11,869 results on '"GAS"'
Search Results
2. Effects of hydrogen sulfide on grass traits and water-gas transport in grass-planted unsaturated soil.
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Feng, Song, Leung, Anthony Kwan, Zhan, Liang Tong, Liu, Hong Wei, Wang, Min, and Guo, Xing Kai
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LANDFILL final covers , *HYDROGEN sulfide , *BERMUDA grass , *LANDFILL gases , *RAINFALL - Abstract
Vegetation has been found to improve the hydrological performance of landfill cover. However, existing studies ignore the effects of hydrogen sulfide (H2S), which forms the toxic odour generated from municipal solid wastes. Hydrogen sulfide is a potential signalling molecule in regulating plant-stomata aperture, but how the plant–hydrogen sulfide interaction affects the water–gas transport in soil remains unknown. This aim of this study was to investigate the effects of hydrogen sulfide on Bermuda grass growth and its influence on water–gas transport in unsaturated soils. Soil columns, with and without vegetation, were prepared and fumigated with different hydrogen sulfide concentrations. These columns were subjected to controlled drought and rainfall sequentially. The results showed that grass leaves almost wilted without hydrogen sulfide fumigation due to the Pythium diseases caused by the antecedent waterlogged conditions. In contrast, hydrogen sulfide fumigation promoted grass growth because of the fungicidal effects of hydrogen sulfide. In drought, hydrogen sulfide fumigation caused stomata closure, which resulted in a lower matric suction in the vegetated soil than that without hydrogen sulfide fumigation. Accordingly, hydrogen sulfide concentration reduced because of oxidation by metal oxides in soil. Upon subsequent rainfall, more infiltration but lower matric suction was observed in vegetated soils than was found in the bare case, whereas hydrogen sulfide concentration decreased continuously due to gas dissolution in the pore water. Direct application of laboratory findings herein to field cases should be used with caution, because the applied continuous lighting and low evapotranspiration rate of the soil column tests may not be representative of field conditions. [ABSTRACT FROM AUTHOR]
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- 2024
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3. Goal attainment in individual and group-based neuropsychological interventions for young adults with dyslexia in a randomized controlled trial.
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Nukari, Johanna M., Laasonen, Marja R., Arkkila, Eva P., Haapanen, Marja-Leena, and Poutiainen, Erja T.
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GOAL Attainment Scaling , *GOAL (Psychology) , *YOUNG adults , *QUALITY of life , *RANDOMIZED controlled trials - Abstract
In this study, we investigated the outcome of goal attainment in individual and group-based neuropsychological intervention for young adults with dyslexia. Participants (N = 120) were randomly assigned to individual intervention, group intervention, or wait-list control group. Attainment of goals set personally before the intervention was evaluated after the intervention using Goal Attainment Scaling. The participants were asked to report the number of concrete changes made in their study or working habits at five months (after intervention or wait-list control time), at ten months, and 15 months post-interventions. Potential predictive factors for predicting goal attainment were evaluated including background and cognitive variables, self-reported psychological variables (mood, cognitive and behavioral strategies, self-esteem, quality of life), and self-reported behavioral variables (concrete changes made, time used to work on intervention matters). Based on the results, personal goals were, on average, met especially in individual intervention. Nearly 50% of goal attainment was explained by intervention type, behavioral and cognitive strategies, concrete changes made, cognitive capacity, and used time. Concrete changes, e.g., adopting new strategies and methods in study or working habits, were reported in both interventions and more than during the wait-list control period. The changes seemed long-lasting as fifteen months post-intervention, 76.4% reported still using the learned strategies. A structured and relatively short neuropsychological intervention for dyslexia in either individual or group format can lead to attaining pre-set personal goals and positive behavioral changes that can last up to over a year post-intervention. [ABSTRACT FROM AUTHOR]
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- 2024
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4. A Buried Gas Pipeline Leakage Model.
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Yan, Mingqing, Xu, Peng, Li, Jun, Zhang, Xuemei, Wei, Ling, Peng, Shanbi, Li, Xuefei, Zhou, Weihong, Wu, Xiaonan, Huang, Xiaomei, and Guan, Yanwen
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GAS leakage , *EQUATIONS of state , *STRUCTURAL models , *LEAKAGE , *COMPUTER simulation - Abstract
Unlike the hydrodynamic model used in the current popular numerical simulation of buried gas pipeline leakage, this paper adopts the Darcy equation of underground seepage, mass balance equation, and equation of state of gas to establish a buried gas pipeline leakage model. Geometrically, the established model is a soil cylinder with the ground as the top surface and the vertical line through the pipeline leakage point as the axis. Due to the axial symmetry, the three-dimensional buried pipeline leakage model is expressed as a two-dimensional mathematical problem. A series of key concepts about the hydrodynamic model of buried pipeline leakage and its solution are presented. A comprehensive description of the physical process (pressure and flow rate) of buried gas pipeline leakage is provided through numerical examples. Quantitative analysis was conducted on the relevant structural parameters of the model and relations of leakage flow rate with related factors of leakage. By providing a comprehensive and quantitative understanding of buried gas pipeline leakage, this paper proposes a flow rate formula and an estimation formula of leak orifice equivalent diameter of leaking buried pipelines, and provides a theoretical and data processing framework for experimental study of buried gas pipeline leakage. [ABSTRACT FROM AUTHOR]
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- 2024
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5. Computational insights into the electronic structure and adsorption properties of CN, CNCl, and NO2 on metal (Na, Zn, and Al,) doped fullerene surfaces.
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Asogwa, Fredrick C., Igwe, Cynthia C., Edet, Henry O., Ikeuba, Alexander I., Imojara, Anna, Igomah, Godwin O., and Odey, Diana O.
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The hazards of pollution are highlighted by gas exposure, and creating effective adsorbents is essential for maintaining clean air, the environment, and human health. In our study, employing the DFT/M062x/def2svp level of theory, the potentials of metal-doped (Na, Zn, and Al) fullerene surfaces as efficient adsorbents for CN, CNCl, and NO
2 gases were evaluated. Investigation revealed that the introduction of metal dopants has visible impacts on the structural and electronic properties of fullerene surfaces. Specifically, a slight increase in the bond length of C–C bonds, with protruded bonds forming between the doped atoms and carbon atoms, was observed. The obtained energy gap (Eg) demonstrated a consistent reduction across the doped surfaces, indicative of heightened sensitivity toward the gas analytes. C59Al exhibited a higher Eg (3.876 eV), while C59Zn displayed a lower value (3.103 eV) compared to C59Na. Topology analysis using the quantum theory of atoms in molecules (QTAIM) predicted non-covalent interactions between gas analytes and metal-doped fullerene surfaces, a finding that was further substantiated by the analysis of non-covalent interactions. Focusing on CN gas adsorption, distinct behaviors emerged, where C59Na exhibited strong adsorption (Eads = −2.67 eV), surpassing C59Al (−1.82 eV) and C59Zn (−0.64 eV). A similar trend was observed for CNCl and NO2 gas adsorption, with C59Na consistently showing higher adsorption energies. This alignment was corroborated by frontier molecular orbital (FMO) and natural bond orbital (NBO) analyses. The results for dipole moment and recovery time emulated those of adsorption energy, emphasizing the stability and uniformity in adsorbed states. This collective evidence highlights the potential of doped surfaces to effectively adsorb specific gas molecules, offering insights into their applicability in gas sensing and environmental remediation. [ABSTRACT FROM AUTHOR]- Published
- 2024
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6. High Performance SPR Gas Sensor by Using Heterostructure of 2D Materials Graphene/Black Phosphorous/MoS2.
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Maurya, Pratiksha, Kushwaha, Anupam, and Verma, Roli
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A detailed analysis of the Surface Plasmon Resonance (SPR) sensor for the detection of gaseous analytes within the detection range (1 - 1.04) RIU was carried out. The proposed sensor is composed of a multilayer structure of prism, plasmonic metal, and 2D materials. The impact of different prisms (KF, LiF, SF-11, BK-7), metals (silver, copper, gold, aluminum), and a heterostructured layer of graphene, black phosphorous, M o S 2 demonstrated to achieve high-performance gas sensor. To achieve minimum reflectance and large shift, thickness optimization of each layer was carried out. A transfer matrix method for the N-Layer model with an angular interrogation method was used for the simulation at 633 nm wavelength. Field intensity demonstrates that the addition of each 2D layer plays an important role in the enhancement of the performance of the sensor. The sensitivity (S) and Figure of Merit (FOM) of the proposed sensor were obtained at 236.64°/RIU, and 24.5 R I U - 1 respectively. [ABSTRACT FROM AUTHOR]
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- 2024
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7. Development of the Separation Column's Temperature Field Monitoring System.
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Kukharova, Tatyana, Martirosyan, Alexander, Asadulagi, Mir-Amal, and Ilyushin, Yury
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ECONOMIC forecasting , *CORPORATE profits , *ECONOMIC efficiency , *PETROLEUM refining , *POWER resources - Abstract
Oil is one of the main resources used by all countries in the world. The ever-growing demand for oil and oil products forces oil companies to increase production and refining. In order to increase net profit, oil producing companies are constantly upgrading equipment, improving oil production technologies, and preparing oil for further processing. When considering the elements of primary oil refining in difficult conditions, such as hard-to-reach or in remote locations, developers face strict limitations in energy resources and dimensions. Therefore, the use of traditional systems causes a number of difficulties, significantly reducing production efficiency. In this study, the authors solve the problem of improving the characteristics of the oil separation process. In their work, the authors analyzed the separation columns of primary oil distillation, identified the shortcomings of the technological process, and searched for technological solutions. Having identified the lack of technical solutions for monitoring the state of the temperature field of the separation column, the authors developed their own hardware–software complex for monitoring the separation column (RF patents No. 2020665473, No. 2021662752 were received). The complex was tested and successfully implemented into production. The study provides an assessment of the economic efficiency of implementation for a year and a forecast of the economic effect for 10 years. [ABSTRACT FROM AUTHOR]
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- 2024
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8. Comprehensive Review of Biomass Pyrolysis: Conventional and Advanced Technologies, Reactor Designs, Product Compositions and Yields, and Techno-Economic Analysis.
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Jerzak, Wojciech, Acha, Esther, and Li, Bin
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CLEAN energy , *SUSTAINABILITY , *RAW materials , *WASTE management , *PYROLYSIS - Abstract
Pyrolysis is an environmentally friendly and efficient method for converting biomass into a wide range of products, including fuels, chemicals, fertilizers, catalysts, and sorption materials. This review confirms that scientific research on biomass pyrolysis has remained strong over the past 10 years. The authors examine the operating conditions of different types of pyrolysis, including slow, intermediate, fast, and flash, highlighting the distinct heating rates for each. Furthermore, biomass pyrolysis reactors are categorized into four groups, pneumatic bed reactors, gravity reactors, stationary bed reactors, and mechanical reactors, with a discussion on each type. The review then focuses on recent advancements in pyrolysis technologies that have improved efficiency, yield, and product quality, which, in turn, support sustainable energy production and effective waste management. The composition and yields of products from the different types of pyrolysis have been also reviewed. Finally, a techno-economic analysis has been conducted for both the pyrolysis of biomass alone and the co-pyrolysis of biomass with other raw materials. [ABSTRACT FROM AUTHOR]
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- 2024
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9. Measurement of inward leakage of full-face masks in EN and ISO standards: comparison of gas and aerosol test agents.
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Santandrea, Audrey, Marchal, Mathieu, Chazelet, Sandrine, and Marsteau, Stéphanie
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RESEARCH funding , *AEROSOLS , *DESCRIPTIVE statistics , *RESPIRATORY protective devices , *MEDICAL masks , *MASS spectrometry , *MEDICAL equipment reliability , *GASES , *SALT - Abstract
In Europe, respiratory protective devices must be certified before they can be marketed. Among the parameters of interest, inward leakage (IL) characterizes the tightness between the face seal and the face, to verify that the device is well-designed. European standard EN 13274-1 (2001) and International Organization for Standardization (ISO) standard ISO 16900-1 (2019) specify that IL should be measured using sodium chloride (NaCl) aerosol or sulfur hexafluoride (SF6) gas. For reusable masks made of nonporous materials, both test agents are considered equally acceptable. However, the few studies that have compared IL values measured with various aerosols and gases have come to divergent conclusions. This work then aimed to measure IL with the test agents recommended by the standards to determine whether they are really equivalent. Since krypton (Kr) is an interesting candidate for replacing SF6 in standard tests, IL was assessed with SF6 and Kr simultaneously, and with NaCl aerosol using various calculation methods. Tests were carried out on 5 models of full-face masks donned on a headform connected to a breathing machine simulating 3 sinusoidal breathing rates of various intensities. The respirator fit on the headform was evaluated using a controlled negative pressure method to determine a manikin fit factor. Four scenarios were then tested to represent very poor, bad, good, and excellent fit. Gas concentration was measured using a mass spectrometer, and IL was calculated for SF6 and Kr. A combination of 3 devices allowed the determination of the number-based concentration of particles with diameters between 20 nm and 2 µm, and IL was calculated for each of the 33 channels, as well as using a cumulative number concentration. In addition, to comply with standards, a conversion was carried out to calculate IL using a cumulative mass concentration. The results of this work evidenced that the IL values measured with NaCl were systematically lower than those determined with gases. IL was also shown to vary with particle size, with a maximum value exceeding that calculated with cumulative concentrations (in number or mass). As part of the revision of the standards, protocols for measuring inward leakage should be redefined. On the one hand, acceptability thresholds should be re-evaluated according to the nature of the test agent (gas or aerosol), as it is clear that the 2 options do not give the same results for a given configuration. On the other hand, the aerosol leakage measurement protocol needs to be reworked to enable the measurement of a well-defined, robust, and reproducible inward leakage value. [ABSTRACT FROM AUTHOR]
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- 2024
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10. Problems of Measuring Gas Content in Oil in a Two-Phase Flow: A Review.
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Edling, Cezary and Śliwiński, Paweł
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PRESSURE drop (Fluid dynamics) , *TWO-phase flow , *CORIOLIS force , *GAMMA rays , *ELECTRIC conductivity - Abstract
In view of the necessity of measuring the air content in oil in two-phase flows in the context of general industry, a review of the most popular methods of measuring the air content in oil was carried out. This review includes an assessment of their advantages and disadvantages and of whether they meet criteria such as the degree of filling, the size and number of bubbles, verification, the absence of additional pressure drops, simplicity, and repeatability. In the review, the following methods were examined: the classic trapping method, a modified trapping method, a trapping method using hydrostatic pressure loss, the pressure loss due to frictional flow resistance, the pressure loss with a rapid increase in diameter, the pressure drop in a Venturi tube, the pressure drop in an orifice, a method using the Coriolis effect, the electrical resistance method, the electrical conductivity method, the electromagnetic method, the electrical capacitance method, the thermal anemometry method, the liquid–solid contact electrification method, the photographic method, holography, light scattering, sound dispersion, the ultrasonic transit-time method, X-ray radiation, gamma radiation, neutron radiation, and fiber-optic methods. [ABSTRACT FROM AUTHOR]
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- 2024
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11. Can gas and infection coexist in the intervertebral disc? A retrospective analysis of percutaneously biopsied suspected discitis-osteomyelitis cases.
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Husseini, Jad S., Hanly, Arnau, Omeroglu, Emre, Nelson, Sandra B., Jesse, Mary Kate, Simeone, F. Joseph, and Chang, Connie Y.
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INTERVERTEBRAL disk , *OSTEOMYELITIS , *RETROSPECTIVE studies , *COMPUTED tomography , *DECOMPRESSION sickness - Abstract
Objectives: To retrospectively evaluate the correlation between intradiscal gas and infection in patients percutaneously biopsied for suspected discitis-osteomyelitis. Materials and methods: We retrospectively reviewed all CT-guided discitis-osteomyelitis biopsies performed between 2002 and 2022. Two independent trained musculoskeletal radiologists evaluated for presence of gas on CT and/or MRI within 1 week of the biopsy. Disagreements were resolved by a third musculoskeletal radiologist. CT was considered the gold standard for the detection of intradiscal gas. Pathology, microbiology, and imaging and clinical follow-up were used as the gold standard for presence of infection. Interrater agreement on CT and MRI, sensitivity, and positive predictive value were calculated, using the presence of gas as an indicator (test positive) for "no infection." Results: There were 284 biopsies in 275 subjects (mean age 58 ± 1.0 (range 4–99) years; 101 (37%) females and 174 (63%) males). Of the biopsies, 12 (4%) were cervical, 80 (28%) were thoracic, 192 (68%) were lumbar, and 200 (70%) were considered true discitis-osteomyelitis based on pathology, imaging, and clinical follow-up. Interrater agreement was excellent for CT (kappa = 0.83) and poor for MRI (kappa = − 0.021). The presence of gas had a 94% specificity and 76% negative predictive value for the absence of infection. Conclusion: CT is the preferred method for detecting intradiscal gas. The presence of gas means that discitis-osteomyelitis is unlikely. If intradiscal gas is present in the setting of discitis-osteomyelitis, the gas bubbles tend to be smaller and fewer in number. [ABSTRACT FROM AUTHOR]
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- 2024
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12. Complicated pneumonia caused by group A Streptococcus in children - 2022/2023 infectious season outbreak and update on clinical characteristics.
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Grochowska, Magdalena, Strzelak, Agnieszka, and Krenke, Katarzyna
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SCARLATINA , *CHILD patients , *COMMUNITY-acquired pneumonia , *CHEST tubes , *VIRUS diseases - Abstract
An increased incidence of group A Streptococcus (GAS) infections has been observed in pediatric population post-COVID-19 pandemic. While the majority of reports refer to scarlet fever or invasive GAS disease, detailed data on pulmonary manifestations such as complicated community-acquired pneumonia (CAP) are scarce. The aim of this study was to assess the contribution of GAS to complicated CAP in children during the 2022/2023 infectious season. We retrospectively analyzed the etiology and clinical presentation of complicated CAP patients hospitalized in our tertiary care center in Warsaw, Poland, between August 2022 and May 2023. Among 91 patients with complicated CAP, GAS was the dominant cause constituting 24.2% (22/91; 95% CI 15.8–34.3%) of the study group. 68.2% of GAS pneumonia patients presented symptoms of scarlet fever, and 27.3% had preceding or concurrent viral infection. GAS complicated CAP was associated with longer hospitalization, higher incidence of chest tube insertion, but shorter duration of chest tube drainage than complicated CAP of other etiology. Children with GAS complicated CAP had higher procalcitonin concentration (28.1 vs. 1.5 ng/dL; p<0.0001) and a lower platelets level (254.5 vs. 422 × 103/μL; p = 0.0031) than those with non-GAS infection. GAS is currently the predominant pathogen of complicated CAP in children. Clinicians should be aware of the current epidemiological situation and a more severe course of GAS pneumonia in this age group, and should monitor patients presenting with symptoms of scarlet fever and preceding viral infection closely. [ABSTRACT FROM AUTHOR]
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- 2024
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13. Experimental study of ECDM using a porous electrode containing internal micropores.
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Kong, Linglei, Zhang, Lei, Lei, Weining, and Li, Qilin
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POROUS materials ,POROUS electrodes ,ELECTROCHEMICAL cutting ,GAS flow ,ROUGH surfaces - Abstract
In electrochemical discharge machining (ECDM), continuous renewal of electrolyte between the tool electrode and the workpiece guarantees stable discharge machining. Proposed in this paper is Porous-electrode ECDM (p-ECDM) using a tool electrode made of porous material containing micrometer pores. The rough surface of the porous electrode promotes electrolyte regeneration between the electrodes to produce a stable and relatively thin gas film. At the same time, the internal connected micropores are used to provide controlled gas flow to the processing area, reduce the energy consumption of electrolytic bubbles, and improve the discharge energy to achieve efficient ECDM processing. Experimental results indicate that compared with a solid electrode, the porous electrode has faster electrolyte renewal, smaller bubble volume, more-stable voltage characteristics, 22.55% less overcut, a 4.7% smaller heat-affected zone, and better deep hole processing ability. Experimental results for p-ECDM assisted by controlled airflow demonstrate a 54.23% increase in the material removal rate. [ABSTRACT FROM AUTHOR]
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- 2024
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14. Soil-Based Emissions and Context-Specific Climate Change Planning to Support the United Nations (UN) Sustainable Development Goal (SDG) on Climate Action: A Case Study of Georgia (USA).
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Nelson, Davis G., Mikhailova, Elena A., Zurqani, Hamdi A., Lin, Lili, Hao, Zhenbang, Post, Christopher J., Schlautman, Mark A., and Shepherd, George B.
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CLIMATE change adaptation ,LAND degradation ,LAND use ,EXTERNALITIES ,FOREST soils ,URBANIZATION - Abstract
Soil-based emissions from land conversions are often overlooked in climate planning. The objectives of this study were to use quantitative data on soil-based greenhouse gas (GHG) emissions for the state of Georgia (GA) (USA) to examine context-specific (temporal, biophysical, economic, and social) climate planning and legal options to deal with these emissions. Currently, 30% of the land in GA has experienced anthropogenic land degradation (LD) primarily due to agriculture (64%). All seven soil orders were subject to various degrees of anthropogenic LD. Increases in overall LD between 2001 and 2021 indicate a lack of land degradation neutrality (LDN) in GA. Besides agricultural LD, there was also LD caused by increased development through urbanization, with 15,197.1 km
2 developed, causing midpoint losses of 1.2 × 1011 kg of total soil carbon (TSC) with a corresponding midpoint social cost from carbon dioxide (CO2 ) emissions (SC-CO2 ) of USD $20.4B (where B = billion = 109 , $ = U.S. dollars (USD)). Most developments occurred in the Metro Atlanta and Coastal Economic Development Regions, which indicates reverse climate change adaptation (RCCA). Soil consumption from developments is an important issue because it limits future soil or forest carbon (C) sequestration potential in these areas. Soil-based emissions should be included in GA's carbon footprint. Understanding the geospatial and temporal context of land conversion decisions, as well as the social and economic costs, could be used to create incentives for land management that limit soil-based GHG emissions in a local context with implications for relevant United Nations (UN) initiatives. [ABSTRACT FROM AUTHOR]- Published
- 2024
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15. 266 nm Laser-Induced Fluorescence Reference Spectra of Ketones and Aromatic Compounds.
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Brunzendorf, Jens, Höltkemeier-Horstmann, Jacqueline, and Markus, Detlev
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METRIC system ,LASER-induced fluorescence ,AROMATIC compounds spectra ,FLUORESCENCE spectroscopy ,GAS distribution - Abstract
Laser-induced fluorescence (LIF) is an established noninvasive measurement method to determine temperature distributions and local gas concentrations in combustion processes with high spatial and temporal resolution. This work presents high-precision LIF spectra of acetone and other tracers at ambient conditions. By using a large UV-sensitive sCMOS camera instead of an image intensified camera, many issues like nonlinearity, varying sensitivity, vignetting, limited resolution etc. could be minimized or eliminated. Particular care was taken to remove residual stray light and to calibrate the spectra with metrological traceability to the International System of Units SI. [ABSTRACT FROM AUTHOR]
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- 2024
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16. Frequency of Group A Streptococcus Infection and Analysis of Antibiotic Use in Patients with Pharyngitis—A Retrospective, Multicenter Study.
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Biała, Martyna, Babicki, Mateusz, Malchrzak, Wojciech, Janiak, Sandra, Gajowiak, Dominik, Żak, Alan, Kłoda, Karolina, Gibas, Piotr, Ledwoch, Justyna, Myśliwiec, Anna, Kopyt, Daria, Węgrzyn, Anna, Knysz, Brygida, and Leśnik, Patrycja
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STREPTOCOCCAL diseases ,STREPTOCOCCUS pyogenes ,MEDICAL records ,PRIMARY care ,INAPPROPRIATE prescribing (Medicine) - Abstract
Streptococcus pyogenes is responsible for 20–30% of pharyngitis in children and 5–15% in adults. The ineffective treatment of group A Streptococcus (GAS) infections can result in postinfectious sequelae. This study aims to evaluate the frequency of GAS pharyngitis and assess the management of patients with pharyngitis and antibiotic use. We conducted a multicenter, retrospective analysis of medical records from nine primary care centers in Poland. The study enrolled 1949 medical records of patients (children 67.4%, adults 32.6%). An infection of Streptococcus pyogenes, based on a rapid strep test, was diagnosed in 830 patients (42.6%). In the comprehensive study group of 1949 patients, 1054 (54.1%) were given antibiotics. Notably, 224 patients had a negative rapid strep test result but still received antibiotic treatment, underscoring the complexity of treatment decisions. The most commonly used antibiotics were oral penicillin V in 431 cases (41%) and amoxicillin in 219 cases (20.8%). We observed no significant difference between positive rapid strep test results and patients' sociodemographic data and comorbidities. The prevalence of GAS was 42.6% in the analyzed records of patients with pharyngitis, and 54.1% were prescribed antibiotics. Antibiotics were overprescribed for sore throats. Strategies are needed to promote rational antibiotic use. [ABSTRACT FROM AUTHOR]
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- 2024
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17. Influence of Central Coke Ratio on the Internal State of Blast Furnace.
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Liu, Pengbo, Cheng, Shusen, and Liu, Zhao
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COKE (Coal product) , *BLAST furnaces , *GAS flow , *HEAT transfer , *MATHEMATICAL models , *PARTICLE motion - Abstract
Central coke charging (CCC) is a widely used burden distribution method for blast furnaces (BFs). Adjusting the central coke ratio can change the burden temperature field and affect the smooth operation of BF. This study presents a coupled physical and mathematical model, incorporating particle motion, gas flow, and heat transfer between the burden and gas in two 5500 m3 BFs. The central coke ratios of the blast furnace A (BFA) and blast furnace B (BFB) is 15% and 20%, respectively. The root positions of the cohesive zone in the BFA and BFB are in the lower part of the stack and bosh zones, respectively. In the central area of the BF, the gas flow rate, gas temperature, and burden temperature of the BFB are higher. In the edge area of the BF, the gas flow rate, gas temperature, and burden temperature of the BFA are higher. The actual top gas temperature and gas pressure verify the accuracy of the proposed model. This model investigates the influence of the central coke ratio on the position of the cohesive zone, gas flow rate, gas temperature, and burden temperature, providing a cost‐effective method for studying the effect of the burden distribution matrix on the internal state of the BF. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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18. Group A Streptococcus infections in children and adolescents in the post-COVID-19 era: a regional Italian survey.
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Cinicola, Bianca Laura, Sani, Ilaria, Pulvirenti, Federica, Capponi, Martina, Leone, Fabrizio, Spalice, Alberto, Montalbano, Agata, Macari, Alessandra, Fonte, Maria Teresa, Giampietro, Paolo Gianni, Buonsenso, Danilo, Zicari, Anna Maria, Rongai, Teresa, Baldini Ferroli, B, Brugnoli, R, Carpita, FM, Caruso, G, Castellano, C, Cives, C, and Costabile, L
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STREPTOCOCCAL disease treatment , *INFLUENZA prevention , *IMMUNIZATION , *T-test (Statistics) , *INFLUENZA vaccines , *KRUSKAL-Wallis Test , *SYMPTOMS , *DESCRIPTIVE statistics , *MANN Whitney U Test , *CHI-squared test , *CLINICAL pathology , *SURVEYS , *STREPTOCOCCAL diseases , *DISEASE relapse , *DATA analysis software , *COVID-19 pandemic , *MIXED infections , *DISEASE complications , *CHILDREN - Abstract
Background: Despite the worldwide increasing incidence of Group A Streptococcus (GAS) infections reported since December 2022, data on noninvasive GAS (nGAS) infections in the post COVID-19 era are limited. By a self-reported survey performed in an outpatient setting, we investigated the number and clinical features of GAS infections, the diagnostic work-up and the type of treatment utilized. In addition, the rate of influenza vaccination was evaluated. Methods: In June 2023 family pediatricians involved in the study sent the survey to parents of patients aged 0–16 years. The survey included questions on GAS infections that occurred from January 1 to May 31, 2023. Results: Among 3580 children, 20.3% had a GAS infection (0,8% < 1 year, 16,4% 1–3 years, 42,3% 3–6 years, 26,5% 6–9 years, 11,4%, 9–12 years, and 2,6% 12–16 years). Symptoms reported were sore throat (76.9%), fever (75.2%), tonsillar exudate (25.2%), lymphadenopathy (21.8%), and scarlet fever (14.7%). A single patient was hospitalized due to GAS meningitis. Twenty four percent of children had more than one GAS infection. In this group, frequencies of symptoms reported in the first and in the following infection were similar, except for fever and scarlet fever which were less frequent during relapses. GAS was identified by rapid antigen detection test in 81.0% of children. Eighty-nine per cent of children were treated with antibiotics, mostly amoxicillin/clavulanate (40.4%) and amoxicillin (39.4%). Thirty four percent of children received influenza vaccine. No difference was observed among immunized and not immunized regarding the number and characteristics of GAS infection. Conclusions: We reported a certain prevalence of nGAS infections in children, mainly those aged 3–6 years age, who were mostly characterized by a low score of symptoms, and in most of the cases diagnosed and treated using a microbiological test as confirmatory tool. In this new clinical setting, a national study would be useful to reach more significant data for the definition of a correct diagnosis and clinical management of nGAS infections in children. Moreover, it is important to improve flu vaccination campaign and coverage to protect children from coinfections that could worsen the disease and misdiagnose the etiology of pharyngitis. [ABSTRACT FROM AUTHOR]
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- 2024
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19. Current Insights into Weak Seed Dormancy and Pre-Harvest Sprouting in Crop Species.
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Matilla, Angel J.
- Subjects
MITOGEN-activated protein kinases ,SEED dormancy ,ABSCISIC acid ,RAINFALL ,PROTEOMICS - Abstract
During the domestication of crops, seed dormancy has been reduced or eliminated to encourage faster and more consistent germination. This alteration makes cultivated crops particularly vulnerable to pre-harvest sprouting, which occurs when mature crops are subjected to adverse environmental conditions, such as excessive rainfall or high humidity. Consequently, some seeds may bypass the normal dormancy period and begin to germinate while still attached to the mother plant before harvest. Grains affected by pre-harvest sprouting are characterized by increased levels of α-amylase activity, resulting in poor processing quality and immediate grain downgrading. In the agriculture industry, pre-harvest sprouting causes annual economic losses exceeding USD 1 billion worldwide. This premature germination is influenced by a complex interplay of genetic, biochemical, and molecular factors closely linked to environmental conditions like rainfall. However, the exact mechanism behind this process is still unclear. Unlike pre-harvest sprouting, vivipary refers to the germination process and the activation of α-amylase during the soft dough stage, when the grains are still immature. Mature seeds with reduced levels of ABA or impaired ABA signaling (weak dormancy) are more susceptible to pre-harvest sprouting. While high seed dormancy can enhance resistance to pre-harvest sprouting, it can lead to undesirable outcomes for most crops, such as non-uniform seedling establishment after sowing. Thus, resistance to pre-harvest sprouting is crucial to ensuring productivity and sustainability and is an agronomically important trait affecting yield and grain quality. On the other hand, seed color is linked to sprouting resistance; however, the genetic relationship between both characteristics remains unresolved. The identification of mitogen-activated protein kinase kinase-3 (MKK3) as the gene responsible for pre-harvest sprouting-1 (Phs-1) represents a significant advancement in our understanding of how sprouting in wheat is controlled at the molecular and genetic levels. In seed maturation, Viviparous-1 (Vp-1) plays a crucial role in managing pre-harvest sprouting by regulating seed maturation and inhibiting germination through the suppression of α-amylase and proteases. Vp-1 is a key player in ABA signaling and is essential for the activation of the seed maturation program. Mutants of Vp-1 exhibit an unpigmented aleurone cell layer and exhibit precocious germination due to decreased sensitivity to ABA. Recent research has also revealed that TaSRO-1 interacts with TaVp-1, contributing to the regulation of seed dormancy and resistance to pre-harvest sprouting in wheat. The goal of this review is to emphasize the latest research on pre-harvest sprouting in crops and to suggest possible directions for future studies. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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20. Effects of clean fracturing fluids on coal microstructure and coalbed gas adsorption.
- Author
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Zhang, Qian, Cai, Feng, Xie, Haotian, and Fang, Yu
- Subjects
- *
FRACTURING fluids , *GREENHOUSE gas mitigation , *GAS absorption & adsorption , *COALBED methane , *METHANE , *WATER salinization , *GREEN business , *COAL - Abstract
Nowadays, some fracking fluids can enable resourceful extraction of coalbed methane and reduce greenhouse gas emissions. However, their toxicity or corrosiveness will cause harm to downhole workers and pollute groundwater resources. Thus, five kinds of clean composite fracturing fluids were developed in this paper by using starch solution as the matrix and adding various preparations. The change rule of methane adsorption capacity by microstructure changes of coal samples was investigated systematically, and the optimal composite fracturing fluid was determined. The results showed that the new fracturing fluid increased the degree of aromatic ring condensation by 43.3% and the average pore size by 52.1%. Also, the adsorption constants of a value decreased by 11.6% and b value decreased by 23.9%, which can remarkably reduce the methane adsorption. The experimental results provide theoretical support for the clean production of coalbed methane. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
21. Review of Some Methods of CO2 Utilization.
- Author
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Gasimova, Gulnara, Gasimzade, Lala, and Aghayeva, Fidan
- Subjects
- *
CARBON emissions , *ENVIRONMENTAL protection , *BIOMASS , *PETROLEUM chemicals , *FISCHER-Tropsch process - Abstract
Protecting the environment from harmful substances (carbon oxides, nitrogen oxides, soot products, etc.) is one of the pressing issues of our time. This article discusses specific topics related to the need to reduce carbon dioxide emissions into the atmosphere, which are generated during biomass gasification, Fischer-Tropsch synthesis, and other processes. The article also identifies alternative methods for producing valuable petrochemical products, which significantly reduce gas emissions into the atmosphere. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
22. Increase in acute mastoiditis at the end of the COVID-19 pandemic.
- Author
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Goldberg-Bockhorn, Eva, Hurzlmeier, Clara, Vahl, Julius M., Stupp, Franziska, Janda, Aleš, von Baum, Heike, and Hoffmann, Thomas K.
- Subjects
- *
COVID-19 pandemic , *ACUTE otitis media , *STREPTOCOCCAL diseases , *AGE groups , *SINUS thrombosis , *BRAIN abscess - Abstract
Purpose: Common respiratory infections were significantly reduced during the COVID-19 pandemic due to general protective and hygiene measures. The gradual withdrawal of these non-pharmaceutical interventions (NPI) was associated with a notable increase in these infections, particularly in pediatric and adult otorhinolaryngology. The aim of this retrospective monocentric study was to evaluate the impact of NPI during the COVID-19 pandemic on the incidence and severity of acute mastoiditis (AM). Methods: Pre-pandemic clinical data of AM cases from 2011 to 2019 were compared with infection counts from January 2020 to June 2023 for seasonal periodicity, age-specific differences, pathogens, and complication rates in a German third-level hospital. Results: Out of 196 patients with AM 133 were children, the majority between 1 and 5 years of age. Complications of AM, such as meningitis, brain abscess, and sinus vein thrombosis, were more common in adults (87%) than in children (17%). Morbidity and mortality rates were similar before, during and after the pandemic. Pneumococci were the most common pathogen in both age groups, with a post-pandemic cumulation of Streptococcus pyogenes infections in children. While pre-pandemic cases clustered in spring, seasonality was absent in all age groups during the main phase of the pandemic. The cessation of NPI caused a steep rise in AM cases in both age groups starting from December 2022. Conclusion: NPI during the COVID-19 pandemic reduced the incidence of AM. Their reversal led to a substantial increase in the incidence of AM during the post-pandemic period, which may be due to a general increase in viral respiratory infections and an insufficiently trained immune system. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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23. The effect of using Filtered Containment Venting System on variation in dose with distance in the prompt accident consequence assessment.
- Author
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Wadayama, Kodai, Kojo, Retsu, and Niisoe, Tamon
- Abstract
In a nuclear emergency, consequence assessment based on the plant conditions using a simple method is important for a prompt response. Response Technical Manual (RTM-96) is a manual calculation method for prompt dose projection at arbitrary distances by converting pre-calculated doses with the conversion factor based on distance and weather. However, the 'conversion factor' in RTM-96 does not consider accident scenarios with filtered containment venting system (FCVS). Therefore, in this study, we defined the ratio of effective dose between 1 km and an arbitrary distance as the 'Distance Conversion Factor (DCF)' and aimed to clarify the difference between DCFs by accident scenarios, focusing on the presence or absence of FCVS. The results showed that the differences in DCFs for different accident scenarios were minor in the case of no rainfall. In contrast, in the case of rainfall, DCF differed significantly with scenarios with FCVS and those with containment failure. Therefore, the authors propose that DCFs with rainfall should be calculated separately for several representative accident scenarios rather than uniformly for all accident scenarios, as in the conventional method. The results can contribute to developing a new prompt consequence assessment method, such as RTM-96, which considers FCVS. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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24. An Evaluation of the Extent of Adoption of Lean in Offshore Facility Maintenance Projects in the Oil and Gas Industry.
- Author
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Achaka, Chimezie Henry, Amade, Benedict, Okorocha, Kevin Aku, and Ubani, Emmanuel Chinenye
- Subjects
CONVENIENCE sampling (Statistics) ,LEAN management ,WASTE minimization ,SERVICE industries ,CRONBACH'S alpha ,OFFSHORE oil & gas industry - Abstract
Lean production can be used to overcome serious organisational performance issues in the oil and gas industry, affecting both production and service delivery. This study will look into the extent and understanding of lean concept adoption in offshore facility maintenance projects in Nigeria's oil and gas industry. The study employed descriptive and survey research design methods of investigation, as well as a purposive and convenience sampling methodology, to pick a sample size from a population of 122 practitioners working in eleven (11) oil servicing enterprises in the Niger Delta region of South-South Nigeria. The data collection and survey instrument included a well-structured questionnaire, semi-structured/focused group discussions, personal observations, and site visits to gather information from respondents, oil and gas servicing firms, and projects. The collected data was displayed using frequency distribution in the form of tables and Cronbach's Alpha test using IBM SPSS Statistics version 26.0. A survey of 113 respondents found that 34.51% are involved in major offshore facility maintenance projects, with the majority (24%) working on pipe and structural maintenance. The study also found that 19.48% of respondents were unaware of lean in offshore facility maintenance projects, with the remainder (45.82%, 18.58%) being slightly knowledgeable. The study also found that 22.12% of respondents were unaware of lean tools for waste reduction in offshore facility maintenance projects, while the remaining respondents (45.13%) were only marginally knowledgeable. [ABSTRACT FROM AUTHOR]
- Published
- 2024
25. Applying Theorem of Ross to Transition Probability Matrix in Energy Options Pricing after Political Tensions and Russia-Ukraine Conflict.
- Author
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Mikhaylov, Alexey, Chang, Tsangyao, Mukhanova, Aigul, Bukharbayeva, Akmaral, and Karpyn, Zuleima
- Abstract
Probability Matrix, it is necessary to obtain energy options pricing. The paper found the true probabilities of transition from the current state of the market to other states. The energy options pricing including effects of Political tensions is proposed. The methods are based on true probabilities of transition to the next state of the energy market. It can be used to predict the movement of the underlying asset of energy options (oil and gas derivatives pricing). For example, one strategy might be to compare the energy sources at the beginning 2022 (before 24.02.2024) with the current state of the market. The results show that this matrix can be implemented in energy options pricing, which represents the true probabilities of transition from the current state of the market to modern state. Practical implementation is an investment strategy in oil and gas futures that should include the median of a given distribution with the current state of the market after beginning of Russia-Ukraine conflict. The absence of arbitrage opportunities is a fundamental principle underlying modern financial pricing theory. This concept is peculiar to the statement of the fundamental theorem of asset pricing. The results prove idea that at a fixed point in time is the information about some market quotations of American Call options can be determined. The results have a set of quotes that are available in both directions: both for strikes and for periods to maturity. [ABSTRACT FROM AUTHOR]
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- 2024
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26. ASSESSMENT OF THE OIL AND GAS POTENTIAL OF THE EASTERN EDGE OF THE NORTHERN USTYURT USING NEW GEOPHYSICAL DATA.
- Author
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Bekeshova, Z. B., Ratov, B. T., Sudakov, A. K., Kozhakhmet, K. A., and Sudakova, D. A.
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CARTOGRAPHIC materials ,GAS-lubricated bearings ,PETROLEUM industry ,SCIENTIFIC method ,BASE oils - Abstract
Purpose. Detailed substantiation of the geological structure of the eastern edge of the Northern Ustyurt, clarification of modern geological and geophysical data, as well as highlighting the mainstages of evaluating the results of exploration work to confirm the oil and gas potential and subsequent exploitation of the fields. Methodology. The authors used the following scientific methods: generalization – to systematize scientific provisions; analogy and comparison – to characterize deflection in different periods; analysis and synthesis – to substantiate geological and geophysical data; algorithmmization – to determine conceptual provisions regarding the assessment of the oil and gas bearing capacity of the trough. Findings. In order to achieve the goals, the indicators of oil and gas capacity in the areas of the eastern side of the Northern Ustyurt of different geological ages were substantiated. The geological and geophysical features of the basin dating back to 2010 compared to modern refinement of geological data were characterized. The productive and unproductive structures of the eastern side of the Northern Ustyurt are characterized, taking into account the showing of oil and gas based on deposits of different geological ages. The importance of conducting geological exploration and creating corresponding cartographic materials is justified, followed by the design of predictive graphical models, geological sections, and a detailed plan of the territory. Originality. The influence of high hydro carbon generation rates on the further identification of “oil windows” has been substantiated for the first time. The hierarchical levels of predicting the oil and gas content of the trough are identified. The necessity of improving the mechanisms for assessing oil and gas content is substantiated. Practical value. The substantiation of the features of the assessment of the oil and gas content of the of the eastern edge of the Northern Ustyurt, which should be based on forecasting promising areas of prospecting, is the key to distinguishing between productive and unproductive objects, determining their real scale and directing investment flow precisely to promising areas with minimal environmental and economic losses. [ABSTRACT FROM AUTHOR]
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- 2024
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27. MATHEMATICAL MODEL FOR HEAT TRANSFER DURING UNDERGROUND COAL GASIFICATION PROCESS.
- Author
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Saik, P. B. and Berdnyk, M. H.
- Subjects
PHASE transitions ,MATHEMATICAL physics ,COALBED methane ,BOUNDARY value problems ,SPECIFIC heat capacity ,SPECIFIC heat - Abstract
Purpose. To develop a mathematical model of the “coal-gas” medium heat transfer during underground coal gasification to predict the combustion face advance velocity and the duration of gasification column mining. Methodology. To detect the temperature fields in the coal seam and gas, depending on the displacement length of the phase transition boundary, a boundary-value problem of mathematical physics has been developed. To solve this boundary-value problem, Boltzmann transformations, as well as methods for solving ordinary differential equations, are used. Newton-Raphson method, which has quadratic convergence, is used to find the roots of the transcendental equation. Findings. Tendencies in the formation of mathematical models when studying temperature fields around an underground gasifier have been analyzed, with highlighting their disadvantages. A mathematical model of heat transfer during underground gasification has been developed, taking into account the phase transition boundaries of the “coal-gas” medium. A computational experiment was conducted to determine the temperature of the phase transition boundary based on the length of the gasification column and the duration of the process. Originality. A mathematical model for heat transfer during coal gasification in the form of a boundary-value problem of mathematical physics, which consists of parabolic heat-transfer equations, the Stefan condition at the phase transition boundary, and the Dirichlet boundary conditions, has been constructed. As a result of solving the boundary-value problem, a self-similar solution has been obtained for the distribution of the coal seam and gas temperature fields, as well as the position of the phase transition boundary depending on the gasification duration and on the medium density, thermal conductivity coefficients, specific heat capacity of gas and coal, specific calorific value and temperature of coal combustion, initial coal temperature and constant temperature of the gasification process. The conducted analysis of numerical calculations provides a deeper understanding of the dynamics of underground coal gasification process and makes necessary corrections to achieve the maximum process efficiency. Practical value. A methodology for determining the displacement length of the phase transition boundary of the “coal-gas” medium has been developed, taking into account the change in the combustion face temperature along the gasification zone length depending on the duration of this process. Application of the methodology makes it possible to predict the time of mining the gasified coal column for drawing up a calendar plan for mining operations. [ABSTRACT FROM AUTHOR]
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- 2024
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- View/download PDF
28. CSGA: A DUAL POPULATION GENETIC ALGORITHM BASED ON MEXICAN CAVEFISH GENETIC DIVERSITY.
- Author
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Alkafaween, Esra’a, Hassanat, Ahmad, Essa, Ehab, and Elmougy, Samir
- Subjects
TRAVELING salesman problem ,SEARCH algorithms ,BASE pairs ,POPULATION genetics ,CROSSBREEDING - Abstract
Genetic algorithms (GAs) are search algorithms based on population genetics and natural-selection concepts. Maintaining population variety in GAs is critical for ensuring global exploration and mitigating the risks of premature convergence. Rapid convergence to local optima is one such challenge in the application of genetic algorithms. To address this issue, we provide Cave-Surface GA (CSGA), an alternative method based on the Dual Population GA and inspired by the genetic variety observed in Mexican cavefish. Through inter-population cross-breeding, CSGA increases diversity via a secondary population (cave population) and facilitates the exchange of information between populations, effectively counteracting premature convergence. Several experiments are carried out utilizing benchmark instances of the Traveling Salesman Problem (TSP) obtained from TSPLIB, a well-known TSP problem library. Our experimental results over many TSP instances show that CSGA outperforms both classic GAs and other GAs that use diversity-preservation techniques, such as Multipopulation GA (MPGA). CSGA has the potential to give promising solutions to challenging optimization issues like TSP. [ABSTRACT FROM AUTHOR]
- Published
- 2024
29. Research Progress on Gas Generation from Waste Plastics Through Pyrolysis.
- Author
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Guangxiong, Ji, Bingguo, Liu, Guolin, Luo, Chao, Yuwen, Fang, Peng, Siyu, Gong, Shenghui, Guo, Wang, Chen, and Keren, Hou
- Abstract
Plastic pyrolysis technology, as an efficient and stable path for chemical recycling of waste plastics, alleviates current energy pressures and solves the problem of continuous accumulation of waste plastics in the environment. At present, the vast majority of research on plastic pyrolysis is focused on how to improve the yield and quality of liquid fuels, while there is generally little research on the gases generated by plastic pyrolysis. However, gases such as H
2 , CH4, and light hydrocarbons generated during pyrolysis also have high utilization value, and have very considerable application prospects in chemical, aerospace, and metallurgical fields. In addition, compared with the separation difficulties of liquid products, the treatment of gas products is easier and more conducive to subsequent utilization. This article discusses and analyzes the yield and composition of gases generated by plastic in three different pyrolysis methods: direct pyrolysis, catalytic pyrolysis, and microwave pyrolysis. Compared to traditional direct pyrolysis, catalytic pyrolysis and microwave pyrolysis can treat plastic waste more efficiently and energy-efficient, and have higher gas yields. This article also discusses various factors such as temperature that influence the formation of gas products and their importance. Finally, the challenges faced are proposed, aiming to provide reference and direction for future research on improving the yield of gas generated by plastic pyrolysis. [ABSTRACT FROM AUTHOR]- Published
- 2024
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30. Group A Streptococcus infections in children and adolescents in the post-COVID-19 era: a regional Italian survey
- Author
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Bianca Laura Cinicola, Ilaria Sani, Federica Pulvirenti, Martina Capponi, Fabrizio Leone, Alberto Spalice, Agata Montalbano, Alessandra Macari, Maria Teresa Fonte, Paolo Gianni Giampietro, Danilo Buonsenso, Anna Maria Zicari, Teresa Rongai, and On behalf of the Italian Pediatrician Federation (FIMP), Lazio Region
- Subjects
Group A Streptococcus infection ,GAS ,Children ,Pharyngitis ,Antibiotics ,Influenza ,Pediatrics ,RJ1-570 - Abstract
Abstract Background Despite the worldwide increasing incidence of Group A Streptococcus (GAS) infections reported since December 2022, data on noninvasive GAS (nGAS) infections in the post COVID-19 era are limited. By a self-reported survey performed in an outpatient setting, we investigated the number and clinical features of GAS infections, the diagnostic work-up and the type of treatment utilized. In addition, the rate of influenza vaccination was evaluated. Methods In June 2023 family pediatricians involved in the study sent the survey to parents of patients aged 0–16 years. The survey included questions on GAS infections that occurred from January 1 to May 31, 2023. Results Among 3580 children, 20.3% had a GAS infection (0,8% < 1 year, 16,4% 1–3 years, 42,3% 3–6 years, 26,5% 6–9 years, 11,4%, 9–12 years, and 2,6% 12–16 years). Symptoms reported were sore throat (76.9%), fever (75.2%), tonsillar exudate (25.2%), lymphadenopathy (21.8%), and scarlet fever (14.7%). A single patient was hospitalized due to GAS meningitis. Twenty four percent of children had more than one GAS infection. In this group, frequencies of symptoms reported in the first and in the following infection were similar, except for fever and scarlet fever which were less frequent during relapses. GAS was identified by rapid antigen detection test in 81.0% of children. Eighty-nine per cent of children were treated with antibiotics, mostly amoxicillin/clavulanate (40.4%) and amoxicillin (39.4%). Thirty four percent of children received influenza vaccine. No difference was observed among immunized and not immunized regarding the number and characteristics of GAS infection. Conclusions We reported a certain prevalence of nGAS infections in children, mainly those aged 3–6 years age, who were mostly characterized by a low score of symptoms, and in most of the cases diagnosed and treated using a microbiological test as confirmatory tool. In this new clinical setting, a national study would be useful to reach more significant data for the definition of a correct diagnosis and clinical management of nGAS infections in children. Moreover, it is important to improve flu vaccination campaign and coverage to protect children from coinfections that could worsen the disease and misdiagnose the etiology of pharyngitis.
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- 2024
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31. Effects of clean fracturing fluids on coal microstructure and coalbed gas adsorption
- Author
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Qian Zhang, Feng Cai, Haotian Xie, and Yu Fang
- Subjects
Gas ,Cleaner production ,Compound flocculant solution ,Functional groups ,Pore structure ,Medicine ,Science - Abstract
Abstract Nowadays, some fracking fluids can enable resourceful extraction of coalbed methane and reduce greenhouse gas emissions. However, their toxicity or corrosiveness will cause harm to downhole workers and pollute groundwater resources. Thus, five kinds of clean composite fracturing fluids were developed in this paper by using starch solution as the matrix and adding various preparations. The change rule of methane adsorption capacity by microstructure changes of coal samples was investigated systematically, and the optimal composite fracturing fluid was determined. The results showed that the new fracturing fluid increased the degree of aromatic ring condensation by 43.3% and the average pore size by 52.1%. Also, the adsorption constants of a value decreased by 11.6% and b value decreased by 23.9%, which can remarkably reduce the methane adsorption. The experimental results provide theoretical support for the clean production of coalbed methane.
- Published
- 2024
- Full Text
- View/download PDF
32. Understanding the origin of hydrogen sulphide in South-Western Gissar, Southern Uzbekistan
- Author
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Svetlana Yessalina, Elena Descubes, Amir Kuvanyshev, Anna Zhelezova, and Dana Shaikhina
- Subjects
H2S ,gas ,Gissar ,Reef ,Jurassic ,Geology ,QE1-996.5 ,Physical geography ,GB3-5030 - Abstract
Hydrogen sulphide (H2S) concentrations across three adjacent gas condensate fields in Southwestern Gissar produced from fractured Middle-Upper Jurassic reef-carbonates with anhydrite-bearing beds have been analysed. Wellsite testing measurements followed by iodometric titration showed concentrations of H2S below 0.2 mole%. Statistical analyses and cross plots of H2S vs. depth, reservoir temperature, porosity, anhydrite content, well tests and water saturation did not reveal linear correlations. Uniform gas condensate compositions and constant souring levels through time rule out secondary bacterial or/and technogenic processes, while temperatures bellow 90–110°С are against thermochemical sources. Low H2S values could result from mineral-fluid interactions within the host rock. However, low abundance of H2S and carbon dioxide (CO2) (
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- 2024
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33. Assessment of the influence of lithofacies conditions on the distribution of organic carbon in the Upper Devonian 'Domanik' deposits of the Timan-Pechora Province
- Author
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Oleg M. Prishchepa, Nikita V. Sinitsa, and Aidar Kh. Ibatullin
- Subjects
domanik type deposits ,facies ,formation ,organic matter ,sedimentary basin ,lithological type ,hydrocarbons ,oil ,gas ,Mining engineering. Metallurgy ,TN1-997 - Abstract
The study of high-carbon formations was instigated both by the decreasing raw material base of oil as a result of its extraction, and by the progress in development of low-permeability shale strata, primarily in the USA, Australia, and China. The most valuable formations occur in traditional hydrocarbon production areas – the West Siberian, Volga-Ural and Timan-Pechora, North Pre-Caucasian and Lena-Tunguska oil and gas provinces. Specific features of the Late Devonian-Early Carboniferous high-carbon formation occurring in the eastern marginal part of the East European Platform are: heterogeneous section due to intense progradation of the carbonate platform from west to east; succession of lithofacies environments that determined the unevenness of the primary accumulation and secondary distribution of organic matter (OM); possible migration or preservation in the source strata during the subsidence stages of the moving parts of bitumides, which determined the prospects for oil and gas potential. The distribution pattern of the present OM content was investigated depending on lithofacies conditions and lithological composition of rocks in the “Domanik type” Upper Devonian-Tournaisian deposits in the Timan-Pechora Province (TPP), its transformation degree to bring it to the initial content of organic carbon and further estimation of the share of stored “mobile oil” in oil and gas source formation. The study was based on the analysis of the data set on organic carbon content in core samples and natural exposures in the Ukhta Region in the Domanik-Tournaisian part of the section including more than 5,000 determinations presented in reports and publications of VNIGRI and VNIGNI and supplemented by pyrolytic and bituminological analyses associated with the results of microtomographic, macro- and lithological studies and descriptions of thin sections made at the Saint Petersburg Mining University. For each tectonic zone of the TPP within the investigated high-carbon intervals, the content of total volumes of organic carbon was determined. The data obtained allow estimating the residual mass of mobile bitumoids in a low-permeability matrix of the high-carbon formation.
- Published
- 2024
34. Pyrolysis of wheat straw pellets in a pilot‐scale reactor: Effect of temperature and residence time
- Author
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Bidhan Nath, Guangnan Chen, Les Bowtell, and Thong Nguyen‐Huy
- Subjects
biochar ,gas ,pyrolysis ,reactor ,wheat straw pellet ,Technology ,Science - Abstract
Abstract Pyrolysis of two types of pellets (T1: 100% wheat straw, and T2: 70% wheat straw; 10% sawdust, 10% biochar, and 10% bentonite clay) was performed in a pilot‐scale reactor under a nitrogen environment at 20°C to 700°C. This was to investigate slow pyrolysis yields and gas composition as a function of temperature and residence time. The experimental data were obtained between 300°C and 600°C, with a residence time of 90 min, a nitrogen flow rate of 50 cm3/min, and a heating rate of 20°C/min. The results indicated that the maximum pyrolysis temperature is 605°C with a residence time of 55 min. The product analysis showed that the proportion of gas was higher than that of biochar and bio‐oil. The conversion efficiency increased with higher temperatures and varied between 66% and 76%. The results showed that carbon dioxide was the main component in the produced gas, and the maximum gas concentration was 63.6% at 300°C for T1. The higher temperature and longer residence time increased the syngas (CO + H2) composition for both T1 and T2 treatments. Nevertheless, the produced biochar had a high carbon content and retained a high calorific value, indicating slow pyrolysis is the ideal utilization route of wheat straw pellet biomass for biochar.
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- 2024
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35. Evaluation of the Accuracy of Intraocular Lens Power Calculation Formulas in Phacovitrectomy
- Author
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Yuichiro Tanaka, Kazutaka Kamiya, Akihito Igarahi, Nobuyuki Shoji, Hiroshi Tsuchiya, Shinya Takahashi, Eri Ishikawa, and Tadahiko Kozawa
- Subjects
Phacovitrectomy ,Rhegmatogenous retinal detachment ,Barrett Universal II ,Prediction error ,Gas ,IOL position ,Ophthalmology ,RE1-994 - Abstract
Abstract Introduction The aim of this study was to evaluate the refractive error in patients undergoing combined phacovitrectomy with and without gas tamponade. Methods This was a retrospective chart review including patients undergoing phacoemulsification alone (Group 1), combined phacovitrectomy for epiretinal membrane (Group 2), and combined phacovitrectomy with gas tamponade for rhegmatogenous retinal detachment (RRD) (Group 3). Axial length and keratometry were measured using an optical biometric system (Argos, Alcon Laboratories. Inc.), and a three-piece intraocular lens (IOL; NX-70S) was implanted in all groups. In each group, the prediction error at 3 months was calculated using IOL power calculation formulas (SRK/T, Hill-RBF, Kane, and Barrett Universal II) for each eye. Outcome measures included the mean prediction error (MPE), its standard deviation (SD), and the mean absolute error (MAE). The change in IOL position at 3 months was also assessed using anterior segment optical coherence tomography. Results A total of 104 eyes were included (Group 1: 30; Group 2: 34; Group 3: 40 eyes). The MPE was −0.08 ± 0.37 diopters (D), −0.26 ± 0.32 D, and −0.59 ± 0.34 D in Group 1, Group 2, and Group 3, respectively, using the Barrett Universal II formula (P
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- 2024
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36. Russian gas sales to Central Asia will rise
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- 2024
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37. Abu Dhabi’s green energy firms acquisitions will grow
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- 2024
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38. Uncertainty over ‘peak oil’ to complicate policymaking
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- 2024
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39. Moscow’s LNG plans disrupted by sanctions
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- 2024
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40. Tourism will grow in economic importance in Oman
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- 2024
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41. Turkmenistan will develop transit corridors
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- 2024
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42. Current account surplus will allow Oman to reduce debt
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- 2024
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43. US presidential candidates differ on energy policies
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- 2024
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44. Algerian president’s win reinforces the status quo
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- 2024
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45. Key underwater cable project poses dilemma for Cyprus
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- 2024
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46. Venezuela stance may hit approval of Colombia’s Petro
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- 2024
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47. Oman will record a budget surplus in 2024
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- 2024
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48. Non-oil sector will drive United Arab Emirates growth
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- 2024
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49. Oman will issue further part privatisations by IPOs
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- 2024
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50. Mexico’s Sheinbaum will inherit major Pemex challenges
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- 2024
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