Gas Scavenging Research Articles

CT measurement of blood perfusion in hepatocellular carcinoma: from basic principle, measurement methods to clinical application

Hepatocellular carcinoma (HCC) is one of the common and fatal malignant tumors worldwide, and the burden of HCC is particularly severe in China. Physiologically, the blood supply to healthy liver is mainly from the portal vein, supplemented by the hepatic artery. While in the development of HCC, the main source of blood supply to HCC is changed from the portal vein to the hepatic artery. The characteristics of HCC vascularization are important for imaging, surgery, interventional therapy, targeted therapy, etc. Even in the future, with the development of radiation therapy technology, such as proton and heavy ion therapy and artificial intelligence technology, the dynamic changes in HCC blood perfusion can be used as a new biomarker of tumor activity to provide accurate information on the intensity modulation of radiotherapy, so that accurate measurements of HCC blood perfusion is of great significance in guiding the diagnosis and treatment of HCC. The technologies for measurement of HCC blood perfusion have developed from invasive techniques, such as inert gas scavenging, electromagnetic flowmeter, and radionuclide-labeled erythrocyte elution in the middle of the last century to the present non-invasive techniques of CT. With the development of CT imaging technology in the last 30 years, the CT-based imaging technology can assess the status of organ and tissue perfusion relatively easily and accurately. In this paper, the various CT measurement techniques of blood perfusion in HCC were categorized into three types: semi-quantitative technique, relative quantitative technique, and absolute quantitative technique. Their basic principle, scanning methods, and clinical applications were discussed to provide a reference for the diagnosis and treatment of HCC.

Anesthetic Gas Scavenging System for Gas Evacuation in the ICU.

Inhaled sedation is increasing in ICUs, with active carbon filters (ACFs) commonly used for evacuating halogenated gases. However, the potential benefits of a waste anesthetic gas system (WAGS) similar to the ones used in operating rooms should be explored. To limit the suction over the flow sensor where the WAGS is connected on ICU ventilators, an anesthetic gas receiving system (AGRS) is required, constituting with the WAGS an active gas receiving and scavenging system (AGRSS). Ensuring that this whole device does not compromise the flow sensor reliability is crucial. The aim of this study was to compare various gas evacuation devices and assess the reliability of AGRSS on ICU ventilators. In this experimental study, pressures and flows were recorded during the ventilation of a test lung using various ventilator settings and gas evacuation methods: no device (reference condition), ACF, the WAGS alone, AGRSS (WAGS and AGRS together), and the expiratory valve connected to the medical vacuum system with the AGRS in between. Visual comparisons of the pressure and flow curves followed by a statistical analysis comparing median pressures and flows of each device to the reference were performed. The test lung model demonstrated consistent comparability in pressures and flows among all devices, except for the WAGS alone, which exhibited discordance through significant overestimation or underestimation. These findings indicate that using a WAGS with the AGRS system appeared to be reliable for managing gas evacuation in ICUs without compromising pressure or flow delivery. The data from this experimental trial should be confirmed with clinical studies involving human subjects. Given the increasing use of inhaled sedation in ICUs, these results support the daily application of the WAGS with the AGRS for gas evacuation, similar to its established use in anesthesiology.

C-doped [formula omitted] monolayer as toxic gas scavenger or sensor based on first-principles study

The selective adsorption mechanism of C-CdS2 monolayer was revealed using density functional theory. The results show that C-CdS2 has good adsorption properties for SO2, NO, NH3, NO2 and Cl2, and all of them are chemisorbed. Under the adsorption of different gas molecules, the electronic structure of C-CdS2 changed to varying degrees, which provided a theoretical basis for the use of C-CdS2 as a gas sensor or scavenger for these gases.

Density function theory investigation of bimetallic phthalocyanine as a potential sensor and scavenger for nitrogen-containing toxic gases

Urbanization and industrialization processes inevitably release a large amount of nitrogen-containing toxic gases (NTGs) such as NO, NO2, NH3 and HCN, posing a serious threat to the ecological environment. Therefore, it is necessary to develop new gas sensors to promptly detect the emission and leakage of these toxic gases. Herein, four bimetallic phthalocyanines (BMPc = FePdPc, FePtPc, MnPdPc and MnPtPc) were designed by introducing pairs of precious metal (Pd/Pt) and inexpensive metal (Fe/Mn) atoms into the phthalocyanine (Pc) monolayer. Subsequently, the adsorption behavior and sensing properties of these BMPc towards NTGs were investigated using density functional theory (DFT) method. The studied results show that the four BMPc exhibit excellent stability and display chemical adsorption for these target gases due to the synergistic effect of bimetallic active centers, with adsorption energy greater than −0.70 eV. The adsorption strength follows the order NO > NO2 > NH3 > HCN, which is further confirmed by electronic properties such as charge density difference and density of states. Additionally, the analyses of work function, bandgap, and sensing response demonstrate the superior sensitivity of BMPc towards NO, NO2, NH3, and HCN. Meanwhile, the MnPtPc monolayer presents suitable adsorption strength for HCN at 298 K, resulting in a short recovery time of only 0.68 s. When the temperature is increased to 348 K, FePdPc and MnPdPc exhibit high reversibility for HCN, while MnPtPc displays favorable performance for NH3. Therefore, MnPtPc is identified as a recyclable HCN gas-sensing material at room temperature, while FePdPc, FePtPc, and MnPdPc are regarded as reusable gas-sensing materials for HCN at high temperature, with their sensing properties remaining unaffected in a humid environment. By contrast, the prolonged recovery times of NOx (x=1, 2) adsorption systems make these four BMPc more suitable as efficient scavengers for NOx. This study provides a new strategy for designing and developing phthalocyanine-based gas sensors and scavengers for the NTGs and other harmful substances.

Extrinsic Positive End-Expiratory Pressure due to Failure of the Positive-Pressure Relief Valve Within the Scavenging System: A Case Report.

The anesthesia gas scavenging system (AGSS) removes waste gases from the anesthesia machine. Within the AGSS, safety features prevent excessive pressures from affecting ventilation. Although the literature contains reports describing failures of the AGSS, we found no reports of positive-pressure relief valve (PPRV) malfunctions. We encountered 2 cases of extrinsic positive end-expiratory pressure (PEEP) resulting from a malfunctioning PPRV. Both cases suffered delayed identification intraoperatively but patients did not experience postoperative complications. These cases highlight the importance of daily scavenger system prechecks, the potential physiologic implications of AGSS malfunctions, and the importance of preplanned contingencies for machine failure.

Volatile gas scavenging in the paediatric intensive care unit: Occupational health and safety assessment.

The use of volatile anesthetic agents in the paediatric intensive care unit (PICU) is experiencing increased interest since the availability of the miniature vapourizing device. However, the effectiveness of scavenging systems in the presence of humidifiers in the ventilator circuit is unknown. We performed a bench study to evaluate the effectiveness of the Deltasorb® scavenging system in the presence of isoflurane and active humidity by simulating both infant and child ventilator test settings. A total of four ventilators were set to ventilate test lungs, all with active humidity and a Deltasorb scavenging canister collecting exhaled ventilation gas. Two ventilators also had isoflurane delivered using the Anesthesia Conserving Device- small (ACD®-S) on the inspiratory limb (also called alternative ventilator configuration). We performed instantaneous measurements of isoflurane and continuous sampling with passive badges to measure average environmental exposure over a test period of 6.5 hours. Scavenging canisters were returned to the company, where desorption analysis showed the volume of water and isoflurane captured in each canister. Both instantaneous point sampling and diffusive sampling results were below the occupational exposure limit confirming safety. The canisters collected both isoflurane and a portion of the water vapour delivered; the percentage of captured water and isoflurane collected in infants was higher than the child ventilator test settings. The tested scavenging configuration was effective in maintaining a safe working environment with active humidity and inspiratory limb (alternative) ventilator configuration of the the miniature vapourizing device.

Adsorption and sensing behavior of Cr-doped WS2 monolayer for hazardous gases in agricultural greenhouses: A DFT study

This study used Density functional theory (DFT) to analyze the adsorption behavior of the Cr-doped WS2 monolayer on five hazardous gases (NH3, SO2, NO, NO2, and CO) in agricultural greenhouses. The optimal stable doped site for the Cr atom was identified, and various adsorption parameters such as adsorption energy, adsorption distance, charge transfer and desorption time were calculated. Results indicated that intrinsic WS2 had limited adsorption capacity for five target gases. Moreover, Cr doped significantly enhanced WS2 monolayer conductivity, shifting NH3, SO2, NO and NO2 adsorption from physisorption to chemisorption with Eads <0.6 eV, while CO remained physisorbed. The conductivity of the five gases underwent significant changes after adsorption on Cr-WS2. Desorption times at four temperatures (298 K, 398 K, 498 K and 598 K) indicate that Cr-WS2 demonstrates ideal gas sensor behavior for NH3 gas. However, the physisorbed and short desorption at room temperature suggested unsuitability for CO detection in practical applications. Conversely, the extended desorption time at 598 K made Cr-WS2 more appropriate as a gas scavenger for SO2, NO and NO2 gases. These findings underscore the potential of Cr-WS2 monolayers as novel gas warning or adsorbent materials, offering crucial applications in detecting and removing hazardous gases in agricultural greenhouses.

The design of CN/C3N2 heterostructures and the potential as gas sensor and scavenger for SF6 decomposed gases

The design, electronic and gas-sensing properties of the CN/C3N2 heterostructures with and without the adsorption of H2S, SO2, HF, SOF2, and SO2F2 were systematically investigated by using DFT calculations. All SF6 decomposition gases can physically adsorb on both sides of the CN/C3N2 heterostructure with significant adsorption strength and charge transfer. Although the adsorption of these gases, in general, hardly affects the electronic properties, but can remarkably tune the work function (Φ) of the heterostructure. The CN/C3N2 heterostructure as Φ-type gas sensors has an ultra-high sensitivity for SF6 decomposed gases (at least over 71.2 %), especially for the C3N2 side (at least over 568.7 %), and has relatively low recovery times for HF, H2S, SOF2, and SO2F2 gases at 300 K, indicating the reusability of the heterostructure at room temperature, but much more favorable at 350∼400 K for SO2 gas. Further, the heterostructure as adsorbents for the capture and scavenging of SF6 decomposition gases has high adsorption capacity and strength. Therefore, our findings reveal that the CN/C3N2 heterostructure is a promising candidate as Φ-type gas sensors with high sensitivity and reusability for the detection of SF6 decomposition gases, while as an optimal scavenger for removing these toxic gases.

Research on intelligent sensor for industrial hazardous gases monitoring based on Tc doped C3N using density functional theory

With the ongoing global industrialization, a considerable amount of hazardous gases is emitted into the atmospheric environment. Achieving intelligent monitoring of industrial hazardous gases is a crucial pathway toward realizing the modernization of electronic information. In this study, the use of Tc doped C3N nanosheet for the intelligent online monitoring of industrial hazardous gases (CO, NO2, O3) is firstly proposed. The doping and modification mechanism of Tc nanoparticle on the C3N surface are revealed. Simultaneously, the adsorption and sensing mechanisms of the three target gases on the surface of pure C3N and Tc doped C3N nanosheet is deeply elucidated through density of states, band structure, and differential charge density analysis. The results indicate that Tc particle can stably bind to the C3N surface, providing numerous active sites for the adsorption of target gases, enabling selective capture and scavenging of hazardous gases. Furthermore, the adsorption type for all three gases shifts from physical adsorption to physicochemical adsorption, with significant changes in the electronic signals during surface reactions, manifested by drastic alterations in the band structure and enhanced electron mobility. The adsorption capacity order for the three gases is O3 > NO2 > CO. The achievements of this work not only provide a theoretical foundation for the design and preparation of Tc doped C3N nanosensors, but also offer a new direction for environmental protection and intelligent detection in industrial applications.

Carbon-based materials impregnated with silver nanoparticle synthesized by gamma irradiation for ethylene gas scavenger application

This study explores the potential of carbon-based materials impregnated with silver nanoparticles, synthesized via gamma irradiation, as ethylene scavengers to address the challenges in post-harvest management of climacteric fruits. Ethylene, an essential plant hormone, significantly impacts fruit ripening and shelf life, necessitating effective management strategies. The research focuses on synthesizing silver nanoparticles at various concentrations (0, 4, 8, and 12 %) and their impregnation onto activated carbon (AC), designated as AC0AG, AC4AG, AC8AG, and AC12AG. These materials underwent comprehensive characterization through scanning electron microscopy (SEM) coupled with energy-dispersive X-ray Spectrometry (EDS) and transmission electron microscopy (TEM). In addition, silver nanoparticles at various concentrations (0, 4, 8, and 12%) in colloidal form designated as 0AG, 4AG, 8AG, and 12AG were characterized through UV-VIS spectroscopy and dynamic light scattering (DLS). The study's findings reveal that AC12AG (AC powder form) demonstrates the most effective ethylene scavenging capability, with a clear inverse correlation between the efficacy and the concentration of AgNO3. Further, the application of these materials in delaying the ripening process and reducing the incidence of pathogens and fungi in tomatoes was evaluated, showing significant efficacy. This research not only elucidates the critical role of silver nanoparticles in enhancing the ethylene scavenging capacity of carbon-based materials but also offers a scientifically grounded approach for improving the shelf life and quality of climacteric fruits, thus contributing a valuable solution to the post-harvest management of agricultural produce.

Report of the 2022 Perfusion Perspectives of Waste Anesthetic Gas Exposure Survey

To describe perfusionist perspectives regarding waste anesthetic gas (WAG) management during cardiopulmonary bypass (CPB) and compare results to existing American Society of Extracorporeal Technology (AmSECT) guidelines and the 2016 National Institute of Occupational Safety and Health Survey of healthcare workers and anesthesia care providers. We developed a questionnaire with 26 questions covering institutional demographics, use of anesthetic gases, scavenging systems, and air monitoring practices. Web-based survey. Self-identified board-eligible perfusionist members of AmSECT, the American Academy of Cardiovascular Perfusion, and the Maryland and Wisconsin State Perfusion Societies in 2022. None. Of the 4,303 providers sent the survey, 365 (8.5%) participated. Although 92% of the respondents (335/364) routinely administered inhaled anesthetics via the oxygenator, only 73.2% (259/354) routinely scavenged WAG during CPB cases. Only 6.6% of the respondents (22/336) conducted environmental monitoring for WAG levels. Cited reasons for not scavenging waste gases included a lack of applicable protocols and waste gas scavenging systems, excessive cost, and no need for scavenging. Our findings identify a gap between AmSECT guidelines and current perfusionist behavior and suggest potential strategies for reducing WAG leakage during CPB. Effective management should incorporate hazard awareness training, availability of standard procedures to minimize exposure, scavenging systems, regular equipment inspection, and prompt attention to spills and leaks. In high-risk environments, environmental surveillance for waste gas levels would also contribute to waste gas safety. A comprehensive approach to managing waste anesthetic gases will reduce WAG leakage, help improve health care worker safety, and prevent potential adverse effects of exposure.

Pd-Adsorbed SiN3 Monolayer as a Promising Gas Scavenger for SF6 Partial Discharge Decomposition Components: Insights from the First-Principles Study.

Gas-insulated switchgear (GIS) equipment must be protected by detecting and eliminating the toxic SF6 partial discharge decomposition components. This study employs first-principles calculations to thoroughly investigate the interaction between a Pd-adsorbed SiN3 monolayer (Pd-SiN3) and four typical SF6 decomposition gases (H2S, SO2, SOF2, and SO2F2). The study also investigates the associated geometric, electrical, and optical characteristics along with the sensing sensitivity and desorption efficiency. The ab initio molecular dynamics (AIMD) simulations demonstrated the favorable stability of the Pd-SiN3 monolayer. Furthermore, the Pd-SiN3 monolayer exhibited strong chemisorption behavior toward H2S, SO2, SOF2, and SO2F2 gases because of the higher adsorption energies of -2.717, -2.917, -2.457, and -2.025 eV, respectively. Furthermore, significant changes occur in the electronic and optical characteristics of the Pd-SiN3 monolayer following the adsorption of these gases, resulting in remarkable sensitivity of the Pd-SiN3 monolayer in relation to electrical conductivity and optical absorption. Meanwhile, all of these gas adsorption systems exhibited extremely long recovery times. The aforementioned theoretical findings suggest that the Pd-SiN3 monolayer has the potential to be an effective gas scavenger for the storage or removal of the SF6 decomposition components. Additionally, it might function as a reliable one-time sensor for detecting these gases. The results potentially provide valuable theoretical guidance for maintaining the normal operation of the SF6 insulation devices.

First‐Principles Study on CdS2 Monolayer as Toxic Gas Sensor or Scavenger

AbstractIn order to explore the possibility of monolayers as high‐performance gas sensors, the electronic properties and gas sensing performance of , , , , and gas molecules adsorbed on monolayers were investigated using a first‐principles approach. It was found that , and had a weak chemisorption effect on the monolayer, while the physisorption of effectively altered the electronic properties and the work function of the monolayer. Compared with other gases, the monolayer has relatively high sensitivity to , and , and the band gap of the system after adsorption changes significantly compared with the intrinsic monolayer, and the characteristics of the work function can effectively distinguish various gases. The results indicate that the monolayer has the ability to detect , and gases with high sensitivity, especially for , and provide a theoretical basis for the development of monolayers for potential applications as gas sensors or scavengers for , and .

Ruthenium, rhodium decorated perfect and Te-vacancy MoTe2 monolayer for industrial hazardous gases detection and scavenging

With the rapid development of industry and soaring of the global economy, the atmospheric pollution and human poisoning problems turn to a harsh circumstance. Accurate online monitoring and scavenging of industrial hazardous gases have become a bottleneck in recent years. In this paper, the adsorption mechanism and electrical properties of Ruthenium, Rhodium decorated perfect and Te-vacancy MoTe2 monolayer towards hazardous gases (SO2, CO, NH3) were firstly explored based on density functional theory. Comparing the adsorption behavior differences between perfect surface MoTe2 and Te atom vacancy MoTe2 through the analysis of density of states differential charge density and molecular orbital theory. The results show that the dopant reduces the band gap and enhances the surface competence. In addition, the trapping ability of the metal-modified defective MoTe2 to hazardous gases is inferior to that of the perfect MoTe2, and both adsorption types are physico-chemical adsorption. Modified MoTe2 could obtain the ideal recovery time as a NH3 gas sensor. CO are more difficult to detach from the mixture’ surfaces, which is a good proof for the CO adsorbent. The data provides the basis for the design of metal particle decoration based MoTe2 nanomaterials employed in the detection and scavenging of hazardous gases.

Cr decorated MoTe2 monolayer as C4F7N decomposed species adsorbent and scavenger: A first-principles study

C4F7N is a novel, dependable, and environmentally friendly insulation gas that can replace SF6 for high voltage insulation equipment. When extreme conditions such as partial discharge occur, the decomposition species of C4F7N following breakdown can have an undesirable impact on the functionality of insulated equipment, environmental safety, and human health. Based on the first- principles, this study enhances the capacity to adsorb and scavenge COF2, CF3CN, C2F5CN, and CF4 by decorating the transition metal Cr atom on the surface of pristine MoTe2 monolayer. The Cr atom can be as an electron donor (0.076 e) and convert the target molecule adsorption mode to chemisorption by greatly optimizing the band structure of the two-dimensional MoTe2 monolayer. The binding energy of the most stable modified structure is −1.330 eV. The C4F7N decomposition species' adsorption properties and electronic behaviors have been significantly improved by the surface decoration. Moreover, Cr-MoTe2 is thermally stable at high temperatures, so it can be applicated as a reliable target gas scavenger in gas insulated switch-gear (GIS) or other high-voltage insulation equipment for adsorption and scavenging.

One Step Closer to Enigmatic USCα Methanotrophs: Isolation of a Methylocapsa-like Bacterium from a Subarctic Soil.

The scavenging of atmospheric trace gases has been recognized as one of the lifestyle-defining capabilities of microorganisms in terrestrial polar ecosystems. Several metagenome-assembled genomes of as-yet-uncultivated methanotrophic bacteria, which consume atmospheric CH4 in these ecosystems, have been retrieved in cultivation-independent studies. In this study, we isolated and characterized a representative of these methanotrophs, strain D3K7, from a subarctic soil of northern Russia. Strain D3K7 grows on methane and methanol in a wide range of temperatures, between 5 and 30 °C. Weak growth was also observed on acetate. The presence of acetate in the culture medium stimulated growth at low CH4 concentrations (~100 p.p.m.v.). The finished genome sequence of strain D3K7 is 4.15 Mb in size and contains about 3700 protein-encoding genes. According to the result of phylogenomic analysis, this bacterium forms a common clade with metagenome-assembled genomes obtained from the active layer of a permafrost thaw gradient in Stordalen Mire, Abisco, Sweden, and the mineral cryosol at Axel Heiberg Island in the Canadian High Arctic. This clade occupies a phylogenetic position in between characterized Methylocapsa methanotrophs and representatives of the as-yet-uncultivated upland soil cluster alpha (USCα). As shown by the global distribution analysis, D3K7-like methanotrophs are not restricted to polar habitats but inhabit peatlands and soils of various climatic zones.

Research on the characteristics of the exhaust energy splitting method for the two-stroke low speed marine diesel engine

Efficient waste heat recovery (WHR) is the key to improve the thermal efficiency of the marine diesel engine and reduce the cost. According to the characteristics of long stroke of low-speed marine diesel engine, the exhaust energy splitting (EES) method based on exhaust energy distribution is proposed in this paper. EES is a new method of improving waste heat grade by separating high temperature exhaust gas and low temperature scavenging air. Compared with other studies on increasing exhaust temperature, EES significantly increases exhaust temperature and improves waste heat recovery efficiency without negatively affecting engine performance. Moreover, due to the adjustable EES valve, the optimal performance of engine and WHR system can be achieved under various operating conditions by adjusting the exhaust splitting phase (ESP). The One-Dimension and Three-Dimension simulation models for a two-stroke low speed marine diesel engine with waste heat recovery system are established. The exhaust energy distribution and the splitting phase to be optimized are also explored synchronously. The results show that by using the exhaust energy splitting method, temperature after turbine can be increased by more than 100 K compared with the baseline of the original engine system. Using Organic Rankine cycle (ORC) as WHR system, the waste heat recovery efficiency can reach over 17 %. Compared with the original engine, the total output power of the optimized EES low-speed engine and ORC system Increase by 100.90 kW under 75 % load and 154.72 kW under 100 % load, and the NOx emissions can be reduced by 5 %.

Associations Between Fresh Gas Flow and Duration of Anesthetic on the Maximum Potential Benefit of Anesthetic Gas Capture in Operating Rooms and in Postanesthesia Care Units to Capture Waste Anesthetic Gas.

Sevoflurane and desflurane are halogenated hydrocarbons with global warming potential. We examined the maximum potential benefit assuming 100% efficiency of waste gas capture technology used in operating rooms and recovery locations. We performed computer simulations of adult patients using the default settings of the Gas Man software program, including the desflurane vaporizer setting of 9% and the sevoflurane vaporizer setting of 3.7%. We performed 21 simulations with desflurane and 21 simulations with sevoflurane, the count of 21 = 1 simulation with 0-hour maintenance + (1, 2, 3, 4, or 5 hours of maintenance) × (0.5, 1, 2, or 4 L per minute fresh gas flow during maintenance). (1) A completely efficient gas capture system could recover a substantive amount of agent even when the case is managed with low flows. All simulations had at least 22 mL agent recovered per case, considerably greater than the 12 mL that we considered the minimum volume of economic and environmental importance. (2) All 42 simulations had at least 73% recovery of the total agent administered, considerably greater than the median 52% recovery measured during an experimental study with one gas capture technology and desflurane. (3) The maximum percentage desflurane (or sevoflurane) that could be captured decreased substantively with progressively longer duration anesthetics for low-flow anesthetics but not for higher-flow anesthetics. However, for all 8 combinations of drug and liters per minute simulated, there was a substantively greater recovery in milliliters of agent for longer duration anesthetics. In other words, if gas capture could be near perfectly efficient, it would have greater utility per case for longer duration anesthetics. (4) Even using a 100% efficient gas capture process, at most 6 mL liquid desflurane or 3 mL sevoflurane per case would be exhaled during the patient's stay in the postanesthesia care unit. Therefore, the volume of agent exhaled during the first 1 hour postoperatively is not a substantial amount from an environmental and economic perspective to warrant consideration of agent capture by having all these patients in the postanesthesia care unit, or equivalent locations, using the specialized anesthetic gas scavenging masks with access to the hospital scavenging system at each bed. Simulations with Gas Man show a strong rationale based on agent uptake and distribution for using volatile anesthetic agent capture in operating rooms if the technology can be highly efficient at volatile agent recovery.

Ethylene gas scavenging properties of nano-silica isolated from rice straw and of its PVA-based formulation coated on duplex paperboard made from softwood and rice straw

Ethylene gas scavenging properties of nano-silica isolated from rice straw and of its PVA-based formulation coated on duplex paperboard made from softwood and rice straw

Adsorption performance and gas sensing of the Ru atomic catalyst on GaN sheets to transformer oil dissolved gases

The Ru atomic catalyst-doped GaN (Ru-GaN) model was established by density functional theory (DFT), and the adsorption models of transformer oil dissolved gas (CO, H2, CH4, C2H2, C2H4 and C2H6) by a Ru-GaN monolayer were optimised. From the adsorption energy, differential charge density, electron state density, molecular orbital and desorption properties, the modification mechanism of Ru-GaN and the gas-sensitive response mechanism of Ru-GaN to CO, H2, CH4, C2H2, C2H4 and C2H6 were systematically studied. The introduction of metal Ru increases the defect state of GaN to provide the active site for the adsorption of gas molecules and reduces the adsorption barrier of GaN to gas molecules. The results show that Ru metal-doped GaN can adsorb CO, C2H2 and C2H4 by chemisorption, with Eads of −2.068 eV, −2.422 eV and −1.877 eV and Qt of −0.1696 e, −0.0671 e, −0.1222 e. In addition, charge redistribution leads to changes in the density of states, molecular orbitals and the conductivity of CO, C2H2 and C2H4 adsorption systems, indicating excellent gas sensitivity to the three gases. The desorption time further verified that Ru-GaN is an ideal CO and C2H2 gas scavenger and a recyclable material for C2H4 gas sensors.