Electrical Dispersion Research Articles

Efficacy of increasing discharge to reduce tow-mediated fish passage across an electric dispersal barrier system in a confined channel

The Electric Dispersal Barrier System (EDBS) in the Chicago Sanitary and Ship Canal (CSSC) was built to limit the interbasin transfer of aquatic invasive species between the Mississippi River Basin and the Great Lakes Basin. Commercial barge traffic, or tows, moving downstream through the EDBS can facilitate the upstream passage of small fish through the barrier by reducing the voltage gradient of the barrier and causing localized upstream return currents. This study tested whether it is possible to prevent upstream passage of small fish across the barrier by preventing upstream return currents. Measurements of water velocity, voltage gradient, and tow speed, as well as sonar-based observations of resident fish, were made as a tow transited the EDBS moving downstream. The results indicate that upstream return currents can be prevented for typical flow conditions in the CSSC (ambient velocity = 0.15 to 0.23 m/s) when tow speeds are <0.46 m/s. Similarly, increasing the ambient velocity above typical values can prevent upstream return currents for faster tow speeds and larger tows. Additionally, preventing upstream return currents at the EDBS may reduce, but does not prevent, tow-mediated upstream fish passages because tows also cause a temporary reduction in the streamwise voltage gradient at the EDBS. These results have implications for the management of invasive bigheaded carps in the Illinois Waterway.

Mesopore‐controllable Carbon Aerogel and their Highly Loaded PtRu Anode Electrocatalyst for DMFC Applications

AbstractCatalyst loading and layer thickness are crucial factors to enhance the cell performance and to reduce cost of membrane electrode assemblies (MEAs). Outstanding properties, such as large surface area to disperse metal nanoparticles and sufficient pore volume and size, is needed in utilization of fuel cell. Carbon aerogels are one of the good candidates that meets the above conditions. Those are synthesized by polycondensation reaction of resorcinol and formaldehyde (RF) polymer, supercritical drying to keep pore skeleton structure caused by capillary force and calcination of RF polymer in nitrogen atmosphere to be controllable meso pore (2∼43 nm) as role of support for electric conductor and dispersion of metal nanoparticles. In order to utilization of anode catalyst in direct methanol fuel cell, highly loaded (80 weight percent) platinum and ruthenium onto carbon aerogel are synthesized by Bönnemann colloid method. The single cell test of carbon aerogel supported PtRu anode catalyst is performed and over 40 nm pore sized‐catalysts are the best performance due to sufficient surface area to anchor uniform and small metal nanoparticles and good pathway to drive fuel and outgas even though PtRu nanoparticles are anchored on the outer surface of carbons.

In vivo electrical impedance measurement in human skin assessment

Abstract Structural and chemical alterations in living tissue are reflected in electrical impedance changes. However, due to the complexity of skin structure, the relation between electrical parameters and physiological/pathological conditions is difficult to establish. The impedance dispersion reflects the clinical status of the examined skin tissue and, therefore, it is frequently used in a non-invasive evaluation of exposing skin to various factors. The method has been used to assess the effect of the fish collagen on the skin of patients suffering from the leg ulcer. Therefore, from a number of different approaches to skin electrical impedance dispersion, the one considered to be safe was selected and applied. This paper presents a short review of different technical approaches to in vivo electrical impedance measurements, as well as an analysis of the results and the effect of fish collagen locally administered on human skin.

The influence of temperature on elastin\u2013water dielectric properties

The main purpose of this article is the in vitro study of elastin from the bovine neck ligament using dielectric spectroscopy in the alpha electric field dispersion region in the temperature range from 22 to 200 °C. The temperature dependence of the relative permittivity of wet elastin indicates a maximum of about 50 °C due to the thermal decomposition of loosely bound water, as well as a rapid decrease in this parameter above 185 °C. For a dry elastin, the change in relative permittivity with temperature represents only one peak of high temperature around 185 °C, corresponding to the glass transition temperature (Tg). Below Tg, the activation energy of conductivity for wet and dry elastin at 50 kHz, responsible for the breaking of hydrogen bonds between bound water molecules and hydrophilic polar groups of the main elastin chains, is 27 and 11 kJ mol−1, respectively, and above Tg, corresponding activation energy values associated with relaxation of the main chain increase to 72 and 34 kJ mol−1. In this article, dielectric processes related to the glass transition temperature, especially in the case of dry elastin, can play an important role in the use of solid-state elastin as a biomaterial for various tissue engineering applications.

Physicochemical behavior of M doped Zn0.95Cu0.05O nanocomposites synthesized by facile sol–gel method

In the present work, the synthesis of Zn0.94Cu0.05M0.01O (M=Ag; Ni; Fe) nanocomposites by a simple sol-gel method is illustrated. XRD, SEM, EDX and FTIR were utilized to characterize the prepared nanocomposites structure; additionally, their porosity and surface area were investigated via N2 adsorption. The XRD data asserted the pertinence of the ZnO hexagonal wurtzite structure with the evolution of a CuO monoclinic phase. The FTIR analysis emphasized the bonding of the metal ions to the ZnO host as dictated by a shift in the Zn–O vibration mode. The dielectric properties variations with frequencies as a consequence of the incorporation of M-ions in the Zn0.95Cu0.05O nanocomposite showed that the dielectric constant, dielectric loss tangent and conductivity values were found to change inversely with the applied frequencies. On the other hand a direct dependence of impedance was observed. Hopping of charge carriers between ions such as Fe2+ → Fe3+ and Cu2+ + M+n → Cu+ + M+n+1 may be the cause for the electrical and dielectric dispersion in the samples. The above mentioned findings make these materials promising candidates for optoelectronic and photocatalytic applications.

Multi-Access RF Frequency Dissemination Based on Round-Trip Three-Wavelength Optical Compensation Technique Over Fiber-Optic Link

In this paper, we propose a tree-like topology networking scheme based on round-trip three-wavelength optical compensation technique over fiber-optic link. This scheme simplifies the system complexity of the local site, improves the scalability of the frequency dissemination network, and reduces the influence of Rayleigh backscattering on the local and remote sites. The feasibility of the scheme is verified by a set of fiber-optic frequency dissemination network, with a transmission frequency of 1 GHz. The network consists of two remote sites with distances of 20 and 55 km far from the local site, and the frequency compensation system is optimized. The experimental results show that the fractional frequency stability of the 20 and 55 km fiber links can reach 8.6 × 10−15@1s, 7.6 × 10−18@104s, and 1.3 × 10−14@1s, and 8.1 × 10−18@104s. The limitations of electrical amplifiers, WDM, and group velocity dispersion on long-term stability and network capacity are discussed. Our system demonstrates that the stable sharing of frequency signals from ultra-stable frequency sources at any site within a large metropolitan area is achievable.

An Automatic Decentralized Control Method for Low Voltage Power for Ship's Shore Power

Peng, H.; Gao, R.; Song, X., and Shen, Q., 2018. An automatic decentralized control method for low voltage power for ship's shore power. In: Liu, Z.L. and Mi, C. (eds.), Advances in Sustainable Port and Ocean Engineering. Journal of Coastal Research, Special Issue No. 83, pp. 851–855. Coconut Creek (Florida), ISSN 0749-0208.Current electrical control methods of ship's shore power can not disperse the electrical distribution and have the problems of poor transport stability, low electrical utilization and long time of electrical transmission. Based on the condition of ship's shore power with low voltage, an automatic decentralized control method is proposed. By determining the maximum and minimum of the required electrical value, it can disperse the electrical accurately, reduce the time of electrical transmission, and improve the electrical utilization. Each closed loop system in the ship's shore power is controlled, to make the index to stabilization, and improve the stability of electrical dispersion. The experimental results show that the method has high dispersive stability, high electrical utilization and short electrical transmission time.

Relationship of left atrial mechanics to electrical activity on surface electrocardiography in idiopathic dilated cardiomyopathy

Aim: (1) Assess left atrial (LA) mechanics and electromechanical delay in patients with idiopathic dilated cardiomyopathy (IDCM), and (2) examine the relationship between atrial electromechanical delay and atrial electrical activity [P-wave duration, P-wave dispersion (PWD) and P terminal force (PTF)] on surface ECG.Methods: 73 IDCM patients (age 36 ± 17 years); 63% men,25 age & sex matched healthy subjects were studied. LA atrial electromechanical delay & mechanics (εsys, SRsys, SRe, SRa) were measured with 2D-strain. From 12-lead electrocardiograms, P-wave duration, PWD and PTF calculated.Results: Reservoir, conduit and contractile functions were predominantly reduced compared to control (P < 0.001). Intra-atrial electromechanical delay was 88.9 ± 84.6 in IDCM versus 27.4 ± 16.5 in control (P < 0.0001). In IDCM, PWD (52.89 ± 15), Pmax(98 ± 17.5) and PTF(58.2 ± 36) were significantly increased compared to control (36.20 ± 8.9, 79 ± 9.9, 25.22 ± 8.76) respectively (P < 0.0001). A positive correlation was detected between intra-atrial electromechanical delay and PWD &PTF (r = 0.5, P < 0.0001). By stepwise multiple linear regression analyses, LA reservoir function (LA εsys) [β = 0.754; CI at 95%:0.356–0.780, P < 0.001] and LA volume [β = 0.743; CI 95%:0.423–0.75, P < 0.001], and PWD [β=0.848; CI 95%:0.311–0.644, P < 0.0001], and PTF [β = 0.927; CI 95%: 0.357–0.722, P < 0.0001] are independent predictors for LA electromechanical delay in IDCM.Conclusion: In addition to altered LA mechanics, atrial electromechanical delay gets longer in IDCM and is correlated with PWD and PTF. Atrial electrical dispersion on surface ECG could be early index of LA dysfunction that deserves further study.

A Debye dispersion model of a two-layered material

Debye formulas are widely used to describe the electrical dispersion characteristics of a uniform lossy material. Debye model uses some empirical coefficients to control the shape and position of spectroscopy curves. It can fit most of the data from experiments. A two-layered model is investigated through its equivalent Debye circuit model. A Finite Difference Method (FDM) is developed to extract the effective permittivity and conductivity of a two-layered model as the verification of the analytical derivation. The computation results indicate the results obtained from FDM and the layered Debye formulas agree very well, which shows the validity of the layered Debye formulas in terms of the original circuit parameters. The derived formulas are used to analyze the relationship between the effective electrical spectra and the electrical parameters of each layer. A few examples are given in the discussions. And it can be concluded that: (1) with the increase of the average value of the conductivity of the two layers, the spectra of effective permittivity transition area shifts to higher frequencies; while the spectra of effective conductivity transition kept the same with the values decrease; (2) with the increase of the average value of the relative permittivity of the two layers, the transition area of the spectra of effective permittivity kept the same with values increase; and the transition area of the spectra of effective conductivity shifts to the lower frequencies; (3) the effective permittivity enhances at the lower frequency region as the ratio between the conductivity of two layers increase.

Probing the dielectric relaxation processes and their correlation with ions transportation in the complexes of plasticized nanocomposite solid polymer electrolyte

Plasticized nanocomposite solid polymer electrolyte (PNSPE) film consisted of poly(ethylene oxide) and poly(methyl methacrylate) blend as host matrix, lithium perchlorate salt as ions dopant, ethylene carbonate as plasticizer, and montmorillonite clay nanoplatelets as inorganic nanofiller has been prepared by solution cast followed by the melt pressing. X-ray diffraction study of the PNSPE film confirms its amorphous structure with the existence of exfoliated nanoplatelets of the nanofiller. Dielectric and electrical dispersion of the film has been characterized systematically by employing the dielectric relaxation spectroscopy in the frequency range 2 × 101 to 1 × 106 Hz, at different temperatures. The relaxation times attributed to the various processes of structural dynamics of the PNSPE film have been probed by considering the individual spectrum of all the dielectric and electrical functions which are further validated by their master plot representation. The relaxation times corresponding to the dynamics of the electric double layers, electrode polarization, and interfacial polarization-affected polymer chain segments, cations coordinated polymers chain segments, and also the ionic conductivity in the ion–dipolar–nanofiller coordinated structures of the film have been determined. A generalized behaviour of these relaxation processes for probing the dynamical structures in all the solid polymer electrolytes has been demonstrated. It is further explored that these relaxation times of the PNSPE film exhibit a correlation with the dc ionic conductivity, and their temperature-dependent variation obeys the Arrhenius behaviour of nearly the same relaxation activation energies which are also found in good agreement with the conductivity activation energy.

Electric Field and Dispersion Characteristic Calculations of Glass Tube Waveguides Filled with Biological Substances

This study presents calculation of dispersion characteristics in the frequency range 1–100 GHz as well as electric field distributions in an open cylindrical waveguide with a central channel. The waveguide is made of glass material. The channel can be either empty or filled with blood plasma or blood cells. We investigated two kinds of electromagnetic (ЕМ) waves, the “tube” and “core” modes, each having a different structure of their electric fields. In the current study, the analysis focused on the fundamental and the first higher hybrid magnetic and electric “tube” modes. The fundamental “tube” mode that propagates in the waveguide filled with blood plasma is characterized by a very small loss at frequencies above 65 GHz. Meanwhile, the first higher mode suffers from strong attenuation in the same frequency range. This calls for finding ways to improve the waveguide’s broad-bandwidth. Our approach involves determining the dependence of this parameter on the inner radius of the waveguide. Extremes of the waveguide’s broad-bandwidth are observed at certain values of its inner radius. When the waveguide is filled with blood plasma or blood cells, the electric fields of the magnetic “tube” mode concentrate around the channel, and the electric field intensity decreases with the propagation of this mode along the waveguide, i.e., with increase of coordinate z. If the channel is filled with blood cells, the electric field of the hybrid magnetic “core” mode is concentrated in the center of the waveguide. This mode is characterized by a large attenuation h”, which reaches 500 m−1 at 30 GHz.

Femtosecond optical two-way time-frequency transfer in the presence of motion

Platform motion poses significant challenges to high-precision optical time and frequency transfer. We give a detailed description of these challenges and their solutions in comb-based optical two-way time and frequency transfer (O-TWTFT). Specifically, we discuss the breakdown in reciprocity due to relativity and due to asynchronous sampling, the impact of optical and electrical dispersion, and velocity-dependent transceiver calibration. We present a detailed derivation of the equations governing comb-based O-TWTFT in the presence of motion. We describe the implementation of real-time signal processing algorithms based on these equations and demonstrate active synchronization of two sites over turbulent air paths to below a femtosecond time deviation despite effective velocities of +/-25 m/s, which is the maximum achievable with our physical setup. With the implementation of the time transfer equation derived here, we find no velocity-dependent bias between the synchronized clocks to within at two-sigma statistical uncertainty of 330 attoseconds.

High electrical conductivity waterborne dispersions of carbon black pigment

The carbon black grades that are employed as pigments in printing inks are characterised by low surface area, low structure and a higher proportion of chemisorbed polar groups on the surface. All of these features render the pigment easily dispersable – a property crucially important in the case of printing inks. However, high electrical conductivity of carbon black is known to be possessed only by the grades that have high surface area, high structure and lower proportion of polar groups, and consequently poor dispersability. The study reported here aimed to resolve such a dilemma between high electrical conductivity and poor dispersability. Thus, novel methodologies were developed to prepare waterborne, binder-free dispersions based on “non-printing ink” grades of carbon black. The particle size analysis, rheological characterisation, sedimentation analyses and electrical characterisation results clearly indicate that the selected pigment grades of carbon black were successfully stabilised as dispersions that possess high electrical conductivity at considerably lower pigment loadings than normal.

Investigation on Structural and Dielectric Properties of Silica Nanoparticles Incorporated Poly(Ethylene Oxide)/Poly(Vinyl Pyrrolidone) Blend Matrix Based Nanocomposites

Inorganic and organic materials based polymer nanocomposite (PNC) films, comprising silica (SiO2) nanoparticles as inorganic filler and the polymer blend of poly(ethylene oxide) (PEO) and poly(vinyl pyrrolidone) (PVP) as organic matrix (i.e., (PEO–PVP)-x wt% SiO2; x = 0, 1, 3 and 5) have been prepared by the solution-casting method. These PNC films are characterized by employing the scanning electron microscopy (SEM), X-ray diffractometer (XRD), Fourier transform infrared (FTIR) spectroscopy, and the dielectric relaxation spectroscopy (DRS). The effect of SiO2 nanofiller on the spherulite and porous morphology, miscibility of the polymers, PEO crystallite size, the degree of crystallinity, polymer–polymer and polymer-nanoparticle interactions, and from 20 Hz to 1 MHz range dielectric and electrical dispersion behaviour and also the structural dynamics of these PNC materials have been investigated. The porous morphology, structures of miscible phases, and the PEO crystallite length greatly alter with the incorporation of merely 1 wt% SiO2 in the polymer blend matrix which further changes with the increase of nanofiller concentration up to 5 wt%. The real part of complex permittivity over the radio frequency range (20 kHz–1 MHz) for these PNC films is found about 2 and their dielectric loss tangent values below 0.03, at the room temperature, which are significantly low. The contribution of interfacial polarization effect at lower audio frequencies enhances the complex permittivity of these materials linearly in the range 2 to 4 with the decrease of frequency from 1 kHz to 20 Hz confirming their frequency tunable dielectric behaviour. The dielectric study of 3 wt% SiO2 containing PNC film in the temperature range 30–60 °C reveals its thermally activated dielectric characteristics, and the temperature dependent values of dielectric relaxation time and dc electrical conductivity obey the Arrhenius behaviour with activation energies in the range 0.2–0.3 eV. The dielectric and electrical parameters ascertain the promising applications of these PNC films in the development of novel electroactive functional materials, and also their use as the dielectric substrate and electrical insulating polymeric nanodielectrics for the fabrication of flexible-type naturally degradable organoelectronic devices.

Manufacture of Cobalt–Chromium Powders by the Electric Discharge Dispersion of Wastes and Their Investigation

An energy-saving, ecologically safe, and resource-saving technology is proposed to fabricate a powder material from the wastes of cobalt–chromium alloys with a given size and shape distribution of particles, which can be used for additive technologies.

A simultaneous approach implementing wind-powered electric vehicle charging stations for charging demand dispersion

Electric vehicle charging demand is highly variable depending on the charging pattern of consumers. If electric vehicle charging time is converged, the charging demand connected to power grids will increase and system instability may be induced. Wind Generating Sources (WGRs) can provide as much of the charging energy as possible. In this paper, we propose a simultaneous approach implementing wind-powered electric vehicle charging stations in order to distribute the charging demand of the electric vehicle with wind generating resources. The Autoregressive Integrated Moving Average with Exogenous Variables (ARIMAX) model is applied to predict hourly wind power outputs. The augmented ARIMAX model is extended from Autoregressive Integrated Moving Average (ARIMA) model by adding exogenous such as a wind speed including grid integration analysis simulation processes. To validate the proposed approach for electric vehicle charging dispersion, we use the empirical data from the Jeju Island's wind farms in South Korea.

Can abnormal dispersion of ventricular repolarization be a predictor of mortality in arrhythmogenic right ventricular cardiomyopathy: The importance of Tp-e interval.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiomyopathy characterized by ventricular arrhythmias and specific ventricular pathology. Repolarization abnormalities, the significant contributor to life-threatening arrhythmias and mortality, are frequently observed ECG changes in patients with ARVC. This study aimed to evaluate the changes in Tp-e interval, Tp-e/QT, Tp-e/QTc ratio, and traditional electrocardiographic features of electrical dispersion in patients with ARVC. A total of 105 participants were enrolled in the current study. The ARVC group consisted of 40 subjects (30 men, with a median of 35 (26-41) years), and the control group included of 65 age and sex-matched individuals (42 men, with a median of 37 (24-45) years). The Tp-e interval, Tp-e/QT ratio, and Tp-e/QTc ratio were measured by the 12-lead electrocardiogram. Tp-e interval, cTp-e interval, Tp-e/QT, and Tp-e/QTc ratio were significantly higher in ARVC patients compared to the control group (all p<0.001). Tp-e interval, cTp-e interval, Tp-e/QT ratio, and Tp-e/QTc ratio were significantly increased in deceased ARVC patients compared to the survival group (p=0.038, p<0.001, p=0.006, p=0.032, respectively). In the multivariate analysis, RV-FAC and cTp-e interval level (p<0.05 for each parameter) were associated with all-cause mortality [odds ratio 1.747 95% CI (1.012-3.018); p=0.045 and odds ratio 1.166, 95% CI (1.017-1.336); p=0.027, respectively]. Tp-e interval, cTp-e interval, Tp-e/QT ratio, and Tp-e/QTc ratio were prolonged in patients with NC. We revealed that abnormal dispersion of ventricular repolarization suggests the increased risk of mortality in ARVC.

Preparation and electrochemical properties of MnO2/PANI-CNTs composites materials

ABSTRACTIn this article, carbon nanotubes (CNTs) was modified with conducting polymer polyaniline (PANI) to produce composite supporters (PANI-CNTs), and then the MnO2/PANI-CNTs composite material was prepared by hydrothermal route through the oxidation of manganese sulfate using ammonium persulphate (APS) as oxidizing agent. XRD, FT-IR, SEM and laser Raman spectroscopy were used to characterize the composition and structure of materials, meanwhile the electrochemical properties of the material were also investigated. In addition, a series of materials such as MnO2, MnO2-CNTs, MnO2-PANI with different supporters were also prepared to investigated the support effects on the structure and electrochemical properties of composite materials. The characterization results show that the dispersion of MnO2 in composites was greatly affected by the constitution of supports. In comparison with poor MnO2 dispersion on MnO2/CNTs, as for the composite materials including PANI, the anchoring of Mn2+ through covalent bond between PANI and Mn2+, which would help to disperse the MnO2, and then uniform ‘starfish-type’ MnO2 was achieved on MnO2/PANI-CNTs composite. Moreover, the addition of PANI would improve the conductivity of composite materials. In conclusion, high electrical conductivity and MnO2 dispersion on MnO2/PANI-CNTs composite results in higher specific capacitance (391F/g), which was triple value of specific capacitance for pure MnO2 (132 F/g). Moreover, high specific capacitance retention (90%) for MnO2/PANI-CNTs composite displays good electrochemical stability in comparison with other composites.

1.6 Tb/s Virtual-Carrier Assisted WDM Direct Detection Transmission Over 1200 km

Single-sideband (SSB) self-coherent detection (SCD) has attracted a lot of attention recently as a promising technology for short and medium reach optical transmission systems, such as data center interconnect (DCI) and metro applications, due to the low cost, the compact module size, and the possibility of electrical dispersion compensation. In addition, it has been shown that the SSB SCD can be effectively realized using a “virtual carrier,” which is generated digitally together with the information-bearing signal to significantly simplify the hardware implementation. In this paper, we present an experimental demonstration of an 8 × 256 Gb/s WDM SSB SCD transmission with virtual carriers over a record distance of 1200 km with Corning TXF fiber. To achieve this performance, two digital linearization techniques have been considered and compared, namely the Kramers–Kronig (KK) field reconstruction and iterative signal-signal beat interference cancellation. Furthermore, we introduce a novel scheme called dc-offset KK to minimize the performance penalty associated with filtering and resampling process of the conventional KK scheme.

The effect of electrical discharge treatment of milk whey on partial conversion of lactose into lactobionic acid

The article considers the scientific aspects of probable partial transformation of lactose into lactobionic acid due to the electrical discharge dispersion of magnesium and manganese conductive granules in milk whey – a traditional lactose-containing raw material. The object of this study was milk whey, defatted and with casein dust particles removed, which was treated in a discharge chamber with a conductive layer of magnesium and/or manganese granules at (20±2)°С with 120–180 s of exposure. A UPLC-MS/MS analysis of milk whey was carried out using a TSQ Vantage chromatograph-mass spectrometer (ThermoFinnigan, USA) connected to a Dionex Ultimate 3000 liquid chromatograph. The changes have been studied taking place in pH and redox potential of milk whey after electrical discharge treatment, as compared to the original whey. It has been established that electrical discharge treatment with 180 s of exposure increases the Mg content in milk whey by approximately 4 times, and increases the Mn content by 3.5 times. The dispersed metal particles are found in nano- (about 30 nm) and microscale (100 nm to 10 µm). The UPLC-MS/MS analysis of the test samples of whey that underwent electrical discharge treatment allowed identifying a chromatographic peak [M–H]–=357 m/z related to lactobionic acid. The derivative lactose content increased by 2 times in the whey samples treated for 180 s in a reaction chamber with a conductive layer of Mg between the corresponding electrodes, as compared to the original whey, and by 4 times in the samples subsequently treated in the reaction chambers with a layer of Mg and Mn granules between the corresponding electrodes, with 120 s of exposure in each chamber. The way has been presented of solving the problem of complex, economically practical and environmentally safe processing of milk whey with the prospect of obtaining lactobionic acid, a biologically valuable derivative of lactose.