Ne Mixtures Research Articles

FT-UV emission spectroscopy of the [formula omitted] progression bands of the [formula omitted] system of [formula omitted]C[formula omitted]O[formula omitted]

We report an experimental investigation of the 0−ν′′ progression bands of the First-Negative (B2Σ+−X2Σ+) system of 12C16O+. The ultraviolet wavelength emission spectrum of CO+ was generated using an air-cooled stainless steel hollow-cathode discharge lamp filled with a mixture of CO2 and Ne. The study includes four bands, i.e. 0−0, 0−1, 0−2 and 0−3, observed in emission with a high-resolution Fourier-transform spectrometer in the 38500–46000 cm−1 region. In total, 541 ro-vibronic transitions have been measured with an absolute accuracy of 0.005–0.010 cm−1. The experimental data were analyzed using the PGOPHER program, which resulted in a set of high accuracy molecular constants and ro-vibronic level positions for the X2Σ+, ν=0−3 and B2Σ+, ν=0 levels. The current values of the band origins have been compared with historical data, including the most recent results obtained by Ventura et al. (2020) and the discrepancies pointed out by the authors were explained.

Comparison of reduced model predictions for divertor detachment onset and reattachment timescales in ASDEX Upgrade and JET experiments

Building on prior analysis of ASDEX Upgrade (AUG) experiments (Henderson et al 2023 Nucl. Fusion 63 086024), this study compares simple analytical formula predictions for divertor detachment onset and reattachment timescales in JET experiments. Detachment onset primarily scales with divertor neutral pressure, impurity concentration, power directed to the targets, machine size, and integral perpendicular power decay length. JET experiments, focusing on seeding mixtures of Ne and Ar, align with the detachment onset predictions. Radiation efficiencies among the impurities show good agreement with the model predictions, contrasting with AUG observations which suggested higher efficiency for Ar and lower efficiency for Ne. The time taken to re-ionise the neutral volume in front of the outer target in fully detached divertor conditions was measured following both abrupt increases in injected neutral beam power and, separately, cutting of the impurity gas flow. Re-ionisation of the neutrals occurs within approximately 1 s on JET, which aligns with the simple model prediction derived from AUG data. While the AUG results are not new, their comparison with the JET results enhances understanding, reinforcing confidence in using simple models to predict future reactor scenarios.

Electric field distribution in natural-ester retrofilled transformers under AC stress

Retrofilling a transformer with natural or synthetic esters leads to a reduction of its fire and environmental risk without making a large investment. Nowadays, most of the retrofilled transformers are medium power and voltage units, but their use in higher rated power units is rapidly expanding. Transformer retrofilling presents certain challenges due to the physico-chemical differences between mineral oil and esters. The insulation system of a transformer is designed to work with mineral oil, performing a double function as dielectric and coolant agent; when replacing mineral oil with an ester, whose relative permittivity and viscosity are different, the ability to perform these two functions must be reassessed.In this work, the electric field distribution of a retrofilled transformer has been analyzed using Finite Element Method. The study was conducted on a 280 MVA transformer which was originally designed to operate with its tank filled with mineral oil. The dielectric margins of the different parts of the insulation were calculated, and then compared with the dielectric margins of the transformer insulation before retrofilling. To improve the accuracy of the study, an experimental study was driven to obtain the permittivity values of mixtures of MO and NE in different proportions and the composition of the solid insulation in retrofilled transformers. The study also investigates the influence of the quality of the retrofilling process on the electric field distribution. The analysis shows that some parts of the insulation, such as the oil channel, operate with lower stress when the insulating liquid is changed to an ester, but other regions, such as the solid insulation in the most stressed areas of the insulation, reduce their dielectric margins significantly.

Estimation of Collisional Broadening and Shift for Argon Lines at 811.5 nm and 912.3 nm in Pure Gas and Ar–Ne Mixture

Estimation of Collisional Broadening and Shift for Argon Lines at 811.5 nm and 912.3 nm in Pure Gas and Ar–Ne Mixture

Laboratory and astronomical discovery of the cyanovinyl radical H2CCCN

We report the first laboratory and interstellar detection of the α-cyano vinyl radical (H2CCCN). This species was produced in the laboratory by an electric discharge of a gas mixture of vinyl cyanide, CH2CHCN, and Ne. Its rotational spectrum was characterized using a Balle-Flygare narrowband-type Fourier-transform microwave spectrometer operating in the frequency region of 8–40 GHz. The observed spectrum shows a complex structure due to tunneling splittings between two torsional sublevels of the ground vibronic state, 0+ and 0−, derived from a large-amplitude inversion motion. In addition, the presence of two equivalent hydrogen nuclei makes it necessary to discern between ortho- and para-H2CCCN. A least-squares analysis reproduces the observed transition frequencies with a standard deviation of ca. 3 kHz. Using the laboratory predictions, this radical was detected in the cold dark cloud TMC-1 using the Yebes 40 m telescope and the QUIJOTE1 line survey. The 40, 4-30, 3 and 50, 5-40, 4 rotational transitions, composed of several hyperfine components, were observed in the 31.0–50.4 GHz range. Adopting a rotational temperature of 6 K, we derived a column density of (1.4±0.2)×1011 cm−2 and (1.1±0.2)×1011 cm−2 for ortho-H2CCCN and para-H2CCCN, respectively. The reaction of C + CH3CN emerges as the most likely route to H2CCCN in TMC-1, and possibly that of N + CH2CCH as well.

Low Pressure DBD in He–Ne Mixture. Spectroscopy of the Afterglow

Low Pressure DBD in He–Ne Mixture. Spectroscopy of the Afterglow

Design and Testing of a Prototype Eddy Current Actuated Valve for the ITER Shattered Pellet Injection System

Reliably mitigating disruptions is essential for ITER to meet its long-term operational research plan without damage to the in-vessel components. Currently, the shattered pellet injection (SPI) technique is the most effective radiator of thermal energy and has been chosen for the baseline disruption mitigation system (DMS) for ITER. The SPI process uses cryogenic temperatures to desublimate material into the barrel of a pipe gun forming a solid cylindrical pellet. Pellets for ITER will initially be hydrogen and hydrogen–neon mixtures. Once formed, pellets are dislodged and accelerated using high-pressure gas (40–60 bar) delivered by a fast-opening valve. The solenoid valves currently used for SPI experiments will not operate in an ITER environment due to the large background magnetic field. An ITER prototype fast-opening valve, called a flyer plate valve (FPV), has been designed and has undergone a wide range of testing. The FPV operates by pulsing current through a pancake coil that is closely coupled with a “flyer plate.” The flyer plate is an aluminum plate in which eddy currents are generated creating a repulsive force from the pancake coil. The force generated in the flyer plate rapidly lifts the valve tip off the seat and delivers a pulse of gas to the rear of the pellet, breaking it free from the barrel and accelerating the pellet downstream to its intended target. The design of the valve has been iterated on over the lifetime of this project, as the DMS for ITER shifted from massive gas injection (MGI) to SPI. The most recent design has been tested, and operational ranges have been mapped. The valve must survive 3000+ cycles in an ITER-like magnetic field. The principal functional requirement of this valve is to reliably dislodge and accelerate hydrogen (or H–Ne mixture) pellets into ITER. The valve was mated with an ITER SPI test stand and has been shown to be capable of launching pellets reliably. The valve and power supply design will be discussed in this article, along with the various testing setups used to determine the feasibility of this valve for use on ITER.

Formation of volume discharges in dense gases at pulse repetition rates up to 10 kHz

AbstactIt is shown that for the formation of stable volume discharges at pulse repetition frequencies up to 10 kHz and more, it is recommended to use sectioning of the discharge gap with subsequent excitation of discharges in each section from an autonomous pulse generator. The role of an autonomous pulse generator can also be performed by an auxiliary circuit that directs the necessary part of the energy stored in the main energy storage of a pulse generator with only a single switch to an individual discharge gaps. The description and results of the study of one of these variants of a partitioned discharge gap and a pulse generator are given. Pumping energy densities of 100–150 mJ-cm−3 at pulse repetition frequencies up to 8 kHz in CO2 laser mixtures and 80–100 mJ-cm−3 in N2-Ne and Xe–Ne mixtures at pulse repetition frequencies up to 10 kHz were achieved.

Light Transmission and Surface Topography of KU-1 Optical Quartz After Sputtering and Cleaning from Al Films in RF Discharge of H2(D2)–Ne Mixtures

Light Transmission and Surface Topography of KU-1 Optical Quartz After Sputtering and Cleaning from Al Films in RF Discharge of H2(D2)–Ne Mixtures

Simulation of Electron Beam Emission in Argon–Neon Mixture Pinch Using the Nonrelativistic 6-D Valsov–Maxwell System Solved by the Forward Semi-Lagrangian Approach

The 6-D Vlasov–Maxwell equations in the cylindrical coordinates have been solved to calculate the electron beam emission from mixtures of argon and neon. The forward semi-Lagrangian approach was used for solutions. The simulation of the electron velocity field has shown that at the early stage of the pinch evolution of a 4-mbar 90% Ar–10% Ne mixture, the sausage instabilities began to develop from the top parts of the pinch due to bigger $B_{\theta }$ with respect to $B_{z}$ . In the turbulence regions, the electrons could accelerate up to speeds of $905 \times 10^{5}$ and $2387.5 \times 10^{5} \,\,{\text {m}}/{\text {s}}$ at 90.9 and 181.82 ns, respectively. It has been observed that in the high turbulence region, $E_{z}=-2.04\times {10}^{7}\,\,{\text {V}}/{\text {m}}$ , while in the weak turbulence region, $E_{z}=-1.46\times {10}^{7}\,\,\text {V}/{\text {m}}$ . Increasing the neon percentage in the mixture changed the turbulence regions and the upstream and downstream emissions.

DC Glow Discharge Plasma Characteristics in Ar/O2 Gas Mixture

In this article, the effects of the O2 ratio on the electrical characteristics, including the I-V characteristic curve, Panchen’s curve, and I-P curve, were tested in a sample of O2/Ar gaseous mixture . The sample was produced by plasma-based DC magnetron sputtering with niobium metal as a target material. The inter-electrode spacing value was 4 cm. Plasma diagnosis via the Optical Emission Spectroscopy (OES) method was used to achieve Te and Ne mixture values of 20 %, 30 %, 50%, and 70% in the Ar/O2 system. The results showed that the discharge is operating in the abnormal glow region and the discharge current was decreased by increasing O2 percentage. In addition, the experimental results showed that the discharge is optimal at 30% gas ratio. It was found that the electron temperature was decreased with increasing working pressure and increased with increasing the O2 percentage, while electron density was increased with increasing both working gas pressure and O2 percentage.

Comparison of Refrigeration Cycles at 28–30 K

A comparative analysis of refrigeration cycles for supporting actual loads at temperatures around 28–30 K is presented. Within this temperature range, such cryoagents as Ne, He, H2, D2 and Ne-He mixture can be used. Refrigeration cycle simulations using various cryoagents were performed using the Aspen HYSYS V8.8 software package.

Diamond-like/graphite-like carbon composite films deposited by high-power impulse magnetron sputtering

Diamond-like carbon (DLC)/graphite-like carbon (GLC) composite films were prepared with high-power impulse magnetron sputtering (HiPIMS) using a mixture of Ar and Ne as the sputtering gas. The effect of the Ne fraction in the sputtering gas on the surface morphology, carbon bonding structure, microstructure, mechanical properties, residual stress, and tribological performance of the deposited films were characterized using laser scanning confocal microscopy, Raman spectroscopy, nano-indentation, residual stress tester, and friction and wear testing using a ball-on- plate tribometer, respectively. The films have a composite surface structure consisting of sp2-rich GLC microparticles embedded in an sp3-rich DLC matrix. Both components can be controlled to some degree by varying the Ne fraction. Specifically, as the Ne fraction is increased, both the number and size of the GLC microparticles decreases, while the sp3 content increases. The GLC microparticles in the film can reduce the real contact area in friction testing, decreasing the friction coefficient, while the sp3-rich DLC phase enables the high hardness and wear resistance of the films. By adjusting the Ne fraction during the HiPIMS process, DLC/GLC composite films with low friction and high wear resistance can be generated.

On the Selectivity of Population of the Neon Excited Levels in the Decaying He–Ne Plasma

The results of a spectroscopic study of the afterglow of a pulsed discharge in a He–Ne mixture are presented, showing the unique selective population of the upper level of the 2p54p configuration (3p1 in Paschen’s notation) of a neon atom at a helium pressure of tens of Torr. The main measurements were conducted under conditions of competition between the excitation transfer from metastable He atoms (21S0) and the dissociative recombination of HeNe+ ions with electrons as sources of excited atoms. Helium pressure PHe ≈ 0.08–20 Torr, neon PNe ≈ 0.0005–0.003 Torr, the electron density [e] < 1011 cm–3. The results of the experiment indicate the existence of a mechanism that forms with an increase of helium pressure such a distribution of populations over 2p54p levels, in which more than 60% of the radiation flux of 2p53s ← 2p54p transitions is concentrated in one spectral line of 352.0 nm.

Argon-neon binary diagram and ArNe2 Laves phase.

Mixtures of argon and neon have been experimentally studied under high pressure. One stoichiometric compound, with ArNe2 composition, is observed in this system. It is a Laves phase with a hexagonal MgZn2 structure, stable up to at least 65 GPa, the highest pressure reached in the experiments. Its equation of state follows closely the one of an ideal Ar+2Ne mixture. The binary phase diagram of the Ar-Ne system resembles the diagram predicted for hard sphere mixtures with a similar atomic radius ratio, suggesting that no electronic interactions appear in this system in this pressure range. ArNe2 can be a convenient quasihydrostatic pressure transmitting medium under moderate pressure.

Overview of HL-2A recent experiments

The mission of HL-2A is to explore the key physical topics relevant to ITER and to the advanced tokamak operation (e.g. the operation of future HL-2M), such as the access of H-mode, energetic particle physics, edge-localized mode (ELM) mitigation/suppression and disruption mitigation. Since the 2016 Fusion Energy Conference, the HL-2A team has focused on the investigations on the following areas: (i) pedestal dynamics and L–H transition, (ii) techniques of ELM control, (iii) turbulence and transport, (iv) energetic particle physics. The HL-2A results demonstrated that the increase of mean shear flow plays a key role in triggering L–I and I–H transitions, while the change of flow is mainly induced by the ion pressure gradient. Both mitigation and suppression of ELMs were realized by laser blow-off seeded impurity (Al, Fe, W). The 30% Ne mixture supersonic molecular beam injection seeding also robustly induced ELM mitigation. The ELMs were mitigated by low-hybrid current drive. The stabilization of m/n = 1/1 ion fishbone activities by electron cyclotron resonance heating was found on the HL-2A. A new m/n = 2/1 ion fishbone activity was observed recently, and the modelling indicated that passing fast ions dominantly contribute to the driving of 2/1 fishbone. The non-linear coupling between the toroidal Alfven eigenmode and tearing mode (TM) led to the generation of a high frequency mode with the toroidal mode number n = 0. The turbulence was modulated by TM when the island width exceeds a threshold and the modulation is localized merely in the inner area of the islands. Meanwhile, turbulence radial spread took place across the island region.

Enhancement of the sensitivity of the light-induced drift effect to interatomic interaction potentials using a mixture of two buffer gases

Based on five different nonempirical (calculated ab initio) interaction potentials for pairs of colliding Li – Ne particles and three different interaction potentials for pairs of colliding Li – Ar particles, we have theoretically investigated the spectral features of the light-induced drift (LID) rate of Li atoms in the buffer Ne gas in a mixture of buffer Ne + Ar gases. The calculations of LID of Li atoms in the buffer Ne gas for two interaction potentials predict anomalous LID and, as a result, strong sensitivity of the spectral shape of the LID lines to the differences in these potentials. For three other potentials (out of the five in question), the shape of the LID line of Li atoms in Ne is insensitive to the shape of the potential, since calculations with these potentials predict a normal LID effect. In this case, as it turned out, by adding a small fraction (approximately 10 %) of Ar to Ne, one can go from normal LID to anomalous LID and thereby radically increase the sensitivity of the LID line shape of Li atoms to the difference in these interaction potentials. The results obtained enable high-precision testing of the interatomic interaction potentials in experiments on anomalous LID.

Spectroscopy of He–Ne afterglow plasma

The afterglow of pulsed low-current discharge in a He–Ne mixture is spectroscopically studied under conditions of competition between the processes of Ne2+ and HeNe+ dissociative recombination with electrons, which are the sources of population of excited levels of neon atoms. The behavior of neon spectral lines in the wavelength range of 350–850 nm corresponding to the transitions from the levels of neon atoms of the 2p53p, 2p53d, 2p54p, 2p54d, 2p55s, 2p55d, 2p56s configurations are studied by the multichannel photoncounting method at electron density ne < 1011 cm–3 and helium and neon pressures PHe = 38 Torr and PNe ≈ 10-5pHe Distributions of recombination fluxes and population over excited states of the neon atom formed in the afterglow by homo- and heteronuclear ions are found. The data obtained show that vibrationally excited molecular ions make no noticeable contribution to the spectrum of decaying He–Ne plasma.

First results from the NEWS-G direct dark matter search experiment at the LSM

New Experiments With Spheres-Gas (NEWS-G) is a direct dark matter detection experiment using Spherical Proportional Counters (SPCs) with light noble gases to search for low-mass Weakly Interacting Massive Particles (WIMPs). We report the results from the first physics run taken at the Laboratoire Souterrain de Modane (LSM) with SEDINE, a 60 cm diameter prototype SPC operated with a mixture of Ne + CH4 (0.7%) at 3.1 bars for a total exposure of 9.6 kg · days. New constraints are set on the spin-independent WIMP-nucleon scattering cross-section in the sub-GeV/c2 mass region. We exclude cross-sections above 4.4×10−37cm2 at 90% confidence level (C.L.) for a 0.5 GeV/c2 WIMP. The competitive results obtained with SEDINE are promising for the next phase of the NEWS-G experiment: a 140 cm diameter SPC to be installed at SNOLAB by summer 2018.

Anti-cancer potential of a mix of natural extracts of turmeric, ginger and garlic: A cell-based study

Cancer related morbidity and mortality is a major health care concern. Developing potent anti-cancer therapies which are non-toxic, sustainable and affordable is of alternative medicine. This study was designed to investigate the aqueous natural extracts mixture (NE mix) prepared from common spices turmeric, ginger and garlic for its free radical scavenging potential and anti-cancer property against human breast cancer cell lines (MCF-7, ZR-75 and MDA-MB 231). Qualitative analysis of their bioactive constituents from turmeric, ginger and garlic were done using liquid chromatography-ESI- mass spectrometry (LC-ESI-MS/MS). To the best of our knowledge, NE mix with and without Tamoxifen has not been tested for its anti-cancer potential. We observed that the NE mix induced apoptosis in all the breast cancer cell lines, but it was more prominent in MCF-7 and ZR-75 cell lines in comparison to MDA-MB 231 cell line. The extent of apoptosis due to combined treatment with NE mix-Tamoxifen was higher than Tamoxifen alone, indicating a potential role of the NE mix in sensitizing the ER-positive breast cancer cells towards Tamoxifen. In support to MTT assay, cell cycle analysis, our RT-PCR results also prove that the NE mix 10μg, Tam 20μg and combination of NE mix 10μg-Tam 20μg altered the expression of apoptotic markers (p53 and Caspase 9) leading to apoptosis in all three cell lines. Our data strongly indicate that our NE mixture is a potential alternative therapeutic approach in certain types of cancer.