results of the nylon-TiO2 hybrid membrane showed that the electrical conductivity of the hybrid membrane increased with the addition of the mass fraction of TiO2, from (0.66 ± 0.04) × 10-9 S / cm for nylon membrane to (9.15 ± 5.71) × 10-9 S / cm for additionalmass fraction of TiO2 5% (w/v). Meanwhile, onadditionThe mass fraction of TiO2 7% (w / v) causes the electrical conductivity of the hybrid membrane to decrease, by obtaining an electrical conductivity value of(2.31 ± 0.45) × 10-9 S / cm

Thermal Conductivity of Supercritical CO2-Saturated Coal

The present study reports the effective thermal conductivity (ETC) of supercritical (SC) CO2-saturated black coal sample at temperatures from (304.15 to 323.15) K and pressures up to 20 MPa using a steady-state guarded parallel-plate method. The expanded uncertainty of thermal conductivity, pressure, and temperature measurements at the 95 % confidence level with a coverage factor of k = 2 was estimated to be 4 % (in the range of regular behavior of the thermal conductivity) and 5–6 % (in the critical region of the saturated CO2), 0.1 %, and 30 mK, respectively. This uncertainty in ETC measurement does not include the uncertainty due to contact thermal resistance and radiative conductivity inherent in this method. The effect of critical anomaly of thermal conductivity and other thermodynamic properties of pure CO2 near- and supercritical conditions on the total measured values of the ETC of SC CO2-saturated coal was studied. The thermal conductivity behavior of pure SC CO2 in coal pores was interpreted based on finite-size scaling theory of critical phenomena.

PREPARATION AND CHARACTERIZATION OF NANOFLUID (CUO – WATER, TIO2 – WATER)

Over the past decade, research in heat transfer enhancement using nanofluids - suspensions of nanometer-sized solid particles in a base liquid has received considerable attention all over the world. Several theoretical works to predict the effective thermo physical properties of the suspension, range from a homogeneous model to complex two phase flow model have been proposed. This work explains the preparation methods of the nanofluids (CuO-water, TiO2-water) and characterizing the nanofluid of different concentrations (0.025%, 0.05%, 0.075%, 0.1% and 0.5%). Here in this work used to calculate the density, viscosity, specific heat of nanofluids and steady state parallel plate method is used to calculate thermal conductivity of nanofluids experimentally. Results of this work show the increase in thermal conductivity, viscosity of the nanofluid by increasing the concentration and decrease of density and specific heat of nanofluid by increasing the concentration.

A comparison between the open-ended coaxial probe method and the parallel plate method for measuring the dielectric properties of low-moisture foods

The dielectric properties of reference materials (deionized water and heptane) and selected low-moisture foods (ground black pepper, all-purpose bleached wheat flour, non-fat milk powder, and whole milk powder) were measured with the open-ended coaxial probe (OECP) and parallel plate (PP) methods from 20 to 60 °C and in the frequency ranges of 5 MHz to 3 GHz for OECP and 5–30 MHz for PP. Overall, the PP method was more accurate at measuring the dielectric properties of the reference materials than the OECP method. Notably, the OECP deviated from expected values below 200 MHz or when the magnitudes of the dielectric properties were small. As for the food products, the OECP and PP data sets were interpolated well with a modified power law model at lower temperatures when the OECP data below 200 MHz were excluded. However, the OECP data largely deviated from PP data at higher temperatures. The results suggest that the PP method may be preferable if the frequencies of interest are below 200 MHz or if the dielectric properties are expected to be small in magnitude.

Bio Phantoms Mimicking the Dielectric and Mechanical Properties of Human Skin Tissue at Low-Frequency Ranges

Tissue phantoms are widely used as substitute materials for real tissue validation of various newly emerging biomedical technologies such as ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI). However, there is no specific recipe for fabricating skin-mimicking phantoms which can mimic both the mechanical and dielectric properties of human skin at lower frequency ranges. &#x0D; &#x0D; The objective of this paper is to present a variety of tissue-mimicking materials for filling this research gap in the lower frequency range from 20 Hz to 300 kHz. The starting point of our experiments is based on the oil-in-gelatin based tissue-mimicking materials (TMMs) that have shown to mimic the dielectric properties of human skin in higher frequency ranges. This paper examines the mechanical and dielectric performance of five major classes of tissue-mimicking materials (1) Oil-in-gelatin, (2) lignin and graphene nanopowder in gelatin, (3) gelatin and distilled water, (4) mixed oil in gelatin and distilled water, and (5) lignin in gelatin and distilled water. &#x0D; &#x0D; Mechanical and electrical testing was performed using compression testing and parallel plate method respectively. The effect of electrode polarization was considered in the measured data and the intrinsic impedance values were found to be following the Cole-Cole equation. The Young&amp;#39;s modulus range of all tissue-mimicking materials was within the range of skin.

Viscosity Measurement of Whole Blood with Parallel Plate Rheometers

There are many factors that affect the increase or decrease of viscosity of the whole blood. Because of this, measuring the viscosity of whole blood is difficult to correlate with specific etiologies, so it tends to disregard the information on blood viscosity. This study is to find out the characteristics of the method of measuring the viscosity of whole blood using the parallel plate method, which is officially registered as a medical device with the approval of the Korea Food and Drug Administration (KFDA), and to apply it to the measurement of whole blood viscosity. The accuracy of the parallel plate measurement is verified by comparing with the measurement results using the commercially available scanning capillary method. In addition, statistically meaningful results are obtained between the viscosity and some components of the whole blood. It is expected that the research will be carried out to understand the correlation between the viscosity of whole blood and specific components of blood and to identify the prognostic signs of etiology in certain diseases, especially in cardiovascular and cerebral vessels diseases.

An Ultra-Wideband Measurement Method for the Dielectric Property of Rocks

Dielectric properties of rocks are the important indicators of subsurface formations when electromagnetic sensing methods are applied. Interpreting those in situ measurements relies on characterizing the dielectric permittivity of rock samples in the laboratory. For solid phase samples, the parallel-plate capacitance method (PCM) serves as one of the most accurate and feasible methods for charactering electrical properties. Low-frequency (~kilohertz) PCM measurements are most common; extending the PCM to an ultra-wideband measurement will establish a general framework for measuring both low-frequency and high-frequency (~gigahertz) properties (e.g., permittivity and conductivity). Major challenges of ultra-wideband measurements using the PCM are: 1) at high frequency, the measurement apparatus may introduce errors due to reflection and dissipation of the electromagnetic waves and 2) resonance caused by impedance mismatching in the apparatus design can occur at higher frequency, which will significantly compromise the accuracy of this method. Thus, the optimization and modification of the method is needed. In this letter, we: 1) show the validity and accuracy of the PCM for permittivity measurement by comparing numerical simulation and experiments; 2) propose a practical geometric parameter to conduct system-level optimization under giving constrains; 3) perform the optimization for the sample holder to increment the measurement accuracy at higher frequency without downsizing the sample. The results show that a satisfactory accuracy and stability can be achieved in an ultra-wide range of frequency spectrum from 100 kHz to 1.5 GHz with the improved PCM apparatus design.