Mixture Plasma Research Articles

Modelling of the Thermodynamic Properties of the Plasma Mixture

Numerical modelling of the thermodynamic properties of plasma mixture is performed using the Thomas – Fermi model with two different approaches. For this purpose, a numerical algorithm, as well as program realization, is developed to solve the Thomas – Fermi equations with quantum-exchange corrections. For the first time a comparison between different methods for taking account of the heterogeneous composition of plasma is made and an algorithm for estimating the corrections for mixtures is developed.

АНАЛІЗ КЛІТИННИХ ЕЛЕМЕНТІВ КРОВІ ЗА ДОПОМОГОЮ ПОВЕРХНЕВОГО ПЛАЗМОН-ПОЛЯРИТОННОГО РЕЗОНАНСУ: МОДЕЛЬ ПЕРЕХІДНОГО ШАРУ

Despite the great practical importance, the control of blood by optical methods is enormously complicated by the strong scattering of light. This is especially true for formed blood elements (FBEs), which are a compact suspension that remains after plasma removal from blood by centrifugation. The study of the surface plasmon resonance (SPR) in Kretchman’s geometry together with measurement of the angular dependence of the light internal reflection R( φ ) at the glass/ FBEs boundary is one of the few possibilities to obtain additional information about the structure and molecular composition of this complex inhomogeneous object. Measurement of R( φ ) for contact FBEs with the glass surface allows to determine the total internal reflection (TIR) angle and the effective refractive index N of the binary of erythrocytes-blood plasma mixture. At the same time, the comparison of the angles of TIR and SPR makes it possible to establish the presence of a transition layer between gold surface and the volume of FBEs. In addition, a detailed matching of the experimental dependence R( φ ) with one of calculated curve by regression method allows minimize the objective function and allows to establish a detailed model of the transition layer. The paper shows that the value of N is 1.4003...1.4008. According to the formula of the effective Bruggeman's medium, the packing density of erythrocytes in the volume of FBEs is about 85%, which is well matched with the data known from the literature. At the same time, at least two intermediate layers were detected at the gold /FBEs interface. (1) A layer 33–38 nm thick adjacent to the hydrophobic surface of the gold film and with a refractive index of N p = 1.356–1.357. Presumably, it is a binary phase with a liquid part in the form of water, a buffer solution or blood plasma and a hard part in the form of proteins non-specifically related to gold, most likely molecules of albumin and fibrinogen. (2) A thicker, transition-to- volume FBEs layer is most likely related to the edges curvature and marginal packing of erythrocytes; the effective thickness of this layer is d m = 130-200 nm, and the effective refractive index N m = 1.356... 1.369. The details of this transition layer are currently of considerable practical interest because they can reflect the physiological state of blood cells and whole body, and the parameters d m and N m can be useful from a biological or medical point of view.

Ecologically evaluated and FDA-validated HPTLC method for assay of pregabalin and tramadol in human biological fluids.

The introduced research presents a novel in vivo quantitative method for assay of mixtures of pregabalin and tramadol as a common combinations approved for treatment of neuropathic pain. Green analytical chemistry is a recently emerging science concerned with control of the use of chemicals harmful to the environment in various analytical methods. Consequently, a green high-performance thin layer chromatography (HPTLC) method was achieved for determination of the mixture in human plasma and urine satisfying both analytical and environmental standards. The separation was achieved on HPTLC sheets using a separating mixture of ethanol-ethyl acetate-acetone-ammonia solution (8:2:1:0.05, by volume) as a mobile phase. The sheets were dried in air then scanned at two wavelengths. For tramadol, 220 nm was chosen; however, pregabalin is an unconjugated drug, so its determination was a challenge. Hence for pregabalin, the plates were sprayed with ethanolic solution of ninhydrin (3%, w/v), to obtain a conjugated complex, which could be assessed at 550 nm. Furthermore, the developed method fulfilled the US Food and Drug Administration validation guidelines, and proved to be useful in therapeutic drug monitoring of this combination. The Eco-scale assessment protocol was implemented to determine the greenness profile of the applied method.

Indications for transfusion of blood components

Indications for transfusion of blood components

Study of cooling process of plasma jet flowing around a thin ablating graphite rod

We present results of spectroscopic measurement of electron temperature in submerged nitrogen and argon mixture plasma jet for cases of free flow and introduction of thin graphite rod into the jet. The observed cooling of plasma caused by rod introduction agrees with the calculated enthalpy decrease from graphite rod heating and ablation. In this experiment, a marker was used to create artificial optical inhomogeneities in the flow, which allowed us to determine flow velocity from the analysis of their movement. In this case, we aim to determine the degree of influence of rod introduction into the plasma on its parameters. Upon introduction into the plasma, the rod was heated and partially destroyed by the plasma flow, reducing its temperature by 8-20% depending on the flow rate of the plasma-forming gas. The observed plasma cooling was compared with the calculated decrease in enthalpy caused by the cost of heating and ablation of the rod material.

Surface charge of polymer materials modified by nanostructured fluorocarbon coatings

The paper presents the results of a study of the surface charge of polymer materials modified with fluorocarbon films formed by ion-plasma technology at different CF4 contents in the CF4 + CeH12 plasma mixture. Nanostructured fluorocarbon films formed on the surface of polyethyleneterephthalate and polystyrene have a positive charge in the region of “transient” processes, and films on the surface of polytetrafluoroethylene have a negative charge, which is associated with different topology of the relief on the surface of these polymers, as well as their polarity.

Influences of substrate temperatures on etch rates of PECVD-SiN thin films with a CF4/H2 plasma

The dependence of substrate temperatures (50 to −20 °C) on etch rate in two kinds of PECVD SiN films were investigated by a CF4/H2 mixture plasma. The XRR and XPS results indicate that the chemical composition and film density were almost identical for the films. The FTIR shows that the ratio of NH and SiH groups were found to be significantly different in the SiN films. The NH rich films exhibited a lower etch rate at −20 °C than that observed at room temperature or higher, whereas the SiH rich films showed a higher etch rate at −20 °C. We found that the fluorocarbon thickness was thicker in the SiH rich samples than NH rich samples. The fact suggests that hydrogen originated from the broken SiH bonds enhanced the polymerization, which causes the decrease of etch rate. A thinner fluorocarbon thickness was found in the SiH rich samples at low temperature, which results in the higher etch rate. Angular-resolved XPS indicates that NH bonding formed easier on film surface at −20 °C. These results indicate that the bonding structure and substrate temperature affected the fluorocarbon thickness, fluorine reaction probability and hydrogen dissociation during the SiN etching.

Characteristics of plasma parameters and turbulence in the isotope-mixing and the non-mixing states in hydrogen–deuterium mixture plasmas in the large helical device

Characteristics of plasma parameters and turbulence in the isotope-mixing and the non-mixing states in hydrogen-deuterium mixture plasmas in the large helical device are discussed. The isotope mixing state is characterized by the uniform isotope ratio profile regardless of the location of the particle source of each species in the isotope mixture plasma. The isotope non-mixing state is identified by the non-uniform isotope ratio profile measured with bulk charge exchange spectroscopy when the beam fueling isotope species differs from the recycling isotope species. The effect of collisionality, ratio, sign of density gradient on transition between isotope mixing and non-mixing is discussed. The plasma parameters preferable for the non-mixing state are found to be lower collisionality, higher , and negative or zero density gradient (peaked or flat density profile). The time scale of transition from non-mixing to mixing is evaluated by the hydrogen and deuterium pellet injection near the plasma edge and is found to be less than 5 ms, which is much shorter than the particle confinement time. The strong correlation between isotope mixing and turbulence characteristics is observed. This strong correlation suggests the change in turbulence is a strong candidate for the mechanism causing the transition between uniform and non-uniform isotope density ratio profiles.

Diagnostic of Ar-CO2 mixture plasma using a fine-structure resolved collisional radiative model

In the present work, we develop a collisional radiative (CR) model for the Ar-CO2 mixture plasma. The model is applied to the diagnostics of a recently reported low-pressure DC generated Ar-CO2 plasma of Rodríguez et al. [Phys. Plasmas 25, 053512 (2018)] utilizing their spectroscopic measurements who reported the plasma parameters at different concentrations of CO2 in Ar at various pressures and powers. Our CR model includes various population transfer mechanisms between the fine structure levels, viz., electron-impact excitation, radiative decay, and ionization, as well as their reverse processes, e.g., electron-impact de-excitation as well as two- and three-body recombination. The effects of radiation trapping and diffusion are also taken into account. The plasma parameters viz. electron density (ne) and electron temperature (Te) are obtained as a function of different pressures (0.2, 0.3, and 0.6 mbars) and discharge powers at 25 and 50% concentrations of CO2 in argon. These results are determined using measured intensities of seven intense emission lines out of 3p54p (2pi) → 3p54s (1si) fine-structure transitions. It is observed that both the electron density and electron temperature increase with the increase of CO2 concentration, which is in confirmation with experimental predictions. The populations obtained for 1si and 2pi levels from our CR model are also reported and compared respectively with the corresponding available values from the simple CR model and experiment of Rodríguez et al. [Phys. Plasmas 25, 053512 (2018)]. A significant difference in the populations is observed from the two models.

Effects of different plasma expanders on rats subjected to severe acute normovolemic hemodilution

BackgroundPlasma expanders are widely used for acute normovolemic hemodilution (ANH). However, existing studies have not focused on large-volume infusion with colloidal plasma expanders, and there is a lack of studies that compare the effects of different plasma expanders.MethodsThe viscosity, hydrodynamic radius (Rh) and colloid osmotic pressure (COP) of plasma expanders were determined by a cone-plate viscometer, Zetasizer and cut-off membrane, respectively. Sixty male rats were randomized into five groups with Gelofusine (Gel), Hydroxyethyl Starch 200/0.5 (HES200), Hydroxyethyl Starch 130/0.4 (HES130), Hydroxyethyl Starch 40 (HES40), and Dextran40 (Dex40), with 12 rats used in each group to build the ANH model. ANH was performed by the withdrawal of blood and simultaneous infusion of plasma expanders. Acid-base, lactate, blood gas and physiological parameters were detected.ResultsGel had a lower intrinsic viscosity than HES200 and HES130 (P < 0.01), but at a low shear rate in a mixture of colloids, red cells and plasma, Gel had a higher viscosity (P < 0.05 or P < 0.01, respectively). For hydroxyethyl starch plasma expanders, the COP at a certain concentration decreases from 11.1 mmHg to 6.1 mmHg with the increase of Rh from 10.7 nm to 20.2 nm. A severe ANH model, with the hematocrit of 40% of the baseline level, was established and accompanied by disturbances in acid-base, lactate and blood gas parameters. At the end of ANH and 60 min afterward, the Dex40 group showed a worse outcome in maintaining the acid-base balance and systemic oxygenation compared to the other groups. The systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) decreased significantly in all groups at the end of ANH. The DBP and MAP in the Dex40 group further decreased 60 min after the end of ANH. During the process of ANH, the Dex40 group showed a drop and recovery in SBP, DBP and MAP. The DBP and MAP in the HES200 group were significantly higher than those in the other groups at some time points (P < 0.05 or P < 0.01).ConclusionGel had a low intrinsic viscosity but may increase the whole blood viscosity at low shear rates. Rh and COP showed a strong correlation among hydroxyethyl starch plasma expanders. Dex40 showed a worse outcome in maintaining the acid-base balance and systemic oxygenation compared to the other plasma expanders. During the process of ANH, Dex40 displayed a V-shaped recovery pattern for blood pressure, and HES200 had the advantage in sustaining the DBP and MAP at some time points.

Effect of argon and oxygen gas concentration on mode transition and negative ion production in helicon discharge

In this paper, the effect of mixing of argon and oxygen gas on the mode transition and negative ion production in the helicon discharge is investigated. In the source chamber of the experimental setup, argon–oxygen gas mixture plasma is produced by applying RF power from 100 W to 2000 W at an applied magnetic field of 0.03 T. In this experiment, the total flow rate is kept at 200 SCCM, corresponding to the working pressure of 4–5 × 10−1 Pa. The mode transition to helicon discharge is investigated by varying the concentration of these two gases. To the best of our knowledge, the literature survey indicates this to be the first study of the influence of the mixing of oxygen–argon gas on the mode transition from the inductive to the helicon mode. It is observed that an increase in the concentration of oxygen gas in the discharge shifts mode transition toward higher RF power values, indicating the influence of the nature of the working gas on the transition to the inductive as well as to the helicon mode. The variation of the electron density and temperature is explained in terms of particle and power balance equation. In the source and in the downstream expansion chamber, the effect of the concentration of argon gas on the negative ion production in oxygen discharge is also studied, and the results are explained in terms of various reactions involved in the production and loss of negative ions.

KINETIC FEATURES OF PLASMA-CHEMICAL MODIFICATION OF POLYCARBONATE IN PLASMA IN ARGON - OXYGEN MIXTURE

This paper presents the results of experimental study of the processes of destruction and changes in the composition of the surface layer of a Lexan 8010 polycarbonate (PC) film during treatment in a positive column of a DC glow discharge in argon, oxygen, and their mixtures. The mass loss rates of the polymer samples were measured depending on the parameters of the discharge and the composition of the plasma-forming gas. The IR spectra of the polymer films after plasma exposure were analyzed. It was shown that the most noticeable changes in the sample destruction rate and the chemical composition of the surface layer occur when the oxygen content in the mixture is up to 20%. With a further increase in the O2 content in the plasma-forming mixture, the changes are insignificant. The main gaseous products of PC destruction in the plasma of an argon-oxygen mixture are H2, CO, and H2O molecules. In the first second after the discharge is turned on, H2 molecules are released at maximum rate and at a lower CO rate. The formation of carbon monoxide and hydrogen molecules occurs without the direct participation of oxygen under the action of active particles of argon plasma without the participation of active oxygen. Exposure to argon plasma leads to an increase in the oxygen content on the sample surface. In this case, the destruction of С – О, О–С(=О)–О bonds, which are part of the structure of the polycarbonate elementary unit, and the formation of new oxygen-containing bonds are observed. Etching of the polymer with active plasma particles leads to a change in the micro relief of the sample surface. A change in roughness and an increase in the concentration of polar functional groups increases the wettability of the PC film surface. A discussion of the possible mechanisms of the processes is made, which allows us to describe the observed results.

Development of radiative opacity code OPIND for high energy density plasma and its application in radiation hydrodynamics

We developed the program OPIND to generate opacity data for use in radiation hydrodynamics simulations. This is an extension of our earlier work on opacity of elemental plasma based on average atom model [1]. In this work, we extended the capability of OPIND to treat mixture plasmas which employs the ideal gas mixing rule to obtain partial densities. Screened hydrogenic model was employed to obtain radiative properties and hence total opacity. Extensive validation for average ionization and Rosseland mean opacity of C, Al, Fe, Ge, Xe and Au plasmas were performed. OPIND was then employed to study the opacity of CH and Au-Gd mixture plasmas. The role of pressure ionization on CH opacity as well as opacity enhancement in Au-Gd plasma due to the presence of Gd were investigated. Further validation of OPIND was done by performing 1D radiation hydrodynamics simulations to study the ablation in Al slab subjected to radiation temperature drives. We studied the shock trajectory, mass ablation rate and evolution of thermodynamic parameters during shock propagation in Al slab. The scaling law for radiation temperature as a function of shock speed for strong shocks was also verified. We observed good agreement of data generated in our simulations with reported experimental and simulation data. Equation of state data were generated using the SBCRIS library developed by us.

Transport Coefficients of Air - PMMA Mixtures Thermal Plasmas

The transport coefficients of Air - PMMA mixtures thermal plasmas is important to estimate the performances of cutting of the electrical arc in this gas by a circuit breaker. In this paper, Air - PMMA mixtures thermal plasmas dynamical viscosity, thermal and electrical conductivities coefficients are calculated in a temperature range from 5000K to 30000K. The calculations are made by supposing thermodynamic equilibrium at pressure of 1 bar to 10 bar. The results of the calculations show the influence of the initial proportion of PMMA but also that of the pressure on the mixture plasma transport coefficients. As the efficiency of the breaking of the electric current by the circuit breaker depends closely on the thermal and electrical characteristics of the extinguishing medium, this extinguishing medium should have a high thermal conductivity and an electrical conductivity varying rapidly with temperature. The plasma of the mixture constituted by 80% of air and 20% of PMMA presents at first sight best characteristics for the breaking of electric current. It has the highest thermal conductivity peak among the plasmas of the mixtures studied.

Multi-gigayear White Dwarf Cooling Delays from Clustering-enhanced Gravitational Sedimentation

Abstract Cooling white dwarfs (WDs) can yield accurate ages when theoretical cooling models fully account for the physics of the dense plasma of WD interiors. We use MESA to investigate cooling models for a set of massive and ultramassive WDs (0.9–1.3 ) for which previous models have failed to match kinematic age indicators based on Gaia DR2. We find that the WDs in this population can be explained as C/O cores experiencing unexpectedly rapid 22Ne sedimentation in the strongly liquid interior just prior to crystallization. We propose that this rapid sedimentation is due to the formation of solid clusters of 22Ne in the liquid C/O background plasma. We show that these heavier solid clusters sink faster than individual 22Ne ions and enhance the sedimentation heating rate enough to dramatically slow WD cooling. MESA models including our prescription for cluster formation and sedimentation experience cooling delays of ≈4 Gyr on the WD Q branch, alleviating tension between cooling ages and kinematic ages. This same model then predicts cooling delays coinciding with crystallization of 6 Gyr or more in lower-mass WDs (0.6–0.8 ). Such delays are compatible with, and perhaps required by, observations of WD populations in the local 100 pc WD sample and the open cluster NGC 6791. These results motivate new investigations of the physics of strongly coupled C/O/Ne plasma mixtures in the strongly liquid state near crystallization and tests through comparisons with observed WD cooling.

Langmuir probe and optical emission spectroscopy studies for RF magnetron sputtering during TiON thin film deposition

Low-pressure plasma of gas mixture of Ar, O2 and N2 generated by RF magnetron sputtering was characterized by Langmuir probe and optical emission spectroscopy (OES). The electron temperature (Te), ion density (ni) and electron energy distribution function (EEDF) in Ar-O2-N2 plasma atmosphere were calculated from I-V characteristic of Langmuir probe. Boltzmann plot method was applied for calculating the vibrational temperature (Tvib) of the second positive system of N2 (N2SPS) in Ar-O2-N2 plasma. The Te, ni, EEDF and Tvib in Ar-O2-N2 plasma were studied as a function of O2 percentages. It was found, the Tvib increased from 0.47 eV to 0.55 eV as the oxygen percentage in Ar-N2-O2 plasma increased from 10% to 40%. Further, the Te increased from 1.6 eV to 3 eV as the O2 concentration increased from 10% to 40%.

Carbon-13 synthesis and NMR spectroscopic geometric isomer evaluation to support the filing of teriflunomide.

The two isotopomers of teriflunomide were synthesized starting from isotopically stable-labeled stocks of [13 C]potassium cyanide and [1-13 C]ethyl bromoacetate. The two 13 C-labeled compounds 1a, b were applied in several NMR studies to study the E/Z ratio in different matrices. In a solution, such as dimethyl sulfoxide (DMSO), a dynamic equilibrium between E/Z-isomers (ratio of 8:92) was determined by initial 13 C-carbon NMR experiments. To get insights into the E/Z ratio of teriflunomide under in vivo conditions, advanced heteronuclear NMR (heteronuclear Overhauser effect spectroscopy [HOESY]) in D2 O and mixtures of D2 O/plasma were performed. Whereas NMR experiments in mixtures of water and plasma failed owing to extreme line broadening, NMR spectra in water at pH 7.4 showed only the Z-isomer.

Fluorescent Imprinted Nanoparticles for the Effective Monitoring of Irinotecan in Human Plasma.

Fluorescent, imprinted nanosized polymers for the detection of irinotecan have been synthesised using a napthalimide polymerisable derivative (2-allyl-6-[2-(aminoethyl)-amino] napthalimide) as functional monomer. The imprinted polymers contain ethylene glycol dimethacrylate (EGDMA) as a cross-linker and were prepared by high dilution radical polymerisation in dimethylsulphoxide (DMSO). The material was able to rebind irinotecan up to 18 nmol/mg with good specificity. Fluorescence emission at 525 nm (excitation at 448 nm) was quenched by increasing concentrations of irinotecan via a static mechanism and also in analytically useful environments as mixtures of human plasma and organic solvents. This allowed the direct detection of irinotecan (in the 10–30 μM range) in human plasma treated with acetonitrile; the limit of detection (LOD) was 9.4 nM, with within-run variability of 10% and day-to-day variability of 13%.

Nitrogen functionalization of MWCNTs in Ar-[formula omitted] dielectric barrier discharge – Gas ratio effect

In this work, the effect Ar-N2 mixture plasma on the surface characters and structure of MWCNTs were investigated. The plasma treatment was performed at various nitrogen gas ratio, while RF power, treatment time and gas pressure were kept fixed. The plasma species were monitored with optical emission spectroscopy. The X-ray photoelectron spectroscopy (XPS) confirmed the formation of nitrogen functional groups on the plasma- treated MWCNTs outer surface and its concentrations are dependent on the nitrogen gas ratio in the mixture plasma. The Raman analysis results are consistent with XPS observation. The MWCNTs surface roughness is enhanced as nitrogen gas ratio is increased in the plasma as observed by TEM and XPS images. The MWCNTs structure was not damaged as observed by XRD pattern. The correlations between the relative intensities of Ar-N2 plasma species and the surface characters of the MWCNTs are also investigated.

RF plasma simulations using the TOMATOR 1D code: a case study for TCV helium ECRH plasmas

The 1-dimensional reaction-diffusion-convection code TOMATOR-1D describes plasma production by RF waves inside a tokamak using the Braginskii continuity and heat balance equations. The model simulates self-consistent radial density and temperature profiles for magnetised plasma mixtures of hydrogen and helium. The model reproduces the density profiles of X2 electron cyclotron resonance heating (ECRH) plasmas on TCV and proposes a Bohm-like poloidal magnetic field dependent scaling for anomalous diffusion and a convection scaling that results from drifts in the toroidal magnetic field configuration. A relation is proposed between the anomalous diffusion and the outward convection in toroidal plasmas. It is found that the EC absorption efficiency decreases at higher power, which is understood from the acceleration of electrons beyond the optimal energy for the electron impact ionisation of helium. A dramatic increase of the absorption efficiency is seen at intermediate vertical magnetic field values of which results in the highest density plasmas. Losses along the field lines in the vertical direction become dominant at higher fields which effectively reduces the plasma density in these discharges. To arrive at predictive capabilities towards ECRH plasmas on JT-60SA and ITER, the proposed scalings, subsuming dependencies on the torus major radius and the toroidal field strength, need to be validated in a multi-machine study.