Gas Mixture Research Articles

Technologies for capturing and storing carbon dioxide during conversion, use of fuel and gaseous waste from energy production

Relevance. The continued dependence on the combustion of carbon-based fuels for energy and industry leads to the need to develop various categories of technologies to reduce carbon dioxide emissions. Aim. Development of carbon capture and storage technologies for all stages of fuel conversion and processing, ensuring a low-carbon cycle for the production of electrical and thermal energy, as well as industrial and social facilities. Methods. Chemical, physical adsorption and absorption. Results and conclusions. For large industrial and energy producers, for small energy consumers, it is necessary to be guided by the principles of environmental friendliness and efficiency when implementing the production process, and to increase the percentage of carbon dioxide removal, implement decarbonization technologies at all stages of producing electricity and thermal energy. For the category of CO2 removal at the stage of preliminary fuel conversion, adsorbent compositions using predominantly environmentally friendly and inexpensive natural materials based on bentonite have been developed and tested. The collection capacity of the developed adsorbents is 85–98%. For the category of CO2 removal at the stage of fuel use, a hybrid energy system is presented, including a microgas turbine with heat recovery, a high-temperature fuel cell and other devices and material flows connecting them. A pilot industrial prototype of a 30 kW hybrid energy system will produce heat, electricity, steam, and hot water. In this embodiment, the hybrid system can work as an autonomous energy source for small social and commercial facilities, representing a pilot stage of the engineering and design implementation of the results of an industrial-level hybrid system. For the category of carbon dioxide removal at the stage of CO2 separation from the flue gas mixture after fuel conversion, a block for removing CO2 from flue gases using the absorption method was proposed. Solutions of 15% monoethanolamine, 15% ammonia solution, and 6% sodium hydroxide solution showed the best absorption capacity. It is proposed to equip the hybrid energy system with a CO2 capture unit for complete decarbonization of gas emissions based on closed-cycle technology. The proposed technology for capturing and storing carbon dioxide at the post-fuel conversion stage is characterized by ease of implementation and economic accessibility.

Systemic Hypoxia and Interventions on Nitric Oxide Metabolism Affect Retinal Vasomotion in Healthy Subjects.

Previous in vitro studies on porcine retinal arterioles have shown that the frequency and amplitude of retinal vasomotion can be affected by hypoxia and nitric oxide (NO). However, it is unknown whether these effects can be reproduced in humans in vivo. Video recordings of retinal arterioles from 40 healthy subjects were studied before and during breathing of a hypoxic gas mixture consisting of 12.5% oxygen and 87.5% nitrogen. The experiments were repeated before and after the addition of either an NO donor or continuous infusion of an NO synthesis inhibitor. The harmonic content of spontaneous diameter changes in retinal arterioles was extracted by Fourier analysis, and the effects of the interventions were studied on the amplitudes of diameter oscillations in the frequency bands 1: 0.5/min-3.5/min, 2: 4/min-7.5/min, 3: 8/min-17.5/min, and 4: 18/min-30/min. Hypoxia significantly increased the amplitude of spontaneous diameter oscillations within the low (1) and high (3-4) frequency bands (P < 0.006 for all comparisons), and the effect in frequency band 1 was eliminated by the NO donor. In frequency band 2, hypoxia had no significant effect on the amplitude of diameter oscillations, but the amplitudes were significantly reduced by the NO donor (P < 0.01) and significantly increased by the NO synthesis inhibitor (P = 0.03). Hypoxia and interventions on NO metabolism can affect spontaneous diameter oscillations in retinal arterioles. Disturbances in vasomotion may play a role in hemodynamic changes in retinal diseases in which hypoxia and changes in NO metabolism are involved in the disease pathogenesis.

Silicon oxide etching mechanism by hydrogen fluoride and methanol vapor mixture

Abstract We investigate mechanisms of SiO2 etching involving HF and CH3OH vapor mixture, particularly, the contributions of H2O and CH3OH. H2O might come from the injected gases, chamber wall, and the SiO2 films, but the amount is very small. Instead, during the etching process, two molecules of H2O are generated, which might affect SiO2 etching. Considering no incubation time and stable etching rates by adding CH3OH, CH3OH could be a primary catalyst according to our investigations. Accordingly, we can suggest a SiO2 etching mechanism by HF and CH3OH. The mixture gases of HF and CH3OH are exposed to the SiO2 surface. When the HF and CH3OH pressures are enough high for condensation on the SiO2 surface, a thin condensed layer is generated. Hydrogen Fluoride can be easily soluble to the condensed layer, at which it is ionized causing the etching of SiO2.

Selection of the Process of Arc Welding of Sealing Surfaces of Power Valves with a Consumable Electrode in the Shielding Gas

Introduction. One of the main requirements to the methods of weld overlay of sealing surfaces of power valve trim parts is to obtain a high-quality wear-resistant pad with minimal penetration and optimal process performance. Currently, arc, electroslag, plasma, beam, induction and other surfacing techniques have been developed and introduced into production. However, the influence of various arc welding processes with a consumable electrode in shielding gas on the geometric parameters of weld beads and metal hardness of sealing surfaces is understudied. The presented research is intended to fill this gap. The objective of its authors is to select such a process of arc welding of beads on parts of the power valve trim with a consumable electrode in shielding gases, which would provide the best workability of the deposited metal.Materials and Methods. Arc surfacing with a consumable electrode in a mixture of gases was performed on steel plates. The welding torch was moved in a straight line, without transverse oscillations, using the FRC-9 mechanism (Fronius). A microprocessor-controlled inverter-type digital current source TransPulsSynergic 3200 CMT (Fronius) was used as the power supply. The following welding processes were analyzed: MIG/MAG process with self-regulation (Standard mode), synergic process of MIG/MAG method (Synergic mode), short arc process with mechanical separation of electrode metal droplets (CMT-ColdMetalTransfer), and synergic pulse-arc process (PulseSynergic). The short-cut process of bead surfacing was evaluated by the stability of the values of the energy parameters of the bead surfacing mode in time at the same electrode wire feed rates, which were recorded by oscilloscopes, as well as by comparing the geometric characteristics of the deposited beads and the hardness of the deposited metal.Results. The analysis of experimental data of the geometrics of the weld beads and their complex dimensional characteristics made it possible to establish that the welding engineering requirements for the welded beads are most fully met by long-arc surfacing by the PulseSynergic pulse-arc process.Discussion and Conclusion. The study and the resulting data make a certain contribution to solving the problem of the influence of arc welding processes on the parameters of weld beads and on the hardness of the metal of sealing surfaces. A detailed analysis of the modes of arc surfacing of beads with a consumable electrode in shielding gases on the trim parts of power valves can be used in further research on this topic. The conclusions of the authors will not only provide considerable theoretical assistance to scientists, but will also make adjustments to the activities of practitioners.

Multiwire Position-Sensitive Neutron Detector with Two Layers of Boron-10

Multiwire position-sensitive neutron detector with two layers of boron-10 was developed to detect both thermal and fast neutrons. Sensitive dimensions of two coordinate neutron detector are 50 × 50 mm. New detector characteristics are compared with ones of 100 × 100 mm detector built earlier which we used in neutron flux spatial distribution measurement. Plane-parallel design of new detector has symmetrical structure with respect to wire anode and also includes two intermediate grids and two cathodes made of parallel wires with 2 mm pitch and two silicon substrates coated boron-10 layers of 0.003 mm thickness. Detector geometry, working gas mixture and pressure are chosen so as to ensure full absorption of secondary alpha particle from reaction with thermal neutron within detector gas medium half thickness. Neutron coordinates are determined from measured ionization loss pulse heights produced by secondary nucleus. Detector expected efficiency to thermal neutrons is about 5%. The detector can be used in small-angle and diffraction scattering setups in condensed matter physics.

A Chemically Robust Microporous Zn-MOF for C2H2 Separation from CO2 and Industrially Relevant Four Component Gas Mixtures.

The separation and purification of acetylene from the light hydrocarbon gas mixtures is considered as one of the most industrially challenging task for the production of fine chemicals. Though metal-organic frameworks (MOFs) are promising candidates for such separation and offer a cost and energy-efficient pathway, achieving the trade-off between sorption capacity and separation selectivity along with framework robustness is a daunting task and demands effective design. Herein, a new 3D chemically stable MOF, IITKGP-24 (stable over a wide range of aqueous pH solution, pH = 2-12) is developed, displaying excellent separation selectivity of 13.9 for C2H2/CO2 (50:50) even at ambient conditions and maintained a trade-off between sorption capacity and separation selectivity. Most importantly, the breakthrough performance analysis under the industrially relevant gas mixture composition revealed that the developed framework possesses excellent separation of acetylene from not only C2H2/CO2 (50:50) gas mixtures but also from the quaternary C2H2/C2H4/C2H6/CO2 (25:25:25:25) feed gas streams. Separation of C2H2 from such a four component gas mixture by MOFs is unexplored. The exceptional framework robustness, high C2H2/CO2 uptake ratio, low heat of adsorption, and excellent recyclability with easy regenerability made the developed framework promising candidate toward this challenging separation.

Dry Etching Characteristics of InGaZnO Thin Films Under Inductively Coupled Plasma-Reactive-Ion Etching with Hydrochloride and Argon Gas Mixture.

Inductively coupled plasma-reactive etching (ICP-RIE) of InGaZnO (IGZO) thin films was studied with variations in gas mixtures of hydrochloride (HCl) and argon (Ar). The dry etching characteristics of the IGZO films were investigated according to radiofrequency bias power, gas mixing ratio, and chamber pressure. The IGZO film showed an excellent etch rate of 83.2 nm/min from an optimized etching condition such as a plasma power of 100 W, process pressure of 3 mTorr, and HCl ratio of 75% (HCl:Ar at 30 sccm:10 sccm). In addition, this ICP-RIE etching condition with a high HCl composition ratio at a moderate RIE power of 100 W showed a low etched pattern skew and low photoresist damage on the IGZO patterns. It also provided excellent surface morphology of the SiO2 film underneath after the entire dry etching of the IGZO layer. The IGZO thin film as an active layer was successfully patterned under the ICP-RIE dry etching under the HCl-Ar gas mixture, affording an excellent electrical characteristic in the resultant top-gate IGZO thin-film transistor.

ИССЛЕДОВАНИЕ СКОРОСТИ УДАЛЕНИЯ ПИРОГЕННОГО SiO2 МЕТОДОМ ПЛАЗМОХИМИЧЕСКОГО ТРАВЛЕНИЯ

The study is devoted to identifying factors affecting the removal rate (etching) of pyrogenic silicon oxide (SiO2) films. The authors select the main adjustable parameters of the reactive ion plasma-chemical etching setup as external factors affecting the removal rate of pyrogenic SiO2. During the study, the authors change etching time, power, chamber pressure, gas proportion in the gas mixture, gas flow while maintaining the pressure in the chamber, and the temperature of the intra-chamber table. The paper analyzes the results of each experiment, makes the necessary calculations, provides with the graphs that clearly explain the effect of a particular external factor or its change on the rate. An optimal set of parameters for reactive ion plasma etching of pyrogenic SiO2 films is determined empirically, which one can use in the process of reverse engineering of semiconductor device crystals and structures with such oxides. In this case, removing the pyrogenic oxide film does not affect the integrity of the studied semiconductor crystals or structures.

ENERGY-EFFICIENT HEATING SYSTEM OF TRANSITIONAL METALLURGICAL LADLES

In practice it was confirmed the effective use of the burner device of the diffusion method of natural gas burning in a high-speed direct-flow torch when heating the lining of transitional metallurgical ladles with the closed lid. Three designs of stabilizers for basal stabilization of the torch were developed and studied: 1) with stabilization flares formed when air flows onto 3 corner poorly streamlined stabilizers, in the shadow of which a part of the gas is supplied; 2) with a ring stabilization torch when burning a pre-mixed mixture of natural gas and air; 3) with a sudden expansion of the gas channel, in which a zone of intensive gas recirculation is formed. The GGPK-1.0 burner was developed for transitional ladles that operate within a wide range of changes in thermal power 1–5.29 and stabilizer with constant burning of the ignition ring, which contributes to the stability of combustion and allows the heating of ladles with tightly closed heat-saving lids. After the introduction of the developed burners at all stands for heating the ladles of the “Azovstal” metallurgical plant in 2019–2020 were obtained a significant improvement in the operation of the stands and a reduction in natural gas consumption. The fuel economy during heating the ladles is at least 20 %. The heating temperature of the inner surface of the lining of the transitional ladles is even over the entire surface. The temperature difference on the surface of the lining does not exceed 50 °C. Bibl. 16, Fig. 6.

Modeling of arcs with binary gas mixtures in a multi‐arc plasma generator

AbstractUsing plasma as an energy source in thermal spraying allows the processing of feedstock materials with high melting temperatures. In plasma spraying, hydrogen or nitrogen is commonly injected into the argon plasma, which increases the specific enthalpy and thermal conductivity. The objective of this study is to improve the understanding of this process through numerical simulation and to investigate the impact on the plasma properties. A comprehensive modelling approach for the electrodes in the three‐cathode plasma generator is built upon the previous work of the authors. The plasma is described as an electromagnetically reactive fluid in local thermodynamic equilibrium using temperature‐dependent thermodynamic and transport properties. The increase of flow temperature and velocity as well as the temperature distribution at the electrodes can be successfully simulated. The simulation model could accelerate parameter development for new coating systems in the future. This study completes the simulation model for multi‐arc plasma spraying using binary gas mixtures.

Innovative urea formation using microwave plasma-water interaction: a study on reactive species and plant growth

Abstract This study explores the production of urea using microwave (MW) plasma-water interaction with air, N₂, CO₂, and a N₂ + CO₂ gas mixture to generate plasma-activated water (PAW). After 180 seconds of plasma exposure, air plasma reduced the pH to 3.3 and increased the oxidizing potential by 127.1%, making the water acidic and oxidizing, while the N₂ + CO₂ plasma raised the pH to 10.1 and reduced the oxidizing potential by 33.8%, creating basic and reducing conditions. PAW from air plasma produced the highest NO₂⁻ (51 mg L⁻¹) and NO₃⁻ (295 mg L⁻¹) concentrations, while the N₂ + CO₂ mixture generated the most NH₄⁺ (2250 mg L⁻¹), and CO₂ plasma produced the most CO₃²⁻ ions. Notably, urea formation (plasma urea) was observed only with CO₂ and N₂ + CO₂ plasmas, attributed to the formation of stable compounds like NH₄⁺ and NH₂COO⁻. In this process, NH₄⁺ ions formed via the reaction between atomic nitrogen and water, and their subsequent reaction with NH₂COO⁻ ions in the aqueous phase led to urea synthesis. The N₂ + CO₂ plasma produced 2991% more urea than CO₂ plasma. Plasma urea enhanced seed germination and plant growth, increasing germination rates for carrots by 10.67% and coriander by 15.6%. Shoot lengths grew by 38.6% for carrots and 30.8% for coriander, while root lengths improved by 24.24% and 37.5%, respectively, compared to controls. This study highlights MW plasma-water interaction as a sustainable, energy-efficient alternative to conventional urea production, offering significant environmental benefits and improved agricultural performance.

Effect of Cold PlasmaTreatment on Physicochemical and Microbiological Properties of Clotted Cream

The aim of this study was to determine the effect of cold plasma treatment, which was applied by using two different gases (O2 and Ar) and their mixtures onto sample surfaces for different intervals, on the physicochemical and microbial parameters of clotted cream during storage for up to 10 days. Cold plasma treatment caused a decrease in pH, aw, L*, and b* values of clotted cream samples and an increase in their a* and TBA values. The pH values of samples ranged from 4.68 to 6.67, and the range for aw values was between 0.903 and 0.803. For TBA, the highest change was observed in the K2 sample with 0.479 mg malondialdehyde/kg. The color L* values of all samples were between 99.79 and 93.82, a* values between 1.82 and 1.22, and b* values between 6.22 and 4.74. Among the treatments, the treatment of O2-Ar gas mixture (50-50%) resulted in the highest decrease in the total counts of aerobic mesophilic bacteria (TMAB), total aerobic psychrophilic bacteria, proteolytic bacteria, yeast-molds, coliform group bacteria, and Staphylococcus aureus. Compared to the control sample, at the end of 10 days of storage, a decrease of 2.41 for TMAB, 3.64 for total yeast-mold, 4.23 for coliform group bacteria, and 4.72 log cfu/g for S. aureus was achieved. Results indicated that the cold plasma treatment did not cause significant changes in the physicochemical values of clotted cream samples but reduced their microbial load.

Cost-Effective, Hydrogen-Rich, and Ultramicroporous Metal-Organic Framework for Efficient Separation of SF6 from N2.

It is essential for the industry to create an adsorbent that combines a high capacity with selectivity to achieve the effective separation of SF6 from gas mixtures. In this study, we prepared a cost-effective nickel-based metal-organic framework (MOF), Ni(BTC)(BPY), which features hydrogen-rich ultramicroporous channels specifically designed for separating SF6/N2 gas mixtures. The findings from the adsorption experiments demonstrated that Ni(BTC)(BPY) achieved a remarkable SF6 adsorption capacity of 5.08 mmol g-1 and an ideal adsorbed solution theory SF6/N2 selectivity of 382. This effectively resolves the trade-off encountered in the development of adsorbents between capacity and selectivity. Theoretical calculations indicated the optimal adsorption sites for SF6 within the pore channels. The strong interactions between the F atoms in SF6 and the numerous H atoms in the channels account for the superior SF6 adsorption performance of this material. Breakthrough experiments provided additional evidence that the MOF can completely separate SF6/N2 mixtures, positioning it as an excellent candidate for recovering SF6 from these gas mixtures.

Possibilities of Improving the Emission Characteristics of Passenger Cars by Controlling the Concentration Levels of Combustion-Generated BTEX Components

Replacing the alkyl lead derivatives with aromatic hydrocarbons and additives in modern reformulated fuels to improve internal combustion engine performance, lower fuel consumption, increase power, and improve emission characteristics have resulted in the emission of large quantities of BTEX (benzene, toluene, ethylbenzene, and xylene) compounds into the atmospheric compartment. In this research, how the different working regimes of an experimental engine affect the BTEX compound concentration levels was observed to evaluate the quantities emitted during the movement of a passenger car in urban driving conditions. The target compounds were analyzed in exhaust gas samples using the Photovac Voyager-mobile GC (Waltham, MA, USA). This experimental research demonstrates that optimizing engine operational parameters significantly reduces the concentration levels of BTEX compounds in exhaust gas mixtures by adjusting specific working regimes, contributing to better emission characteristics and promoting sustainable transportation solutions. The most significant effect of the independent increase in air quantity in the feed mixture is realized through the decrease in concentration levels of toluene in the exhaust gas mixture of approximately 81%. A significant reduction in concentration levels is achieved with m,p-xylene (79%) and o-xylene (79%) as well, whilst the lowest effect has been noted with benzene (73%) and ethylbenzene (71%).

Predicting viscosities and thermal conductivities from dilute gas to dense liquid: Deriving fundamental transfer lengths for momentum and energy exchange in revised Enskog theory.

Chapman-Enskog theory has long provided an accurate description of the transport properties of dilute gas mixtures. At elevated densities, revised Enskog theory (RET) provides a framework for describing the departure of the transport properties from their dilute-gas values. Various methods of adapting RET for the description of real fluids have been proposed in the literature. The methods have in common that they incorporate one or more length scales to describe molecular interactions. With few exceptions, the required length scales have been estimated from experimental transport property data. In this work, we introduce two transfer lengths that describe the residual transport of momentum and energy. We derive a model called the exchange-weighted closest approach (EWCA), which links the transfer lengths to the intermolecular potential. Combining the EWCA model with Mie potentials fitted to experimental equilibrium properties yields accurate predictions for several real fluids, including a binary mixture. At higher temperatures, the theory is accurate at surprisingly high densities, even up to the liquid-solid transition of argon. We demonstrate how the transfer lengths can be computed from experimental data or correlations for the transport properties. The transfer lengths obtained in this manner are in good agreement with those obtained from the EWCA model paired with an accurate abinitio potential for argon. The results suggest that kinetic theory, after further developments, can become a predictive theory also for liquids.

Decoupling H2 and O2 Release in Particulate Photocatalytic Overall Water Splitting Using a Reversible O2 Binder.

H2 and O2evolutions occur simultaneously for conventional particulate photocatalytic overall water splitting (PPOWS), leading to a significant backward reaction and the formation of an explosive H2/O2 gas mixture. This is an issue that must be addressed prior to industrialization of PPOWS. Here, a convenient, cost-effective, and scalable concept is introduced to uncouple hydrogen and oxygen production for PPOWS. Based on this idea, a three-component photocatalyst, Co(5%)-HPCN/(rGO/Pt), is constructed, consisting of a photoresponsive chip (HPCN), a H2 evolution cocatalyst (rGO/Pt), and a cobalt complex capable of reversibly binding O2 (Co), to achieve the decouplingof PPOWS under alternating UV and visible light irradiations. The asynchronousO2 and H2 evolution strategy have considerable flexibility regarding the photocatalyst structure and light sources suitable for PPOWS.

­­­­­­Exploring surface diversification of polyvinyl alcohol/polyethylene glycol Composites by cold plasma: Ompact of Argon and oxygen plasmas on biomedical application

Tetraethyl orthosilicate was used as a crosslinker to create composites made of polyvinyl alcohol and polyethylene glycol (PVA/PEG (PP)). The composites were exposed to non-thermal plasma (NTP) treatment with an Argon and oxygen gas mixture. The NTP treatment resulted in an improvement in surface hydrophilicity. Physiographical investigations indicated surface nanotexturing, but bulk properties were unaffected. After twenty days of exposure to air, there was no detectable ageing effect, showing that the NTP-modified composites were extremely robust. The composites swelled more in intestinal pH than at gastric pH. The NTP-modified composites shown significant Biofilm eradication activity against E. coli. Plasma treated composites shown Greater antibacterial activity against E.coli and enterobacilous bacteria. Mechanical properties enhances with application of different carrier gases in the non-thermal plasma process. Release characteristics of the composites validated the controlled delivery of anticancer drug sulforaphane to the intestine. Biodegradability character increases for the plasma treated composites over the subsequent days. It was also discovered that the hydrogels were biodegradable. PVA/PEG composites treated with O and Ar plasma are therefore effective for a variety of biomedical applications.

Production of Novel Energy Gases in Bioprocesses Using Undefined Mixed Cultures.

Three phases of matter intermingle in various environments. The phenomena behind these fluctuations provide microbial cultures with beneficial interphase on the borderlines. Correspondingly, a bioreactor broth usually consists of a liquid phase but also contains solid particles, gas bubbles, technical surfaces, and other niches, both on a visible scale and microscopically. The diffusion limitation in the suspension is a remarkable hindrance to the reaction sequence during production. It must be overcome technically. Gas flow into the reactor could serve this purpose, and the outgoing stream or bubbling contains volatile products. The various mixing elements or gas flows should be moderated if shear forces disturb the cell growth, biochemical production, enzymatic activity, or any other crucial biological or physicochemical parameters. The focus is to optimize energy production in the form of liberated gases or their mixtures. Many combustible flows need to get purified, depending on their purpose, for example, for various engines. They provide novel sources for traffic in the air, streets, roads, and waterways, not forgetting space technology dimensions.On the other hand, industrial fuels are often used as mixtures of gases or gases with other substances. This approach may facilitate the utilization of side streams. Also, municipal energy needs can be fulfilled by microbial gases. Microbial mixed cultures could play an essential role in the big picture of sustainable industries,living and agriculture, exhibiting an excessive total effect on societies' multifactorial development. The gas phase is the key to realizing their potential.Gaseous emissions are inherent part of all forms of microbial metabolism, both aerobic and anoxic ones. Carbon dioxide is liberated both in respiration and fermentation, but the microbiota also binds volatile carbon compounds. CO2 is also a raw material for plant cultivation, e.g., in greenhouses or in algal pools which both represent the first steps of food chains. Additionally, they produce biomass to produce energy, biochemicals, nutrition, and soil improvement. Gaseous products of the mixed microbial cultures are valuable sources for energy production as purified gases (e.g., biomethane, biohydrogen) or as mixtures (e.g., bio-hythane, volatiles). These relatively simple molecules also serve as supplies for other hydrocarbons (e.g., methanol). Also, many microbial metabolites serve as fuel sources (e.g., bio-oil) and substrates for further biosynthesis. This versatility of potential technological options in energy making and for industrial processes could offer huge opportunities for green energies and sustainable industries, transportation, or municipalities. In the agriculture sector, the complete recycling also includes the consideration of gas phase. This aspect provides increasing sources for clean food production. Moreover, the chemoautotrophic bacteria, including the archaeal strains, could emanate novel streams of biobased products for human use.The bioprocess always consists of a biological component and a reactor or vessel solution, plus its control and adjustment means. Some project examples are taken up introducing the combinations of these two technological mainstreams, which should be in "symbiosis" for the best results. This novel approach could lead the human activities in industries, agriculture, and municipalities into "no waste" situations. At the same time, new global resources for economically feasible and sustainable raw material sources and processes thereof will emerge. In this novel technological ecosystem, connectivity to biosphere will return and remain our societies on healthy foundations, thanks to the microbes and their communities. This chapter introduces some of the potentials.

Gas-compensated thermal flow sensor using an integrated velocity-independent gas properties meter

Abstract A gas-compensated thermal flow sensor is presented that measures the flow rate in real-time, independent of the type of gas, by simultaneously measuring and compensating for the thermal conductivity and volumetric heat capacity of the gas. The thermal flow sensor consists of two free-hanging, heated wires, forming a calorimetric flow meter. The temperature difference between the two wires is a function of the flow rate and the fluid thermal properties. An additional heated wire is integrated on the same chip and used to measure the gas properties. This wire is suspended over a shallow V-groove cavity, and oriented perpendicular to the flow direction, so that it is only affected by the gas properties and not by the flow. DC excitation is used to measure the thermal conductivity, and AC excitation with the 3$\omega$ method is used to determine the volumetric heat capacity. The output of the thermal flow sensor is automatically corrected for the medium using these measured parameters. Measurements were performed with 11 different gases and gas mixtures, and in all cases the deviation between the applied flow rate and measured flow rate is less than 10\%.

Study on the Explosion Mechanism of Low-Concentration Gas and Coal Dust

In coal mines, the mixture of coal dust and gas is more ignitable than gas alone, posing a high explosion risk to workers. Using the explosion tube, this study examines the explosion propagation characteristics and flame temperature of low-concentration gas and coal dust mixtures with various particle sizes. The CPD model and Chemkin-Pro 19.2 simulate the reaction kinetics of these explosions. Findings show that when the gas concentration is below its explosive limit, coal dust addition lowers the gas’s explosive threshold, potentially causing an explosion. Coal particle size significantly affects explosion propagation dynamics, with smaller particles producing faster flame velocities and higher temperatures. Due to their larger surface area, smaller particles absorb heat faster and undergo thermal decomposition, releasing combustible gases that intensify the explosion flame. The predicted yield of light gases from both coal types exceeds 40 wt% daf, raising combustible gas concentrations in the system. When accumulated reaction heat elevates the gas concentration to its explosive limit, an explosion occurs. These results are crucial for preventing gas and coal dust explosion accidents in coal mines.