Gas Components Research Articles

Resolving the mass transfer in the symbiotic recurrent nova T Coronæ Borealis

T Coronæ Borealis (T CrB) is a symbiotic recurrent nova with an 80-year recurrence interval whose next eruption is imminent. We aim to resolve the accretion mechanism of the binary system governing the mass transfer during its super-active phase. Using phase-resolved high-resolution spectroscopy, we analyzed the zoo of spectral-line profiles arising from the symbiotic activity. We performed Doppler tomography of selected emission lines to resolve the system's gaseous components and their different velocity regimes. We find evidence of enhanced accretion through Roche lobe overflow during the super-active phase, as traced by the oxygen, helium, and hydrogen lines. The accretion disk is found to be fully viscously evolved and extends up to its maximal radius. By mapping the kinematics of lines probing different excitation energies, we can identify distinct interaction sites. These include the bright spot at the stream impact on the accretion disk outer radius, the irradiation at the red-giant facing side, the stream-disk overflow, the accretion disk wind, and an expanding nebula. The nebula emerged at the rise of the super-active phase and underwent an acceleration phase of about five years. The temporal evolution of the lines supports the scenario where the departure from quiescence started in the disk, likely triggered by a disk instability similar to what occurs in dwarf novae outburst, leading to an increased mass accretion and causing important irradiation of the giant that has further enhanced the mass-transfer rate during the super-active phase. Symbiotic recurrent nova, such as T CrB, are governed by similar mass-transfer mechanisms as found in cataclysmic variables despite their different orbital properties (longer orbital periods imposing larger accretion disks) and evolutionary pathways.

Enhanced Prediction of CO2-Brine Interfacial Tension at Varying Temperature Using a Multibranch-Structure-Based Neural Network Approach.

Interfacial tension (IFTC-B) between CO2 and brine depends on chemical components in multiphase systems, intricately evolving with a change in temperature. In this study, we developed a convolutional neural network with a multibranch structure (MBCNN), which, in combination with a compiled data set containing measurement data of 1716 samples from 13 available literature sources at wide temperature and pressure ranges (273.15-473.15 K and 0-70 MPa), was used to quantitatively explore the correlation of various chemical components with IFTC-B at varying temperature, aiming to achieve accurate predictions of IFTC-B under complex conditions. Our multibranch neural network analysis yielded some important insights: (1) Leveraging the convolutional and multibranch structure, MBCNN effectively mitigates the adverse effects of sparse matrices resulting from the absence of certain basic components, exhibiting higher prediction accuracy particularly for low IFTC-B scenarios (MAE = 0.47, and R2 = 0.9921) than other AI models. (2) The multibranch structure allows MBCNN to additionally capture the interattribute relationship between temperature and each chemical component. Such interattribute relationships are quantitatively correlated with IFTC-B, demonstrating that varying temperature significantly influences the dependence of IFTC-B on chemical components in gas and brine by causing the variation in their solubility. Specifically, the ratio of IFTC-B to the molality of monovalent cations (Na+ and K+) and bivalent cations (Ca2+ and Mg2+) in brine, as well as to the mole fraction of non-CO2 components (CH4 and N2) in the gas phase, varies with increasing temperature, approximately following a quadratic function. (3) By formulating the effect of each attribute on IFTC-B and quantifying their respective weight, we derived a new piecewise function for predicting IFTC-B at three temperature intervals (T ≤ 293.15 K, 293.15 K < T ≤ 324.4 K, and T > 324.4 K), with high prediction performance (MAE = 2.3672, R2 = 0.9263) across a wide temperature range in saline aquifers.

Synthesis of ethane from CO2 by a methyl transferase–inspired molecular catalyst

Molecular catalysts with a single metal center are reported to reduce CO2 to a wide range of valuable single-carbon products like CO, HCOOH, CH3OH, etc. However, these catalysts cannot reduce CO2 to two carbon products like ethane or ethylene and the ability to form C-C from CO2 remains mostly limited to heterogeneous material-based catalysts. We report a set of simple iron porphyrins with pendant thiol group can catalyze the reduction of CO2 to ethane (C2H6) with H2O as the proton source with a Faradaic yield >40% the rest being CO. The mechanism involves a CO2-derived methyl group transfer to the pendant thiol akin to the proposal forwarded for methyl transferases and a follow-up C-C bond formation of the thioether thus formed and a Fe(II)-CH3 species generated by the reduction of a second molecule of CO2. The availability of a "parking space" in the molecular framework for the first reduced C1 product from CO2 reduction allows C-C bond formation resulting in a unique case where a component of natural gas can be generated from direct electrochemical reduction of CO2.

Storage Stability of pre-lithiation agent Li6CoO4: Exposed to components of dry air and moist gases

Pre-lithiation is a critical technology in the field of lithium-ion batteries (LIBs). The unfavorable storage conditions of the pre-lithiation agent Li6CoO4 (LCO) lead to harmful surface reactions, resulting in poor electrochemical performance and limiting its practical application. In this work, we have synthesized LCO with high initial charge capacity (826.5 mAh g-1) and low coulombic efficiency (6.5%). Ex-situ XRD reveals the structural evolution of the LCO material during the first charge and the O2 evolution was measured by differential electrochemical mass spectrometry (DEMS), and the de-lithiation mechanism of LCO was proposed. On the other hand, the formation of non-active LiOH and Li2CO3 impurities on the surface of the material under different storage conditions was revealed by Raman spectroscopy. According to the results of LCO materials stored in different air components, it can be found that moisture and CO2 are the key factors causing the degradation of LCO materials, and LCO materials in dry environment or protective atmosphere have good storage stability.

Synergistic removal of Hg0, HCl, and SO2 from flue gas in municipal solid waste incineration by mechanically modified fly ash.

The emissions of flue gas components (such as Hg0, SO2, HCl) and the generation of hazardous waste fly ash from municipal waste incineration pose a significant threat to environmental integrity. In this study, a mechanochemical method combined with a modifier is innovatively proposed for the modification of fly ash to remove Hg0. In the fixed bed adsorption experiment, the removal efficiency of up to 60 percent can be achieved by ball milling (700rap,30min) alone. The modification of fly ash by mechanical force coupling with pyrite can achieve Hg0 removal efficiency is increased to more than 90 percent. By taking advantage of the excellent adsorption capacity of modified fly ash for acidic gases, the enhancement of S and Cl∗ active sites on the surface of modified fly ash strengthened the removal efficiency of modified fly ash for Hg0. DFT simulations evidenced that the defective S sites caused by the ball milling process could enhance the adsorption capacity of pyrite for Hg0. The fly ash was modified with mechanically coupled pyrite and alkalis and was able to have good adsorption capacity for acidic gases, the highest removal effect reached 93.1% and 96.7% for SO2 and HCl, respectively. The adsorbed acid gases increased the S and Cl∗ active sites, which led to the removal of Hg0 from the modified fly ash to more than 94.4%, achieving the synergistic removal of acid gases and Hg0. This method can realize the integrated technical route of "Fly ash collection - Online modification - Timely injection". A novel investigation was conducted on the elimination of flue gas contaminants and the reutilization of perilous fly ash.

Modified Biochar Adsorption Combined with Alkaline Solution Absorption for Sulfur-Containing Odor Gases Removal from Domestic Waste Transfer Stations

Odor emission has become a major issue in waste transfer stations. Hydrogen sulfide, methyl mercaptan (MM), and dimethyl disulfide (DMDS) are the main odorous gases. They have a low odor threshold and are difficult to remove. In this study, pine bark biochar was produced and modified with metal ions, including Ni2+, Ti2+, Mn2+, Zn2+, Mg2+, and Cu2+. It was then used for the removal of hydrogen sulfide, methyl mercaptan, and dimethyl disulfide. Among all modifications, the Cu2+ modified biochar showed the best sorption capacity, and the maximum sorption amounts were 20.50 mg/g for H2S, 36.50 mg/g for MM, and 57.98 mg/g for DMDS. To understand the adsorption, BET, SEM, and XPS of the original and modified biochar were performed. This illustrated that modification with Cu2+ increased the surface area and porosity, thus enhancing the adsorption capacity. In the alkaline absorption study, it was found that the removal of the three odor gases increased with the pH increase. Based on the results, a combined process called absorption–adsorption was established to treat the odor gas generated in a local waste transfer station. Thirty-one gas components were detected in the odor gas of the waste transfer station. The process proceeded for 30 days, and these gas components were not found in the effluent during treatment. Regarding H2S, MM, and DMDS, they were not detected even after 90 days. This indicates the high adsorption capacity of the modified biochar toward the three odor gases. In addition, the process is simple and easy to operate. This suggests that it is suitable for treating odor in places where there is no technician, and the odor needs efficient treatment. The study provides a feasible alternative for domestic waste transfer stations to control the odor problem.

Improved method for calculating fuel burnout in pulverized coal furnaces

An improved method of engineering calculation of the degree of burnout of pulverized solid organic fuel in the flare furnaces of steam boilers is proposed, taking into account the kinetics of the processes of moisture evaporation, the release of volatile substances with a separate assessment of individual gaseous components and tar release and their combustion, secondary cracking of tars, combustion and gasification of coke residue, conversion of mineral part of the fuel, which allows for assessment and control of the implementation of material balances of individual stages, stages and, in general, the entire gross process of coal combustion, and ultimately an adequate determination of the magnitude of heat losses with mechanical and chemical incompleteness of combustion. Methodological provisions have been developed to take into account the kinetic and diffusion processes of the thermochemical transformation of coal to establish a quantitative relationship between the temperature-time characteristics of the combustion of pulverized coal particles and the local parameters of the combustion process. The technique is implemented in the form of specialized algorithmic and software and makes it possible to assess the degree of fuel burnout, both for the active combustion zone and for zones located in the cooling chamber of the combustion space during design and operational adjustment work.

Powerful Outflows of Compact Radio Galaxies

Gigahertz peaked spectrum (GPS) and compact steep spectrum (CSS) sources are compact radio galaxies (RGs), with jets extending up to 20 kpc and ages <103 yr. They are considered to evolve to Fanaroff–Riley RGs, but the real scenario to explain the compact sources remains unsolved. The young compact jets make GPS/CSS ideal for studying feedback in the nuclear region of active galactic nuclei because the jets are just starting to leave this region. Numerical simulations and jet power estimates suggest that compact sources can drive outflows on scales several times larger than the radio source itself, but the lack of suitable data limits comparisons between theory and observation. We carried out an optical spectroscopic study of 82 CSS/GPS with Sloan Digital Sky Survey-DR12 data to investigate the influence of compact jets in the gas. We found outflowing gas components in the [O iii] λ5007 emission lines in half of our sample. The kinetic energy of the outflowing gas in compact sources is comparable to that observed in extended RGs, indicating that the compact jets can drive powerful outflows similar to those in FR RGs. The observed anticorrelation between the kinetic power of the outflow and the radio luminosity suggests an interaction between the young jet and the interstellar medium (ISM). This finding provides significant observational support for previous simulations of jet–ISM interactions and supports the evolutionary scenario for RGs. However, the lack of sources with high kinetic efficiency indicates that some compact galaxies may be frustrated sources.

Unravelling the Effect of Oxygen on the Sintering Mechanism of Pt/CeO2 in the CO Oxidation Reaction.

Sintering significantly contributes to the deactivation of supported metal catalysts under reaction conditions, influenced by various factors, including temperature, atmosphere, and metal-support interactions. The sintering mechanism under the reaction conditions remains complex and ambiguous. This study delves into the sintering behavior of platinum on CeO2 under CO oxidation conditions, mainly employing transmission electron microscopy to elucidate the effects of different gas components on the sintering mechanism at elevated temperatures. An atmosphere rich in oxygen promotes the sintering of Pt via the Ostwald ripening mechanism, characterized by the growth of larger nanoparticles at the expense of smaller ones. Conversely, sintering proceeds through particle migration and coalescence in the absence of oxygen, leading to the aggregation of nanoparticles. The obtained Pt/CeO2 catalysts exhibit enhanced catalytic performance after treatment with argon and stoichiometric reaction gases, contrasting with the deactivation observed under oxygen-rich conditions, which is attributed to varied Pt valence states. These findings provide insights into understanding the sintering mechanisms and inform the design of heterogeneous catalysts.

The ALMA-CRISTAL Survey. Spatial extent of [CII] line emission in star-forming galaxies at z=4-6

We investigate the spatial extent and structure of the line emission in a sample of 34 galaxies at $z=4-6$ from the Resolved ISM in STar-forming galaxies with ALMA (CRISTAL) Survey. By modeling the distribution of the line emission in the interferometric visibility data directly, we derive the effective radius of line emission assuming an exponential profile. These measurements comprise not only isolated galaxies but also interacting systems that were identified thanks to the high spatial resolution of the data. The line radius ranges from 0.5 to 3.5 kpc with an average value of $ e CII kpc. We compare the sizes with the sizes of rest-frame ultraviolet (UV) and far-infrared (FIR) continua, which were measured from the HST F160W images and ALMA Band-7 continuum images, respectively. We confirm that the line emission is more spatially extended than the continuum emission, with average size ratios of $ e CII /R_ e UV and $ e CII /R_ e FIR although about half of the FIR-detected sample shows a comparable spatial extent between the line and the FIR continuum emission e CII e FIR $). The residual visibility data of the best-fit model do not show statistical evidence of flux excess, indicating that the line emission in star-forming galaxies can be characterized by an extended exponential disk profile. Overall, our results suggest that the spatial extent of line emission can primarily be explained by photodissociation regions associated with star formation activity, while the contribution from diffuse neutral medium (atomic gas) and the effects of past merger events may further expand the line distributions, causing their variations among our sample. Finally, we report the negative correlation between the surface density ($ CII $) and the Lyalpha equivalent width (EW$_ Ly alpha $), and a possible negative correlation between $R_ e CII /R_ e UV $ and $ EW Ly alpha $, which may be in line with the scenario that atomic gas component largely contributes to the extended line emission. Future three-dimensional analysis of Lyalpha and Halpha lines will shed light on the association of the extended line emission with atomic gas and outflows.

Metabolomic markers of electrolytes, gases and internal environment of the content of chronic subdural hematomas.

Chronic subdural hematoma is one of the most common diseases in neurosurgical practice. The content of electrolytes and gases in the collection could participate in the growth and expansion mechanism, however, there is no evidence that they have been studied before. The objective has been to identify electrolyte, gas and internal metabolomic markers of the content of chronic subdural hematomas, with the possibility of participating in their growth and expansion and to substantiate a pathophysiological hypothesis that interacts with existing ones. A descriptive study was carried out with 53 patients operated on for chronic subdural hematoma, at the "Roberto Rodríguez Fernández" General Teaching Hospital of Morón in Ciego de Ávila, Cuba, in the period between January 2019 and December 2023. The diagnoses were obtained with computed axial tomography. The electrolyte and blood gas components of hematomas are correlated with clinical and neuroimaging variables. Patients over 70 years of age predominated, 37 (69.81%) and males 38 (71.70%). The Markwalder scale upon admission showed a predominance of Grade III in 24 cases (45.28%). The Glasgow outcome scale showed a predominance of Grade V, 31 (58.49%). Electrolyte and gasometric metabolomic markers of subdural blood can promote the phenomenon of progressive growth and expansion and have a synergistic effect with the rest of the pathophysiological mechanisms.

The Khangalas orogenic Au deposit, Yana-Kolyma metallogenic belt (Northeast Russia): structure, ore mineral and isotopic (O, S, Re, Os, Pb, Ar, He) composition, fluid regime and formation conditions

The Khangalas orogenic gold deposit is located in the central part of the Yana-Kolyma metallogenic belt. The structure of the deposit is determined by several mineralized crush zones with a thickness of up to 70 m and a length of up to 1400 m in the arch and on the southwest wing of the anticline of the northwest strike. Host rocks – Upper Permian terrigenous deposits. Ore bodies are characterized by massive, banded, veined, disseminated and breccia structures. The main vein minerals are quartz, carbonates, sericite is less common. The main ore minerals are pyrite, arsenopyrite; minor – galena, sphalerite, chalcopyrite, native Au; rare – Fe-gersdorffite, tetrahedrite, argentotennantite. Hypergenic minerals – sulfates, phosphates, arsenates and hydroxides – are widely manifested in the linear oxidation zone. Mineral formation occurred in two stages – gold-sulfide-quartz and silver-quartz ones. Quartz veins with visible Au were formed with the involvement of low-concentrated (about 5.0 wt.% eq. NaCl) of hydrocarbonate hydrotherms with CO2 in the gas component, at a temperature of 330–280 °C and a pressure of about 0.8 kbar. Disseminated gold-bearing pyrite-3 (up to 39.3 g/t Au) and arsenopyrite-1 (up to 23.8 g/t Au) from sericite-carbonate-quartz metasomatites have a non-stoichiometric composition, Fe excess and S lack (and As in Ару), Fe/(S+As)=0.47–0.52 (Py3) and 0.47–0.50 (Ару1). The predominant form of “invisible” gold in Py3 and Apy1 is structurally related Au+. Isotopic composition of oxygen δ18O quartz (from +15.2 to +16.1‰), oxygen in the fluid δ18OH2O (from +8.4 tо +9.2‰)‰), sulfur δ34S in sulfides (from –2.1 to –0.6‰); isotopic ratio 187Os/188Os (from 0.2212 to 0.2338) in native gold and Pb in galena (206Pb/204Pb=18.0214, 207Pb/204Pb=15.5356, 208Pb/204Pb=38.2216), as well as the geochemical features of Py3 and Apy1 suggest the participation in ore formation mainly of sources from the subcontinental lithospheric mantle and, to a lesser extent, crustal reservoirs. The formation of the gold ore bodies of the deposit is related to the completion of reverse and thrust fault progressive deformation of the stage D1, which occurred in the Valanginian of the Early Cretaceous (about 137 million years ago) during late-orogenic processes in the Yana-Kolyma belt with regional south-western transport of rocks. The results obtained are important for predictive metallogenic and prospecting work aimed at identifying large-volume gold mineralization of orogenic belts.

Effect of Acids on Biomass Growth and Development of Chlorella vulgaris Culture

Background. Influence of dissolved nitrogen and sulfur oxides, as components of flue gases, on the cultivation of microalgae Chlorella vulgaris. Objective. To study biomass production and changes in cells of the microalgae Chlorella vulgaris with the introduction of nitrogen and sulfate acids tor simulate the effects of dissolved nitrogen and sulfur oxides, aiming to develop biotechnology for the utilization of gas emissions by microalgae. Methods. The effect of the constant introduction of small concentrations of nitrogen (up to 0.47%) and sulfate (up to 1.5%) acids on the development of Chlorella vulgaris cultures, pH changes in the cultural envi­ronment, and biomass growth were studied. Results. The utilization of gaseous emissions by Chlorella vulgaris depends on the content of nitrogen and sulfur oxides that are constantly supplied to the cultivation medium, the initial biomass concentration, and pH. It was determined that for an initial cells concentration of (85 ± 5)×104 cells/ml in the culture medium, the threshold values of acids that do not cause significant changes in the cultivation process are 0.1% H₂SO₄ and 0.19% HNO₃. At a sulfuric acid concentration of 0.2%, the culture cells become discolored. Conclusions. It is shown that with a constant supply of sulfuric or nitric acids above the threshold values of 0.1% H2SO4 and 0.19% HNO3, the pH of the culture medium decreases, leading to the suspension of deve­lopment and the death of the Chlorella vulgaris culture. Therefore, controling these parameters will improve the ecological state of the environment and form the basis for developing biotechnology for the utilization of gas emissions by microalgae.

Spatially coherent 3D distributions of HI and CO in the Milky Way

The spatial distribution of the gaseous components of the Milky Way is of great importance for a number of different fields, for example, Galactic structure, star formation, and cosmic rays. However, obtaining distance information to gaseous clouds in the interstellar medium from Doppler-shifted line emission is notoriously difficult given our vantage point in the Galaxy. It requires spatial knowledge of gas velocities and generally suffers from distance ambiguities. Previous works often assumed the optically thin limit (no absorption), had a fixed velocity field, and lacked resolution overall. We aim to overcome these issues and improve previous reconstructions of the gaseous constituents of the interstellar medium of the Galaxy. We used three-dimensional (3D) Gaussian processes to model correlations in the interstellar medium, including correlations between different lines of sight, and enforce a spatially coherent structure in the prior. For modelling the transport of radiation from the emitting gas to us as observers, we took absorption effects into account. A special numerical grid ensures that there is high resolution nearby. We inferred the spatial distributions of atomic hydrogen (HI ), carbon monoxide (CO ), their emission line widths, and the Galactic velocity field in a joint Bayesian inference. We further constrained these fields with complementary data from Galactic masers and young stellar object clusters. Our main result consists of a set of samples that implicitly contain statistical uncertainties. The resulting maps are spatially coherent and reproduce the data with high fidelity. We confirm previous findings regarding the warping and flaring of the Galactic disc. A comparison with 3D dust maps reveals a good agreement on scales larger than approximately $ pc $. While our results are not free of artefacts, they present a big step forward in obtaining high-quality 3D maps of the interstellar medium.

Application of Isotope Geochemistry in Determining the Extraction Ratio of Target CBM from Multi-Seams

In most coal mines in China, the target coalbed methane (CBM) and its adjacent CBM generally require joint extraction before the target coalbed can be mined. But only the mixed CBM from multi-seams can be measured at the mouth of boreholes, and it is not possible to individually measure the CBM from a target coalbed. In view of this issue, the application of isotope geochemistry is proposed for the first time in the industry. Based on the law of mass conservation for the chemical composition of mixed CBM, according to the gas components and isotope difference characteristics of each coalbed in multi-seams, a calculation model for the extraction ratio from a target coalbed is established. Field experiments were selected in the Xiaotun Mine in Guizhou Province. The extraction ratio of the target coalbed 6m determined by isotope geochemistry ranged from 57.81% to 69.58%, and the deviation from the extraction ratio determined by the measured flow method was less than 7%. The residual gas content of the No. 14 mining face was calculated by combining the results of the above two methods, and the deviation from the measured residual gas content was less than 6%, indicating that the results obtained scientifically by isotope geochemistry were reliable. The results of the study can provide a new research tool for the judgment of target CBM extraction standards and, ultimately, ensure the safety of coal mine operation.

Theoretical Study on the Spectroscopic Properties and Line Intensities of the O2+ Cation.

O2+ cation, as one of the major gas components in the near space environment, has attracted significant attention due to its spectroscopic properties. In this study, we systematically investigate the spectroscopic properties of the O2+ cation using ab initio methods. The potential energy curves and transition dipole moments of O2+ were obtained using the icMRCI + Q method combined with the ACV5Z-DK basis set. Subsequently, the vibrational and rotational energy levels, as well as the corresponding spectroscopic constants for both ground and excited states, were determined by solving the one-dimensional radial Schrödinger equation. Based on the vibrational and rotational energy levels of bound electronic states, the internal partition function of O2+ was computed over the temperature range of 100-10,000 K. Utilizing the precise potential energy functions, transition dipole moment functions, and internal partition functions, the line intensities for the First Negative Band System (a4Πu-b4Σg-) and the Second Negative Band System (X2Πg-A2Πu) were calculated. For the first negative band system, the spectral line intensity of Δν = 1 is maximized at temperatures ranging from 100 to 7000 K. In the case of the second negative band system, the strongest vibrational band shifts with increasing temperature. We also discuss the impact of temperature on spectral lines; at higher temperatures, a greater number of energy levels are populated, allowing for the observation of more spectral lines. These findings are significant for understanding the spectral behavior of high-temperature nonequilibrium plasmas and their role during spacecraft reentry, providing a theoretical basis for experimental research.

Study on Fire Characteristics of Flame-Retardant Polycarbonate Under Low Pressure

This work presents experimental and numerical research on the pyrolysis and combustion characteristics of flame-retardant polycarbonate under low ambient pressure. A novel experimental low-pressure combustion platform was constructed to determine the heat release rate, a key combustion parameter of polycarbonate. The ignition process of polycarbonate under external radiation was analyzed, and an ignition time prediction model was developed. In addition, theoretical calculations of the main gas components and concentrations during the pyrolysis stage of polycarbonate and estimations of the calorific values of the combustible gas components produced during pyrolysis were carried out, providing a new explanation for the phenomenon of advancing ignition time in low-pressure environments.

Torrefaction Temperature Effects on Grindability of Wheat Straw Using TG-FTIR Analysis

Abstract Torrefaction used for pretreatment of biomass can enhance grindability along with significant reduction of energy consumption required for pulverization to aid in large-scale utilization of biomass energy. In this study, torrefaction experiments of wheat straw were conducted at different temperatures using an experimental furnace facility. The influence of torrefaction temperature on the grindability of resulting wheat straw was explored using a Hardgrove grindability index tester and thermogravimetric-Fourier transform infrared spectroscopy (TG-FTIR). Increase in torrefaction temperature significantly enhanced the carbon content of wheat straw and decreased oxygen content to result in decreased O/C ratio from 0.66 to 0.39. The calorific value increased by 24% from 15.42 MJ/kg to 19.17 MJ/kg. Increase in torrefaction temperature from 220 °C to 269 °C increased the grindability index from 29 to 115. The grindability of wheat straw can be controlled to values similar to that of coal by tuning the torrefaction temperature. The main gas components released during torrefaction were H2O, CH4, CO2, and CO. Thermogravimetric data showed 29% solid residue from the raw wheat straw. Increase in torrefaction temperature increased the solid residue to 41%. Pyrolysis of wheat straw at different torrefaction temperatures can be grouped into three stages of dehydration, rapid pyrolysis, and carbonization. This study reveals effective large-scale utilization of torrefied wheat straw biomass having high heating value of the solid fuel after torrefaction pretreatment.

Analysing the Impact of Second Gas Component on Pulse Pirani Gauge

Abstract This numerical study investigates the influence of a second gas component concentration on Pirani gauge readings. The analysis aims to provide insights into how the presence of additional gas components affects the accuracy and reliability of Pirani gauge measurements. By simulating different gas mixtures and examining the resulting readings, this study sheds light on the complex interactions between gases in Pirani gauge applications.

Evaluation of rheological properties of guar gum-based fracturing fluids enhanced with hydroxyl group bearing thermodynamic hydrate inhibitors.

Naturally occurring gas clathrates are a significant methane resource-the primary component of natural gas, regarded as the cleanest hydrocarbon and a key feedstock for producing gray and blue hydrogen. Despite the global abundance of gas hydrate reserves, extraction via depressurization has yet to achieve commercially viable production rates. The primary limitation lies in the low permeability of hydrate-bearing sediments, where solid clathrates obstruct porous pathways, hindering dissociation and slowing gas recovery. Hydraulic fracturing has emerged as a promising technique to enhance conductivity, with initial studies indicating substantial increases in production rates when stimulation is applied. This study investigates the integration of thermodynamic hydrate inhibitors (THIs), such as methanol and polyethylene glycol 200 (PEG-200), into conventional polymer-based linear and crosslinked fracturing gels to improve performance. By targeting both rock and the embedded gas hydrates, these inhibitor integrated fracturing gels aim to facilitate faster fracture propagation and accelerate hydrate dissociation. The rheological performance of THI-integrated gels at varying concentrations is analysed, crucial for fracture formation, propagation, and proppant transport efficiency. Additionally, microscopic observations of additive interactions followed by fluid disintegration according to time are compared to evaluate residue formation and long-term integrity. Results indicate that methanol slightly increased the viscosity of linear gels at low concentrations and improved stability, reducing residue and slowing degradation, while higher concentrations required additional polymerizing agents to maintain performance. PEG-200 enhanced viscosity and stability in guar-based gels at low concentrations but caused shear-thinning at higher levels, limiting its suitability for high-viscosity operations. Crosslinked gels demonstrated superior proppant suspension and stability, generating less sediment-damaging residue compared to linear gels, with methanol further enhancing performance. Optimized integration of PEG-200 during borate crosslinking is critical, as higher concentrations risk premature gel degradation.