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Ferrocene [Fe(C5H5)2 or FeCp2] is a well-known precursor molecule for iron in vapor deposition of iron containing films by, e.g., chemical vapor deposition (CVD) processes. CVD processes often use the energy in plasma discharges to decompose precursor molecules, which allows lowering the substrate temperature for deposition on sensitive materials. Herein, we studied the plasma decomposition of ferrocene in a plasma CVD reactor using in situ optical emission spectroscopy and quadrupole mass spectrometry, coupled with in silico quantum chemical modeling. We suggest a plasma chemical decomposition model under medium vacuum conditions where FeCp2 is likely to undergo neutral decomposition, detaching both Cp ligands from the iron center, followed by fragmentation via C2H2− and C3H3 to C2, CH, H2, and H. [ABSTRACT FROM AUTHOR]

Optical emission spectroscopy (OES) is an important technique for plasma diagnostics. Random deviation is inevitable during the measurement of plasma emission spectra due to the imperfection of instruments and other interferences. On the other hand, inaccuracies in the collision cross-section data can lead to distortion of the collisional-radiative (CR) model. The coupling of theoretical and experimental error factors can pose difficulties for accurate diagnostics of plasma. This work presents the development of the OES method for xenon plasma that employs a neural network model to integrate prior information on the characteristics of instrument noise and model distortions, thereby improving the accuracy of OES diagnostics. The neural network model takes emission line ratios as input and normalized electron density as output and is trained using a dataset that is generated with a CR model and an instrument disturbance model. The neural network-based OES method is implemented to determine the electron density in a microwave discharge chamber and compared with a traditional OES method with a multi-variant fitting technique. A significant improvement on relative deviation of diagnostic results is observed, which promises a good prospect for further development. [ABSTRACT FROM AUTHOR]

This study uses concurrent spectroscopic measurements that provide evidence of the predator–prey behavior between ions, neutral atoms, and electrons that is theorized to drive the Hall thruster breathing mode, a crucial oscillation in Hall thrusters impacting their efficiency and stability. A novel fast optical emission spectroscopy diagnostic is employed to simultaneously measure the characteristics of neutral and ion populations through their respective emissions. A quasi-1D predator–prey model of the breathing mode is utilized to predict the phase difference between neutral and ion populations according to the predator–prey theory. The observed phase difference between Xe I and Xe II emissions is consistent with the expected phase difference between neutral and ion populations predicted by the quasi-1D model. Several operating conditions are explored, and the impact of adjusting the plasma conditions are explored both through experiments and modeling. [ABSTRACT FROM AUTHOR]

This study presents a proof-of-principle for using optical emission spectroscopy and artificial neural networks for real-time monitoring and control of the operational parameters of a Hall effect thruster: the anode voltage, the anode xenon injection, the discharge current, and the coil current. In that regard, we build an optical database of 26 spectral lines across 6469 operating conditions to train and test the neural network. We then reduced the learning lines from 26 to 15 based on their statistical correlation with the target parameters. After tuning the hyperparameters of the network, the network predicted the thruster's parameters with notable accuracies: 95% for the anode voltage, 84% for the coil current, and 99% for both the anode flow rate and the discharge current. The estimated uncertainty of predictions, at 3 σ , is ± 51 V for voltage, ± 1 A for coil current, ± 0.15 A for discharge current, and ± 0.15 mg s − 1 for anode flow rate. The prediction calculations were within milliseconds and enabled real-time monitoring of the thruster parameters. Therefore, a proportional-integrator-derivative controller (PID) controller was implemented to regulate the anode voltage and flow rate based on the optical emission of the plume. The PID showcased short settling times from 0.1 to 0.4 s and overshoot levels up to 3% of the target value for the voltage and 10% of the target value for the flow rate. These results were for a fixed coil current at 4 A. The study showed that changing the coil current may necessitate more sophisticated prediction models and control strategies. Future work will expand the model's generalizability to different thruster types, propellants, and magnetic field configurations. [ABSTRACT FROM AUTHOR]

A reduced pressure glow discharge is produced by passing a high-power pulsed DC source of 0–500 W with a frequency of 50 Hz across two parallel disk electrodes. A hydrogen peroxide aqueous solution is used as a flowing gas for discharge generation. Optical emission spectroscopy is employed to diagnose the discharge generated at a reduced pressure of 0.2 mbar with an electrode gap of 4 cm. The spectra are recorded at a power density of 9.4 mW/cm3 and typically lie in the visible wavelength range of 380–880 nm. The spectra are analyzed using the line intensity ratio method to estimate electron temperature and density. The results indicated that the electron temperature and density are, respectively, 0.87 eV and 6.4 × 1014 cm−3. [ABSTRACT FROM AUTHOR]

Helium metastable densities in the COST Reference Microplasma Jet are estimated for a variety of He/N2 admixtures and dissipated powers by applying a collisional-radiative model to absolutely calibrated optical emission spectroscopy measurements. This is accomplished by delineating the excitation mechanisms that result in the N2(C–B) and N 2 + (B–X) emission bands, the latter of which is strongly coupled to the presence of helium metastables. A number of other plasma parameters are established and discussed for each operating condition including the electron energy distribution function, reduced electric field, rate constants, and electron density. With these parameters, the reaction rates for the primary ionization pathways are also calculated, emphasizing the importance of helium metastables for discharge sustainment. Good agreement with the existing literature is found for most plasma parameters and for helium metastable densities, in particular. A clear [N2] − 1 relationship between the nitrogen concentration and density of helium metastables is demonstrated, as has been identified in previous studies in analogous atmospheric pressure plasma jets. This validates the efficacy of this optical technique for determining helium metastable densities and establishes it as a viable, and in many cases, more accessible alternative to other means of quantifying helium metastables in low-temperature plasmas. [ABSTRACT FROM AUTHOR]

As a threat to meeting the global demand for food created by the continued growth of population, different methods are being applied to enhance seed germination and plant growth. This study investigates the effect of hydrogen-rich water (HRW) and different plasma-activated waters (PAW) and their combinations including HRW, PAW1, PAW2, HPAW1, and HPAW2 on the seed germination of lentils. Different arc discharge reactors are generated under atmospheric pressure in the air. Optical emission spectroscopy was used to detect the radiative species formed in the plasma zone. Raman spectra and physicochemical properties of different waters were investigated. The results demonstrated significant differences in the properties of different activated waters compared to control water. On day 3 after treatment, the fraction and length of germinated seeds were evaluated. During germination, treated water significantly increased germination parameters such as final germination percentage, mean germination time, germination index, and coefficient of germination velocity. HPAW2 exhibited the highest germination index (GI), which combines germination percentage and speed. The plasma systems also effectively reduced the pH of PAW1 and PAW2, with a greater decrease observed in HPAW1 and HPAW1. Analysis of nitrite and nitrate levels revealed that HPAW2 had the highest concentrations, indicating more reactive processes in the presence of hydrogen. Based on our results, it can be concluded that lentil seed germination can be increased using PAW and hydrogenated PAW combined. [ABSTRACT FROM AUTHOR]

Standing striations with a unique pattern have been observed in a radio-frequency-generated hydrogen plasma. The striation pattern consists of a sequence of closely spaced bright ring doublets and two types of dark gaps of different widths. The bright and dark regions in striations were spectroscopically resolved with the Balmer series and the Fulcher band emission lines of hydrogen. Temperatures in these fine structures were determined. In general, the wider dark gap has a higher excitation temperature than the nearby narrower ones in the striation pattern sequence. Bright regions are rotationally hotter than the adjacent dark ones. However, for vibrational temperatures, the trends are not so obvious. No clear pressure dependence of temperatures was observed in striations within the pressure range of maintaining stable standing striations in this work. In addition to optical emission spectroscopy, we used graphite granules as in situ probes for plasma conditions in different striation regions. The striated hydrogen plasma-treated graphite granules were analyzed with Raman spectroscopy. The observed hydrogen-graphite interaction was correlated with the measured temperatures and the fine structures of striations in a discharge tube. [ABSTRACT FROM AUTHOR]

Pulsed discharge nozzles (PDNs) have been successfully used for decades to produce rotationally cold (Trot ∼ 20 K) radicals and ions of astrophysical interest and to characterize these species spectroscopically. In this work, an evolution of the PDN, the piezostack pulsed discharge nozzle (P2DN), is used for the first time to investigate the characteristics of the still poorly understood supersonic plasma expansion. The P2DN allows for a better control of the reservoir pressure of which an accurate measurement is required to characterize the plasma expansion. This new source, thus, gives the opportunity to further optimize the plasma conditions and extend its use to new target species. The spatial distribution of an argon plasma and the effect of the supersonic flow for different pressures are studied by combining a two-dimensional extended fluid model (extFM) and a direct simulation Monte Carlo (DSMC) method. The combined simulation is validated with experimental results obtained through emission spectroscopy associated with a group-code collisional-radiative model to retrieve the plasma parameters. The validated numerical approach (DSMC-extFM) allows for an accurate characterization of the plasma structure in our typical experimental conditions (a reservoir pressure ranging from 90 to 905 mbar). Thus, this simulation will be used in future studies to improve the plasma conditions to favor the synthesis of (transient) hydrocarbon species as found in space, by seeding the argon gas with a suitable precursor, such as acetylene. [ABSTRACT FROM AUTHOR]

GaCH2, a free radical thought to play a role in the chemical vapor deposition of gallium-containing thin films and semiconductors, has been spectroscopically detected for the first time. The radical was produced in a pulsed discharge jet using a precursor mixture of trimethylgallium vapor in high pressure argon and studied by laser-induced fluorescence and wavelength resolved emission techniques. Partially rotationally resolved spectra of the hydrogenated and deuterated species were obtained, and they exhibit the nuclear statistical weight variations and subband structure expected for a 2A2–2B1 electronic transition. The measured spectroscopic quantities have been compared to our own ab initio calculations of the ground and excited state properties. The electronic spectrum of gallium methylene is similar to the corresponding spectrum of the aluminum methylene radical, which we reported in 2022. [ABSTRACT FROM AUTHOR]

Optical emission spectroscopy studies of vanadium plasma in a cathodic-arc discharge in a nitrogen atmosphere have been carried out. Spectral lines of neutral atoms and ions of the cathode material V, V1+, and V2+, and nitrogen N2 and N2+ were observed in the discharge plasma. Analysis and comparison of the intensity of vanadium and nitrogen spectral lines as a function of nitrogen pressure showed that in vacuum excited ions V2+ and V+ are registered, with increasing pressure, the lines V+*, N2*, and N2+* are observed, and at pressures above 0.5 Pa, the neutral vanadium lines are additionally registered. The electron temperature of Te decreases from 5.9 to 3–4 eV with increasing pressure. Studies of cross-sectional scanning electron microscopy images of VN coatings deposited at different nitrogen pressures have shown that a dense, homogeneous, fine-grained microstructure is formed in the coating when the number of neutral V in the plasma is low, while in the presence of a large number of neutrals, the coating structure changes to a dense structure with columnar growth. [ABSTRACT FROM AUTHOR]

Gallium-tellurite glass is a new optical material with good transmittance in the infrared region up to 6.5 μ m. Three different tellurate glasses were prepared: TeO2–ZnO–Ga2O3(TZG), TeO2–ZnO–La2O3(TZL) and TeO2–ZnO–B2O3(TZB). X-ray diffraction indicates that no crystal precipitates in the three glass systems, which maintain a stable glass state. Raman scattering experiments and fluorescence emission spectroscopy measurements were carried out on the tellulate glasses doped with the same concentration of Tm 3 + . It was found that the phonon energy of TZG(TeO2–ZnO–Ga2O3)-doped thulium glass is the lowest, and the emission light at 1380 nm is the strongest with ∼ 5 1 nm fluorescence FWHM. These results show that Tm-doped TZG glass is a good luminescent material. Refractive indices were measured by the minimum deviation method. Sellmeier dispersion equation is obtained, which can be used to calculate the refractive index within visible and near-infrared spectral range. Furthermore, different Tm 3 + concentrations (0.4%, 0.8%, 1.2% and 2%) TZG glasses were prepared, the emission spectra and fluorescence lifetime were measured, and the emitted light was strongest when the thulium ion doping concentration is 1.2%. All the results suggest that these newly developed ternary tellurite glass systems are promising candidates for near/mid-infrared laser glass fibers, fiber amplifiers, or lasers. [ABSTRACT FROM AUTHOR]

Environmental pollution caused by heavy metals are problems worldwide. In particular, pollution and poisoning by lead ions (Pb2+) continue to be common and serious problems. Hence, there is a need for a widely usable method to easily detect Pb2+ from solutions containing organic materials from environmental water such as seas, ponds, etc. Here, we established a system to easily detect Pb2+ from such mixture solutions using Pb2+ binding peptide immobilized beads (peptidyl beads) and ultraviolet (UV) absorption measurements. This method could detect Pb2+ at low concentrations equivalent to inductively coupled plasmon-atomic emission spectroscopy (ICP-AES). Using the detected values to create a calibration curve, it was found that there was a positive correlation between the concentration of Pb2+ and absorbance, which also made it possible to quantify sub-µM Pb2+ in the solutions. Furthermore, Pb2+ was detected and quantified under mixed conditions of environmental water such as seas, rivers, and ponds. This method is expected to become a versatile and easy-to-use Pb2+ detection method for end-users worldwide. [ABSTRACT FROM AUTHOR]

A methodology is proposed, which addresses the caveat that line-of-sight emission spectroscopy presents in that it cannot provide spatially resolved temperature measurements in non-homogeneous temperature fields. The aim of this research is to explore the use of data-driven models in measuring temperature distributions in a spatially resolved manner using emission spectroscopy data. Two categories of data-driven methods are analyzed: (i) Feature engineering and classical machine learning algorithms, and (ii) end-to-end convolutional neural networks (CNN). In total, combinations of fifteen feature groups and fifteen classical machine learning models, and eleven CNN models are considered and their performances explored. The results indicate that the combination of feature engineering and machine learning provides better performance than the direct use of CNN. Notably, feature engineering, which is comprised of physics-guided transformation, signal representation-based feature extraction and Principal Component Analysis is found to be the most effective. Moreover, it is shown that when using the extracted features, the ensemble-based, light blender learning model offers the best performance with RMSE, RE, RRMSE and R values of 64.3, 0.017, 0.025 and 0.994, respectively. The proposed method, based on feature engineering and the light blender model, is capable of measuring nonuniform temperature distributions from low-resolution spectra, even when the species concentration distribution in the gas mixtures is unknown. [ABSTRACT FROM AUTHOR]

Narrow band green emitting phosphors have gained widespread attention due to their application in white light emitting diode (wLED) backlight displays. Commercial backlight displays have a broad band green phosphor which limits their performance. In this work, bright, narrow and thermally stable green emitting MgGa2O4:Mn2+ (MGO-Mn) has been synthesized. Time-resolved emission spectroscopy suggested that Mn2+ ions are distributed at both Mg2+ and Ga3+ sites of the MGO spinel, which resulted in a high internal quantum efficiency of 63%. The colour purity of MGO-Mn (76.4%) superseded that of the commercial green phosphor ß-SiAlON:Eu2+ (59.12%). Doping-induced creation of oxygen vacancies endows MGO-Mn with excellent persistent luminescence with a time duration of more than 900 s upon 4 min charging with 270 nm UV light and persistent radioluminescence of more than 6000 s when charged with X-rays for 1 min. Finally, tunable white LEDs (cool and neutral white LEDs) are fabricated by combining the RGB mixture of the green phosphor with commercial red and blue phosphors along with a 280 nm UV LED chip. This work also showcases the importance of different annealing atmospheres in the photoluminescence and persistent luminescence of the MGO-Mn phosphor. [ABSTRACT FROM AUTHOR]

Titanium dioxide, when doped with nitrogen, exhibits significant efficacy in various photocatalytic and photoelectrochemical applications. However, precise adjustment of nitrogen doping concentrations and a proper balance between substitutional to interstitial nitrogen are essential for optimal device functionality. Sputtering, a plasma-based technology, excels in achieving high-quality nitrogen-doped titanium dioxide films that maintain this stability. As the most widely used method for producing nitrogen-doped titanium dioxide, sputtering faces challenges related to controlled growth. Discrepancies between nitrogen gas flow rates and the resulting nitrogen content in thin films have been noted, yet comprehensive analyses of these inconsistencies are scarce. This oversight reflects a broader trend in semiconductor materials where fundamental properties and mechanisms are often overshadowed by practical applicability. In this study, we focus on plasma species and energy in the sputtering process, employing plasma optical emission spectroscopy and detailed discharge parameter monitoring to gain a nuanced understanding of plasma kinetics. This approach allows us to integrate plasma characteristics with doping levels, successfully resolving longstanding discrepancies in growth of nitrogen-doped titanium dioxide films. [ABSTRACT FROM AUTHOR]

In the last few decades, planet search surveys have been focusing on solar-type stars, and only recently the high-mass regimes. This is mostly due to challenges arising from the lack of instrumental precision, and more importantly, the inherent active nature of fast-rotating massive stars. Here, we report NGTS-33b (TOI-6442b), a super-Jupiter planet with mass, radius, and orbital period of 3.6 |$\pm$| 0.3 M |$_{\rm J}$|⁠ , 1.64 |$\pm$| 0.07 R |$_{\rm J}$|⁠ , and |$2.827\,972 \pm 0.000\,001$|  d, respectively. The host is a fast-rotating (⁠|$0.6654 \pm 0.0006$|  d) and hot (T |$_{\rm eff}$| = 7437 |$\pm$| 72 K) A9V type star, with a mass and radius of 1.60 |$\pm$| 0.11 M |$_{\odot }$| and 1.47 |$\pm$| 0.06 R |$_{\odot }$|⁠ , respectively. Planet structure and gyrochronology models show that NGTS-33 is also very young with age limits of 10–50 Myr. In addition, membership analysis points towards the star being part of the Vela OB2 association, which has an age of |$\sim$| 20–35 Myr, thus providing further evidence about the young nature of NGTS-33. Its low bulk density of 0.19 |$\pm$| 0.03 g cm |$^{-3}$| is 13 per cent smaller than expected when compared to transiting hot Jupiters (HJs) with similar masses. Such cannot be solely explained by its age, where an up to 15 per cent inflated atmosphere is expected from planet structure models. Finally, we found that its emission spectroscopy metric is similar to JWST community targets, making the planet an interesting target for atmospheric follow-up. Therefore, NGTS-33b's discovery will not only add to the scarce population of young, massive and HJs, but will also help place further strong constraints on current formation and evolution models for such planetary systems. [ABSTRACT FROM AUTHOR]

Light–matter coupling-induced hybrid states provide the potential to tune the emission dynamics of molecular chromophores having multilevel systems. We demonstrate the alteration of delayed fluorescence dynamics by hybrid states formation through the interaction of light with a thermally activated delayed fluorescence molecule embedded in a conventional Fabry–Pérot cavity. The proximity of cavity resonance with the excited state absorption is modified by manipulating the incident angles (with sample) instead of varying the active layer thickness. The coupling-induced hybrid states are observed by angle-dependent emission spectroscopy and lifetime measurements. The variation in average emission lifetime with respect to incident angle is over 10 μ s and is accompanied by significant changes in the full width at half maxima (factor of three). The control of emission via a barrier-free route or reverse intersystem crossing transition is demonstrated from these measurements. These findings suggest the possibility of tailoring intermediate states for lasing, where exciton density inversion can enhance spontaneous emission. [ABSTRACT FROM AUTHOR]

ABSTRACT Inductively coupled plasma (ICP) is ideal for powder spheroidization due to its large plasma volume, high purity and high temperature. This study investigates the interaction between plasma and in‐flight particles using optical emission spectroscopy, discharge imaging and DPV evolution diagnostics, focusing on the effects of plasma power and powder feed rate. The results demonstrate that powder injection slightly decreases plasma temperature. As the powder feed rate increases, both the ICP temperature and the spheroidization rate decreases. Under optimal plasma power and powder feed rate conditions, particles achieve higher temperatures and velocities, and the prepared spherical powder exhibits higher sphericity. This research provides valuable reference for optimizing the preparation of high melting point and high purity spherical powders. [ABSTRACT FROM AUTHOR]

The morphology and crystalline quality of polycrystalline diamond samples were studied by systematically varying the flowrate of nitrogen gas in the microwave plasma. A slight improvement in both crystallite size and crystalline quality is observed for a low concentration of 0.5 sccm nitrogen. With a further increase in nitrogen concentration, diamond switches from micro-crystalline to nanocrystalline (NCD) with a nitrogen flow of 2.5 sccm (10% of methane concentration). The surface roughness of the sample is found to depend strongly on the crystallite size of the sample. Extensive spectroscopic studies have been done to understand the presence and formation of different defect complexes in diamond. XPS and Raman analysis of the films reveal the variation of graphitic content as a function of nitrogen addition. The presence of nitrogen-containing defect complexes has been studied thoroughly and their concentration has been found to be limited by the solubility limit rather than the availability of reactants in the gas environment. In contrast, the effect these complexes have on the strain of the diamond film is found to be negligible. Optical emission spectroscopy of the plasma reveals the presence of C2 dimers as well as C-N radicals. However, they have little role in modifying diamond grain morphology or crystalline quality. [ABSTRACT FROM AUTHOR]

The design of efficient reaction units and the use of efficient catalysts for green and non-polluting ammonia synthesis is an important and challenging issue. In this paper, we design a high-efficiency reaction device, a coaxial double dielectric barrier discharge plasma reactor, which produces a more uniform plasma discharge during operation, changes the discharge characteristics, promotes the physicochemical reactions of ammonia synthesis, improves the efficiency of ammonia production, and reduces the energy consumption. The use of transition metal Ni and its metal oxide NiO loaded on the carrier as catalysts. The catalyst was comprehensively characterized by X-ray photoelectron spectroscopy, X-ray diffraction, and scanning electron microscope. The reaction mechanism of plasma-catalyzed ammonia synthesis was studied in detail by combining discharge characteristics, optical emission spectroscopy, and catalyst characterization. The reaction conditions and discharge parameters of the dielectric barrier discharge plasma reactor were optimized, which greatly improved the energy efficiency and synthesis rate, which could reach 1002 μmol g−1 h−1 under the optimal conditions. Based on the experimental results, we analyzed how different conditions and parameters affect the reaction of ammonia synthesis. • Designed a double dielectric barrier discharge reactor for NH 3 synthesis. • Plasma-assisted Ni/Al 2 O 3 enhances NH 3 synthesis with improved energy efficiency. • The mechanism of plasma catalytic NH 3 synthesis was proposed and analyzed. • Plasma parameters in NH 3 synthesis were analyzed via optical emission spectroscopy. [ABSTRACT FROM AUTHOR]

The emission of mixed inert/reactive gas plasmas, commonly used in a variety of industrial applications and laboratory settings, is relatively unquantified in the vacuum ultraviolet (VUV) wavelength range. VUV emission spectroscopy of mixed H2:Ar/Ne/He inductively coupled radio frequency (RF) plasmas was conducted for pressures in the range 20–80 mTorr with 400 W input RF power and H2 concentrations of 0% to 100%. For H2:Ar mixtures at 80 mTorr, the Ly- α (121 nm) emission was observed to reach a maximum at 27.5% H2: 72.5%Ar, approximately 3.3 × greater than a pure hydrogen discharge at the same pressure, and the total emission in the range 115–200 nm increased by a factor of 1.5. By increasing the pressure at which the mixtures were maintained, the maximum Ly- α emission was increased, and the H2 concentration at which that maximum occurred decreased. Comparisons to a simple collisional model indicate a significant pressure dependence, which is consistent with observations of self-absorption of Ly- α by ground state hydrogen atoms. Experiments across the full range of H2:Ar/Ne/He mixtures revealed that admixed gases with heavier atomic masses are more effective at increasing the Ly- α emission. A similar pressure dependence was also observed, indicating self-absorption phenomena are still highly relevant to emission spectroscopy of mixed hydrogen/inert gas plasmas. The development of high efficiency sources in the VUV wavelength range is especially useful for space applications where there is no atmospheric absorption of the VUV. [ABSTRACT FROM AUTHOR]

ABSTRACT This study investigates the effects of an open‐to‐air helium plasma jet, generated by sub‐microsecond discharges, on polystyrene (PS) surfaces positioned at distances of 1 and 10 mm from the nozzle. Optical emission spectroscopy revealed that at 1 mm the plasma spectrum is dominated by N₂⁺ emission, while at 10 mm N₂ emission prevails. Surface analysis showed that at 1 mm PS surfaces developed micro‐ and nanostructures with varying compositions, particularly in the outer regions, while at 10 mm the surface exhibited a uniform nanostructure distribution. X‐ray photoelectron spectroscopy and X‐ray diffraction analyses indicated the incorporation of oxygen and nitrogen species and suggested the formation of functionalized graphene/graphite oxide microstructures. [ABSTRACT FROM AUTHOR]

In this review we detail the expansion of laser-induced shock waves into the air following nanosecond-pulsed laser ablation of energetic materials for comparison of the microsecond-timescale energy release among different samples; subsequent self-sustained combustion reactions provide information about the millisecond-timescale energy release. This technique is called laser-induced air shock from energetic materials (LASEM). A detailed description of the processes involved in LASEM is presented, along with the experimental conditions for successfully differentiating similar energetic materials. The influence of material properties and sample preparation, laser properties, high-speed imaging parameters, and data fitting methodology on the characteristic laser-induced shock velocities is reviewed with relevant examples. Related work by other groups is also discussed, demonstrating the increasing usage of laser-induced plasmas and their subsequent effects for energetic material characterization on a laboratory scale. We provide examples of recent capability upgrades. Finally, we enumerate the open questions relating to LASEM experimental results and their relationship to detonation chemistry. [ABSTRACT FROM AUTHOR]

In the context of chiral π‐conjugated materials, the use of enantiopure alkylthio appendages represents a valid alternative to conventional alkoxy groups: sulphur atom is bigger and more electron‐rich than oxygen, thus allowing for higher polarizability, greater flexibility, larger bulkiness and lower structural anisotropy. In light of these considerations, here we report two new chiral alkylthio‐decorated 1,4‐phenylene/thiophene dyes, obtained by simple synthetic strategies involving Pd‐catalyzed cross‐coupling protocols, looking for strong non‐reciprocal chiroptical features in thin films. In particular, for the chiral alkylthio‐decorated 1,4‐phenylene–bis(thiophenylpropynone) (Thio‐PTPO) dye, which proved to be the most promising for our purpose, a detailed investigation in thin films was carried out, involving optical and chiroptical spectroscopies in absorption and emission, as well as optical microscopy techniques. [ABSTRACT FROM AUTHOR]

In this work, a long surface wave plasma column is generated using high power pulse-modulated microwave power in argon at atmospheric pressure. The temporal evolutions of the electron density and temperature are diagnosed by optical emission spectroscopy. It is found that the emission intensity peaks correspond to the nodes of standing surface waves where the local electric field is reduced, rather than the antinodes, which is in contrast with that in low pressure discharges. The reasons for this behavior are discussed by considering the excitation balance of the excited levels of Ar I in the plasma. A standing surface wave pattern propagating with the movement of the ionization front in the plasma column, which plays the role of a discontinuity, is observed by means of microsecond time-resolved imaging. Another standing wave at the location of the launcher is also described which indicates that the region below the gap also acts as a discontinuity for the wave propagation. The formation of the propagating standing wave is discussed with respect to the wave propagation characteristics by using an electromagnetic (EM) model based on the propagation of the surface wave. This study underlines the fundamental differences in the EM wave/plasma interactions between continuous and pulsed surface wave discharges and provides new insights into the importance of the microwave applicator segment for a complete description of the plasma column formation. [ABSTRACT FROM AUTHOR]

Marine tourism is authorized in Jakarta Bay's Angke Kapuk mangrove forest. Maritime vessel activities, maintenance, and land reclamation can pollute nearby aquatic environments and sedimentary deposits. This study examines lead (Pb), a heavy metal, in water and sediment samples to measure contamination. Lead pollution in aquatic habitats can harm aquatic organisms and humans through bioaccumulation in the food chain. The sampling was done twice in August 2023, seven days apart. This technique was done at three stations with different activities. Microwave Plasma-Atomic Emission Spectroscopy (MP-AES) was used to measure lead amounts in the samples. The water sample analysis showed 0.0022-0.0092 mg/L, matching Indonesian Government Regulation No. 22 of 2021 standards. Conversely, sediment samples showed 0.067-0.200 mg/kg, which is below the quality criteria set by ANZECC&ARMCANZ in 2000 for Australia and New Zealand and CCME in 2001 for Canada. Despite low pollution according to recognized criteria, heavy metals in ecotourism zones require government and public attention. Additional information, in-depth research on water contamination, and heightened awareness of the impacts of heavy metals may be necessary. [ABSTRACT FROM AUTHOR]

Many known rocky exoplanets are so highly irradiated that their dayside surfaces are molten, and 'silicate atmospheres', composed of rock-forming elements, are generated above these lava pools. The compositions of these 'lava planet' atmospheres are of great interest because they must be linked to the composition of the underlying rocky interiors. It may be possible to investigate these atmospheres, either by detecting them directly via emission spectroscopy or by observing the dust tails which trail the low-mass 'catastrophically evaporating planets'. In this work, we develop a simple chemical model of the lava pool–atmosphere system under mass-loss, to study its evolution. Mass-loss can occur both into space and from the day to the nightside. We show that the system reaches a steady state, where the material in the escaping atmosphere has the same composition as that melted into the lava pool from the mantle. We show that the catastrophically evaporating planets are likely to be in this evolved state. This means that the composition of their dust tails is likely to be a direct trace of the composition of the mantle material that is melted into the lava pool. We further show that, due to the strength of day-to-nightside atmospheric transport, this evolved state may even apply to relatively high-mass planets (⁠|$\gtrsim 1\mathrm \,{M}_{\oplus }$|⁠). Moreover, the low pressure of evolved atmospheres implies that non-detections may not be due to the total lack of an atmosphere. Both conclusions are important for the interpretation of future observations. [ABSTRACT FROM AUTHOR]

Elemental Te and Cd are successfully recovered from CdTe via a combinatorial process involving chemical vapor transport (CVT) using sulfur as transport agent giving elemental Te being deposited. Separation is successfully enabled by the first process for CVT of Te starting with CdTe. Cd is subsequently recovered by an oxidation of the formed CdS to CdO followed by reduction to Cd metal with natural gas, in which Cd can also be separated via the gas phase. Hereby, the process addresses the main critical elements of the active material in thin film CdTe solar cells regarding both, scarcity and toxicity. Both, closed and open systems were investigated displaying more or less thermodynamic control of the system. Transport rates were determined for the closed system as well as for an open system working with sulfur vapour at moderate temperatures below and close to the boiling point of sulfur. Excellent purity of tellurium was achieved already by the initial transport, leading to low Cd2+ concentrations in the obtained Te being below the quantification limit of microwave plasma‐atomic emission spectroscopy (MP‐AES) (≪0.05 wt %). [ABSTRACT FROM AUTHOR]

A novel, modified coflow burner was developed to study the effect of charge injection from a non-thermal plasma into three helium-diluted laminar coflow diffusion ethylene flames. The frequency of the high voltage (HV) signal was varied to control the ion concentration (charge) injected into the flames. Optical emission spectroscopy was used to characterize the non-thermal plasma while a bias plate methodology was used to gauge the relative amount of charge generated. For different HV signal frequencies, the laser-induced fluorescence of OH, chemiluminescence of CH*, and laser-induced incandescence of soot in flames were measured. The OH and CH* measurements showed that the flames retained the classic flame shape with charge injection. Significant soot reduction was observed at low HV signal frequencies, corresponding to an increase in charge injection. Notably, at low HV signal frequency, soot reduction in highly concentrated (60%) ethylene flame is three times lower than the less concentrated (32%) ethylene flame. This can be attributed to the decrease in the injected charge to soot precursor concentration ratio when the concentration of ethylene in the flame is increased. These results demonstrate that the current system is a promising candidate for studying the charge effect from non-thermal plasma on soot formation in laminar coflow diffusion flames. [ABSTRACT FROM AUTHOR]

A dissolution method for analyzing the elemental composition of fuel debris using the sodium peroxide (Na2O2) fusion technique has been developed. Herein, two different types of simulated fuel debris (such as solid solution of (Zr,RE)O2 and molten core – concrete interaction products (MCCI)) were taken. At various temperatures, these debris samples were subsequently fused with Na2O2 in crucibles, which are made of different materials (Ni, Al2O3, Fe, and Zr). Then, the fused samples are dissolved in nitric acid. Effects of the experimental conditions on the elemental composition analysis were evaluated using inductively coupled plasma-atomic emission spectroscopy (ICP – AES), which suggested the use of a Ni crucible at 923 K as an optimum testing condition. The optimum testing condition was then applied to the demonstration tests with Three Mile Island unit-2 (TMI-2) debris in a shielded concrete cell, thereby achieving complete dissolution of the debris. The elemental composition of TMI-2 debris revealed by the proposed dissolution method has good reproducibility and has an insignificant contradiction in the mass balance of the sample. Therefore, this newly developed dissolution method can be effectively utilized in practical applications by dissolving fuel debris and analyzing its elemental composition. [ABSTRACT FROM AUTHOR]

The slow evaporation solution growth technique (SEST) was used to successfully grow inorganic single crystals of sodium sulphamate (NaS) in ambient conditions. The titled crystal's structural and optical characteristics were evaluated using a variety of spectroscopic techniques. Powder X-ray diffraction (PXRD) analysis and Fourier transform infrared (FT-IR) spectroscopy were used to examine the crystal structure characteristics. Using UV-Vis spectroscopy, the optical properties of the NaS crystal were carefully examined, and the optical bandgap was determined using Tauc's plot. The HR-XRD analysis examined crystalline perfection. Additionally, photoluminescence spectroscopy determined the emission spectra, and time-resolved photoluminescence measured the decay rate. The Z -scan technique was also used to examine the titled crystal's nonlinear optical (NLO) performance. [ABSTRACT FROM AUTHOR]

Ni, Ni–Zn, and Ni–Zn–P coatings were electrodeposited on the surface of X80 pipeline steel to explore their hydrogen barrier behavior. Hydrogen adsorption and desorption as well as the absorption and diffusion process were investigated by experiments with Devanathan-Stachurski double electrolytic cell and electrochemical impedance spectroscopy (EIS), and the kinetic parameters of hydrogen permeation were estimated via modelling and data fitting. Furthermore, the distribution, hydrogen concentrations and corresponding binding energies of different hydrogen traps in the coatings and at the coating/substrate interface were measured by the glow discharge optical emission spectroscopy (GDOES) and thermal desorption spectrum (TDS). Although hydrogen is more likely to be produced and accumulated on the surface of Ni-based coatings than that of the bare X80 steel, it is confirmed that amorphous Ni–Zn and Ni–Zn–P coatings can effectively reduce the apparent hydrogen diffusion coefficient of the coated sample, with Ni–Zn–P exhibiting more pronounced effect. This is mainly attributed to the high concentration of reversible hydrogen traps at the coating and coating/substrate interface. • Amorphous Ni–Zn–P coating is prepared on X80 pipeline steel by electrodeposition. • Effective hydrogen barrier behavior of Ni–Zn–P coating was found. • Reversible hydrogen traps in the coating or at the interface inhibit H diffusion. • The adsorption, desorption, absorption and diffusion of H are investigated. [ABSTRACT FROM AUTHOR]

AbstractA hexanuclear cerium(IV) complex with a non–steroidal anti–inflammatory drug mefenamic acid (Hmef) as a ligand has been synthesized and characterized by diverse techniques. The molecular structure of the complex was determined by single–crystal X–ray crystallography revealing the formula [Ce6(O)4(OH)4(mef)12(DMF)2]. The antioxidant activity of the complex was evaluated for its ability to scavenge free radicals. The interaction of the complex with calf–thymus DNA was studied by diverse techniques showing its potency to intercalate to DNA. The interaction of the complex for human and bovine serum albumins was studied by fluorescence emission spectroscopy and revealed its tight and reversible binding to the albumins. [ABSTRACT FROM AUTHOR]

The concentrations of selected elements in wood chips and in the corresponding ashes after combustion in a wood combustion plant with an output of 300 kWth were determined using inductively coupled plasma‐optical emission spectroscopy (ICP‐OES). Mass balances for the individual elements were calculated using the analysis results from wood chips and ashes. The recovery rates of the elements were compared with literature data on volatility. [ABSTRACT FROM AUTHOR]

Featured Application: The SDBD plasma reactors has recently found many practical applications, including aviation, ozone production and environmental protection. We characterized non-thermal plasma generated in two types of Surface Dielectric Barrier Discharge (SDBD) reactors, one with a planar and the other with a cylindrical electrode. Plasma was examined using the time-resolved imaging and Optical Emission Spectroscopy (OES) methods. We observed that the cylindrical electrode suppresses plasma formation during both discharge modes: positive streamers and pseudo-Trichel microdischarges. The propagation velocity of the plasma front was estimated to be in the range 12–15 m/s, regardless of the discharge mode and electrode type. Spectral analysis showed that the plasma emission spectrum consisted mainly of the first and second positive nitrogen bands. Using Specair software, we calculated the plasma thermodynamic parameters and found that, despite morphological differences, the plasma generated in both reactors had similar thermodynamic properties. Finally, we discussed the temporal evolution of the discharge and attributed the plasma suppression caused by the cylindrical electrode to the characteristic uniformity of the electric field around and along this electrode. [ABSTRACT FROM AUTHOR]

Two new complexes of Pd(II), [Pd(L1)Cl]Cl (Pd1) and [Pd(L2)Cl]Cl (Pd2), (where L1 = N2,N6-bis(5-methylthiazol-2-yl)pyridine-2,6-dicarboxamide and L2 = N2,N6-di(benzo[d]thiazol-2-yl)pyridine-2.6-dicarboxamide) were synthesized. Characterization of the complexes was performed using elemental analysis, IR, 1H NMR spectroscopy and MALDI-TOF mass spectrometry. The nucleophilic substitution reactions of complexes with L -Methionine (L -Met), L -Cysteine (L -Cys) and guanosine-5′-monophosphate (5′-GMP) were studied by stopped-flow method at physiological conditions (pH = 7.2 and 37 °C). Complex Pd1 was more reactive than Pd2 in all studied reactions, while the order of reactivity of the selected ligands was: L -Met > L -Cys > 5′-GMP. The interaction of complexes with calf thymus-DNA (CT-DNA) was studied by Uv–Vis absorption and fluorescence emission spectroscopy. Competitive binding studies with intercalative agent ethidium bromide (EB) and minor groove binder Hoechst 33258 were performed as well. Both complexes interacted with DNA through intercalation and minor groove binding, where the latter was preferred. Additionally, the interaction of Pd1 and Pd2 complexes with human serum albumin (HSA) was studied employing fluorescence quenching spectroscopy. The results indicate a moderate binding affinity of complexes, with slightly stronger binding of the Pd1. Fluorescence competition experiments with site-markers (eosin Y and ibuprofen) for HSA were used to locate the binding site of Pd1 to the HSA. Additionally, the interaction with DNA and HSA was studied by molecular docking and the revealed results were in good agreement with the experimentally obtained ones. Pd1 complex exhibited cytotoxicity toward human (HCT116) and mouse cell lines (CT26) of colorectal cancer, mouse (4T1) and human (MDA-MB468) breast cancer lines and non-cancerous mouse mesenchymal stem cells (mMSC). In addition, Pd1 complex demonstrated significant selectivity towards cancer cells over non-cancerous mMSC, indicating a high potential to eliminate malignant cells without affecting normal cells. It induced apoptosis in CT26 cells, effectively arrested the cell cycle in the S phase, and selectively down-regulated cyclin D and cyclin E. Moreover, it can alter the expression of cell cycle regulators by increasing p21 and decreasing p-AKT. These findings confirm its ability to disrupt key tumor cell survival signals and suggest that the Pd1 complex is a potent candidate for effective cancer treatment. [ABSTRACT FROM AUTHOR]

A series of phosphine oxide‐containing gold(III) complexes with tunable emission colors spanning from sky‐blue to near‐infrared region is reported. This is accomplished by the switching of the excited state characters from intraligand to ligand‐to‐ligand charge transfer through the replacement of the auxiliary ligand from aryl to nitrogen‐based ligands. In addition to high photoluminescence quantum yields in both solution and solid‐state thin films, these complexes exhibit large radiative decay rate constants of the order of 106 s−1, much larger than those commonly found for other gold(III) complexes. The origin of such enhanced performance is believed to be arising from the occurrence of both thermally activated delayed fluorescence and thermally stimulated delayed phosphorescence processes within the emitters. This is probed by ns‐ and fs‐transient absorption spectroscopy, time‐resolved, and temperature‐dependent emission spectroscopy. In particular, the direct observation of the upconversion processes and the determination of the activation barriers are achieved in the variable‐temperature fs‐transient absorption spectroscopic studies. Solution‐processed organic light‐emitting devices with satisfactory external quantum efficiencies of up to 15.2% are achieved, which could be ascribed to the presence of thermally activated delayed fluorescence and/or thermally stimulated delayed phosphorescence processes. [ABSTRACT FROM AUTHOR]

Thiophene polycyclic derivatives are widely used in organic light‐emitting diodes, photovoltaics, and medicinal chemistry applications. Understanding the electronic and structural factors controlling their intersystem crossing rates is paramount for these applications to be successful. This study investigates the photophysical, electronic structure, and excited state dynamics of 1,2‐benzodiphenylene sulfide, benzo[b]naphtho[1,2‐d]thiophene, and benzo[b]naphtho[2,3‐d]thiophene in polar aprotic and non‐polar solvents. Steady‐state absorption and emission spectroscopy, femtosecond transient absorption spectroscopy, and DFT and TD‐DFT calculations are employed. Low fluorescence quantum yields of 1.2 to 2.7 % are measured in acetonitrile and cyclohexene, evidencing that the primary relaxation pathways in these thiophene derivatives are nonradiative. Linear interpolation of internal coordinates calculations predict that an S−C bond elongation reaction coordinate facilitates the efficient intersystem crossing to the T1 state. Excitation of 1,2‐benzodiphenylene sulfide and benzo[b]naphtho[1,2‐d]thiophene at 350 nm or benzo[b]naphtho[2,3‐d]thiophene at 365 nm, populates the lowest‐energy 1ππ* state, which relaxes to the 1ππ* minimum in tens of picoseconds or intersystem crosses to the triplet manifold in ca. 500 ps to 1.1 ns depending on the position at which the benzene rings are added. Excitation at 266 nm does not affect the intersystem crossing rates. Laser photodegradation experiments demonstrate that the thiophene polycyclic derivatives are highly photostable. [ABSTRACT FROM AUTHOR]

This technical paper presents a comprehensive study on the properties of geopolymer coating applied to mild steel pipelines as a potential alternative to Ordinary Portland cement (OPC) concrete structures. The geopolymer paste was formulated using a mixture of fly ash and alkaline activators, specifically sodium hydroxide (NaOH) solution and sodium silicate (Na2SiO3) solution. Two types of primers, epoxy metal primer and self-etch primer were applied before the geopolymer coating and various curing conditions were investigated. The geopolymer samples were subjected to two different curing processes: one set was cured in an oven at 60°C for 24 hours while the other set was left to cure under ambient conditions. After the curing period, the samples were aged at ambient conditions for 28 days. The properties of the fly ash and geopolymer paste were evaluated through a range of tests including phase analysis, morphology analysis, optical emission spectroscopy (OES) analysis, chemical composition analysis and adhesion strength testing. The results revealed that the geopolymer coatings exhibited surface cracks and efflorescence attributed to unreacted sodium oxide. X-Ray diffraction (XRD) analysis confirmed the presence of quartz, hematite, magnetite, aluminum oxide and mullite in the geopolymer coating. The self-etch primercoated samples demonstrated improved adhesion and corrosion resistance properties with a denser and more cohesive microstructure. The geopolymer coating when applied with a self-etch primer and cured at 60°C for 2 hours, achieved the highest adhesion strength of 2.2 MPa, indicating strong bonding with the mild steel pipelines. These findings contribute to the understanding of geopolymer coatings and their potential application in enhancing the performance and durability of mild steel pipelines, offering a sustainable alternative to conventional concrete coatings with improved corrosion resistance and adhesion properties. [ABSTRACT FROM AUTHOR]

The characteristics of a high-frequency discharge during plasma-liquid treatment of the surface of a metal plate made of copper grade M1 under atmospheric illumination were studied. The high-frequency (HF) discharge is ignited by supplying an electrolyte to the surface of a metal electrode. The surface temperatures of the electrodes during the burning of an HF discharge were studied using infrared thermography. The types and shapes of plasma structures generated in the interelectrode gap are described. The crystal composition, electron concentration, variable and rotational temperatures were determined using optical emission spectroscopy (OES). The morphology and surface of the plates were studied before and after processing. [ABSTRACT FROM AUTHOR]

Chemical reduction of a dinuclear [(di‐NHC)Au2Cl2(di‐NHC)] complex (NHC=imidazol‐2‐ylidene), using excess NaBH4 as reducing agent in presence of dichloromethane (DCM) as solvent, provides a molecular cluster with formula [Au13(di‐NHC)5(CH3)2]Cl3, exhibiting covalent bonds between gold atoms of the cluster core and methyl groups. The presence of Au‐CH3 bonds, which is unprecedented in gold cluster chemistry, is confirmed by high resolution mass spectrometry (HRMS), NMR and the reactivity of the reported cluster in solid state. The cluster has been further characterized with single crystal X‐ray diffractometry, UV‐Vis and emission spectroscopies. The cluster displays remarkable stability in solution, which is indicative of the possible role played by Au‐CH3 bond formation in the conventional preparation of molecular gold nanoclusters by reduction with excess borohydride in DCM. [ABSTRACT FROM AUTHOR]

Background: Cerebral syphilitic gummas are rare. However, numerous case reports on them have been published recently, consistent with the resurgence of syphilis and its accompanying atypical manifestations. We here present a patient with a cerebral syphilitic gumma and an unusual clinical course and review recent case reports. Case Presentation: A 49-year-old woman had a generalised seizure and was found by computed tomography and magnetic resonance imaging to have a brain mass that mimicked a brain abscess or malignant tumour. Further imaging with magnetic resonance spectroscopy and positron emission tomography did not contribute further to the differential diagnosis. Because treatment with ceftriaxone was ineffective, the lesion was resected. Serological tests on serum and cerebrospinal fluid were positive for syphilis and histopathological examination of the operative specimen revealed a syphilitic gumma. Antibiotic treatment is preferred over invasive interventions for cerebral syphilitic gumma. However, as in our case, radical resection is required when antibiotic treatment is ineffective. Conclusions: It has recently been reported that the prevalence of syphilis is increasing in older individuals, including in patients without HIV infection or prior treatment for early syphilis. Though advanced imaging and molecular biological techniques are often used to help make a diagnosis, they are of limited value. Because the clinical and imaging features are nonspecific, some neurosurgeons do not include cerebral syphilitic gummas in their differential diagnoses. It is vital that this possibility be considered when a patient has a tumour-like cerebral mass and serum positivity for syphilis. [ABSTRACT FROM AUTHOR]

Laser-induced Terahertz (THz) Emission Spectroscopy (TES) has demonstrated its potential utility in the realm of Metal-Oxide-Semiconductor (MOS) devices as an expedient and noncontact estimation methodology. Owing to its discerning response to the interface electric field, the amplitude of the THz emission peak in time-domain spectroscopy encapsulates rich information regarding MOS properties, notably the flat-band voltage. This paper concentrates on the precise quantitative estimation of the flat-band voltage within the Si MOS structure, elucidating the intricacies of the estimation process through the THz emission model. [ABSTRACT FROM AUTHOR]