Capacitance Data Research Articles

Promoting Active Electronic States in LaFeO3 Thin-Films Photocathodes via Alkaline-Earth Metal Substitution.

The effects of alkaline-earth metal cation (AMC; Mg2+, Ca2+, Sr2+, and Ba2+) substitution on the photoelectrochemical properties of phase-pure LaFeO3 (LFO) thin-films are elucidated by X-ray photoemission spectroscopy (XPS), X-ray diffraction (XRD), diffuse reflectance, and electrochemical impedance spectroscopy (EIS). XRD confirms the formation of single-phase cubic LFO thin films with a rather complex dependence on the nature of the AMC and extent of substitution. Interestingly, subtle trends in lattice constant variations observed in XRD are closely correlated with shifts in the binding energies of Fe 2p3/2 and O 1s orbitals associated with the perovskite lattice. We establish a scaling factor between these two photoemission peaks, unveiling key correlation between Fe oxidation state and Fe-O covalency. Diffuse reflectance shows that optical transitions are little affected by AMC substitution below 10%, which are dominated by a direct bandgap transition close to 2.72 eV. Differential capacitance data obtained from EIS confirm the p-type characteristic of pristine LFO thin-films, revealing the presence of sub-bandgap electronic state (A-states) close to the valence band edge. The density of A-states is decreased upon AMC substitution, while the overall capacitance increases (increase in dopant level) and the apparent flat-band potential shifts toward more positive potentials. This behavior is consistent with the change in the valence band photoemission edge. In addition, capacitance data of cation-substituted films show the emergence of deeper states centered around 0.6 eV above the valence band edge (B-states). Photoelectrochemical responses toward the hydrogen evolution and oxygen reduction reactions in alkaline solutions show a complex dependence on alkaline-earth metal incorporation, reaching incident-photon-to-current conversion efficiency close to 20% in oxygen saturated solutions. We rationalize the photoresponses of the LFO films in terms of the effect sub-bandgap states on majority carrier mobility, charge transfer, and recombination kinetics.

Pulsed laser deposition of single phase n- and p-type Cu2O thin films with low resistivity

Low resistivity (ρ ~ 3–24 mΩ·cm) with tunable n- and p-type single phase Cu2O thin films have been grown by pulsed laser deposition at 25–200 °C by varying the background oxygen partial pressure (O2pp). Capacitance data obtained by electrochemical impedance spectroscopy was used to determine the conductivity (n- or p-type), carrier density, and flat band potentials for samples grown on indium tin oxide (ITO) at 25 °C. The Hall mobility (μH) of the n- and p-type Cu2O was estimated to be ~0.85 cm2/V.s and ~ 4.78 cm2/V.s respectively for samples grown on quartz substrate at 25 °C. An elevated substrate temperature ~ 200 °C with O2pp = 2–3 mTorr yielded p-type Cu2O films with six orders of magnitude higher resistivities in the range, ρ ~ 9–49 kΩ.cm and mobilities in the range, μH ~ 13.5–22.2 cm2/V.s. UV–Vis-NIR diffuse reflectance spectroscopy showed optical bandgaps of Cu2O films in the range of 1.76 to 2.15 eV depending on O2pp. Thin films grown at oxygen rich conditions O2pp ≥ 7 mTorr yielded mixed phase copper oxide irrespective of the substrate temperatures and upon air annealing at 550 °C for 1 h completely converted to CuO phase with n-type semiconducting properties (ρ ~ 12 Ω.cm, μH ~ 1.50 cm2/V.s). The as-grown p- and n-type Cu2O showed rectification and a photovoltaic response in solid junctions with n-ZnO and p-Si electrodes respectively. Our findings may create new opportunities for devising Cu2O based junctions requiring low process temperatures.

Molecular Mean-Field Theory of Ionic Solutions: A Poisson-Nernst-Planck-Bikerman Model.

We have developed a molecular mean-field theory—fourth-order Poisson–Nernst–Planck–Bikerman theory—for modeling ionic and water flows in biological ion channels by treating ions and water molecules of any volume and shape with interstitial voids, polarization of water, and ion-ion and ion-water correlations. The theory can also be used to study thermodynamic and electrokinetic properties of electrolyte solutions in batteries, fuel cells, nanopores, porous media including cement, geothermal brines, the oceanic system, etc. The theory can compute electric and steric energies from all atoms in a protein and all ions and water molecules in a channel pore while keeping electrolyte solutions in the extra- and intracellular baths as a continuum dielectric medium with complex properties that mimic experimental data. The theory has been verified with experiments and molecular dynamics data from the gramicidin A channel, L-type calcium channel, potassium channel, and sodium/calcium exchanger with real structures from the Protein Data Bank. It was also verified with the experimental or Monte Carlo data of electric double-layer differential capacitance and ion activities in aqueous electrolyte solutions. We give an in-depth review of the literature about the most novel properties of the theory, namely Fermi distributions of water and ions as classical particles with excluded volumes and dynamic correlations that depend on salt concentration, composition, temperature, pressure, far-field boundary conditions etc. in a complex and complicated way as reported in a wide range of experiments. The dynamic correlations are self-consistent output functions from a fourth-order differential operator that describes ion-ion and ion-water correlations, the dielectric response (permittivity) of ionic solutions, and the polarization of water molecules with a single correlation length parameter.

Permittivity Reconstruction in Electrical Capacitance Tomography Based on Visual Representation of Deep Neural Network

Electrical Capacitance Tomography (ECT) has been developed for many years and made great progresses. Successful applications of ECT depend on the accuracy and speed of image reconstruction. In this paper, we propose a new image reconstruction method based on deep neural network. The proposed neural network mainly consists of three parts, i.e. a forward problem network, an inverse problem network and a permittivity prediction network. Compared to previous reconstruction algorithms, the benefit of our method is that it can not only reconstruct the object shape, but also predict its permittivity value with the preset resolution which is desired in many multiphase flow applications. In experiment, 10000 frames of simulation data and additional measured capacitance data were used. The results show that the proposed method can reconstruct images more accurately than typical iterative methods with real permittivity values of objects predicted correctly, and reduce the computational cost to about 2.24 seconds per frame for an image resolution of 200*200.

Current-voltage and capacitance study of light-induced metastabilities in CuZnSnSSe thin film solar cells

White, red and blue light-induced metastabilities in Cu2ZnSnS4(Se4) solar cells were investigated by temperature dependent current-voltage measurements, drive level capacitance profiling, impedance and thermal admittance spectroscopy. A set of devices were studied where white and blue light soaking at room temperature led to degradation of the device performance, while after red light soaking the solar cell efficiency did not change.We observed a significant effect of light soaking on capacitance data measured in both low and high-temperature ranges for these devices. In particular, the net doping concentration extracted from drive-level capacitance profiling substantially increased after light soaking treatments.Low and high-temperature capacitance steps observed in the reference capacitance-frequency spectra were assigned to Fermi level pinning and bulk defects, correspondingly. Light soaking with different-wavelength light led to a shift of both steps toward the high-frequency range, and hence a decrease in the thermal admittance activation energies.A low-frequency ‘inductive’ loop was detected in the impedance spectra after light soaking, regardless of wavelength. It was proposed that the appearance of the ‘inductive’ loop is due to the formation of a negative electric field at the highly defected CdS/Cu2ZnSnS4(Se4) hetero-interface. This result also leads us to conclude that such electric field is responsible for the metastable behaviour of these devices at room temperature, while the low temperature metastable changes might have a different origin.We also discuss the methodology for electrical characterization of the metastable solar cells in detail.

Hybrid iterative reconstruction method for imaging problems in ECT

As a powerful visualization tomography technique, electrical capacitance tomography (ECT) method, which reconstructs the permittivity distribution in a sensing domain according to the measured capacitance data, has been widely used in different industry scenarios. However, the image reconstruction in ECT is an ill-posed problem, and its application is plagued by low-quality reconstructions, and seeking for a robust algorithm to reduce reconstruction errors and artifacts is crucial. To increase the reconstruction quality, a novel cost function is built for imaging, in which the $L_{1-2}$ norm is designed as a regularizer for encoding the sparsity prior of imaging objects. The ant lion optimizer (ALO) algorithm and the alternating direction method of multipliers (ADMMs) with the Douglas–Rachford splitting (DRS) method and the soft thresholding algorithm as powerful optimizers for minimizing the subproblems are combined into a novel solver for solving the built cost function more effectively. Simulation and experimental results indicate that the proposed imaging technique can improve the quality of reconstructed images.

Dynamic measurement of gas volume fraction in a CO2 pipeline through capacitive sensing and data driven modelling

Gas volume fraction (GVF) measurement of gas-liquid two-phase CO2 flow is essential in the deployment of carbon capture and storage (CCS) technology. This paper presents a new method to measure the GVF of two-phase CO2 flow using a 12-electrode capacitive sensor. Three data driven models, based on back-propagation neural network (BPNN), radial basis function neural network (RBFNN) and least-squares support vector machine (LS-SVM), respectively, are established using the capacitance data. In the data pre-processing stage, copula functions are applied to select feature variables and generate training datasets for the data driven models. Experiments were conducted on a CO2 gas-liquid two-phase flow rig under steady-state flow conditions with the mass flowrate of liquid CO2 ranging from 200 kg/h to 3100 kg/h and the GVF from 0% to 84%. Due to the flexible operations of the power generation utility with CCS capabilities, dynamic experiments with rapid changes in the GVF were also carried out on the test rig to evaluate the real-time performance of the data driven models. Measurement results under steady-state flow conditions demonstrate that the RBFNN yields relative errors within ±7% and outperforms the other two models. The results under dynamic flow conditions illustrate that the RBFNN can follow the rapid changes in the GVF with an error within ±16%.

REMOVED: The diffusion and adhesion relationship between free films and epoxy coated mild steel

Abstract In order to investigate the effect of adhesion on ionic resistance of coatings, non-pigmented epoxy/polyamide free film and applied coating were compared. The results obtained from electrochemical impedance spectroscopy (EIS) after various immersion times in 3.5 wt.% sodium chloride solution showed that the corrosion resistance of the free film attached to the steel surface was by approximately one order of magnitude less than the applied one, indicating the important role of adhesion on the anti-corrosion properties of coatings. For the applied coating, the first signs of corrosion products appeared after 20 days of immersion, while this time was reduced to merely 2 days for the attached free film. Coating capacitance data pointed out that saturation with water for the attached free film was faster and also the amount of absorbed water was higher than the applied coating. Gravimetric water uptake of epoxy/polyamide free film was also determined and compared via EIS data. In addition, epoxy/polyamide free films were placed as membranes against NaCl and KCl solutions with different concentrations. The concentration of alkaline ions in the solution was measured using the flame photometry technique. Among epoxy membranes, the degradation of the sample which faced 3.5 wt.% NaCl was more remarkable comparing EIS and FT-IR analysis.

Determination of current transport and trap states density in AlInGaN/GaN heterostructures

The energy distribution and the relaxation time constant of the trap states with respect to conduction bands in the (Ni/Au) Schottky contact on AlInGaN/GaN heterostructures were investigated using the admittance technique. The potential dependent capacitance/conductance measurements were done in the frequency range of 5 kHz to 5 MHz at a temperature of 300 K. We found strong frequency dispersions at the accumulation regions and at the sharp transition regions (depletion region) in the capacitance curves. High frequency dispersion at the accumulation regions in C-V characteristics indicates that there is a high-density of surface traps between the metal–AlInGaN quaternary layer interfaces. Furthermore, the frequency dispersion at the sharp transition regions behavior can be attributed to the interface traps state between the AlInGaN quaternary layer and GaN layer. A detailed analysis of the frequency-dependent capacitance and conductance data was performed, assuming the models in which traps are located between the metal–AlInGaN interface (surface traps) and between AlInGaN/GaN interfaces (interface traps). The trap states density and time constants of the traps states were calculated as a function of energy separation from the conduction-band edge. The trap states' densities change between 1.3 × 1011 eV−1 cm−2 and 6.2 × 1011 eV−1 cm−2. Also, 4.8 to 5.3 μs time interval calculated for the relaxation times.

Non-ferroelectric relaxor properties of BMN, Bi3.55Mg1.78Nb2.67O13.78 pyrochlore

Phase-pure Bi3.55Mg1.78Nb2.67O13.78, BMN pyrochlore was prepared by conventional solid-state reaction at 1025 °C for 2–3 days. Electrical properties measured by impedance spectroscopy over the range 10–1073 K showed relaxor behaviour with a maximum dielectric constant, ε′max of 209 at its temperature maximum, Tmax of 204 K. Impedance data were analysed by fixed-frequency sweeps of dielectric constant and tan δ and variable frequency scans at fixed temperature. Low temperature data were modelled using the classic dielectric relaxation circuit that consists of a resistance in combination with series and parallel capacitances, but modified to include a constant phase element that introduced variable resistances and capacitances into the equivalent circuit. There was no evidence of ferroelectric behaviour, either from extrapolation of high temperature Curie-Weiss plots or the temperature-dependence of low temperature capacitance data. At intermediate temperatures, ∼240–623 K, BMN is an insulator with resistivity >10 MΩ cm. Above ∼623 K, it is a modest electrical conductor, activation energy 1.07 eV; the charge carriers are probably oxide ions.

Proportional–Integral Controller Modified Landweber Iterative Method for Image Reconstruction in Electrical Capacitance Tomography

While Landweber iteration is a popular image reconstruction algorithm for electrical capacitance tomography (ECT), it suffers from semi-convergence. In process control, PID controllers are commonly used, where P stands for proportional, I stands for integral, and D stands for derivative. Proper setting of the PID parameters can reduce the response time and enhance the accuracy and stability of control systems. In this paper, an extended PI controller is integrated with the Landweber method to relieve its semi-convergence, which is named the Landweber-PI method. To stabilize the iteration process, constraints are imposed on the integral term of the PI controller. In comparison with the conventional Landweber method and its modified variants, simulation was conducted to verify the effectiveness of the proposed method by imaging typical distributions using ECT sensors with different number of electrodes, 8 or 12 or 16 electrodes, and capacitance data without and with noise. The simulation results were validated by static experiment, showing that the proposed method converges within 50 iterations for the specified core, annular, stratified, and other two complex distributions and remains stable after 1000 iterations, while the other methods converge slowly and become divergent eventually. Regarding the reconstruction accuracy, the derived void fractions by the proposed method have smaller absolute deviations than the other methods in most cases, with a minimum of 0.3% and a maximum of 4.3%. The gas–solid flows in a real fluidized bed were imaged, with more image details reconstructed after five iterations. The improved performance of the Landweber-PI method was justified by singular value decomposition analysis.

Cross-Plane Acquisitions in Electrical Capacitance Volume Tomography

Electrical capacitance tomography (ECT) is a widely used imaging modality to image two-dimensional cross sections of multiphase flows. Recent developments in electrical capacitance volume tomography (ECVT) have made it possible to directly obtain volumetric images from measured data. An ECVT is instrumental for obtaining accurate phase hold up information and velocity information that are needed for the optimization of certain flow processes. However, compared to ECT, the high correlation between the measurements in ECVT exacerbates the ill-conditioning of the associated image reconstruction problem. Previous studies have suggested that neglecting mutual capacitance data between the ECVT electrodes located at cross-planes that are well separated along the sensor axis can be done without significantly affecting the reconstructed image. In addition, this may help constrain the ill-conditioning of the reconstruction problem. In this paper, we examine in detail and quantify the effect of reduced cross-plane acquisition strategies for optimizing the image reconstruction and constraining the ill-conditioning of typical ECVT settings.

P‐16.3: Research of the influence of OGM pattern design structure on capacitance

This paper aims to research the influence of the metal mesh pattern design structure on capacitance. Firstly, the capacitance data of different pattern design products are collected. Through the Minitab analysis, it is presented that the Tx/Rx channel area, the Tx&Rx overlap area and the space size are significant factors for capacitance. Furthermore, three groups of experiment were designed, and the following conclusions were drew: the capacitance is positively correlated with the mesh width, negatively correlated with the space size, positively correlated with the mesh area of channel region.The research results have an important guiding role for OGM pattern design and touch‐related issue analysis.

Modeling the negative capacitance effect in dispersive organic materials using modified Drude theory

Frequency- and mobility-dependent admittance have been observed in organic polymer light-emitting diodes. In this paper, we developed a model to describe this dispersive behavior using a modified Drude theory. In this model, a phase angle difference between the applied electric field and the average displacement of the charge carriers is introduced rather than using a complex mobility. This newly proposed model successfully describes the dispersive nature, as well as the negative capacitance effect, at low frequencies in organic polymers. The simulation results of this model also fit the negative capacitance data reported in the literature, provided that a suitable phase angle difference is given.

Tuning the Electrical Properties of Electrospun Nanofibers with Hybrid Nanomaterials for Detecting Isoborneol in Water Using an Electronic Tongue

The presence of contaminants in water is a subject of paramount importance nowadays, which can make water improper to human consumption even when these contaminants are present at very low concentrations, causing health issues and economic losses. In this work, we evaluated the performance of nanocomposites based on nylon 6,6/chitosan electrospun nanofibers modified by cellulose nanowhiskers combined with functional materials like silver nanoparticles, gold nanoparticles, and reduced graphene oxide to be used as sensing layers of an electronic tongue (e-tongue) to detect Isoborneol. This compound, found in some plants and essential oils, is used as a natural repellent and also to produce many other chemicals. Additionally, its chemical structure is related to that of 2-methylisoborneol, a critical pollutant in aqueous media. The synergism between the nanomaterials combined with electrospun nanofibers could be verified by the enhancement of the charge transference ability. Additionally, electrical capacitance data measured with the impedimetric e-tongue were treated by Principal Component Analysis (PCA), and revealed the sensing system was able to discriminate samples contaminated with Isoborneol at nanomolar concentrations. Moreover, the electronic tongue system could detect Isoborneol in real water samples under different concentrations.

Electrically-functionalised nanoindenter dedicated to local capacitive measurements: Experimental set-up and data-processing procedure for quantitative analysis

In this work, we report the experimental development and the application of a new characterisation tool combining mechanical testing and dielectric characterisation. The experimental set-up is essentially a nanoindentation head functionalised for capacitive measurements. First the experimental procedure for the characterisation of dielectric thin films is given: detailed set-up description, procedure for the capacitance-vs-voltage (C-V) measurements, stray capacitance. Secondly, a complete data-processing method is proposed to perform the quantitative analysis of capacitance data. To this end, a fully analytical model has been developed, able to relate the C-V curves to the system characteristics (set-up geometry and specimen properties) without any fitting parameter. Finally dielectric films with different thicknesses and relative permittivities have been tested to validate both the characterisation tool and the data-processing method. The analytical model has been used to predict the permittivity of each dielectric thin film. The extracted data have been compared to data obtained from a calibrated macro-scale technique and showed remarkable agreement. One of the strengths of the data-processing method is to eliminate the stray capacitance which usually disturbs local capacitance measurements. Even though the effect of mechanical load is not investigated in the present study, the experimental proof-of-principle is shown and the data-processing method is validated. This work opens prospects for local and quantitative dielectric characterisations under mechanical loads. It should also fill a gap between quantitative characterisations at macro-scales and spatially highly-resolved characterisations at nano-scale.

Dielectric Characteristics Analysis of Aluminum Electrolytic Capacitors Based on Linear Response Function

Introduction The electrical characteristics of aluminum electrolytic capacitors are usually measured in frequency domain. The measured data of capacitance and dissipation or equivalent series resistance (ESR) has been treated individually for each frequency, and the “LCR” model has been developed by utilizing the measurement data in frequency domain (1, 2). Therefore, these models don’t show any relation between capacitance and dissipation which should follow the Kramers-Kronig relation. In this paper, we discuss the dielectric characteristics of aluminum electrolytic capacitors based on linear response theory. Furthermore, a useful formula had been derived to analyze the dielectric properties of aluminum oxide layer in aluminum electrolytic capacitors. Experiments The specifications of the capacitors under test are as follow: “400V / 280μF / D25mm X L40mm”. These capacitors were fabricated with the following raw materials. Anode foil: 120HB15S-580V (HEC), Cathode foil: 50CK (JCC), Spacer Paper: PE4-30 (NKK), Electrolyte: resistivity 600Ωcm at 30oC (an organic acid ammonium salt in a solvent mainly containing ethylene glycol). The impedance parameters, |Z|, Capacitance, ESR, tanδ (dissipation factor ) were measured for 3 pieces of the capacitors under tests, in a frequency range from 20Hz to 1MHz, with respect to temperatures in the range from -40oC to 105oC. Results and Discussion The electric current of the dielectric absorption in aluminum electrolytic capacitors has a time dependency of ∝ t-n (0 < n ≈< 1) (3). That means the linear response function of the dielectric of aluminum electrolytic capacitors is also dependent on t-n. This has been proved through mathematical derivation, and the equations will be presented in the final manuscript. In this discussion, it is considered that the aftereffect (εr0 >> 1) should be much larger than the instantaneous response (εr∞), the mathematical term (ε0E) shown in eq. [1] can be neglected, therefore, the electric flux density is equal to the dielectric polarization and the eq. [2], [3], [4] and [5] can be obtained. Then, the expressions of the real and imaginary parts of relative permittivity εr, and the tanδ were derived as shown in eq. [7], [8] and [9] based on the linear response function φ0(t) = A / tn (0 < n ≈< 1). Furthermore, to consider the linear response function of aluminum electrolytic capacitors, the parameter τ∞ was proposed. Where the parameter τ∞ is defined as time interval until the dielectric relaxation is saturated. The parameter of the linear response function is expressed by A = (1-n) / τ∞ 1-n as shown in eq. [5]. These formulae based on the linear response function are consistent with the impedance measurement data. (see Fig.1 and Fig.2). These figures can be obtained by calculating only two key parameters n(θ) and τ∞(θ). Where, θ is temperature in degrees Celsius. That means these two parameters can explain the properties of εr ′ and εr″ of the dielectric of aluminum oxide layer in aluminum electrolytic capacitors against frequency and temperature while fulfilling the Kramers – Kroning relation. Furthermore, the formula of this linear response function expressed by n(θ) and τ∞(θ) can explain the dielectric absorption phenomenon such as the recovering voltage of aluminum electrolytic capacitors. The voltage recovery speed of aluminum electrolytic capacitors is dependent on the temperature and it follows “Double relaxation time for every 10degC reduction” which is expressed by the eq. [14]. If the relaxation time of the voltage recovery phenomenon is proportional to the relaxation time τ∞ in eq. [4] and [5], it leads the capacitance temperature coefficient : 6.91x10-4 per 1oC as shown in the calculation results of eq. [15]. And this should refer to the result of 7.529x10-4 per 1oC in this paper result eq. [10]. Conclusion The linear response function contains the whole information of the dielectric, and it can explain the temperature and frequency characteristics of complex permittivity of aluminum oxide of aluminum electrolytic capacitors by only two key parameter n(θ) and τ∞(θ). They satisfy the relation of capacitance and dissipation which is expected by the Kramers – Kroning relation. Furthermore, this theory can be applicable for the relaxation phenomenon such as the recovery voltage of aluminum electrolytic capacitors. Reference: R. H. Broadbent, Electrochem. Technol., 6, 163 (1963)S. G. Parler, IEEE Trans. Ind. Appl., vol. 39, no. 4, pp. 929–935, 2003.J. M. Albella et al., J. Appl. Electrochem. 14 (1984) 9-14D. A. McLean, J. Electrochem. Soc. 108, 48 (1961) Figure 1

A new approach based on a combination of capacitance and near-infrared spectroscopy for estimating the moisture content of timber

The moisture content (MC) of wood influences its material properties. Determination of MC is essential in both the research and manufacturing fields. This study examined a nondestructive method for estimating MC rapidly and effectively. A capacitance sensor and a near-infrared (NIR) spectrometer were used to measure the MC of Japanese cedar and Japanese cypress timber. High-frequency capacitance (20 MHz) and NIR spectral absorption (908–1676 nm) data were collected for cross section and tangential section, as well as for the whole-sample average, in two MC ranges: from the green to the fiber saturation point (FSP) and from FSP to air-dried state. The results indicated that when standard error of prediction (SEP) is compared, the performance in [FSP to air-dried state] was better; when coefficient of determination in cross-validation ( $$R_{\text{val}}^{2}$$ ) and residual predictive deviation in cross-validation (RPDval) were compared, the performance in [Green to FSP] was better. Statistical analysis was performed using multiple linear regression and partial least squares. Combining capacitance and NIR absorbance at two wavelengths (Capacitance + NIR-MLR calibration) from the green to FSP was the best calibration yielding the most promising results: $$R_{\text{val}}^{2}$$ = 0.96, SEP = 5.20% and RPDval = 4.97 on the cross section of samples. The results were higher than those of other calibrations in R2 and SEP and RPD values. The NIR-PLS calibration performed better than others with quite good R2, lower SEP and higher RPD in the MC range from FSP to air-dried state. The first calibration using only capacitance of wood was good in the first range of MC, but it is not good in the second range (R2 under 0.5). Depending on the MC range, the performance of each calibration was different. In both MC ranges, the results on the cross section were higher than on the tangential section due to the anisotropic characteristics of wood material. From Capacitance + NIR-MLR calibration, the predicted models were developed using multiple linear regression and logarithmic regression. Results suggest the possibility of developing a new portable device combining a capacitance sensor and NIR spectroscopy to accurately predict the MC of wood.

High level extracellular production of recombinant human interferon alpha 2b in glycoengineered Pichia pastoris: culture medium optimization, high cell density cultivation and biological characterization.

The present study was aimed at design of experiments (DoE)- and artificial intelligence-based culture medium optimization for high level extracellular production of a novel recombinant human interferon alpha 2b (huIFNα2b) in glycoengineered Pichia pastoris and its characterization. The artificial neural network-genetic algorithm model exhibited improved huIFNα2b production and better predictability compared to response surface methodology. The optimized medium exhibited a fivefold increase in huIFNα2b titre compared to the complex medium. A maximum titre of huIFNα2b (436mgl-1 ) was achieved using the optimized medium in the bioreactor. Real-time capacitance data from dielectric spectroscopy were utilized to model the growth kinetics with unstructured models. Biological characterization by antiproliferative assay proved that the purified recombinant huIFNα2b was biologically active, exhibiting growth inhibition on breast cancer cell line. Culture medium optimization resulted in enhanced production of huIFNα2b in glycoengineered P. pastoris at both shake flask and bioreactor level. The purified huIFNα2b was found to be N-glycosylated and biologically active. DoE-based medium optimization strategy significantly improved huIFNα2b production. The antiproliferative activity of huIFNα2b substantiates its potential scope for application in cancer therapy.

Analysis of electrical double layer structure in molten salts.

This paper reports the results of analysis of the electrical double layer (EDL) phenomenon in molten salts to provide information on the influence of short range interaction type on the shape of charge distribution and the effect of the charge distribution shape on capacitance values. A new method of analysis is proposed, which allows a quantitative discussion. It is assumed that EDL can be modelled as a number of capacitor plates connected in series. This paper reports the application of the proposed method in quantitative analysis of the molten salt capacitance data obtained for different short range potentials. The data to be analysed were obtained from the Monte Carlo simulations of the symmetrical molten salt electrolyte for the following short range interaction potentials: hard spheres, Lennard-Jones repulsions, and full Lennard-Jones. The new analysis method gives a more detailed understanding of EDL in molten salts and can become an inspiration for new researches in this field.