Electrode Axis Research Articles

Tutorial and comprehensive computational study of acceptance and transmission of sinusoidal and digital ion guides.

A quadrupoles acceptance is a measure of its ability to catch ions with certain trajectories. One way to calculate acceptance is the method of ellipses. The method arose partly from a simplification that trajectories could be calculated for an electrode axis independently of others. It has been used to calculate the acceptance and transmission of sine-driven quadrupole mass filters for over 50years. Although the method is straightforward, it is generally described with little detail or presented as a confusing string of equations. As such, it may not be decipherable by all practitioners. For this reason, the first half of this paper presents a practical explanation of the method of ellipses and the concepts that make it work. Only equations necessary to describe the method are introduced. The tutorial also prepares the reader for the second half, which presents an alternative approach for calculating acceptance based on an array of initial trajectories. The alternative approach is used to compare the acceptance of simplified sinusoidal and digital ion guides. The method of ellipses was applied to validate results of the new approach for calculation of acceptance.

Head orientation and electrode placement potentially influence fetal scalp ECG waveform.

BackgroundFetal monitoring based on electrocardiographic (ECG) morphology is obtained from a single unipolar fetal scalp electrode. Ideally, it should be obtained from multiple leads, as ECG waveform depends on alignment between electrode and electrical heart axis. This alignment is unknown in fetuses. Besides, fetuses are surrounded by conductive media, which may influence ECG waveform. We explored the influence of electrode position and head orientation on ECG waveforms of unipolar and bipolar scalp ECGs recorded in air and in conductive medium.MethodsWe recorded ECGs in one adult subject at five different scalp positions in five different head orientations both in dry and immersed conditions. The ratio between T-amplitude and QRS-amplitude (T/QRS ratio) of unipolar and bipolar scalp ECGs was determined and compared between all conditions.ResultsIn the dry condition, we observed in the unipolar leads little to no difference between different electrode positions (maximal T/QRS difference 0.00–0.01) and minor differences between head orientations (0.02–0.03), whereas bipolar leads showed no recognizable ECG signal at all. During the immersed condition, we found variation in the unipolar leads, both between electrode positions (maximal T/QRS difference 0.02–0.05) and between head orientations (0.03–0.06). Bipolar leads showed different ECG signals in contrasting head orientations.ConclusionsBoth unipolar and bipolar scalp lead-derived ECG waveforms are influenced by electrode position and head orientation when the subject is submerged in a conductive medium. Fetal monitoring based on single scalp lead ECG waveform might be suboptimal, as it lacks correction for fetal head orientation and electrode position.

Improvement of Arc Properties in GTAW of Aluminium Alloys

Gas tungsten arc welding (GTAW) is a widely used method of joining aluminium and its alloys. Despite the fact that a lot of research has been done in this area for several decades, there are many unresolved issues on the welding process control. Optimization of square wave alternating current profiles is one of them. This paper presents the results of studies on control of spatial position of an arc by an improved heat input algorithm taking into account the necessary relationship between direct current of straight and reverse polarity. It is shown that an increase in direct current reverse polarity to over 10 A contributes to expansion of a cathode spots space and, consequently, a greater deviation of the arc from the axis of a tungsten electrode. The spatial position of the arc is almost coaxial to the tungsten electrode when direct current reverse polarity is short-term reduced to 5 A at the final stage. These results are correct for a wide range of the square wave alternating current profiles.

Simultaneous and direct determination of urea and creatinine in human urine using a cost-effective flow injection system equipped with in-house contactless conductivity detector and LED colorimeter

This work presents a cost-effective and simple flow injection analysis (FIA) system for simultaneous and direct determination of urea and creatinine in human urine. The FIA system comprises two in-house detectors, a contactless conductivity detector and a light emitting diode (LED) detector. The contactless detector was built as a flow-through detection cell with axial electrodes, commonly known as capacitively coupled contactless conductivity detector (C4D) and the diode detector was fabricated based on the concept of paired emitter detector diodes (PEDD). With appropriate dilution of urine, the sample is directly injected into a stream of glycine-NaOH buffer pH 8.8 (the gas donor stream) and is carried by the carrier through a urease minicolumn for on-line enzymatic hydrolysis. The generated NH3 diffuses from the carrier stream through a porous polytetrafluoroethylene (PTFE) membrane into a stream of deionized water (the acceptor stream) leading to an increase in the signal at the C4D due to the NH3 dissolution in the water. In this system, creatinine is determined based on the Jaffé reaction by merging a stream of alkaline picrate with the gas donor stream. The change in color is detected using the PEDD equipped with two green LEDs. Under the optimum condition, the linear range of urea and creatinine were 30–240 mg L−1 and 10–500 mg L−1, with limits of detection of 9.0 mg L−1 and 0.9 mg L−1, respectively. The proposed system provides satisfactorily good precision (RSD < 3%), with sample throughput of 31 sample h−1 for the two analytes. The FIA system tolerates potential interference commonly found in human urine. The system was successfully applied and validated with selected reference methods.

Efficient atomization method using a rectangular electrode on an ultrasonic transducer

We have developed an efficient atomization method using modification of a silver electrode on an ultrasonic transducer. A circular silver electrode, which is conventionally used as a standard electrode on a transducer, is chemically replaced with a rectangular silver electrode. The rectangular electrode inherently creates a flattened conical water column, generating laterally directional wobbling perpendicular to the long axis of the rectangular electrode. This directional wobbling generates intense centrifugal force, stretching the water column and reducing the pressure in the column, thus causing more cavitation for effective atomization, achieving 2.93 times more efficient atomization than a standard circular electrode. This method will greatly contribute to the fields of engineering, medicine, and biology where various types of solutions are highly expected to be atomized more efficiently.

The Role of a Curved Electrode with Controllable Direction in the Radiofrequency Ablation of Liver Tumors Behind Large Vessels.

To investigate the role of a novel curved radiofrequency ablation (RFA) electrode with controllable direction in the ablation of tumors behind large hepatic vessels in ex vivo bovine and in vivo canine liver experiments. Approval from the institutional animal care and use committee was obtained. In ex vivo experiments, conventional multi-tines expandable electrodes, conventional monopolar straight electrodes and novel curved electrodes were used in the ablation of the bovine liver (n = 90). The ablated area, parallel axis, vertical axis and shape of different electrodes were compared. Then, 24 beagle dogs (10months old, female) were used for in vivo experiments. Visual tumor targets deeply located in the portal vein were established, and ultrasound-guided liver ablation was performed with different electrodes. The ablation range, target coverage rate, percentage of normal tissue injury and damage to adjacent vessels were evaluated. The Kruskal-Wallis test and the Chi-squared test were used for statistical analysis. For the ex vivo study with a 3-cm electrode, the ablation area of the multi-tines expandable electrode group (7.14 ± 0.16cm2) was significantly larger than that of the novel curved electrode group (5.01 ± 0.30cm2, P < 0.001) and the monopolar straight electrode group (5.43 ± 0.15cm2, P < 0.001). The results obtained with the 4-cm electrode in the three groups were in accordance with those of the 3-cm electrode. In vivo, the normal tissue damage area of the novel curved electrode group was smaller than that of the multi-tines expandable electrode group (1.10 ± 0.18cm2 vs. 4.00 ± 0.18cm2, P < 0.001). The target coverage rate of the novel curved electrode group was better than that of the monopolar straight electrode group (100% vs. 80.86 ± 1.68%, P < 0.001). The hematoxylin and eosin (H&E) and TUNEL staining results showed that the ablation necrosis area was adjacent to large vessels, but the vascular wall was not significantly damaged in the novel curved electrode group. Our preliminary results showed that the novel curved RFA electrode with controllable direction could achieve accurate ablation for tumors behind large hepatic vessels, with a better target coverage rate and less damage to normal tissue, than conventional multi-tines expandable electrodes and monopolar straight electrodes.

Velocity field of EHD flow during back corona discharge in electrostatic precipitator

Particle Image Velocimetry studies of velocity field of the EHD flow during the back corona discharge at atmospheric pressure in an electrode system comprising a needle discharge electrode at negative potential and a grounded plate collection electrode covered with fly ash layer are presented in this paper. It was found that the magnitude of velocity vector of the EHD flow starting from the crater formed in fly ash layer after the onset of back corona discharge is of the same order of magnitude as for the flow generated by the corona discharge from the needle electrode. The measurements have shown that both these flows do not mix, but deflect each other off the axis of the needle electrode. The conclusion from this research is that the EHD deflection of the trajectories of particles flowing towards the collection electrode by the particles erupted from the crater at the collection electrode probably prevents those particles from the precipitation on the collection electrode that can result in a decreased collection efficiency of electrostatic precipitator during back corona discharge. This new mechanism has been called the “dynamic” process of the collection efficiency reduction.

Modeling and compensation of cross-axis coupling in an electrostatic accelerometer for testing the equivalence principle.

Electrostatic accelerometers have extremely high sensitivity and are ideal scientific instruments for measuring very weak acceleration. In particular, a single-sensitive-axis electrostatic accelerometer can be used for testing the equivalence principle in space. Sensitive-axis capacitances formed by axial electrodes and a cylindrical proof mass vary with the axial motion of the mass and are also affected by radial motion, which results in cross-axis coupling disturbances. A quantitative model is built to analyze the cross-axis coupling effect on the sensitive axis from the radial suspension loop, including a nonlinear model for large radial motion and a linear model for small radial motion. Frequency response simulation shows that the cross-axis coupling effect for a small signal case arises mostly in the high-frequency range. Experiments are carried out with a ground-based electrostatic accelerometer made of a single, non-rotating test cylinder, and in this case, the experimental results are utilized to verify the mathematical model. Cross-axis coupling for small signal perturbations is virtually removed if the equilibrium position of the proof mass is calibrated to the null position of the sensor cage. In addition, data post-processing can further attenuate the cross-axis coupling disturbances when dealing with large radial motion. The cross-axis coupling disturbances on both the position and the acceleration measurement signals in the sensitive axis are mostly removed in ground-based experiments. The proposed model and compensation can be extended to space equivalence principle instruments and other electrostatic accelerometers with a cylindrical proof mass.

Lead Electromagnetic Model to Evaluate RF-Induced Heating of a Coax Lead: A Numerical Case Study at 128 MHz

One of the major components of magnetic resonance imaging safety for patients with an active implantable medical device is the evaluation of in vivo radio frequency induced heating of tissue near a lead electrode, which can result in tissue damage. This numerical case study investigated a number of the recommendations, assumptions, and requirements of Clause 8 of the technical specification ISO/TS10974. For this, a lead electromagnetic model (LEM) of a generic coax lead at 128 MHz was evaluated with 3-D electromagnetic and thermal cosimulations of the entire lead. Two sets of 120 incident electric fields with different profiles were generated in a homogenous medium using the electrical properties of blood by an array of four antennas. Substantial dependence of power deposition and temperature profiles around lead electrodes on the incident electric field did not reduce the quotient of the variances of the fitted LEM values, observed values of power deposition, and the net temperature increase, above background, with the presence of the generic coax lead. Our results indicate that the power injection approach based only on the comparison of the temperature increase in the medium along the lead tip electrode axis can result in substantial underestimation or overestimation of power deposition around lead electrodes.

A numerical study on striped lithiation of tin oxide anodes

High energy storage capacity of tin oxide (SnO2) makes it a promising anode material for high capacity lithium (Li)-ion batteries. Previous experiments reported by Nie et al. (2013) and Huang et al. (2010) have shown that SnO2 lithiation occurs in two stages. First, Li diffuses rapidly through distinct narrow stripes along the electrode axis. This is followed by a second stage where the diffusion/amorphization of the nanowire occurs. In order to understand and possibly predict this complex chemo-mechanical phenomenon, a finite element (FE) model is developed in this work. The model captures the formation of the striped diffusion regime and the corresponding expansion of the nanowire during the lithiation of SnO2. The effect of the stress on the Li diffusion is modeled at the macroscopic level by implementing a stress-dependent expression for the diffusion coefficient. The modeling results clearly show the formation of the striped diffusion regime due to the induced stresses, at low concentrations of Li. This results in a small strain of 0.017 within the nanowire followed by a bulk diffusion and expansion at higher Li concentrations. Thus, the model allows for the spatiotemporally resolved analysis of Li diffusion/intercalation and helps predicting its influence on the mechanical performance of the electrode under the realistic operational conditions.

Electric Field Effect on the Thermal Decomposition and Co-Combustion of Straw Pellets with Peat

The main goal of the present study is to obtain a more effective utilization of wheat straw for energy production during a co-combustion with peat. For this purpose, an electric field was applied to the flame produced by the combustion of volatiles. This work combines experimental study and mathematical modelling of the processes developing during the co-combustion of straw pellets with peat pellets. The main gasification/combustion characteristics, the heat output from the device and the composition of the flue gas were analysed by varying separately the bias voltage of the axial electrode and the straw mass load in the mixture with intention to assess the electric field impact. A mathematical model of the electric field impact on the main combustion characteristics (flow velocity, flame temperature and composition) of co-combustion have been built within the MATLAB environment. The numerical simulation was performed for two dominant second order combustion reactions of CO and H2 with account for the electric field effect on the displacement of equilibrium during the thermal decomposition of the biomass.

A new bronchoscopic catheter for the transbronchial ablation of pulmonary nodules

ObjectivesWith the objective of simultaneous bronchoscopic biopsy and ablation of malignant solitary pulmonary nodules, we have developed a flexible monopolar radiofrequency (RF) catheter that can be deployed through the working channel of most bronchoscopes. Materials and MethodsFresh tumor specimens were heated in a water bath to 37 °C, and the RF catheter was inserted into the tumors within the specimen. Temperature sensors were positioned 3 mm, 5 mm and 7 mm from the electrode to measure the temperature of the surrounding tissue every 1 s. The ablation was conducted by applying RF energy for 8 min. The ablated specimens were evaluated by cutting the tissue samples along the top of the device and measuring the ablation zones. ResultsFive ablations were performed in 3 specimens. All of the ablation zones had a major axis length (along the electrode axis) between 18.9 mm and 22.8 mm and a minor axis length (perpendicular to the major axis) between 13.3 mm and 18.0 mm. The temperature data showed that all of the temperature sensors detected 60 °C or higher. These results demonstrate that the RF catheter was capable of generating ablation zones that were locally contained in ex vivo human cancerous lung specimens and that incorporated the tumor tissues. ConclusionWe present the results of a benchtop study demonstrating the local control of ablation achieved using the RF device. This study suggests that the ex vivo ablation of lung malignancy with a new bronchoscopic RF catheter is feasible and that in vivo tumor ablation with this method in humans merits further study.

Introduction to investigations of the negative corona and EHD flow in gaseous two-phase fluids

Research interests have recently been directed towards electrical discharges in multi-phase environments. Natural electrical discharges, such as lightning and coronas, occur in the Earth’s atmosphere, which is actually a mixture of gaseous phase (air) and suspended solid and liquid particulate matters (PMs). An example of an anthropogenic gaseous multi-phase environment is the flow of flue gas through electrostatic precipitators (ESPs), which are generally regarded as a mixture of a post-combustion gas with solid PM and microdroplets suspended in it. Electrical discharges in multi-phase environments, the knowledge of which is scarce, are becoming an attractive research subject, offering a wide variety of possible discharges and multi-phase environments to be studied. This paper is an introduction to electrical discharges in multi-phase environments. It is focused on DC negative coronas and accompanying electrohydrodynamic (EHD) flows in a gaseous two-phase fluid formed by air (a gaseous phase) and solid PM (a solid phase), run under laboratory conditions. The introduction is based on a review of the relevant literature. Two cases will be considered: the first case is of a gaseous two-phase fluid, initially motionless in a closed chamber before being subjected to a negative corona (with the needle-to-plate electrode arrangement), which afterwards induces an EHD flow in the chamber, and the second, of a gaseous two-phase fluid flowing transversely with respect to the needle-to-plate electrode axis along a chamber with a corona discharge running between the electrodes. This review-based introductory paper should be of interest to theoretical researchers and modellers in the field of negative corona discharges in single- or two-phase fluids, and for engineers who work on designing EHD devices (such as ESPs, EHD pumps, and smoke detectors).

STUDY OF THE BEHAVIOR OF CURRENT-CARRYING LIQUID IN THE BATH OF DC ARC FURNACE BY AN EXTERNAL VERTICAL MAGNETIC FIELD ON A PHYSICAL MODEL

When an external vertical magnetic field is applied to a current-carrying melt in the bath of a DC arc furnace, volumetric electromagnetic forces arise that drive it. Flows of metal and slag occur in the bath of the DC arc furnace. This can lead to their efficient mixing, but can also carry negative aspects,for example, associated with an increase in wear oflining in the region of the bottom electrode. The processes of conductive mixing in the bath of the DC arc furnace during smelting of metals and alloys remain poorly understood, there arise both theoretical questions related to the nature of the flows in the bath under the action of external and intrinsic magnetic fields of a given intensity, and practical with the absence of simple and reliable sources of external magnetic fields. The purpose of this paper isto qualitatively test the capabilities of a physical model, to study the nature of currents of a current-carrying liquid under the action of an external vertical magnetic field, and to analyze the possibility of transferring simulation results to processes occurring in a five-ton bath of an industrial DC arc furnace. The principal possibility of studying the current flow behavior of a current-carrying melt under the influence of external magnetic fields on models using non-metallic electrically conducting transparent liquids is shown. In this work the authors have used a water solution of table salt, it allowed to estimate the velocity of the liquid on itsfree surface and near the bottom electrode using video. The physical modeling of the effect of an external vertical magnetic field on the current flowing current in a bath was carried out for different combinations of connecting the bottom electrode and different currents flowing through the bath. The current flowing current in the bath under the influence of an external vertical magnetic field was established when the central electrode or the bottom electrode is displaced from the axis of the bath. It was revealed that when the axis of the bottom electrode is displaced from the bath axis, the average rotation speed of the liquid in the horizontal plane increases. An estimate of the value of the vertical magnetic field strength (about 5 kA/m) is obtained, which should be accompanied by conductive mixing the metal bath of the five-ton steel-smelting arc furnace.

DC negative corona discharge characteristics in air flowing transversely and longitudinally through a needle-plate electrode gap

The electrical characteristics of a steady-state DC negative corona discharge in air flowing transversely or longitudinally in relation to the needle-to-plate (or mesh) electrode axis were experimentally investigated. The velocity of air flowing into the corona discharge chamber was limited to a range from 0 to 6 m/s, typical of electrostatic precipitators, gas ionisation sensors and EHD pumps. The investigations showed that in this airflow velocity range three discharge current modes of the DC negative corona could exist: the Trichel-pulse corona mode, the ‘Trichel pulses superimposed on the steady current (or DC) component’ mode and the steady glow (the steady current or DC) corona mode, regardless of the airflow direction. The average corona discharge current, which is a macroscopic corona discharge parameter, was almost not affected by the airflow. However, both microscopic corona discharge parameters: the electric charge and the repetition frequency of Trichel pulses were influenced by the airflow. The transverse airflow caused an increase in the electric charge and a decrease in the repetition rate of Trichel pulses, the both by about 25% at a velocity of 6 m/s. In the case of longitudinal airflow the average corona current slightly increased when the airflow was directed towards the mesh and decreased when the airflow was directed towards the needle tip. Similarly as in the case of transverse airflow, the electric charge and the repetition frequency of Trichel pulses were affected by the longitudinal airflow. The electric charge and the repetition frequency of Trichel pulses increased and decreased, respectively, with growing airflow in the direction towards the needle electrode. The airflow growing in the direction towards the mesh electrode produced the opposite effect - the electric charge and the repetition frequency of Trichel pulses decreased and increased, respectively. The opposite behaviours of the electric charge and the repetition frequency of Trichel pulses with growing airflow velocity could explain the weak dependence of the negative corona average current on transverse or longitudinal airflow. Therefore, the independence of the negative corona average current of the airflow cannot be considered as sufficient proof that the airflow (up to 6 m/s) does not affect the negative corona parameters.

Asymmetric Coulomb oscillation and giant anisotropic magnetoresistance in doped graphene nanojunctions

We report here the charge transport behavior in graphene nanojunctions in which graphene nanodots, with relatively long relaxation time, are interfaced with ferromagnetic electrodes. Subsequently we explore the effect of substitutional doping of transition metal atoms in zigzag graphene nanodots (z-GNDs) on the charge transport under non-collinear magnetization. Only substitutional doping of transition metal atoms in z-GNDs at certain sites demonstrates the spin filtering effect with a large tunnelling magnetoresistance as high as 700%, making it actually suitable for spintronic applications. From the electrical field simulation around the junction area within the electrostatic physics model, we find that the value of electric field strength increases especially with doped graphene nanodots, as the gap between the gate electrode and tip axis is reduced from 3 nm to 1 nm. Our detailed analysis further suggests the onset of asymmetric Coulomb oscillations with varying amplitudes in graphene nanodots, on being doped with magnetic ions. Such kind of tunability in the electronic conductance can potentially be exploited in designing spintronic logic gates at nanoscale.

Characteristics of sliding bubble in aqueous electrolyte: In presence of an external magnetic field

An experment was carried out to examine the influence of an external magnetic field on a bubble in an aqueous electrolytic cell. In the electrolysis process, bubbles nucleate instateneously and the electrolytic flow is mostly caused by swarm of bubbles, which makes it difficult to quantify the impacts of various forces, in particular the magneto-hydrodynamic (MHD) and gravity forces in Hall-Héroult cells. In this paper, an aqueous-electrolytic cell was designed to allow a single bubble to slide underneath the inclinde anode in an electrolytic environment and in presence of an external magnetic field. Air was injected at a constant flow rate of 6.2ml/min through a 3mm diameter orifice into a quiescent conducting aqueous electyrolytic media. Experiments were conducted both with and without external-magnetic field for varying anode-inclinations ranging from θ=4°, 6° and 8° in order to quantify the order of magnitude of MHD force in comparison to the gravity force. The data clearly shows that, in presence of the magnetic field, the bubble changes its shape and orientation at the onset of nucleation, which in turn gives rise to a non-linear trajectory across the longitudinal axis of electrode establishing a large circulatory flow within the electrolytic cell. In general, the experimental data shows that the bulk velocity was found to be dominated by the MHD driven flow overshadowing the influence of gravity force.

GEO-ELECTRICAL MAPPING OF BEACHROCK IN VATERA BEACH, LESVOS

Beachrock (Br) is encountered on the coastal zones, playing an important but also complex role in their morphodynamic evolution. Although Br has been widely studied, two important issues require further investigation. The first concerns the importance of the interaction of the dynamically changing coastal environment with the temporal changing surficial and underground hydrogeological balance. The second has to do with the spatial distribution and the evolution of Br with respect to the specific “host” coastal zone geo environment. This paper designates the electrical resistivity method as a tool that contribute in arguing in the abovementioned issues. The research comprised subsurface measurements with the DC resistivity method along two profiles located on Vatera beach (Lesvos Island), where there is a significant Br outcrops. Twelve geoelectric soundings were carried out using the Axial Pole-Dipole electrode array. The electrical resistively measurements permitted an indirect estimation of TDS, which depicts the coastal interface of fresh water - sea water. The interpreted geoelectric model shows two thin formations attributed to Br. The first is the inland extension of the Br outcrop and the second it is believed to be a primary stage of Br build up.

Temperature sensitive liposomes combined with thermal ablation: Effects of duration and timing of heating in mathematical models and in vivo.

BackgroundTemperature sensitive liposomes (TSL) are nanoparticles that rapidly release the contained drug at hyperthermic temperatures, typically above ~40°C. TSL have been combined with various heating modalities, but there is no consensus on required hyperthermia duration or ideal timing of heating relative to TSL administration. The goal of this study was to determine changes in drug uptake when heating duration and timing are varied when combining TSL with radiofrequency ablation (RF) heating.MethodsWe used computer models to simulate both RF tissue heating and TSL drug delivery, to calculate spatial drug concentration maps. We simulated heating for 5, 12 and 30 min for a single RF electrode, as well as three sequential 12 min ablations for 3 electrodes placed in a triangular array. To support simulation results, we performed porcine in vivo studies in normal liver, where TSL filled with doxorubicin (TSL-Dox) at a dose of 30 mg was infused over 30 min. Following infusion, RF heating was performed in separate liver locations for either 5 min (n = 2) or 12 min (n = 2). After ablation, the animal was euthanized, and liver extracted and frozen. Liver samples were cut orthogonal to the electrode axis, and fluorescence imaging was used to visualize tissue doxorubicin distribution.ResultsBoth in vivo studies and computer models demonstrate a ring-shaped drug deposition within ~1 cm of the visibly coagulated tissue. Drug uptake directly correlated with heating duration. In computer simulations, drug concentration increased by a factor of 2.2x and 4.3x when heating duration was extended from 5 to either 12, or 30 minutes, respectively. In vivo, drug concentration was by a factor of 2.4x higher at 12 vs 5 min heating duration (7.1 μg/g to 3.0 μg/g). The computer models suggest that heating should be timed to maximize area under the curve of systemic plasma concentration of encapsulated drug.ConclusionsBoth computer models and in vivo study demonstrate that tissue drug uptake directly correlates with heating duration for TSL based delivery. Computational models were able to predict the spatial drug delivery profile, and may serve as a valuable tool in understanding and optimizing drug delivery systems.

Experimental study of magnetized plasma rotation in crossed fields

Rotation of magnetized plasma between two coaxial electrodes in crossed electric and magnetic fields was studied experimentally. Three regimes of plasma rotation were observed. In the first regime, the radial electric field is created by a beam−plasma discharge due to the charging of the inner axial electrode by electrons, the outer electrode being grounded. Plasma rotation in this case is accompanied by strong high-frequency current oscillations detected by a Mach probe. When a negative voltage was applied to the coaxial electrodes, the second regime was observed, in which weakly perturbed quasi-stationary plasma rotation occurred at a relatively low radial current. The third regime of plasma rotation was observed upon a spontaneous disruption of the second regime. It is characterized by high currents of ~1 kA, sheared plasma rotation, and excitation of high-frequency perturbations.