Treatment Of Electric Field Research Articles

Dynamic and static dipole polarizability of an Aharonov–Bohm ring

The properties of nanoscale rings are sensitive to Aharonov–Bohm fluxes threading the ring. In particular, neighboring angular momentum eigenstates become degenerate in cases of half-integer flux. Such degeneracies have a profound effect on the dipole polarizability leading to a divergent response. We analyze circular finite-width nanorings and derive a simple and compact expression for the polarizability valid for arbitrary ring geometry, frequency and magnetic flux. The dipole response is significantly reduced by finite-width effects, yet divergencies at half-integer flux are predicted irrespective of width. Finally, a non-divergent (but large) response is restored through a non-perturbative treatment of both magnetic and electric fields.

Accurate and Wide-Voltage-Range Modeling of Electrowetting with a Lattice Boltzmann Approach.

The lattice Boltzmann method (LBM) has been widely used in multi-phase fluid mechanics and is known to be more computationally efficient than the traditional method of numerically solving Navier-Stokes and Cahn-Hilliard equations. Electrowetting is an important component of interfacial sciences, in which the liquid-liquid and solid-liquid interfaces are tuned by electrostatics. Modeling electrowetting using the LBM can be categorized into surface and bulk methods. By modifying the surface tension scalar, the surface method easily reproduces the fundamental Young-Lippmann (YL) equation at low voltages but fails to capture contact angle saturation at high voltages. With fully coupled hydrodynamics and electrostatics in the form of spatially dependent matrices, the bulk method can successfully show contact angle saturation, but it is often unable to reproduce the YL equation due to its intrinsic inaccuracies. The inaccuracies are mainly due to the fact that while the hydrodynamics are all described by continuous physical quantities in the framework of diffusive interfaces, the interfacial electrostatics are governed by discontinuous electric fields caused by sheet charge density. In this paper, we show that accurately modeling electrowetting using the LBM is non-trivial. Additional modeling work, especially the treatment of interfacial electric fields, is needed to recover the fundamental YL equation at low voltages and predict contact angle saturation at high voltages, with a systematic model validation over key parameters and applications.

Effect of Zn atomic diffusion due to pulsed electric field treatment on the thermoelectric properties of Zn–Sb films

Zn4Sb3 has brought into sharp focus by its low cost and excellent thermoelectric (TE) properties in the medium temperature range. Zn atoms can diffuse in the Zn4Sb3 matrix under the treatment of temperature or current. This provides a way to control its TE performance. In this study, the TE properties of the Zn4Sb3 films were improved by the Zn atomic diffusion under the treatment of periodic pulsed electric field. The Zn atomic diffusion is caused by the electrostatic interaction of the pulsed electric field and the diffusion mode is related to the pulse period. When the pulse period is smaller than 10 s, the interstitial Zn atom diffuses first. The Zn vacancy increases, leading to the increase of the carrier concentration and the decrease of the resistivity. When the pulse period increases to 100 s, more Zn(1) atoms diffuse through the interstitial position, resulting in a small amount of ZnSb phase. Thereby in the Zn4Sb3 films, the carrier concentration decreases and the Seebeck coefficient increases. This kind of the synergistic effect decreases the resistivity and increases the Seebeck coefficient. The power factor of the Zn4Sb3 films treated with a pulse period of 100 s is more than 4500 μW m−1 K−2 in the range of 373 K–573 K. This study presents a new method to control atomic diffusion by periodic pulsed electric field, and the TE properties of the Zn4Sb3 films are improved.

Combining pulsed electric field and cross-linking to enhance the structural and physicochemical properties of corn porous starch

In this study, corn porous starch (CPS) was firstly prepared using enzymatic hydrolysis, followed by pore formation enhancement using the treatment of a pulsed electric field (PEF). Subsequently, the PEF treated porous starch (CPS-PEF) was cross-linked with sodium trimetaphosphate (STMP) to investigate its structural and functional properties. The results showed PEF treatment increased the oil absorption of CPS by 26.92% and improved its specific surface area, total pore volume value, solubility and swelling power. After cross-linking of the CPS-PEF, C-O-P covalent bonds were formed between CPS-PEF molecules, resulting in a further increase in oil absorption and specific surface area properties. Moreover, the covalent bonds enhanced the intermolecular forces, resulting in increased thermal stability of the cross-linked porous starch (ScPS). The double modification resulted in significantly improved adsorption properties and better thermal stability of the ScPS, indicating that the double modification is an effective method for the preparation of porous starches.

Application of Supercooling for the Enhanced Shelf Life of Asparagus (Asparagus officinalis L.).

Freezing extends the shelf-life of food by slowing down the physical and biochemical reactions; however, ice crystal formation can result in irreversible damage to the cell’s structure and texture. Supercooling technology has the potential to preserve the original freshness of food without freezing damage. In this study, fresh asparagus was preserved in a supercooled state and its quality changes such as color, weight loss, texture, chlorophyll and anthocyanin content, and enzymatic activities (superoxide dismutase and catalase) were evaluated. The asparagus samples were successfully supercooled at −3 °C with the combination treatment of pulsed electric field (PEF) and oscillating magnetic field (OMF), and the supercooled state was maintained for up to 14 days. Asparagus spears preserved in the supercooled state exhibited lower weight loss and higher levels of quality factors in comparison to the frozen and refrigerated control samples.

Post treatment of swine anaerobic effluent by weak electric field following intermittent vacuum assisted adjustment of N:P ratio for oil-rich filamentous microalgae production

A weak electric field (EF) was applied to decolorize the swine anaerobic effluent, which was followed by N:P ratio adjustment via intermittent-vacuum stripping (IVS) system for oil-rich filamentous microalgae Tribonema sp. cultivation. A higher electric field strength, higher temperature, and lower pH conditions showed higher efficiency in decolorization and nutrients removal during EF application. In the group of 30:1 (N:P) ratio, Tribonema sp. had the largest biomass accumulation (2.04 g·L−1) after 14 days cultivation. However, the 20:1 group had highest oil accumulation (oil content 55.4 ± 3.4%), while 30:1 (N: P) group was 42.3 ± 1.8%. Under the conditions of sufficient nitrogen (50:1 group), the highest contents of α-linolenic acid (15.5%) and ω-3 fatty acids (21.8%) were reached. The integrated treatment of EF, IVS and microalgae cultivation demonstrated to be effective for nutrients recycling and sustainable biomass production.

The combined effect of magnetic and electric fields using on/off infrared light on the blood sugar level and the diameter of Langerhans islets of diabetic mice.

Background and Aim:At present, diabetes is treated with oral antidiabetic medicines, such as sulfonylureas and thiazolidine, as well as insulin injection. However, these methods have several shortcomings. Therefore, alternatives for treating diabetes mellitus (DM) are needed. This study aims to determine the combined effect of magnetic and electric fields on blood sugar levels and the diameter of Langerhans islets of diabetic mice.Materials and Methods:Induction of DM in mice was carried out by administering lard for 2 weeks and continued with an intraperitoneal injection of streptozotocin, dissolved in a 4.5 pH citrate buffer, and administered in a dose of 30 mg/kg bodyweight for 5 days. Treatments were used in combination with magnetic and electric fields using on/off infrared light. Blood samples were pipetted through the tip of mice’s tails to establish the blood sugar level for each individual mouse. Histology preparation of the pancreas organ was affected using the histology standard as well as hematoxylin and eosin staining methods. Langerhans islet diameter data were analyzed using analysis of variance followed by Duncan’s multiple range test. Data analysis was performed at ssssssss=0.05.Results:The results showed that the combined treatment of permanent magnetic and unidirectional electric fields (PS) caused changes in blood sugar levels that were not significantly different from the normal control group. The PS treatment improved the diameter of the Langerhans islets but not to a significant degree compared to other treatments.Conclusion:The use of PS treatment is effective for reducing the blood sugar levels of diabetic mice and improving the diameter of their Langerhans islets.

The effect of electric field, magnetic field, and infrared ray combination to reduce HOMA-IR index and GLUT 4 in diabetic model of Mus musculus

Diabetes mellitus (DM) is a metabolic disorder characterized by high blood glucose level (hyperglycemia). Type 2 diabetes mellitus is mainly featured by low cell sensitivity towards insulin stimulation, caused by ectopic fat storage. Insulin resistance can be quantified from high number of HOMA-IR index and observed from glucose transporter 4 (GLUT-4) translocation on membrane of skeletal muscle cells. Combined treatment of electric field, magnetic field, and infrared ray have potential to reduce insulin resistance due to improving blood circulation and increasing intracellular Ca2+ level. The aim of study was to determine the effect of electric field, magnetic field, and infrared ray combination to lower insulin resistance in the type II diabetic model of Mus musculus. This study used 30 adult male mice strain BALB/c. Diabetes was induced using high-fat diet/streptozotocin method until random blood glucose level reached > 200 mg/dL. Diabetic mice were then exposed to electrical field (static and dynamic), magnetic field (static and induce), and infrared ray (with or without infrared ray) combination therapy 15 min daily for 28 days. Fasting blood glucose level, plasma insulin level, HOMA-IR index, and membrane GLUT-4 density after treatment were analyzed statistically at α = 0.05. Result showed that exposure combination of electrical field, magnetic field, and infrared were found to be able to lower fasting blood glucose level and HOMA-IR index significantly, but plasma insulin level and GLUT-4 density were not found to be significantly different compared to diabetic control. Based on current study result, the best combination for reducing insulin resistance in diabetic mice is BsEsI (combination of static magnetic field (Bs), static electric field (Es), with infrared (I)), indicated by lowest HOMA-IR compared to other groups. Exposure to combination of magnetic field, electrical field, and infrared resulted in lowering fasting blood glucose level and HOMA-IR index in diabetic mice, indicating reduced insulin resistance.

Investigation of uniform sized multicellular spheroids raised by microwell arrays after the combined treatment of electric field and anti-cancer drug.

Nowadays, cancer disease is continuously identified as the leading cause of mortality worldwide. Cancer chemotherapeutic agents have been continuously developing to achieve high curative effectiveness and low side effects. However, solid tumors present the properties of low drug penetration and resistance of quiescent cells. Radiation therapy is concurrently given in some cases; but it induces different levels of adverse effects. In the current work, uniform sized multicellular spheroids were raised by microwell arrays to mimic the architecture of solid tumors. Investigation of the response of the spheroids was conducted after the treatment of alternating electric field. The result showed that the electric field could induce early apoptosis by disturbing cell membrane. Moreover, combined treatment of electric field and anti-cancer drug was applied to the spheroids. The electric field synergistically enhanced the treatment efficacy because the anti-cancer drug could permeate through the disrupted cell membrane. Significant improvement of late apoptosis was shown by the combined treatment. Because the electric field treatment induces limited side effect to the patient, lower dosage of anti-cancer drug may be applied to the patients for achieving curative effectiveness.

Hydrogen Production in Acousto-Plasma Discharge from Direct Water-Hydrocarbon Emulsions

In this work, a low-temperature plasma initiated in liquid media between electrodes is shown to be able to decompose hydrogen containing organic molecules resulting in obtaining gaseous products with volume part of hydrogen higher than 90%. As feedstocks, the direct water-hydrogen emulsions obtained by ultrasonic treatment and action of electric field are used. Hydrogen productivity from emulsions is shown to be not less than that from individual substances. The measurement of the amount of the gas mixture formed during the decomposition of organic liquids demonstrates that the output is highly dependent on the discharge current, and also on the volume of the discharge which can vary depending on the distance between the electrodes in the reaction chamber. In current experiments, the discharge current is from 4A to 8A, the discharge voltage depending on the type of liquid is 30-45 V. It has been established that using the acoustoplasmic method allows the use of raw materials of the lowest quality, i.e. there is no need to spend expensive cleaning to remove impurities. A significant advantage is also the absence of toxic and difficult to digestible by-products of this synthesis, as well as the fact that the gas mixture leaves the reactor at a low pressure (0.2-0.3 atm) which facilitates its primary transportation. Hydrogen-containing gas can be used as fuel directly after synthesis, i.e. does not require separation, since in addition to hydrogen contains only impurities of CO 2 and water vapor. A by-product in the production of hydrogen by the acousto-plasma discharge method in the decomposition of organic liquids is carbon formed in the form of agglomerates of nanoparticles of different structures and precipitated during the reaction at the bottom of the reaction chamber. As the results of analyzes and stoichiometric calculations have shown, most of the carbon and oxygen contained in the molecules of the initial liquid are consumed to form these by-products, so that the gaseous mixture formed is significantly enriched in hydrogen. Nanoparticles obtained and their agglomerates can also be used as fillers, dyes, components of composite materials, etc.

A reflection on the use of ‘electric flux’ in introductory physics instruction

The treatment of electric fields and flux in most textbooks on introductory physics, at least in the English language, differs radically from the nomenclature recommended by all relevant standards organisations and authorities. The general approach also conflicts with the usual methodology adopted in electrical engineering texts. The origin of the discrepancy is outlined and it is suggested that resolving the conflict would be beneficial to the teaching and learning of this and related topics.

Enhancements of magnetic properties and planar magnetoresistance by electric fields in γ-Fe2O3/MgO thin films

The treatment of perpendicular electric field upon γ-Fe2O3/MgO film at room temperature could adjust the magnetic properties (saturation magnetization, magnetic remanence, coercivity, and saturation magnetizing field) of the film. The enhancement of saturation magnetization after the treatment of electric field may be connected with the combined shift effects of Mg ions from MgO to γ-Fe2O3 and O2− ions from γ-Fe2O3 to MgO. The negative magnetoresistance of the γ-Fe2O3/MgO film also enhances with the treatment of perpendicular electric field at room temperature, possibly due to the increasing of electron hopping rate between Fe2+ and Fe3+.

Improvement of Interfacial Shear Strength of Mendong Fiber (Fimbristylis globulosa) Reinforced Epoxy Composite Using the AC Electric Fields

The effects of the AC electric field treatment on the interfacial shear strength of mendong fiber-reinforced epoxy composites were investigated. For this purpose, the epoxy (DGEBA) with a cycloaliphatic amine curing agent was treated by the AC electric field during the curing process. The heat generated during the epoxy polymerization process was monitored. Structure of the epoxy was studied by X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), and Scanning Electron Microscope, respectively. The interfacial shear strength (IFSS) was also measured using a single fiber pull-out test. XRD analyzes indicated that the treatment of AC electric fields was able to form a crystalline phase of epoxy. IFSS of the mendong fiber-reinforced epoxy composites was optimum increased by 38% in the AC electric fields treatment of 750 V/cm.

Numerical Treatment of Plasma Dynamics in Linear Devices - Impact of Plasma Source Shaping

A global drift-fluid model is employed to study plasma discharges in linear devices including self-consistent treatment of electric fields. Numerical results on plasma rotation and turbulent scales are found to be very similar to experimental observations. Also a pronounced intermittent plasma transport in radial direction is observed for particular conditions. Extended filaments are expelled from the plasma column. In the simulations numerical probes have been implemented for detailed statistical analysis of the plasma fluctuations suitable for comparison with experimental data. In this contribution particular attention is paid to the impact of the plasma source on the intermittencies in the plasma column. It is found that even slight modifications in the shape of the plasma source can strongly change the plasma dynamics.

초음파와 전기장 처리에 의한 하수슬러지 탈수성 향상

The sludge disposal is a major economic factor in the sewage treatment facility operation. Moreover, since the ocean dumping will be prohibited by Korean environmental law from 2013, sludge should be eliminated or sludge volumetric reduction should be performed urgently. In this study, improvement of the sewage sludge dewaterability was investigated by ultrasound and electric field treatment. Sludge was treated by a single or in combination of either the electric field or ultrasound on a pilot pretreatment facility, then it was dewatered by lab-scale filter press. The operating input energy of ultrasound device was varied from 225~1,200 kJ/L and electric field device was varied from 4.5~24 kJ/L. The water contents of dewatered sludge cake treated with ultrasound (1,200 kJ/L) and combination of ultrasound/electric field (1,224 kJ/L) were decreased 10~12% by comparing non-treated sludge. At that time, water contents were 65~66%. The combination treatment of ultrasound/electric field was effective to reduce water content of dewatered sludge cake, however, water content was not changed by a single treatment of electric field because of low energy density.

On the applicability of a semi-analytical approach to determining the transient electron transport response of gallium arsenide, gallium nitride, and zinc oxide

We critically examine the applicability of the semi-analytical approach of Shur (M. Shur, Electron Lett 12, 615 (1976)) in evaluating the transient electron transport response of gallium arsenide, gallium nitride, and zinc oxide. In particular, we contrast results obtained using this semi-analytical approach of Shur with those obtained using Monte Carlo simulations of the electron transport. Our approach will be to examine the response of an ensemble of electrons to the application of a constant and uniform applied electric field. For the purposes of this analysis, three aspects of the transient electron transport response will be considered: (1) the dependence of the electron drift velocity on the time elapsed since the onset of the applied electric field, (2) the dependence of the average electron energy on the time elapsed since the onset of the applied electric field, and (3) the dependence of the average electron displacement on the time elapsed since the onset of the applied electric field. The results obtained show that this semi-analytical approach of Shur produces results that are very similar to those produced using Monte Carlo simulations. Thus, this semi-analytical approach of Shur should be applicable for the treatment of non-uniform and time-varying electric fields, making it a useful tool for the treatment of the transient electron transport response within electron device configurations.

Electro-optical Properties, Polarity and Chain Rigidity of Poly(dialkoxyphosphazene)s with Variable Side-Chain Length

Molecular properties of poly(dialkoxyphosphazene) (PDAOP) series with the aliphatic side-chains contained 3, 4, 6, and 7 carbon atoms were investigated in dilute benzene solutions by techniques of electro-optical Kerr effect and dynamo-optical Maxwell effect, and by dielectric spectroscopy. The sign inversion of Kerr effect and Maxwell effect in PDAOP solutions from positive to negative was detected at the side-chain length range of 5–6 carbon atoms. These phenomena were explained by the strong dependence of anisotropy of optical polarizability of PDAOP monomeric unit on chemical structure and change of its sign at the indicated side-chain lengths. It was demonstrated that PDAOPs possess a critical side-chain-length interval at which their physical properties, depending on the intramolecular ordering, display a singularity. It was also shown that the studied PDAOP samples are not flexible-chain polymers. They are characterized by Kuhn segment 47–65 A, the value of which increases with the elongation of aliphatic side-chain. Dielectric properties of PDAOP were correlated to the properties of the macromolecules with manifestation of kinetic rigidity under a treatment of electric field.

A combined treatment of UV-light and radio frequency electric field for the inactivation of Escherichia coli K-12 in apple juice

Radio frequency electric fields (RFEF) and UV-light treatments have been reported to inactivate bacteria in liquid foods. However, information on the efficacy of bacterial inactivation by combined treatments of RFEF and UV-light technologies is limited. In this study, we investigated the relationship between cell injury and inactivation of Escherichia coli K-12 in apple juice treated with a combination of RFEF and UV-light. Apple juice purchased from a wholesale distributor was inoculated with E. coli K-12 at 7.8 log CFU/ml, processed with a laboratory scale RFEF unit at 20 kHz, 15 kV/cm for 170 µs at a flow rate of 540 ml/min followed by UV-light treatment (254 nm) for 12 s at 25, 30 and 40 °C. Treated samples were analyzed for leakage of UV-substances as a function of membrane damage and were plated (0.1 ml) on Sorbitol MacConkey Agar (SMAC) and Trypticase Soy Agar (TSA) plates to determine the viability loss and percent injury. At 40 °C, UV-light treatment alone caused 5.8 log reduction of E. coli in apple juice while RFEF caused only 2.8 log reduction. A combination of the two processing treatments did not increase cell injury or leakage of intracellular bacterial UV-substances more than that from the UV-light treatment. Similarly, the viability loss determined was not significantly ( P < 0.05) different than UV-light treatment alone. However, the UV-substances determined in apple juice treated with RFEF was significantly ( P > 0.05) different than UV-light treated samples. The results of this study suggest that RFEF treatment causes more injury to the bacterial cells leading to more leakage of intracellular UV-substances than cells treated with UV-light alone. Also, the effect of the two processing treatment combination on bacterial inactivation was not additive.

Theory-inspired development of organic electro-optic materials

Real-time, time-dependent density functional theory (RTTDDFT) and pseudo-atomistic Monte Carlo–molecular dynamics (PAMCMD) calculations have been used in a correlated manner to achieve quantitative definition of structure/function relationships necessary for the optimization of electro-optic activity in organic materials. Utilizing theoretical guidance, electro-optic coefficients (at telecommunication wavelengths) have been increased to 500 pm/V while keeping optical loss to less than 2 dB/cm. RTTDDFT affords the advantage of permitting explicit treatment of time-dependent electric fields, both applied fields and internal fields. This modification has permitted the quantitative simulation of the variation of linear and nonlinear optical properties of chromophores and the electro-optic activity of materials with optical frequency and dielectric permittivity. PAMCMD statistical mechanical calculations have proven an effective means of treating the full range of spatially-anisotropic intermolecular electrostatic interactions that play critical roles in defining the degree of noncentrosymmetric order that is achieved by electric field poling of organic electro-optic materials near their glass transition temperatures. New techniques have been developed for the experimental characterization of poling-induced acentric order including a modification of variable angle polarization absorption spectroscopy (VAPAS) permitting a meaningful correlation of theoretical and experimental data related to poling-induced order for a variety of complex organic electro-optic materials.

Antimicrobial effect and shelf-life extension by combined thermal and pulsed electric field treatment of milk

The impact of a combined hurdle treatment of heat and pulsed electric fields (PEF) was studied on native microbiota used for the inoculation of low-fat ultra-high temperature (UHT) milk and whole raw milk. Microbiological shelf-life of the latter following hurdle treatment or thermal pasteurization was also investigated. UHT milk was preheated to 30 degrees C, 40 degrees C or 50 degrees C over a 60-s period, pulsed for 50 micros or 60 micros at a field strength of 40 kV cm(-1) or for 33 micros at 50 kV cm(-1). Heat and PEF reduced the microbial count by a maximum of 6.4 log in UHT milk (50 degrees C; 50 kV cm(-1), 33 micros) compared to 6.0 log (P > or = 0.05) obtained by thermal pasteurization (26 s, 72 degrees C). When raw milk was treated with a combination of hurdles (50 degrees C; 40 kV cm(-1), 60 micros) a 6.0 log inactivation of microbiota was achieved and microbiological milk shelf-life was extended to 21 days under refrigeration (4 degrees C) vs 14 days in thermally pasteurized milk. Native microbiota was decreased by 6.7 log following conventional pasteurization. The findings suggest that heat and PEF achieved similar inactivation of native microbiota in milk and longer stabilization of microbiological shelf-life than thermal pasteurization. A hurdle approach of heat and PEF could represent a valid milk processing alternative to conventional pasteurization. Hurdle treatment might also preserve native milk quality better due to less thermal exposure.