Gas Mixture Research Articles

Study on Characterization of SrO Aerosols Generated by Optimized Thermal Plasma Torch Aerosol Generator

AbstractPlasma Torch Aerosol Generation System (PTAGS) has been employed to generate nano aerosols with desirable characteristics. The operational parameters of PTAGS installed in the aerosol test facility have been optimized, and aerosols are generated using non-radioactive SrO2 powder. The current-voltage characteristics, electro-thermal efficiency and torch power are studied as a function of the flow rate of the plasma-generating gas (mixture of argon and nitrogen) and the arc current of the plasma torch. The relation of arc characteristics is determined using the Nottingham formulation. Based on this, torch parameters evolved and optimized as 20 kW power, 70% electro-thermal efficiency, 25 L min− 1 flow rate of plasma forming gas, 5 mg min− 1 powder feed rate and for 4–5 min torch operation towards the generation of SrO nano aerosols to achieve 1012 m− 3 and ~ 25 mg m− 3 for the count and mass concentration of aerosol respectively. The initial size distribution of the aerosols is in the few tens of nanometre range (10–40 nm) with a mean diameter of 26 nm (σg = 1.45). Scanning Electron Microscope and Energy dispersive X-ray analysis revealed that the morphology of nano aerosols was nearly spherical and the formation of SrO nanoparticles. A set of PTAGS operational parameters has been standardized to perform further experiments related to reactor safety analysis. PTAGS shall be tuned for aerosol generation in a large facility to achieve the characteristics equivalent to reactor accidental conditions.

Empirical Modal Decomposition Combined with Deep Learning for Photoacoustic Spectroscopy Detection of Mixture Gas Concentrations.

In photoacoustic spectroscopy based multicomponent gas analysis, the overlap of the absorption spectra among different gases can affect the measurement accuracy of gas concentrations. We report a multicomponent gas analysis method based on empirical modal decomposition (EMD), convolutional neural networks (CNN), and long short-term memory (LSTM) networks that can extract the exact concentrations of mixed gases from the overlapping wavelength-modulated spectroscopy with second harmonic (WMS-2f) detection. The WMS-2f signals of 25 different concentration combinations of acetylene-ammonia mixtures are detected using a single distributed feedback laser (DFB) at 1531.5 nm. The acetylene concentrations range from 2.5 to 7.5 ppm and the ammonia concentrations from 12.5 to 37.5 ppm. The data set is enhanced by cyclic shifting and adding Gaussian noise. The classification accuracy of the test set reaches 99.89% after tuning. The mean absolute errors of the five additional sets of data measured under different conditions are 0.092 ppm for acetylene and 1.902 ppm for ammonia, within the above concentration ranges.

Adsorption-absorption technique for effective CO2 capture

ABSTRACT This paper presents a study on the removal of CO2 gas from gas mixture (CO2/N2) of 14% CO2 using adsorption onto zeolite 13X in a fluidized bed at 298 K and 1 atm pressure. The effects of static bed height (5–25 cm) and rate of flow of the gas mixture (6–14 L/min) on the breakthrough time were studied. The desorption of CO2 was performed by absorbing the adsorbed CO2 molecules using NaOH solution (0.1 M). The absorption process which was accompanied with chemical reaction achieved two objectives. The first was converting CO2 gas into a valuable substance (Na2CO3) which could be used in many industries. The second was the storage of CO2 gas in what was called a chemical carrier which could emit the gas when it was needed. The effect of static bed height (5–25 cm) on the absorption process in the fluidized bed was also studied. For the adsorption process, the results showed that the breakthrough time increased with decreasing the flow rate but with increasing the static bed height. In the desorption process, the total amount of absorbed CO2 molecules was 396 mg, achieving a recovery of 90.8% at 5 cm static bed height.

Quantum mixtures of ultracold gases of neutral atoms

Quantum mixtures of ultracold gases of neutral atoms

Oxygen‐Stable Electrochemical CO2 Capture using Redox‐Active Heterocyclic Benzodithiophene Quinone

AbstractElectrochemical carbon capture offers a promising alternative to thermal amine technology, which serves as the traditional benchmark method for CO2 capture. Despite its technological maturity, the widespread deployment of thermal amine technologies is hindered by high energy consumption and sorbent degradation. In contrast, electrochemical methods, with their inherently isothermal operation, address these challenges, offering enhanced energy efficiency and robustness. Among emerging strategies, electrochemical carbon capture systems using redox‐active materials such as quinones stand out for their potential to capture CO2. However, their practical application is currently limited by their low stability in the presence of oxygen. We demonstrate that benzodithiophene quinone (BDT‐Q), a heterocyclic quinone, exhibits high stability in electrochemical carbon capture processes with oxygen‐containing feed gas. Conducted in a cyclic flow system with a simulated flue gas mixture containing 13 % CO2 and 3.5 % O2 for over 100 hours, the process demonstrates high oxygen stability with an electron utilization of 0.83 without significant degradation, indicating a promising approach for real world applications. Our study explores the potential of new heterocyclic quinone compounds in the context of carbon capture technologies.

Oxygen-Stable Electrochemical CO2 Capture using Redox-Active Heterocyclic Benzodithiophene Quinone.

Electrochemical carbon capture offers a promising alternative to thermal amine technology, which serves as the traditional benchmark method for CO2 capture. Despite its technological maturity, the widespread deployment of thermal amine technologies is hindered by high energy consumption and sorbent degradation. In contrast, electrochemical methods, with their inherently isothermal operation, address these challenges, offering enhanced energy efficiency and robustness. Among emerging strategies, electrochemical carbon capture systems using redox-active materials such as quinones stand out for their potential to capture CO2. However, their practical application is currently limited by their low stability in the presence of oxygen. We demonstrate that benzodithiophene quinone (BDT-Q), a heterocyclic quinone, exhibits high stability in electrochemical carbon capture processes with oxygen-containing feed gas. Conducted in a cyclic flow system with a simulated flue gas mixture containing 13 % CO2 and 3.5 % O2 for over 100 hours, the process demonstrates high oxygen stability with an electron utilization of 0.83 without significant degradation, indicating a promising approach for real world applications. Our study explores the potential of new heterocyclic quinone compounds in the context of carbon capture technologies.

Investigation of carbon-black emissions of a tractor biofuel diesel

BACKGROUND: On the one hand, a petroleum-based liquid fuel diesel engine is a reliable basis for tractors and self-propelled agricultural machines, and on the other hand, the current trends make us to think about the environmental component of these diesel engines and besides to remember about reasonable use of non-renewable petroleum motor fuel. In order to reduce the anthropogenic impact on natural ecosystems and to assess the smokiness of exhaust gases from a tractor diesel running on ethanol and rapeseed oil, the paper considers the relevant model of the carbon-black formation inside it. AIM: Development of the relevant model of carbon-black emission in a tractor diesel running on ethanol and rapeseed oil to assess the smokiness of exhaust gases and to reduce anthropogenic impact on natural ecosystems. METHODS: To simulate the processes of formation and burnout of carbon-black particles in a tractor diesel engine, the volume of the combustion chamber was conditionally divided into several areas (soot content indicators in different areas were added up), and the cycle of calculating the exhaust gas smokiness level included several stages (determination of pressure, integral and differential characteristics of heat dissipation, average temperature of the working fluid, fuel supply indicators and fuel evaporation rate, local coefficients of excess air, composition of gases, concentration of decomposition and oxidation products of rapeseed oil and ethanol, the number of carbon-black particles, the mass of dispersed carbon, the rate of transition of particles to the burnout zone). RESULTS: The developed mathematical model is capable of calculating the carbon-black concentration and the main components of the gas mixture in the reaction zone of the combustion chamber, the content of carbon-black in the exhaust gases at various speed and load modes of operation of a tractor diesel engine. It is capable of obtaining valuable information about the dynamics of the main stages of carbon-black formation and burnout in the cylinder of a tractor diesel engine running on ethanol and rapeseed oil. The results of numerical simulation of carbon-black formation and burnout in a tractor diesel cylinder when running on diesel fuel, ethanol and rapeseed oil are obtained and presented. CONCLUSION: Based on the developed relevant model of carbon-black emission in a tractor diesel engine running on ethanol and rapeseed oil, an assessment of its exhaust gas smokiness was carried out, clearly showing a decrease by 3.4–3.8 times in comparison with diesel fuel operation. The presented method for calculating the carbon-black emission of tractor diesel can be used in the multi-area modeling and researches of such in-cylinder processes as heat generation, heat transfer, etc. The accuracy of calculations based on the proposed model is characterized by the perfection of mathematical algorithms describing the rate of fuel evaporation, the development of a fuel flare, the determination of local temperatures, the rate of flame propagation, the local composition of gases in the cylinder, etc.

Genesis of an Inorganic CO2 Gas Reservoir in the Dehui–Wangfu Fault Depression, Songliao Basin, China

This study systematically examines the origins and formation mechanisms of inorganic CO2 gas reservoirs located within the Dehui–Wangfu Fault in the southeastern uplift region of the Songliao Basin. The research aims to clarify the primary sources of inorganic CO2, along with its migration and accumulation processes. The identification of the Wanjinta gas reservoir within the Dehui–Wangfu Fault Zone, abundant in inorganic CO2, has sparked significant interest in the pivotal roles of volcanism and tectonic activity in gas generation and concentration. To analyze the release characteristics of CO2, this study conducted degassing experiments on volcanic and volcaniclastic rock samples from various boreholes within the fault trap. It evaluated CO2 release behaviors and controlling factors across varying temperatures (150 °C to 600 °C) and particle sizes (20, 40, and 100 µm). The findings indicated a negative correlation between CO2 release and particle size, with a notable transition at 300 °C—marking this temperature as critical for the release of adsorbed and lattice gases. Moreover, volcaniclastic rocks exhibited higher CO2 release compared to volcanic rocks, attributable to their larger specific surface area and higher porosity. At 600 °C, the decomposition of the rock crystal structure results in substantial gas escape. These observations suggest that the inorganic CO2 in this area derives not only from mantle sources but is also influenced by crustal components. Elevated temperatures prompted by tectonic activity and magmatic intrusion facilitated the degassing of the surrounding rocks, allowing released CO2 to migrate upwards through the fracture system and accumulate in the shallow crust, ultimately forming a gas reservoir. This study enhances the understanding of volcanic rock’s roles in inorganic CO2 gas generation and migration, highlighting the fracture system’s critical controlling influence on gas transport and aggregation. The findings indicate that inorganic CO2 gas reservoirs in the Dehui–Wangfu Fault Zone primarily originate from mantle sources with a mixture of crustal gases. This discovery offers new theoretical insights and practical guidance for the exploration and development of gas reservoirs in the Songliao Basin and similar regions.

Influence of Detonation Spraying Parameters on the Microstructure and Mechanical Properties of Hydroxyapatite Coatings

The process of osteointegration depends significantly on the surface roughness, structure, chemical composition, and mechanical characteristics of the coating. In this regard, an important direction in the development of medical materials is the development of new techniques of surface modification and the creation of bioactive ceramic coatings. Calcium-phosphate materials based on hydroxyapatite have been proposed as bioactive ceramic coatings on titanium implants for the effective acceleration of bone tissue healing. To obtain bioactive ceramic coatings, pulse power sources are best suited, namely detonation spraying, in which the energy of the explosion of gas mixtures is used as a source of pulse action. The pulse mode of operation in the detonation spraying method is preferable for the formation of bioactive ceramic coatings. It provides a high velocity of hydroxyapatite particles, which promotes their effective fixation on the titanium substrate, while minimizing the heating of the material. This approach preserves the substrate structure and improves the coating adhesion. Four different types of coatings with varying O2/C2H2 molar ratios, ranging from 2.6 to 3.7, were obtained using detonation spraying. Powders and obtained coatings of hydroxyapatite were studied by Raman spectroscopy and XRD structural analysis. The results of XRD phase analysis showed the partial conversion of the hydroxyapatite phase to the α-tricalcium phosphate (α-TCP) phase during the detonation spraying process. The results obtained by Raman spectroscopy indicate that hydroxyapatite is the main phase in coatings. All hydroxyapatite-based coatings exhibited hydrophobic properties, which was confirmed by contact-angle values above 90° in wettability tests, characteristic of hydrophobic surfaces. The adhesive strength of the coatings was measured by the scratch test method. Tribological tests were conducted using the ball-on-disk method under both dry conditions and in Ringer’s solution. This approach enabled the evaluation of wear resistance and friction coefficient of the coatings in different environments, simulating both lubrication-free conditions and those resembling physiological environments.

Semiconductor WO3 thin films deposited by pulsed reactive magnetron sputtering

A pulsed reactive magnetron sputtering system with a tungsten target and a gas mixture of argon and oxygen was investigated as a source for the deposition of semiconductor WO3 thin films on soda lime glass substrates and on the glass with transparent conductive SnO2:F (FTO) electrode. The reactive sputtering process was performed in HiPIMS mode with low pulse repetition frequency fp ≈ 50–100 Hz and short pulse duration in HiPIMS discharge Ton = 100 μs. The second mode investigated was the mid-frequency (MF) magnetron discharge with pulse frequency fp = 40 kHz and pulse length Ton = 15 μs. The plasma parameters were investigated for both HiPIMS and MF modes using the planar RF probe operating at the frequency fprobe = 350 kHz and the grid QCM with biased collector electrode. Ion density ni and tail electron temperature (Te) were determined in both pulsed reactive magnetron sputtering discharge modes with time resolution. The maximum value ni ≈ 5 · 1017 m−3 was found in the reactive HiPIMS mode, and the maximum value ni ≈ 7 · 1016 m−3 was found in the reactive MF (40 kHz) mode. The degree of ionization of sputtered particles in reactive HiPIMS was determined for different values of (QO2) and was found to be in the range of ri ≈ 0.1–0.3. The deposition rate determined by QCM in reactive HiPIMS was practically independent on (QO2), but in the case of reactive MF, the measured deposition rate decreased significantly with increasing (QO2). The WO3 films deposited in both modes have a predominantly monoclinic crystal structure. The light and dark conductivity and the light/dark conductivity ratio (Ld) were measured under dark conditions and UV light illumination. At higher (QO2), the maximum value of Ld ≈ 300 was found for MF deposited WO3 and the maximum value of Ld ≈ 30 was found for HiPIMS deposited WO3. The photoelectrochemical measurement of WO3 deposited on FTO electrodes confirmed the n-type conductivity, and these films functioned as photoanodes in photoelectrochemical cells. MF deposited WO3 films systematically exhibited slightly higher photocurrents than HiPIMS deposited WO3. It was shown that these optimum photocurrents for HiPIMS and MF were found at QO2 ≈ 80 sccm and could not be improved by further increasing of (QO2).

Exploring the Efficiency of Caprylic Acid and Quaternary Ammonium Salt-Based Deep Eutectic Solvents for Separation of CO2 and H2S from Gas Mixtures Using Molecular Dynamics Simulations and COSMO-RS

In the present study, quaternary ammonium salts (QAS) and caprylic acid based deep eutectic solvents (DES) were employed for the separation of CO2 and H2S from natural gas (NG). To understand the extraction mechanisms of H2S from NG, we utilized MD simulations to understand intermolecular interactions between the gases and the eutectic solvents. Our detailed analysis for better understanding of QAS absorption capability in H2S extractions included combined distribution functions (CDFs), which encompass radial distribution functions (RDFs), angular distribution functions (ADFs), hydrogen-bonding networks, density profiles, spatial distribution functions (SDFs), and the non-bond energies between H2S and the DES components, all measured at 310 K. Additionally, we calculated the solubility of H2S and CO2 gases as well as the solubility selectivity and diffusivity selectivity parameters to evaluate the performance of the QAS-based DES in sweetening processes of NG. The results represent that eutectic solvents based on quaternary ammonium chloride are effective for H2S adsorption and show selectivity for H2S in gas mixtures. Furthermore, the COSMO-RS model was used to predict the solubility of various gases (H2S/CO2) in the QAS-based DES, providing further insights into their effectiveness.

Process swing adsorption with selective purge gas recirculation (PSA-SPUR): Adsorption process technology optimised for separation of the heavy component from a gas mixture and its design for CO2 capture through Equilibrium Theory analysis

PSA-SPUR (Pressure Swing Adsorption – Selective Purge Gas Recirculation) has been developed aimed at separating the most strongly adsorbing component from a gas mixture at high product purity and recovery. The innovative strategy for designing a Pressure Swing Adsorption system features recycling its purge gas stream exiting the column and mixing it back into the feed. This operation enriches the mixed feed with an elevated fraction of the heavy component during the adsorption step, thus enhancing the PSA’s performance greatly. Reusing the purge gas helps significantly increase the product recovery compared to conventional methods where purge gas is simply discarded. For theoretical analysis of a PSA-SPUR system, a bespoke Equilibrium Theory model was developed and solved successfully, providing valuable insights into the performance of the PSA-SPUR system designed for capturing CO2 from a flue gas. The study revealed that there exists an optimum extent of purging that maximises the heavy component mole fraction in the mixed feed, leading to the best possible feed throughput of the adsorption system. Furthermore, the effects of the desorption pressure and feed composition on the PSA-SPUR system’s performance were investigated. The results indicate that the CO2 capture PSA-SPUR system using commercial zeolite 13X has excellent potential to achieve very high product purity and recovery, being allowed to operate at moderate vacuum pressures without having to compress the flue gas feed, even when the gas feed contains less than 10 mol% CO2.

Silica conversion of polysilazanes by low-temperature plasma jet generated from Ar and water-vapor mixed gas

Perhydropolysilazane (PHPS), which contains no organic catalyst, chemically reacts with H2O in the atmosphere by heating it at 450 °C for more than 1 h to turn it into a SiO2 film. If silica conversion can be achieved at temperatures below 100 °C, which plastics can withstand, it may be applicable to a wide range of applications, such as flexible electronics. Here, we report a technique for forming SiO2 films with leakage current characteristics very close to those of thermally oxidized (THOX) films that works at a very low temperature of 52 °C with high speed. Using a 9-kV, 30-kHz power supply, a low-temperature plasma jet containing a gas mixture of Ar and water vapor irradiated an 8 nm thick PHPS thin film, inducing silica conversion at a maximum substrate temperature of 52 °C. The current density-electric field strength (J-E) characteristics of metal oxide semiconductor capacitors fabricated with this SiO2 film showed characteristics very close to those of THOX films. In addition, the mechanism of silica conversion of PHPS through low-temperature plasma jet irradiation using this gas mixture was clarified in real-time FT-IR measurements.

Identification of incipient cavitation in control valve

Control valves as important elements in hydraulic systems are used to transport liquid and gaseous media, for example, water, water vapor, and hydrogen. They are mainly used in the power engineering, chemical industry, and so forth. Due to their large dimensions, the verification of hydraulic parameters is problematic. In the case of liquid flow, cavitation can occur, which is mainly characterized by noise, vibrations, or changes of hydraulic parameters. During the incipient cavitation in the valve, there are no noticeable changes in the hydraulic characteristics. The article, therefore, deals with the methodology of determining the cavitation by measuring and evaluating the characteristics of the valve, spectral analysis of noise, and vibrations during water flow. Mathematical modeling is also a suitable tool for determining the extent of cavitation in valve design. Newly created modified cavitation model, where the flowing medium is defined as a mixture of incompressible water and compressible gases (vapor and air), better corresponds to physical principles than the two-phase approach (water and vapor) with experimentally modified density and viscosity. Measured noise and vibration frequency characteristics and mathematically modeled pressure frequency characteristics identify cavitation in the (1 to 10) kHz range. The article proves that when identifying cavitation, the method of measuring hydraulic characteristics fails, but the method of measuring noise and vibrations is suitable in practice, i.e., in real industrial equipment, and the modified cavitation model is suitable for identifying cavitation regions in structural designs of the hydraulic elements.

Intensifying the CO2/N2 separation performance of PVAm membrane by amine-functionalized porous montmorillonite

Multilayered montmorillonite (MMT) exhibits the building block stacking in polymer matrix, which has tortuous transport passageways and a few CO2 affinity sites, thus mixed matrix membranes incorporated with MMT have low molecular recognition ability for CO2. Herein, the porous MMT (p-MMT) was initially prepared through the solid-phase desilication reaction, and then amine-functionalized p-MMT (P3.2@p-MMT) was synthesized by the electrostatic interaction between positively charged polyethyleneimine (PEI) and negatively charged p-MMT, in which PEI was confined within the pore. Subsequently, mixed matrix composite membranes (MMCMs) were developed by the dispersion of polyvinylamine (PVAm) and P3.2@p-MMT, as well as hydrophilic-modified polysulfone as a support. It was observed that P3.2@p-MMT was uniformly dispersed in polymer matrix, and two phases had good interfacial compatibility due to hydrogen bonding. As a result, the gas separation performance of as-prepared MMCMs achieved a CO2 permeance of 217 GPU with a CO2/N2 selectivity of 112.3, which were 2.97 and 2.45 times that of the pristine PVAm membrane, and 1.57 and 2.49 times that of MMCMs incorporated with p-MMT respectively. The excellent gas separation performance is attributed to the relatively straight transport passageways, which originates from P3.2@p-MMT. Moreover, the amine groups within the pore of P3.2@p-MMT facilitate CO2 transport in the MMCMs. In addition, as-prepared MMCMs had high stability during over 360 h-testing, which displayed an average CO2 permeance of 238 GPU with the CO2/N2 selectivity of 124.1 utilized a gas mixture as the feed gas.

Mathematical Modeling of the Transport of H2O–CH4 Steam–Gas Mixtures in Hydrodynamic Devices: The Role of Helical Screws

Mathematical Modeling of the Transport of H2O–CH4 Steam–Gas Mixtures in Hydrodynamic Devices: The Role of Helical Screws

Synthesizing gas-filled anti-resonant hollow-core fiber Raman lines enables access to the molecular fingerprint region

The synthesis of multiple narrow optical spectral lines, precisely and independently tuned across the near- to mid-infrared region, is a pivotal research area that enables selective and real-time detection of trace gas species within complex gas mixtures. However, existing methods for developing such light sources suffer from limited flexibility and very low pulse energy, particularly in the mid-infrared domain. Here, we introduce a concept that is based on the combination of an appropriate design of near-infrared fiber laser pump and cascaded configuration of gas-filled anti-resonant hollow-core fiber technology. This concept enables the synthesis of multiple independently tunable spectral lines, with >1 μJ high pulse energies and a few nanoseconds pulse width in the near- and mid-infrared regions. The number and wavelengths of the generated spectral lines can be dynamically reconfigured. A proof-of-concept laser beam synthesized of two narrow spectral lines at 3.99 µm and 4.25 µm wavelengths is demonstrated and combined with photoacoustic modality for real-time SO2 and CO2 detection. The proposed concept also constitutes a promising way for infrared multispectral microscopic imaging.

Measurements of line parameters for 12C16O2 near λ = 1.05 μm by cavity ring-down spectrometer

The absorption spectra of 12C16O2 within the wavenumber range of 9358–9648 cm−1 have been precisely measured using a continuous-wave cavity ring-down spectrometer at room temperature. Employing synthetic gas mixtures comprising carbon dioxide, nitrogen, and argon, the line parameters, including line intensities and self-, N2- and Ar- broadening coefficients have been retrieved in the 2003r-00001 (r = 1,2,3) bands. This retrieval process was facilitated by a multi-spectral fitting program that utilizes Voigt line profiles. A comparative analysis of our measured line intensities and self-broadening coefficients with those present in established databases, such as HITRAN2020, CDSD296, AMES-2021, and HITEMP2010, has been conducted. The line intensities and self-broadening coefficients for 12C16O2 deviate by an average of less than 1 % from the values reported in the HITRAN2020 database. The J-dependence of N2- and Ar- broadening coefficients has been investigated by comparing this work with experimental results and theoretical predictions from other vibrational bands. This research offers important experimental references for the improvement of computational models and the exploration of Venus and Mars.

Assessing the potential accuracy of a small-sized goniometer with extended dynamic range based on nuclear magnetic resonance

This paper evaluates potential accuracy characteristics of a small-sized goniometer based on nuclear magnetic resonance with an extended dynamic range. This required constructing a model of goniometer errors, estimating its accuracy based on this model, and formulating practical recommendations for the design of such a device based on the accuracy assessment. To evaluate the accuracy of a nuclear goniometer, a theoretical model was built that makes it possible to determine the optimal operating parameters of the cell gas mixture, the ranges of their permissible changes, the sensitivity of the goniometer, and the dependence of its characteristics on external and internal factors. In particular, the dependence of output signal of the device on the parameters of gas mixture and optical pumping has been determined. For a goniometer with a cell volume of 8 cm3, the optimum temperature is 130 °C, and the optimum intensity of the pumping radiation is 5 mW. The dependence of output signal on the measured angle of rotation was also established, as well as the noise and error dependence of the device on the permissible values of its parameters. Based on the model built, parameters of a goniometer with a cell volume of 8 cm3 were determined; the maximum angular sensitivity of such a goniometer with complete suppression of technical noise is δφsen=1.0 arcsec. The greatest contribution to the angle measurement error is from the instability of pumping power Ip (ΔIp/Ip=0.05) – 85 %, magnetic field B0 (ΔB0/B0=10-8) – 13 %, temperature T (ΔT/T=0,1) – 2 %. The goniometer under consideration corresponds to the medium accuracy class, δφtot≥10 arcsec. It could be used in optical manufacturing for operational control, calibration, and certification of optical products. To improve the angular accuracy of the goniometer, it is necessary to increase the stability of the laser pumping intensity

Superselective Hydrogen Separation through a Mixed Conducting Graphene Oxide Membrane.

A cost-effective H2 separation method is required for the purification of gaseous mixtures containing H2. Thus, in this study, we investigate the H2 separation properties of Ce ion-doped partially reduced graphene oxide (prGO) membranes. Pt/C-catalyst-coated, dense, micrometer-thick membranes are fabricated by stacking Ce-prGO nanosheets, followed by thermal annealing. They are permeable to only H2 at room temperature. H2 permeation occurs based on mixed conduction; the H2 initially dissociates into protons and electrons at the feed side. Thereafter, they diffuse into the membrane and recombine to produce H2 at the permeate side. However, the diffusion of other molecules, such as He and CO2, is inhibited, resulting in superselective separation. The developed carbon-based mixed proton/electron conduction (MPEC) membrane can be employed for H2 capture, deuterium gas production from D2O, and organic molecule deuteration.