Carbon Dioxide Production Research Articles

Effect of biodegradable mulching plastics on soil chemical properties, greenhouse gas emission, and plant growth under aerobic and flooding conditions

ABSTRACT This study aims to examine the effect of biodegradable mulching plastics on soil chemical properties, greenhouse gas emission, and paddy rice growth under flooding conditions to compare with aerobic upland soil conditions. Four treatments were set-up with sandy paddy soil. Incubation experiment was conducted using three materials under aerobic pre-flooding condition for 0–3 months and then anaerobic flooding conditions for 3 months, measuring soil pH, carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) productions; rice growth, and yield. Amendments were biodegradable mulching sheets made of polybutylene adipate terephthalate (PBAT), or polybutylene-succinate (PBS), to compare with non-biodegradable mulching sheet made of low-density polyethylene (LDPE), mixed with paddy soil or without amendment (soil only; as control). Pot experiment was also conducted with the same materials, amended to the same soils, and rice seedings were transplanted 1 month after amendment and pre-flooding period under aerobic condition. During aerobic incubation, soil pH and CO2 was higher with plastics. N2O was produced during pre-flooding period, but no significant difference among the treatments. During anaerobic period, both CO2 and CH4 production were larger with biodegradable plastics with aerobically preincubated for 1 month than control and aerobically preincubated for 2–3 months. Rice growth, grain yield, and yield components had no significant difference among treatment, except gain number reduction with PBS. More CH4 was emitted with LDPE per yield scale. Biodegradable mulching plastics increased soil pH, CO2, and CH4 production under anaerobic conditions, although paddy rice growth was not affected. We need further examination with different materials, soils, and crop rotation.

Enteric methane emission classification and ranking of growing steers during the backgrounding and finishing phases.

There is limited information regarding the effect of beef cattle enteric methane (CH4) classification during the backgrounding and finishing phases and the impact of using metabolic modulators such as growth-promoting implants. This experiment aimed to determine how CH4 and residual CH4 emission (RME) classification impact gas flux and whether implanted or non-implanted growing steers maintain the same CH4 and RME classification during the backgrounding and finishing phases. A total of 46 Angus steers (approximately 8 months of age and 244 ± 11.1kg of initial body weight [BW]) were enrolled. During the finishing phase, 23 steers were implanted, while 23 did not receive an implant. Individual animal growth performance and gas flux (CH4 and carbon dioxide (CO2) production and oxygen (O2) consumption) were determined during the backgrounding and finishing phases. In addition, RME was individually determined using metabolic BW and dry matter intake (DMI). In the backgrounding and finishing phases, steers were ranked in ascending order according to their CH4 production (g/d), CH4 yield (g/ kg of DMI), CH4 intensity (g/ kg of average daily gain), and RME. Consequently, steers were classified as low, medium, and high emitters based on the quartile distribution. Then, gas flux was analyzed using a completely randomized design for each phase. The relationship between the initial CH4 and RME classification during the backgrounding and the subsequent classification during finishing was analyzed using Fisher's exact test. Steers classified as low CH4 or RME had lower (P < 0.05) CH4 production than high emitters during the backgrounding and finishing phases. The production of CO2 varies among classification groups regarding the growing phase and the use of growth-promoting implants. The consumption of O2 was lower (P < 0.05) in steers classified as low CH4 emitters during the backgrounding but not (P > 0.05) during the finishing phase. In addition, between 35 and 83% of the steers re-ranked according to CH4 and RME classification from the backgrounding to the finishing phase. In conclusion, the classification of growing steers using CH4 production, yield, intensity, or RME results in animals with lower CH4 production during the backgrounding and finishing phases. However, CH4 or RME classification should be conducted in each phase because growing steers re-ranked when changing from the backgrounding to the finishing phase.

Novel Triple-Oxygen Isotope Study Indicates Unprecedented Ozone-Particulate Interaction Pathways in Atmospheric Pollution Chemistry.

Ozone plays a fundamental role in the chemistry of the atmosphere, mediating oxidation reactions in phases and at phase boundaries. Here, we investigate the least-explored solid-phase heterogeneous processes involving ozone to understand the reaction pathways of O3 with airborne aerosols. Using triple oxygen isotope ratios as tracers, we found that the ozone reaction oxidizes organic particles and produces carbon dioxide, with oxygen atoms largely from O3. Along with the formation of CO2, an equal amount of O2 from water decomposition is inferred. Chemical reaction kinetics, however, is yet to be identified. One hypothetical pathway is through Criegee intermediates, formed by the reaction of ozone with aldehyde/ketone-like organic compounds (unsaturated hydrocarbons) catalyzed by metal oxides. Inclusion of the process in a chemistry-transport model could yield a significant change in the ozone budget. The study shows the importance of ozone-induced heterogeneous chemical reactions on aerosol surfaces occurring in polluted atmospheres.

Co-delivery of doxorubicin and glycyrrhetinic acid via acid/glutathione dual responsive nano-prodrug with sodium bicarbonate carry-on for advanced combinational cancer treatment.

The combination of doxorubicin (Dox) and glycyrrhetinic acid (GA) has been widely explored for treating various cancers, while the heterogeneous distribution, uncontrolled release and acid tumor microenvironment often hinder their synergistic effects. Herein, we introduce an acid/glutathione (GSH)-dual responsive nano-prodrug (AS1411@Dox+GA/NPs) enabling precise co-delivery of Dox and GA for enhanced combination therapy. The GSH-activated Dox prodrug [Poly(lactic-co-glycolic acid)-disulfide-Dox, PLGA-ss-Dox], GA, and sulfur-terminated D-α-tocopherol polyethylene glycol succinate (TPGS-SH) are combined to form a nanoemulsion with sodium bicarbonate (NaHCO3) in the aqueous phase. The AS1411 aptamer is modified on the surface for tumor-specific targeting. Upon reaching the tumor via enhanced penetration and retention effects, AS1411 aptamer medicates specific endocytosis of AS1411@Dox+GA/NPs into tumor cells. Intracellularly, the acidic endosomal environment promotes carbon dioxide (CO2) production from NaHCO3, disrupting the nanoemulsion and causing a burst release of GA and PLGA-ss-Dox prodrug. Concurrently, high levels of GSH in the cytoplasm triggers the cleavage of the disulfide linker, thereby releasing Dox. Notably, the released NaHCO3 consumed hydrogen ion (H+), amplifying the sensitivity of tumor cells to Dox. As a consequence, AS1411@Dox+GA/NPs exhibits remarkable synergistic therapeutic efficacy in mouse models of both liver cancer and breast cancer. This work presents an appealing approach utilizing stimuli-sensitive nano-prodrug for advanced combinational cancer treatment.

Effect of different moisture content on nitrous oxide production in aggregated soil of Shintoku, Japan

Agricultural soils are the major source of the potent greenhouse gas and ozone-depleting substance, N2O. An incubation study was carried out using the volcanic ash fine textured soil of Shintoku. Soil samples used in this study were taken from managed grassland at Shintoku Experimental Livestock Farm of Hokkaido University in Southern Hokkaido, Japan (N43º05′, E142º51′). Soil aggregates were air-dried, and sieved with 4.5 mm and 2 mm and adjusted the soil moisture of 60% and 80% of field water capacity (FWC). Just after the moistening, the aggregates were incubated for 9 days under a temperature of 20°C. Just after starting the incubation, the flush of N2O production was observed. Similar flushes of carbon dioxide (CO2) and nitric oxide (NO) productions were also observed. All of the gas productions were higher in larger aggregates with 80% of field water capacity. The concentrations of Water Extractable Organic Carbon (WEOC), NH4+-N, pH and total N were significantly different before and after incubation. Shintoku soil showed a significant correlation between before and after incubation for all soil chemical properties except pH. Especially WEOC and NH4+-N changed immediately after the addition of water and this situation continued during the incubation. Larger aggregates showed higher amounts of NH4+-N and NO3-–N and were responsible for higher N2O production compared to smaller aggregates. In Shintoku the results of N2O-N/NO-N ratio in both moisture contents indicated nitrification as a main process of N2O production. It is very well known that N2O is produced more from the denitrification process than nitrification. Poor aeration and less diffusion of NO3-N and WEOC from the aerobic area to the anaerobic area reduce N2O production in the denitrification process of fine textured Shintoku soil. Int. J. Agril. Res. Innov. Tech. 14(2): 99-110, December 2024

Prediction of left ventricular reverse remodeling in patients with heart failure with reduced ejection fraction using cardiopulmonary exercise testing.

With advances in the treatment of heart failure with reduced ejection fraction (HFrEF), the prediction of left ventricular reverse remodeling (LVRR) has become increasingly important. Cardiopulmonary exercise testing (CPET) is a non-invasive test recommended for prognostic risk assessment in HFrEF; however, it is not known whether it predicts LVRR. We aimed to investigate whether the parameters obtained from CPET are useful in predicting LVRR in HFrEF. We retrospectively evaluated 230 consecutive patients with HFrEF [left ventricular ejection fraction (LVEF) ≤40 %] hospitalized for acute heart failure (59 ± 14 years, 78 % males) who underwent CPET before discharge. We investigated whether the CPET parameters, peak oxygen consumption (VO2), and the minute ventilation (VE) vs. carbon dioxide production (VCO2) slope could predict LVRR within 1 year (LVEF >50 %). Among 230 patients, 89 (39 %) exhibited LVRR. In multivariable logistic analysis, higher peak VO2 [odds ratio (OR): 1.13, 95 % confidence interval (CI): 1.05-1.22, p < 0.001] and lower VE vs. VCO2 slope (OR: 0.95, 95 % CI: 0.91-0.98, p < 0.001) were independently associated with LVRR. In receiver operating characteristic curve analysis, peak VO2 [area under the curve (AUC): 0.657, p < 0.001, optimal cut-off: 15.5 mL/min/kg] and VE vs. VCO2 slope (AUC: 0.663, p < 0.001, optimal cut-off: 35.8) were significant predictors of LVRR. Moreover, combining the peak VO2 and VE vs. VCO2 slope improved the predictive value (AUC: 0.682). CPET is a valuable test for the non-invasive detection of LVRR. The combination of peak VO2 and the VE vs. VCO2 slope is useful for predicting LVRR among hospitalized patients with HFrEF receiving pharmacological treatment.

The Negative Legacy Effect of Extreme Drought on Soil Respiration Is Unaffected by Post-Drought Precipitation Regime in a Temperate Grassland.

Soil respiration, the main ecosystem process that produces carbon dioxide into the atmosphere, is sensitive to extreme climatic events. The immediate, usually negative effect of droughts on soil respiration has often been observed, but the recovery of soil respiration following drought is rarely documented. Soil respiration can be reduced beyond the drought year if drought-induced changes suppress soil activity. Alternatively, reduction in soil respiration may be overcompensated in the subsequent years due to increased substrate input and soil moisture, resulting from plant dieback during drought. In addition, post-drought weather patterns may also affect the recovery of soil respiration. In a full-factorial grassland experiment, we combined an extreme (5 months) summer drought in 2014 with four levels of post-drought precipitation regimes, including severe (2 months) droughts, moderate (1 month) droughts, ambient weather, and water addition (four large rain events) in summers of 2015 and 2016. We measured soil respiration monthly between May and November, from 2013 to 2016. The extreme drought had an immediate strong negative effect, decreasing soil respiration by 50.8% in 2014 compared to the control plots, and it had a negative legacy effect in 2015 (14.5% reduction), but not in 2016. This legacy effect was unaffected by the post-drought precipitation regime. Moderate drought decreased soil respiration by 12.1% and 18.6%, while severe drought decreased soil respiration by 18.3% and 27.3% in 2015 and 2016, respectively, while water addition had no effect. Since soil water content in extreme drought plots recovered by 2015, we hypothesize that changes in soil biota and reduced root activity are responsible for extreme drought's long-term negative effects. Overall, our results highlight that extreme droughts may have negative effects on soil respiration well beyond the event, and thus the full effect on carbon cycling may be much larger than what is estimated solely based on the immediate effects.

Methanogenesis rather than carbon dioxide production drives positive priming effects in anoxic sediments of saline lakes

Methanogenesis rather than carbon dioxide production drives positive priming effects in anoxic sediments of saline lakes

The complex relationship between arterial carbon dioxide levels and acute heart failure: implications for prognosis and management

Acute Heart Failure (AHF) can affect carbon dioxide levels in the body by altering the balance between ventilation and carbon dioxide production, leading to either hypocapnia or hypercapnia. Arterial carbon dioxide (CO2) levels are essential for maintaining respiratory function and acid-base balance. However, the relationship between arterial CO2 levels and AHF remains complex and not fully understood. Diverse factors affect arterial CO2 levels in patients with AHF, including neurohormonal activation, respiratory compensation for hypoxemia, and changes in pulmonary perfusion. Hypocapnia, characterized by low arterial CO2 levels (PaCO2 &lt; 35 mmHg), is commonly observed in AHF due to hyperventilation-driven respiratory alkalosis secondary to pulmonary congestion. It showed a strong connection with the survival rates of patients following a cardiac arrest. Nevertheless, elevated levels of carbon dioxide in the blood, known as hypercapnia, with a partial pressure of arterial carbon dioxide (PaCO2) exceeding 45 mmHg, can also arise in the later phases of acute heart failure (AHF), indicating fatigue in respiratory muscles or deterioration in pulmonary edema. Abnormal arterial CO2 levels have been associated with increased morbidity and mortality in AHF patients, serving as a valuable prognostic marker. Keywords: Acute Heart Failure, Arterial Carbon Dioxide, Hypercapnia, Hypocapnia

Adjusting the Ratio of Oxidation States in a CuO@Cu2O for the Optimization of Electrocatalytic CO2 Conversion to Ethylene.

Understanding the impact of surface copper valence states on the distribution of electrochemical carbon dioxide products is critical. Herein, CuO@Cu2O with a Cu2+/Cu+ interface was fabricated using wet chemical etching approach. The hollow shape offered a large region for gas adsorption, while the interfacial mixed chemical state of Cu2+/Cu+ with tunable control ratio raised the local density of CHO* and accelerated the carbon-carbon coupling reaction. The H-cell test results demonstrate that, as result of this precise structural design, the Faraday efficiency of ethylene is enhanced from 15.2 % to 43.5 %, and the service life is increased 4 times. In addition, its selectivity is almost 50 % and its partial current density in MEA is 93.2 mA cm-2. In situ Raman and DFT data demonstrate that the Cu2+/Cu+ interface effect enhances the concentration of COCHO intermediates and lowers the energy barrier for the conversion of CO* to COCHO* intermediates.

Theoretical Insights into Methanol Electro-Oxidation on NiPd Nanoelectrocatalysts: Investigating the Carbonate–Palladium Oxide Pathway and the Role of Water and OH Adsorption

We conducted a theoretical and experimental study on the electro-oxidation of methanol (MOR) on NixPdy nanoparticles. The results are presented in terms of kinetic parameters, surface concentrations, and peak currents, showing significant differences between three main compositions: Ni3Pd1, Ni1Pd1, and Ni1Pd3. The kinetic mechanism adopted for accounting the linear voltammetry experiments performed follows the carbonate–palladium oxide pathway of the MOR. Numerical simulations of the kinetic equations, fitted to experimental data obtained at varying methanol concentrations, allowed us to distinguish the adsorption contributions of methanol, water, and OH ions from the nonlinear contribution associated with palladium oxide and carbon dioxide production. The synergistic effects of Ni:Pd nanoalloys on the MOR were then assessed by analyzing the behavior and tendencies of the reaction rate constants for different bulk methanol concentrations. Our results suggest that a higher Pd content favors more efficient oxidation mechanisms by reducing the formation of intermediate products that cause surface poisoning, such as CO, carbonates, or palladium oxide. However, as the proportion of Ni increases, an increase in the concentration of adsorbed OH is observed, which dominates the blocking of active sites even greater than the palladium oxide blocking.

Feasibility and inter-reporter variability of submaximal outcomes derived from cardiopulmonary exercise testing in people with advanced cystic fibrosis lung disease

BackgroundCardiopulmonary exercise testing (CPET) provides prognostic information in people with advanced cystic fibrosis lung disease (pwACFLD). This project aimed to ascertain feasibility and inter-reporter variability in the identification of submaximal CPET outcomes for pwACFLD as potential predictors of prognosis where no peak exercise data are available.MethodsWe utilised data from an international retrospective multicentre study involving pwACFLD, for whom raw CPET data were available. Two experienced operators independently reviewed and analysed CPET tests with a focus on three pre-defined measures: oxygen uptake (V̇O2) at the anaerobic threshold (AT), the breathing reserve index at the AT (BRIAT), and the slope of the minute ventilation to carbon dioxide production ratio (V̇E/V̇CO2-slope). We calculated intra-class correlation coefficients (ICC) with their 95% confidence intervals (CI), and limits of agreement using the Bland-Altman method.ResultsThe original cohort included 174 pwACFLD. Among those, raw CPET data were available for 101 individuals, of which 89 tests were of sufficient technical quality for submaximal analysis. In 72 out of 89 technically-acceptable tests (81%), the AT could be confidently identified by both operators. Furthermore, ICCs indicated good-to-excellent inter-reporter agreement for V̇O2at the AT [ICC (95% CI) 0.79 (0.62 to 0.88)], the V̇E/V̇CO2-slope [0.95, 0.93 to 0.97)], and BRIAT [0.76, 0.63 to 0.85].ConclusionsSubmaximal CPET data can be reliably obtained in most pwACFLD by trained CPET operators. Future studies may ascertain the prognostic value of submaximal CPET outcomes in pwACFLD.

The Effect of a Novel Functional Solid Drink on Obesity Management and Its Underlying Mechanisms

ABSTRACTObesity has become a global public health concern, yet an effective, low‐toxic, and high‐compliance strategy for its control remains elusive. This study aims to develop a novel comprehensive intervention method for the management of obesity and its complications. Thus, we designed a functional solid beverage named RLMCR, which consists of medicinal and edible Chinese herbs. We identified its chemical composition and evaluated its efficacy. Our results indicated that RLMCR was abundant in various functional ingredients, including flavonoids, polyphenols, and terpenoids. It could mitigate lipid accumulation in 3T3‐L1 cells by upregulating the expression of lipolysis‐related genes. We then established diet‐induced obese (DIO) mice models, which were administered with low, middle, and high doses of RLMCR for 8 weeks. Our findings indicated that the optimal dosage of RLMCR for weight loss was 3.0 g/kg, which effectively mitigated weight gain, lipid accumulation, hepatic steatosis, and abnormal glucose metabolism. Following treatment, oxygen consumption, carbon dioxide production, and thermogenesis were increased in DIO mice, without affecting food intake. The content of brown adipose tissue was significantly elevated, and the expression of thermogenesis‐related genes and lipolysis‐related genes in the epididymal white adipose tissue was upregulated. So, we developed a novel functional food that effectively mitigates obesity and its related metabolic disorders.

Terrestrial Organic Matter Contributes to CO2 Production From Siberian Shelf Sediments

AbstractArctic climate warming is causing permafrost thaw and erosion, which may lead to enhanced inputs of terrestrial organic matter into Arctic Ocean shelf sediments. Degradation of terrestrial organic matter in sediments might contribute to carbon dioxide production and bottom water acidification. Yet, the degradability of organic matter in shallow Arctic Ocean sediments, as well as the contribution of terrestrial input, is poorly quantified. Here, potential organic matter degradation rates were investigated for 16 surface sediments from the Kara Sea, Laptev Sea, and the western East Siberian Sea and compared with physicochemical sediment properties including molecular biomarkers, stable and radioactive carbon isotopes, and grain size. Aerobic oxygen and carbon dioxide fluxes, measured in laboratory incubations of sediment slurry, showed high spatial variability and correlated significantly with organic carbon content as well as with the amount and degradation state of terrestrial organic matter. The dependency on terrestrial organic matter declined with increasing distance from land, indicating that the presence of terrestrial organic matter is likely a constraining factor for organic matter degradation in shallow shelf seas. However, sediment oxygen consumption rates, measured in incubations of intact sediment cores, also exhibited substantial spatial variability but were not related to organic carbon content or terrestrial influence. Oxygen consumption of intact sediments may be more strongly influenced by in situ redox conditions. Together with previous observations, our findings support that terrestrial organic matter is easily degradable in shelf sea sediments and might substantially contribute to aerobic carbon dioxide production and oxygen consumption.

Substantial and overlooked greenhouse gas emissions from deep Arctic lake sediment

Thermokarst lakes cause abrupt and sustained permafrost degradation and have the potential to release large quantities of ancient carbon to the atmosphere. Despite concerns about how lakes will affect the permafrost carbon feedback, the magnitude of carbon dioxide and methane emissions from deep permafrost soils remains poorly understood. Here we incubated a very deep sediment core (20 m) to constrain the potential productivity of thawed Yedoma and underlying Quaternary sand and gravel deposits. Through radiocarbon dating, sediment incubations and sediment facies classifications, we show that extensive permafrost thaw can occur beneath lakes on timescales of decades to centuries. Although it has been assumed that shallow, aerobic carbon dioxide production will dominate the climate impact of permafrost thaw, we found that anaerobic carbon dioxide and methane production from deep sediments was commensurate with aerobic production on a per gram carbon basis, and had double the global warming potential at warmer temperatures. Carbon release from deep Arctic sediments may thus have a more substantial impact on a changing climate than currently anticipated. These environments are presently overlooked in estimates of the permafrost carbon feedback.

Quantification Of Greenhouse Gas Emissions in a Cement Company and System Dynamics Modeling Toward Carbon Neutral

The cement industry is one of the sectors that produces carbon dioxide (CO2) emissions due to its raw material processing and energy requirements. CO2, as a greenhouse gas (GHG) emission, contributes to global warming, leading to environmental, health, and economic losses. To address these issues, Indonesia is committed to reducing GHG emissions in the industrial sector by 2050. To effectively plan for the reduction of GHG emissions generated by companies, this study aims to quantify emissions from a cement company, representing the cement industry in Indonesia, to understand the current state of the company's carbon footprint and identify feasible mitigation measures. The cement industry utilizes a GHG quantification system to calculate emissions from raw material processing, thermal energy consumption, and electricity purchases. The calculation results from a cement company are used for system dynamics modeling with Vensim PLE software for the period from 2021 to 2050, under business-as-usual (BAU) conditions with various emission reduction strategies. The results show that GHG emissions under BAU conditions with emission reduction strategies do not achieve carbon neutrality by 2050. More intensive adoption of decarbonization technologies, research on process optimization, and government policies such as carbon taxes and carbon trading are required to achieve carbon neutral goals.

Solar Distillation of White Wine to Obtain Brandy

Aim: The aim of the research was to replace gas energy with renewable solar thermal energy in a white wine distillation process to obtain brandy. Theoretical background: Almost all distillers of spirits in the world use conventional energy that produces carbon dioxide, solar energy in this distillation process is an environmentally friendly alternative. Method: In this study, a reused ck-002 parabolic solar cooker was used and the wine was obtained from a fermentation of Italian white grapes. In each distillation, the black painted still was filled with 4 L of wine. When distilling, solar energy was compared to liquefied petroleum gas (LPG) energy. The distillation tests were carried out from 10:00 to 14:00 h under ambient conditions. Results and conclusion: The solar distillation time was 140 min and its boiling temperature in the receiving of the spirit was between 88 to 93 °C, in the gas cooker the time was 240 min and boiling temperature was 84 to 93°C. The heating of the still using solar energy was homogeneous with respect to the gas cooker. Solar energy presents a good alternative to replace gas energy in the distillation process to obtain brandy, reducing its cost without producing CO2. Implications of the research: To look for alternatives that can substitute gas energy, such as solar energy, which produces less negative impacts on the environment. Originality/value: The use of solar distillers is a technology that will reduce the production of CO2.

The influence of increasing doses of mineral fertilizers on the balance of organic carbon in spring wheat crops in the forest-steppe zone of the Trans-Urals

The global community is currently solving several interconnected problems of global climate change and food security. The key to solving these problems is carbon, which is one of the most active greenhouse gases, as well as humic substances, which are the basis of arable land fertility. To implement the adopted "4 ppm" concept, it is necessary to find solutions to increase the absorption of organic carbon by arable soils and select the optimal elements of the farming system for specific soil and climatic conditions. The objective of the study was to study the effect of increasing doses of mineral fertilizers on the balance of organic carbon in spring wheat crops in 2023 in the, Tyumen Region (forest-steppe zone of the Trans-Urals). The scheme of the experiment: control (natural nutrition level) and variants with doses of NP fertilizers calculated for the planned yield: 3.0 t/ha (N95P46); 4.0 t/ha (N153P94); 5.0 t/ha (N211P142) and 6.0 t/ha (N270P190). Carbon dioxide emissions were measured using a chamber method and an AZ77535 infrared gas analyzer. Before harvesting, sheaves were sampled to determine the straw yield in 4-fold repetitions per 1 m2 , after harvesting – soil to determine the amount of root and stubble residues (RCR) using the method of N. Z. Stankov. Subsequently, the organic carbon content in plant residues was determined according to GOST 27980. During the growing season, carbon emissions in spring wheat crops without the use of fertilizers amounted to about 2400 kg/ha. The application of mineral fertilizers increased carbon dioxide production by 28–73 % relative to the control. It was noted that every 10 kg/ha active ingredient of mineral fertilizers increased carbon emission by 40.6 kg/ha in terms of pure carbon. Fertilizers in doses of N95-153Р46-94 did not affect the Corg content in spring wheat straw. The use of higher doses of mineral fertilizers led to a decrease in this indicator by 0.8 %. No reliable effect of mineral fertilizers on the Corg content in RCR was noted, the values of which varied from 41.3 to 42.0 % of dry matter. The return of organic carbon to the soil with plant residues in the control reached 2.2 t/ha, in the fertilized variants this indicator increased to 2.8–3.8 t/ha. When refusing to use fertilizers, a negative carbon balance is observed in the soil – Corg losses over the year of study amounted to 196 kg/ha. Fertilizer application at doses from N95P46 to N153P94 provided an increase in Corg in the soil of 93–96 kg/ha over the study period. Fertilizer application at doses above N211P142 led to a negative balance of Corg in the soil – losses reached 188–350 kg/ha.

Analysis on the Impact of Different Fuels on Aircraft Contrails and the Environment

Aircraft contrails significantly impact the environment, primarily because they emit gases such as carbon dioxide and nitrogen oxides. These contrails are a type of 'cirrus cloud,' composed of young linear condensation trails and older, irregularly shaped trails that they produce. As contrails form, the byproducts of fuel combustion, such as carbon dioxide, linger in the air for a long time, altering the concentration of carbon dioxide in the atmosphere and causing the atmospheric temperature to rise. Different fuels produce different gases when burned, some of which may be harmful to the environment. In this article, this paper will summarize articles on how different fuels affect contrails and the environment. The results show that different fuels produce different gases when burned, some of which are harmful to the environment, while others are not. Traditional fuels like jet fuel generate carbon dioxide and water vapor, whereas new energy sources like hydrogen do not produce carbon dioxide. Different fuel types primarily influence aircraft contrails through their combustion products and efficiency. Aviation kerosene, as the mainstream fuel, produces water vapor that easily forms contrails under high-altitude, low-temperature conditions. In contrast, biofuels or alternative fuels, due to differences in their chemical composition, may produce less water vapor or other gases that affect contrail formation during combustion.

A LOW-IMPACT HIGH-EFFICIENCY BRAYTON CYCLE CONCEPT WITH EVAPORATIVE COOLING DURING THE COMPRESSION PROCESS USING H2/CH4 FUEL BLENDS

Towards a low-impact, high-efficiency Brayton cycle concept, a gas generator system including a compressor with evaporative cooling, a combustion chamber using H2/CH4 fuel blends, and a gas turbine is being analyzed at this preliminary stage. The Constructal approach on the effectiveness of compressed air temperature control by evaporative cooling, previously carried out by the authors, shed some light on the potential growth of mechanical power provided by gas turbine power plants of 45.81% and a simultaneous reduction of 2.26% in specific fuel consumption. The current study carried out on the combustion chamber reveals that increasing the H2 fraction in the fuel blend results in a direct reduction in carbon dioxide production and a decrease in CO and NOx emissions when the temperature of the flue gas is maintained at 1450 K. Meanwhile, the exergy efficiency of the combustion chamber remains almost constant at 39.3%. Studying the two components already analyzed, the compressor and the combustion chamber, allows us to move towards a low-impact, high-efficiency Brayton cycle concept as close as possible to its technical implementation.