A major barrier to integrating pyrolysis-derived oil into conventional refinery technology is the presence of impurities, particularly halogens and metals, that can deactivate catalysts. This study presents a novel, cost-effective approach for the simultaneous analysis of a subset of halogens, metals, nonmetals, and metalloids in complex, industrially relevant distilled pyrolysis oil samples, this was previously achievable only through multiple techniques. Excellent results were obtained using a widely accessible inductively coupled plasma mass spectrometry (ICP-MS) method with helium gas mode and standard laboratory consumables, enabling high-throughput analysis and efficient evaluation of adsorbent performance. Sample preparation is straightforward, requiring only dilution in a compatible matrix, and provides accurate and precise quantification, with 75%-137% spike recovery for Be, Ti, V, Cr, Fe, Ni, Co, Cu, As, Se, Mo, Cd, Sb, Tl, and Pb, and 62%-65% spike recovery for Cl and 109%-133% spike recovery for Br. Additionally, an enhanced version of the method using ICP-MS/MS and hydrogen gas is described, which has higher accuracy with 69%-112% spike recovery for Be, B, Ti, V, Fe, Co, Ni, Cu, As, Se, Mo, Cd, Sb, Tl, and Pb, with 85%-102% spike recovery for Cl and 63%-93% spike recovery for Br. Helium mode detection limits for industrially relevant elements (V, Fe, Ni, Cu, As, and Pb) are less than 1.7 µg/kg, and less than 0.2 mg/kg for Br and Cl. This methodology facilitates rapid systematic evaluation of adsorption capacities of materials under time-on-stream conditions and supports robust comparisons across diverse operating environments.

The chemistry of the radioelement polonium has attracted increasing attention owing to its formation in accelerator-driven systems and its high radiotoxicity. Being the lighter homologue of the superheavy element livermorium, whose chemistry is still unexplored, studies of polonium provide a benchmark for verifying the structure of the periodic table at the heavy-element frontier. While the reactivity of elemental polonium towards various surfaces in inert or reducing atmospheres has been investigated previously, the reactivity of oxidized polonium towards quartz has not been explored in detail. Here, we report on gas-solid thermochromatography studies of polonium on quartz glass and α-Al2O3 surfaces in helium, as well as in oxygen- and water-containing atmospheres in the atom-at-a-time regime. We found that polonium chemically reacts in an oxygen-containing atmosphere, forming two oxidized species, which are less volatile than elemental polonium. The chemical reaction is influenced by the water vapour concentration in the carrier gas and the applied temperature. The adsorption enthalpy of elemental polonium on α-Al2O3 in pure helium gas was determined to be -85+4-3 kJ mol-1, which is identical to the adsorption enthalpy on quartz as reported earlier. The results of the reported measurements will support future experiments with the superheavy element livermorium.

There is a revamped interest in the transport properties of quasi-free electrons in dense and cold hydrogen gas because it has recently been shown that multiple scattering effects modify their drift mobility in the same way as they do in helium and neon gases. Owing to the similarities in the electron-atom/molecule scattering cross sections, there is the possibility that also in hydrogen, electrons self-localize in bubbles as they do in dense gaseous helium and neon and in their liquids. A very scant number of experiments suggest that this may happen. In this paper, we investigate this possibility by numerically carrying out the prediction of the optimum fluctuation model. We show that electron self-localization is a very likely process and that the model accurately predicts the density at which quasi-free electrons and electron bubbles coexist in equal proportions, as inferred from the experiments.

Since its commissioning, the RIKEN Radioactive Isotope Beam Factory (RIBF) has achieved a sustained increase in uranium beam intensity by more than two orders of magnitude. A key enabling technology has been a helium (He) gas stripper, which overcomes the severe lifetime limitations of conventional carbon foil strippers under high-intensity irradiation. This paper presents a comprehensive account of the design, long-term operation, and performance of the He gas stripper at the RIBF. A large-scale windowless He gas target was realized using a five-stage differential pumping system and high-flow gas recirculation, enabling stable operation with areal densities up to 0.7 mg/cm2. A gas diffuser, optimally positioned with respect to the Mach disk of the He jet, significantly improved stage-to-stage gas separation. At high uranium beam intensities, beam-induced gas heating gives rise to a pronounced gas-thinning effect in the He gas stripper. This effect was characterized using time-of-flight measurements and simplified thermal modeling, showing that purely thermal descriptions overestimate the gas temperature rise. The results suggest that nonthermal energy dissipation processes, most plausibly vacuum-ultraviolet radiation from excited He atoms, limit the temperature increase. To suppress He leakage into the cyclotron and maintain stable vacuum conditions under high-intensity operation, a nitrogen (N2) gas-jet curtain technique was developed. This method provides effective sealing of the He flow, replacement of residual He with N2, and a moderate pre-stripping effect, enabling stable long-term operation at the highest uranium beam intensities at the RIBF.

A concept for a gas-cooled plasma-facing component (PFC) has been investigated that utilizes a multijet pressurized gas (helium or nitrogen) for the extraction of heat energy. A finger-type module of the gas-cooled PFC is designed and fabricated to withstand 5 MW/m2 heat flux. Two nondestructive testing techniques, namely, (1) ultrasonic flaw detection and (2) eddy current thermography (ECT), are implemented for assessment of the curved and straight interfaces of the gas-cooled finger-type module. First, an ultrasonic technique with phased array (PA) C-scan imaging is implemented. The ultrasonic probe, PA test parameters, and test sensitivity are optimized using CIVA 10.1 simulation. Validation of the ultrasonic technique is performed on calibrated samples with reference defects with 0.5-, 1-, and 2-mm–diameter flat bottom holes. Further, metallic joints of similar (W/WL-10) and dissimilar (WL-10/Type 304 stainless steel) materials used in fabrication of the gas-cooled PFCs are investigated. Second, the ECT technique with a specially designed thermal wave excitation coil is implemented to assess the heat transfer characteristics of the gas-cooled PFC. Transient thermal profiles are obtained using COMSOL simulation for known reference defects ranging from 0% to 100% of the bond area. Experimental validation is performed on a sample with calibrated reference defects. Thermal profiles on the gas-cooled PFCs are investigated successfully. Ultrasonic testing techniques realize the size and location of defects present at the joint interfaces, and the ECT provides heat transfer characteristics, which helps to assess the quality of the multilayered gas-cooled PFCs effectively, and the obtained results are utilized for improvements in the fabrication technologies. This paper presents in detail the experimental methods, their simulations, and the results of the nondestructive tests conducted on the gas-cooled finger-type module of the PFC.

The objective of the APEX (A Positron-Electron eXperiment) project is to magnetically confine and study positron-electron pair plasmas. For this purpose, a levitated dipole trap (APEX-LD) has been constructed. The magnetically levitated, compact (7.5-cm radius), closed-loop, high-temperature superconducting floating (F-)coil consists exclusively of a no-insulation rare-earth barium copper oxide winding pack, solder-potted in a gold-plated-copper case. A resealable in-vacuum cryostat facilitates cooling (via helium gas) and inductive charging of the F-coil. The 70-minpreparation cycle reliably generates persistent currents of ∼60 kA-turns and an axial magnetic flux density of B0 ≈ 0.5 T. We demonstrate levitation times in excess of 3h with a vertical stability of σz < 20 μm. Despite being subjected to routine quenches (and occasional mechanical shocks), the F-coil has proven remarkably robust. We present the results of preliminary experiments with electrons and outline the next steps for injecting positron bunches into the device.

ABSTRACT Helium‐rich coalbed methane (CBM) represents a promising new target for boosting helium production, and gas exsolution from groundwater is a critical process for helium accumulation. Ion compositions of groundwater generally affect gas solubility, but the coupling relationships among helium and other components in CBM controlled by hydrogeochemical compositions remain unclear. To clarify the gas–water interactions and their effects on helium concentration variations in coal measure systems, in this study, gas and water samples from 16 CBM wells were collected for geochemical experiments, with supplementary simulations of helium exsolution induced by CO 2 /N 2 injection. Gas provenance analysis indicated mixed thermogenic‐biogenic CH 4 , biogenic CO 2 , crustal helium and N 2 primarily of atmospheric genesis. Helium concentrations reached a maximum of 0.97%, with an average of 0.12%. The helium concentration showed parabolic correlations with CO 2 and N 2 concentrations, a pattern attributed to the dilution effects exerted by elevated CO 2 and N 2 concentrations. Following equal‐duration interactions with CO 2 and N 2 , helium‐containing aqueous solutions produced gaseous helium concentrations of 16.52% and 2.16% respectively, suggesting that CO 2 plays a more significant role in the helium enrichment. Considering the generation and migration of CBM, the helium, N 2 and CO 2 concentrations displayed zonal variations controlled by hydrogeochemical fields. Under similar geological conditions, the biogenic CH 4 and mixed CH 4 areas in runoff or weak runoff zones exhibit enhanced helium enrichment potential. This study established an innovative distribution model for helium, CO 2 and N 2 in CBM controlled by hydrochemical compositions, which advances the understanding of the hydrological processes associated with helium enrichment.

Dental caries, a multifactorial disease, is primarily driven by acidogenic bacteria such as Streptococcus mutans (S.mutans) and Lactobacillus acidophilus (L.acidophilous). Conventional antimicrobial treatments may be insufficient for complete bacterial eradication. Non-thermal atmospheric pressure plasma (NTAPP) has emerged as a novel antimicrobial strategy. This study aimed to evaluate the antibacterial efficacy of NTAPP on S.mutans and L.acidophilous in carious dentin under clinical conditions. A plasma jet device utilizing helium gas (purity 99.999%, nozzle diameter 3 mm, voltage 10 kV, frequency 6 kHz, flow rate 2 L/min) was employed to irradiate the Class I, II, and III cavities in 15 teeth with dentin caries extending no deeper than the middle third of the dentin. Carious dentin was excavated using an excavator immediately before and after plasma treatment. Plasma was applied from a 10 mm distance for one min. Colony-forming unit (CFU) counts were determined for S. mutans and L. acidophilus. Statistical analysis was conducted using the Wilcoxon Signed-Rank Test (P value = 0.05). Helium Plasma irradiation resulted in a significant reduction in CFU counts for both S. mutans and L. acidophilus (P < 0.001). The reduction rates were 76.01 ± 25.17% for S. mutans and 76.14 ± 23.88% for L. acidophilus. No significant difference was observed in CFU reduction between the two bacterial species (P > 0.05). Helium-based NTAPP demonstrated a significant antibacterial effect against S. mutans and L. acidophilus in this clinical study, suggesting its potential as an antibacterial treatment for dentin caries lesions.

Experimental investigation of helium gas heat exchangers for vibration and thermal noise control in closed-cycle cryostats

Design and characterization of an alumina coated helium gas gap heat switch with adjustable gap width

Temperature equalization control method for rotor magnet of HTS synchronous condenser with circulating cold helium gas

Does fogging impact container closure integrity for a lyophilized drug product?

The safe ignition of cryotechnic space launchers is threatened by flow instabilities that occur before ignition, a phase that remains poorly understood. While most research focuses on post-ignition instabilities, we investigated the critical few hundred milliseconds preceding ignition. Using injectors simulating liquid oxygen LOX flow in European space engines (full-scale injector mock-up with liquid nitrogen LN2 at 3.5bar and 77K), we studied the 300ms transient phase for two conditions: 1) with LN2 only, 2) with helium gas injected simultaneously with LN2 during the first 150ms. Thrust, pressure and microwave resonator density sensors were used to calculate the flow rate. Map flow analysis and frequency analysis were undertook to characterize the flow. Our measurements revealed that helium sweep reduces the effect of the secondary 50Hz mode and that it lessens the amplitude of the dominant 13Hz mode during the first 150ms, resulting in reduced amplitudes of these modes for the last 150ms with a stabilizing effect on the flow. We hypothesize this is due to a reduction in the thermal gradient between the wall and the flow, which likely enhances engine ignition reliability. Further experiments or calculations are required (heat flux, subcooling) to better understand the stabilizing effect of the inert gas sweep.

Environmental concerns have prompted the development of new technologies aimed at producing low-carbon energy carriers, such as hydrogen. Non-thermal plasma has emerged as a promising option, enabling the conversion of methane into hydrogen at room temperature and atmospheric pressure using dielectric barrier discharge reactors. This study employs a zero-dimensional (0D) model to investigate the temporal evolution of densities and selectivities of the various species within the reactor. The model investigates the impact of noble gases (helium and argon) at varying proportions on methane conversion. An in-depth analysis of the reactions in the kinetic model has been conducted to investigate the mechanisms behind the conversion of methane to hydrogen using the non-thermal plasma process. The reactor has demonstrated remarkable performance, achieving a total methane conversion of up to 100% and a maximum hydrogen yield of 48% for a mixture containing 10% methane and 90% Argon.

We investigate the Fourier-transform infrared spectra of hydrogen fluoride dimers in solid parahydrogen, the detailed analysis of which has remained unexplored. We propose a plausible analysis based on concentration dependence, light polarization, annealing, and time evolution. The absorption lines exhibited multiple peaks, with intensity ratios significantly altered by annealing and by time evolution at a constant temperature. The spectral patterns and isotopic effects suggest that the dimers do not rotate freely in solid parahydrogen, while multiple peaks arise from different stable structures, including single and double substitution sites. Unlike in the gas phase and helium droplets, no tunneling splitting was observed. The broad ν1 band suggests that some dimer structures may exhibit axial rotation. Spectral changes due to annealing likely result from site conversion, while observed IR-induced changes indicate preferential dissociation of dimers in double substitution sites. These findings still remain tentative, necessitating further experimental and theoretical studies.

Establishing a measurement system for infrared spectroscopy experiments under the three synergetic extreme physical conditions-strong magnetic fields, high pressures, and low temperatures-is quite challenging. Here, we present an experimental setup for performing infrared spectroscopy measurements (in the photon energy range from 100 to 6000 cm-1) simultaneously at strong static magnetic fields (up to 22T), high hydrostatic pressures (up to ∼20GPa), and low temperatures (down to 2.0K). In this setup, a diamond anvil cell (DAC) and a superconducting solenoid magnet are utilized to apply high hydrostatic pressures and strong static magnetic fields on a tiny sample. Moreover, a small-diameter optical parabolic cone compatible with the sample chamber of the superconducting solenoid magnet is employed to condense the infrared light on the tiny sample, which solves the difficulty in making the light flux through the tiny sample inside the restricted sample chamber high enough. In addition, a probe containing the optical parabolic cone, the sample, the DAC, and the bolometer detector is inserted into the liquid helium immersing the superconducting solenoid of the magnet not only to cool the sample by cold helium gas between the DAC and the probe shell but also to place the tiny sample at the magnetic-field center. We demonstrated the application of this setup in the infrared spectroscopy measurements of a topological insulator, ZrTe5, which reveals the pressure-induced redshift of the absorption features arising from the optical transitions of the magnetic-field-caused Landau levels at low temperatures.

Introduction Bismuth-based perovskite solar cells are gaining attention as a promising alternative to lead-based solar cells due to environmental concerns. However, the c-axis growth preferred, electrotonic anisotropic and deep-defect nature of Bi-based perovskite materials presents significant challenges in depositing non-(006) orientation and reducing defect density [1]. We have proposed a surface reaction model to better understand the chemical vapor deposition (CVD) growth kinetics of the thin films, as shown in Fig. 1 [2]. Although the bismuth-based perovskite film (CH3NH3)3Bi2I9 (MABI) has been widely studied at a processing temperature of 160 °C, its undesired orientation and high defect density have limited its power conversion efficiency. Fine control of the deposition temperature and rate is crucial to improving thin-film quality. This work aims to investigate the thin film crystal orientation and defect density at unconventional preparation temperature. Experimental Fig. 2. shows the schematic of MABI production by CVD. HI gas was supplied to the reactor tube (SUS316), diluted with helium gas through inlet 1, and reacted with bismuth oxide to generate BiI3 as equation (1) expressed.The remaining HI gas and BiI3 vapor were diluted again with helium gas, added up from inlet 2. Following this, it reacted with helium-diluted methylamine (MA) from inlet 3 at the junction to form methylammonium iodide (MAI) and flowed downstream to the deposition section. The reaction at the mixing junction was expected to be expressed by equations (2) and (3).TiO2 coated FTO substrates (6 mm × 20 mm × 1.1 mm, Asteratec) were placed in the deposition section and deposited at 1.33×103 Pa. MABI was confirmed by the X-ray diffraction (XRD) patterns (Rigaku, UltimaIV). Results and Discussion The XRD patterns of the resulting thin films were compared with theoretical patterns to verify the product. SEM images obtained at 160 °C, 180 °C, and 200 °C are presented in Fig. 3. As the deposition temperature increased, the crystal grain size grew, and higher temperatures promoted the grain boundary merging, forming a more compact thin film.We examined the grain orientations and the crystallite sizes for planes (100), (101), (103), and (006). As shown in Fig. 4, at 200 °C the deposition rate had little effect on the orientation to selected planes, although the texture coefficients (TCs) of the (100) and (101) planes increased slightly, suggesting that most crystal planes were favored at this temperature. Consequently, no single orientation dominated the growth competition, resulting in weakened TCs. In contrast, the (100) plane showed an elevated TC at 160 °C with a low deposition rate (Fig. 4a). The (101) plane, considered as the most compact plane in MABI with low surface energy, exhibited low TCs that decreased further as the deposition rate increased at 160 °C and 180 °C (Fig. 4b). Additionally, increasing the deposition rate favored growth of the (103) plane at 160 °C and 180 °C (Fig. 4c), suggesting that its high reactivity makes this facet in deposition rate limited. In Fig. 4d, the (006) plane displayed dominant TC values as the preferred growth direction for hexagonal crystals, although its dependency on precursor flux remains unclear.The grain sub-crystallite sizes (or crystallite sizes) were determined from the full width at half maximum (FWHM) of the XRD peaks using the Scherrer equation. Table 1 shows that increasing the temperature effectively enlarges the crystallite size and reduces defects within the grains. Higher temperatures facilitate faster precursor migration and promote crystal reconstruction to heal defects. The (101) plane was relatively insensitive to the deposition rate, while the (103) and (006) planes exhibited a slight increase in crystallite size with higher deposition rates, suggesting that unwanted species may form defects and compete with crystal growth. Conclusions Within the studied range, increasing the processing temperature is more effective in enlarging crystallite size than adjusting the deposition rate. However, the texture coefficients were weaken at 200 °C. The growth of the (100) plane was favored at 160 °C with low deposition rate, but it remained less competitive compared to other planes. While the texture coefficient of the (103) plane increased with deposition rate at 180 °C, which may serve as a compromise for depositing thin films that are not predominantly (006)-oriented. Acknowledgment This work was supported by JST SPRING, Grant Number JPMJSP2110. Reference [1] M. Wang, W. Wang, B. Ma et al., Nano-Micro Lett. 13, 62 (2021).[2] Z. Yang, K. Togami, M. Tanabe, S. Kimura and M. Kawase. “Reaction Rate Analysis of Chemical Vapor Deposited Bi-based Perovskite Thin Film”, presented at ISCRE 28, F54, Turku Finland, Jun. 17 – 19, 2024. Figure 1

BACKGROUND: oneof the maincomponents of a photodetectorcryomoduleis a microcryogenicsystemforcryostating a matrix of photosensitiveelements.Theproposedarticlediscusses a passivecryostatingsystem for laboratoryphotodetectorsforconductingresearch in order to expand the capabilities of cooledinfraredsystems. The passivemicrocryogenicsystemisa high-vacuumnitrogencryostat, the mostcommonproblem of which is the loss of thermal insulationpropertiesdue to atmosphericairleakage. AIMS: the purpose of the studyis to minimize the ingress of atmosphericairinto the pumpedvolume of the laboratorycryostat,thusprolonging the service life of the device. MATERIALS AND METHODS: the research method is a correlation–experimental one basedonmonitoringthecryostatresource,identifying a waytoincrease it by reducing the amount of leakageandsubsequentleakcontrol. The object of researchis a high-vacuumcryostatbased on a Dewarvessel of solderedconstruction. The studies were carried out fortwoweeks.. The solderingtechnology was selected,anexperiment was conducted withsubsequentflowcontrolandevaluationofthecryostat's service life. RESULTS: the research was carried out by three highly qualifiedspecialists,twoofwhomarein the field of cryogenictechnology,aswell as a specialistin the field of physicalchemistry.The research results visualizephotographstakenforvarioussolderingtechnologies. The seamobtained with solder of the ПСр8КЦНbrandhasnoerosion of the basemetal,with a minimumcontent of a chemicalcompoundlayer,withnocracks. CONCLUSION: the amount of leakage into the vacuum cavity of a laboratory cryostat for gaseous helium of the brand was 3.2∙10-13 Pa∙m3/s,whichcorresponds to the time of continuousoperation of the product for at least5yearsunderlaboratoryoperatingconditions.

We report atomic mass measurements of the unstable nuclides 73−75 Ni, 73−78 Cu, and 74−78 Zn, which have been accomplished using multi-reflection time-of-flight mass spectrometry combined with new technical developments to resolve challenges for exotic-isotope identification and selection. The isotopes were produced in-flight at the RIKEN’s Radioactive Ion Beam Facility and delivered to the combined gas cell and multi-reflection system installed downstream of the ZeroDegree spectrometer. The incoming high-energy beam was energy-degraded and subsequently stopped in a helium gas cell. The energy degrader thickness was optimized using a new method that employs signals from plastic scintillators located upstream and downstream of the helium-filled gas cell. Extracted isotopes of interest were mass-selected by the in-MRTOF deflector method, for which we discuss simultaneous selection of multiple isobar chains. The ions of interest were identified unambiguously using β-decay-correlated mass measurements for the first time, which is demonstrated for 78 Zn. The new mass values are compared with literature values and recent measurements performed at JYFLTRAP and ISOLTRAP, where a generally good agreement is observed.

To achieve stimulation effects in deep brain regions, this study proposes a simplified model of Hesed coil (H-coil) based on the design concept of helmet-style stimulation coils. It presents the distribution of the induced electric field within the intracranial space. This study provides a detailed analysis of how structural parameters, including wire angle, loop height, and wire spacing, affect stimulation depth. Additionally, it addresses coil heating caused by high-frequency pulses. A deep internal-cooling TMS coil is designed, utilizing cold helium gas as the cooling medium to achieve continuous coil cooling. It is verified that a reasonable hollow pipe size does not affect the stimulation effect. Changes in outlet temperature, coil temperature rise, inlet-outlet pressure difference, and coil temperature distribution are analyzed under different helium gas flows. Simulation results indicate that the optimal coil structure, under the combined effect of each segment angle, achieves a stimulation depth of 49% and a maximum induced electric field of 26.6 V/m at 20 mm intracranially. Simultaneously, the loop height is minimized to facilitate stimulation of deep intracranial brain regions. Furthermore, by combining with the internal cooling method and specific cooling parameters, coil temperature rise can be effectively controlled within safe threshold limits.