Gas Balance Research Articles

The global energetics of radio AGN kinetic feedback in the local Universe

AGN feedback is a crucial ingredient for understanding galaxy evolution. However, a complete quantitative time-dependent framework, including the dependence of such feedback on AGN, host galaxy, and host halo properties, is yet to be developed. Using the complete sample of 682 radio AGN from the LOFAR-eFEDS survey (z<0.4), we derive the average jet power of massive galaxies and its variation as a function of stellar mass (M_*), halo mass (M_h) and radio morphology. We compare the incidence distributions of compact and complex radio AGN as a function of specific black hole kinetic power, λ_ Jet, and synthesise, for the first time, the radio luminosity function (RLF) by M_* and radio morphology. Our RLF and derived total radio AGN kinetic luminosity density, log kin W Mpc^ align with previous work. Kinetic feedback from radio AGN dominates over any plausible inventory of radiatively driven feedback for galaxies with log M_*/M_⊙ > 10.6. More specifically, it is the compact radio AGN that dominate this global kinetic energy budget for all but the most massive galaxies ($10.6 < ⊙ < 11.5$). Subsequently, we compare the average injected jet energy (overline E_ Jet ) against the galaxy and halo binding energy (U_ bin), and against the total thermal energy of the host gas (E_ th) within halos. We find that compact radio AGN lack the energy to fully unbind galaxies, but complex AGN reach E_ Jet > U_ bin in the most massive systems (log M_*/M_⊙ > 11.5), where such energy is likely deposited beyond the typical galaxy sizes. On halo scales, neither compact nor complex radio AGN provide enough energy to fully disrupt the global gas distribution, especially not for the most massive clusters. On the other hand, overline E_ Jet greatly surpasses the global E_ th for groups, thereby providing a crucial input to the gas and thermodynamical balance in these systems. Finally, we show that AGN jets can also significantly impact the local thermodynamical balance in the cores of large groups and massive clusters. Overall, our findings provide important insights into jet powering, accretion processes and black hole-galaxy coevolution via AGN feedback.

Study on methane flux variation characteristics and regulation mechanisms in urban wetlands under different restoration years and moisture gradients.

Study on methane flux variation characteristics and regulation mechanisms in urban wetlands under different restoration years and moisture gradients.

Development of an estimation tool for monitoring growth and starch storage in microalgae cultures based on gas balance analysis

Development of an estimation tool for monitoring growth and starch storage in microalgae cultures based on gas balance analysis

How do diet shifts affect the greenhouse gas balance of agricultural soils? Denmark as a case study

How do diet shifts affect the greenhouse gas balance of agricultural soils? Denmark as a case study

CH3OH•+ + CH4 Reaction: Mechanistic Insights and Reaction Rates for Astrochemical and Atmospheric Environments

The reaction between methanol radical cations and methane, producing methyl radicals and protonated methanol, is pivotal to both astrochemical and atmospheric processes. Methanol and methane are the most abundant organic molecules in space and Earth’s atmosphere and central to molecular synthesis under different environmental conditions. Here, we present a combined experimental and theoretical investigation of the ion–molecule reaction between CH3OH•+ and CH4. The study explores the reaction mechanism and energetics under ionized conditions utilizing quantum chemical methods and experimental data. The findings reveal that the reaction’s non-thermal behavior becomes pronounced when CH3OH•+ is vibrationally excited by photon absorption above the ionization threshold, as can happen in the presence of ionizing agents like cosmic rays. Conversely, in thermal equilibrium conditions, the reaction accelerates as temperatures decrease, as suggested by canonical rate coefficient calculations. The products can initiate further chemical reactions, shaping molecular networks in the interstellar medium and affecting atmospheric trace gas balances.

Introduction to the Use of Microbial Communities.

Microbes are the third major group of biospheric organisms after plants and animals. They are responsible for many natural circulations, including the rotation of elements. They return organic carbon for plants' use and dissolve minerals into organic cycles. Microbes contribute to the global gas and water balances. In animal digestion, they partake in the degradation and assimilation of nutrients. Typically, they act as communities where some strains are the most active at a given time point in the prevailing conditions. But they also live in a continuous state of succession, which precludes the maintenance of changeable balances. Whether functioning in soil, in our alimentary tract, or elsewhere, the micro-organisms decisively contribute to the restoration of various balances. As the microbiological scale differs significantly from our comprehension, we must nurture our understanding of the microbiome wherever itoccurs. For example, one spoonful of yoghurt contains approximately as many bacterial cells as there are humans residing on Earth. Therefore, flexibility and interaction are the most advisable modes of operation in microbial biochemistry and biotechnological applications. As microbes tend to form communities, this modus operandi is worth instigating in our process industries and production technologies. The use of microbial mixed cultures most appropriately corresponds to the natural systems [1]. As biocatalysts in human endeavours of biorefining and bioengineering, they have become the most utilizable and producible kind of microbial components. Cooperation with microbes is a prerequisite for the continuous development of sustainable industries and food and health production. The microbial communities can be used to prevent and clean up pollution. In the process design, the microbiological dynamic balances make the highest productivity, repeatability, controllability, and withstanding of entropy. Although their effects have been familiar to our societies, e.g. in the fermentation of foods, their total capacity remains to be put into service. Hopefully, this book could help turn the next page in the development.

A comparison of fast-growing maritime pine (Pinus pinaster Aiton.) plantations with native broadleaved vegetation for greenhouse gas balances

Establishing fast-growing plantations is a long-term strategic climate change mitigation option, since these plantations may absorb carbon at an accelerated rate and alleviate the pressure on natural forests. In Istanbul, nearly 5% of the forests, totaling 32 603 ha of natural oak–beech forest ecosystems, were converted to maritime pine ( Pinus pinaster Aiton.) plantations in the 1990s. Maritime pine grows faster than native mixed broadleaf forests but introduces a higher fire risk. The objective of this study was to assess the greenhouse gas (GHG) consequences of these conversions by analyzing wildfire emissions and carbon stock changes for a period of two decades after conversion. The carbon modeling was done using the Carbon Budget Model of the Canadian Forest Sector model calibrated with ground measurements. The results revealed that the total ecosystem carbon stocks would remain at 97.9 tC/ha (Avoided Species Conversion scenario) compared to 116.7 tC/ha in the Business as Usual (BAU) scenario. The BAU scenario refers to real-life conditions that the species conversions have occurred. The fire emissions had a minor share in total ecosystem GHG balance, because the burnt area rate was low (around 0.1%) during the assessment period.

Prematurity and growth retardation: different causes of fetal coagulation disorders

prematurity and fetal growth retardation complicates in general one in five pregnancies. The combination of prematurity with severe growth retardation and hypoxia worsens the prognosis due to increase of periventricular hemorrhage incidence, and later coronary heart disease, hypertension, stroke, miscarriage and fetal growth retardation in own pregnancies in adulthood. The causes of impaired blood coagulation and fibrinolysis in retardated and premature newborns remain poorly understood. The goal of the study - to compare the parameters of blood acid-base and gases balance, coagulation and fibrinolysis in prematurity and growth retardation. Material and methods. Newborns of three clinical groups were examined. 24 full-term newborns with a postnatal diagnosis of I-II growth retardation stage constituted group I. 18 newborns of group II were born prematurely, corresponding to pregnancy term of 28-34 weeks. Control group III consisted of 20 full-term healthy infants. The birth took place without emergency interventions and without perinatal losses. Blood samples of the umbilical cord artery were obtained immediately after it was clamped. The parameters of blood acid-base and gas compositionof mothers and newborns blood and the fetal kinetic characteristics of blood coagulation and fibrinolysis were compared. Results. Newborns of group I had a pH of 7.27±0.012, in group II - 7.33±0.022, in group III - 7.30±0.024, which corresponded to the difference between maternal and fetal values of 0.10; 0.07 and 0.13. The pH difference in growth retarded fetuses is higher than in premature fetuses, closely to that of full-term fetuses, despite the lowest pH. Parameters of pO2 and pCO2 in labor do not have an indicative difference in newborns of all groups. Thromboelastometric parameters of the premature infants blood indicate low density and accelerated clot lysis, but while growth retarded fetuses accelerated formation and incomplete clot lysis. That is because of notable predominance of endothelial origin procoagulant factors in growth retarded fetuses. Indicators of acid-base and gas balance in newborns with growth retardation are shifted towards acidosis, in contrast to anthropometrically similar premature infants, whose indicators are higher than full-term fetuses ones.

Adaptive mechanisms to hypoxia and hyperoxia in juvenile turbot, Scophthalmus maximus

In recirculating aquaculture systems (RAS), the impact of dissolved oxygen (DO) fluctuations on turbot is still not fully understood. This study investigated these impacts by selecting 135 turbot (average dry weight: 6.0 ± 0.5 g) and exposing them to three DO levels: hypoxia (4.0 ± 0.5 mg/L), normoxia (7.5 ± 0.5 mg/L), and hyperoxia (23.5 ± 0.5 mg/L). These groups were labeled as LF (low oxygen), NF (normal oxygen), and HF (high oxygen). The study aimed to explore the adaptive mechanisms of turbot under hypoxic and hyperoxic conditions, using microbiome, transcriptome, and hematological analyses over a 40-day period. The results suggest that hyperoxia significantly enhances turbot growth without compromising the composition of intestinal microbiome, whereas hypoxia markedly impairs growth and induces alterations in intestinal microbiome. Transcriptomic analysis revealed various pathways implicated in adaptation to both hypoxic and hyperoxic conditions, encompassing amino acid metabolism, protein metabolism, lipid metabolism, carbohydrate metabolism, the PPAR signaling pathway, etc. However, pathway changes are not completely consistent. For instance, pancreatic secretion is crucial for hyperoxia adaptation, while the HIF1α pathway plays a key role in hypoxia adaptation and tissue repair. Furthermore, genes ATP6, HIF1, HSP90, and CYP450 exhibited high expression levels during hypoxia, whereas Hbae5 and Man-SL showed elevated expression during hyperoxia. In hematological indicators, there are ways to help adapt to hypoxia and hyperoxia, including increased red blood cell (RBC) and hemoglobin (HGB) counts; gas and ion balance; elevated blood urea nitrogen (BUN) and malondialdehyde (MDA); increased polyphenol oxidase (PPO) and lysozyme (LZM) activity. Although turbot have adaptive mechanisms to both hypoxia and hyperoxia, extended exposure to hypoxia detrimentally affects growth, whereas hyperoxia facilitates it. These findings provide significant insights into the adaptive mechanisms of turbot in response to fluctuating DO levels.

Acid-base composition of mice blood during the progression of toxic pulmonary edema

BACKGROUND: Modeling toxic pulmonary edema for the purpose of studying the effectiveness of drugs is associated with difficulties in model validation and objectification of drug effectiveness criteria. To confirm the significance of changes in pulmonary coefficients and visual changes in lung tissue, acid-base balance and blood gas analysis are often used to objectify emerging gas exchange disorders. AIM: To investigate the acid-base composition and blood gases in mice during the progression of toxic pulmonary edema caused by inhalational phosgene exposure. MATERIAL AND METHODS: Toxic pulmonary edema was induced by exposing mice to phosgene at a dose corresponding to LCt50 in an inhalation chamber. Blood samples were analyzed for acid-base balance and gas parameters, including partial oxygen pressure (pO2), partial carbon dioxide pressure (pCO2), total hemoglobin (tHb), oxyhemoglobin (O2Hb), carboxyhemoglobin (COHb), methemoglobin (MetHb), reduced hemoglobin (RHb), oxygen saturation (sO2), oxygen concentration (O2ct), oxygen capacity (O2cap), partial oxygen pressure at 50 % saturation (P50), total carbon dioxide (tCO2), true and standard bicarbonate (HCO3–, SBC), actual and standard base excess (BEb, BEecf), anion gap, lactate, and concentrations of sodium, potassium, chloride, and ionized calcium. Measurements were performed using a gas analyzer at 30 minutes, 3 hours, and 24 hours after exposure initiation. RESULTS: Significant shifts in blood gas composition and acid-base balance were observed 3 hours after pulmonary edema initiation. These included decreased acid-base balance, reduced oxyhemoglobin levels, lowered oxygen saturation, and elevated partial carbon dioxide pressure, indicating respiratory insufficiency and compensated respiratory acidosis. Major changes in acid-base parameters were observed after 24 hours, with normalization of pH accompanied by increases in true and standard bicarbonate levels, as well as total carbon dioxide content. Changes in actual and standard base excess were observed, reflecting a reduction in base deficit. Electrolyte levels remained unchanged in all experimental groups throughout all observation periods. CONCLUSIONS: The study elucidated the progression of respiratory hypoxia during toxic pulmonary edema and confirmed that respiratory hypoxia serves as a key pathogenic link, leading to significant disruptions in energy metabolism during the progression of pulmonary edema.

Rising water levels increase CH4 emissions and decrease CO2 exchange in a temperate salt marsh

AbstractSaline wetlands play a crucial role in climate regulation through their robust cooling effect, attributed to rapid carbon sequestration and minimal methane production. However, a comprehensive understanding of the mechanisms controlling their greenhouse gas (GHG) balance is lacking, particularly in salt marshes that are fully or partially submerged due to rising sea levels. We conducted a controlled manipulative experiment to test the effect of water levels on GHG emissions, including four water table levels: ‐10, 0, +5 cm and a fluctuating water table. We used soil cores from a Spartina anglica‐dominated salt marsh and examined the CO2 and CH4 fluxes over a growing season. Daylight CO2 uptake and dark CO2 emission were highest at the ‐10cm water table, while CH4 emissions were lowest at this water table. CO2 and CH4 fluxes were primarily driven by air and water temperature and solar irradiance. Our results indicate that salt marshes with near‐surface water levels (‐10 to 5 cm) function as potent CO2 sinks and minor sources of CH4 during the growing season. The high photosynthetic carbon assimilation combined with low CH4 fluxes resulted in a Global Warming Potential value of ‐326 g CO2eq m−2 on a 100‐year scale. Our study accounted for CH4 fluxes, CO2 uptake and emission together, and identified the mechanisms controlling CO2 and CH4 exchange. This approach is crucial for evaluating the potential of saline tidal wetlands as net carbon sinks and for developing scientifically sound climate mitigation policies.

Drivers and Annual Totals of Methane Emissions From Dutch Peatlands.

Rewetting peatlands is required to limit carbon dioxide (CO2) emissions, however, raising the groundwater level (GWL) will strongly increase the chance of methane (CH4) emissions which has a higher radiative forcing than CO2. Data sets of CH4 from different rewetting strategies and natural systems are scarce, and quantification and an understanding of the main drivers of CH4 emissions are needed to make effective peatland rewetting decisions. We present a large data set of CH4 fluxes (FCH4) measured across 16 sites with eddy covariance on Dutch peatlands. Sites were classified into six land uses, which also determined their vegetation and GWL range. We investigated the principal drivers of emissions and gapfilled the data using machine learning (ML) to derive annual totals. In addition, Shapley values were used to understand the importance of drivers to ML model predictions. The data showed the typical controls of FCH4 where temperature and the GWL were the dominant factors, however, some relationships were dependent on land use and the vegetation present. There was a clear average increase in FCH4 with increasing GWLs, with the highest emissions occurring at GWLs near the surface. Soil temperature was the single most important predictor for ML gapfilling but the Shapley values revealed the multi-driver dependency of FCH4. Mean annual FCH4 totals across all land uses ranged from 90 ± 11 to 632 ± 65 kg CH4 ha-1 year-1 and were on average highest for semi-natural land uses, followed by paludiculture, lake, wet grassland and pasture with water infiltration system. The mean annual flux was strongly correlated with the mean annual GWL (R2 = 0.80). The greenhouse gas balance of our sites still needs to be estimated to determine the net climate impact, however, our results indicate that considerable rates of CO2 uptake and long-term storage are required to fully offset the emissions of CH4 from land uses with high GWLs.

Simulation analysis of the internal flow field in single screw compressor using local re-meshing method

Abstract The single screw compressor (SSC) is considered an excellent competitor to the twin screw compressor due to its symmetrical structure and balanced gas forces on the screw rotor. To enhance the performance of SSC, it is crucial to have a thorough understanding of the internal flow field, particularly in the leakage channels. Nevertheless, the vertical relationship between the star wheel axis and the screw axis leads to mesh distortion, which presents technical challenges for mesh division in CFD simulations. In this paper, the method of local re-meshing is employed to simulate the comprehensive flow field using the Forte software. The mesh is regenerated near the motion boundary, while the mesh in the remaining areas remains unchanged. The pressure and temperature distribution of the internal flow field of the compressor are obtained, as well as its variation during operation. The results indicate a noticeable pressure gradient change in the leakage gap. The pressure and temperature of gas gradually increase along the axis direction of the screw, reaching the maximum value in the exhaust channel. The research can provide support for the future optimization design of the SSC.

Site-dependent carbon and greenhouse gas balances of five fen and bog soils after rewetting and establishment of Phalaris arundinacea paludiculture

Site-dependent carbon and greenhouse gas balances of five fen and bog soils after rewetting and establishment of Phalaris arundinacea paludiculture

Investigation of enclosure fire dynamics with inclined ceilings

Investigation of enclosure fire dynamics with inclined ceilings

Impact of crop type on the greenhouse gas (GHG) emissions of a rewetted cultivated peatland

Abstract. Raising the water table is an effective way to abate greenhouse gas emissions from cultivated peat soils. We experimented a gradual water table rise at a highly degraded agricultural peat soil site with plots of willow, forage and mixed vegetation (set-aside) in southern Finland. We measured the emissions of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) for 4 years. The mean annual groundwater table depth was about 54, 40, 40 and 30 cm in 2019–2022, respectively. The results indicated that a 10 cm rise in the water table depth was able to slow down annual CO2 emissions from soil respiration by 0.87 Mg CO2-C ha−1. CH4 fluxes changed from uptake to emissions with a rise in the water table depth, and the maximum mean annual emission rate was 11 kg CH4-C ha−1. Nitrous oxide emissions ranged from 2 to 33 kg N2O-N ha−1 yr−1; they were high in bare soil at the beginning of the experiment but decreased towards the end of the experiment. Short rotation cropping of willow reached net sequestration of carbon before harvest, but all treatments and years showed a net loss of carbon based on the net ecosystem carbon balance. Overall, the short rotation coppice of willow had the most favourable carbon and greenhouse gas balance over the years (10 Mg CO2 eq. on average over 4 years). The total greenhouse gas balance of the forage and set-aside treatments did not go under 27 Mg CO2 eq. ha−1 yr−1, highlighting the challenge in curbing peat decomposition in highly degraded cultivated peatlands.

Ecological status and type of alteration determine the C-balance and climate change mitigation capacity of Mediterranean inland saline shallow lakes

Saline shallow lakes may play an important role in carbon exchange with the atmosphere, but their alteration may change carbon balance and greenhouse gas emissions patterns. This study investigated the relationship between carbon metabolic processes and environmental factors, focusing on alterations in salinity, hydroperiod length, and trophic status. The results revealed that disruptions to natural salinity patterns, driven by hydrological changes and ecological degradation, enhanced carbon greenhouse gas emitting metabolisms. In contrast, well-preserved lakes demonstrated significantly higher carbon retention and climate mitigation capacities (–188 ± 412 g C m−2 yr−1) compared to lakes with hydrological and trophic disturbances (–30 ± 141 g C m−2 yr−1). These findings emphasize the relevance of the metabolic activity of saline shallow lakes and highlight the need for targeted management and restoration efforts to maximize their climate regulation potential. The insights gained from this study may also be applicable to similar ecosystems in other regions.

Birth spine and spinal cord injury (Draft of the clinical recommendations)

Birth spinal cord injury is damage to the spinal cord of a neonates due to mechanical causes during childbirth. The leading role in the development of spinal cord injury in newborns is played by excessive longitudinal or lateral traction of the spine or excessive twisting. The true incidence of birth spinal cord injury is unclear. There is currently no single classification of birth spinal cord injury and the distinction is made based on morphology, localization, nature and type of disorders. Birth spinal cord injury has 3 main groups of manifestations: stillbirth or rapid death of the newborn; respiratory failure; muscle weakness and hypotension, alternating with spasticity. Along with a visual examination of the newborn, it is recommended to conduct a study of the acid-base balance and blood gases in order to clarify the nature and treatment of respiratory failure; X-ray of the cervical and thoracic spine, ultrasound examination of the spinal cord, computed tomography of the spine and / or magnetic resonance imaging of the spine and spinal cord for the purpose of differential diagnosis; ultrasonic examination of the lungs to detect high placement of the diaphragm in case of damage to the C3–C5 segments of the spinal cord, consultations with a neurologist, anesthesiologist-resuscitator and a neurosurgeon. Mechanic respiratory ventilation is recommended for a newborn with birth spinal cord injury and with signs of damage to the C3–C5 segments and respiratory failure; in the presence of extramedullary damage, fracture or dislocation of the vertebrae — emergency neurosurgical treatment. Rehabilitation includes measures in the form of massage of the upper limb, therapeutic exercise, individual lessons, physiotherapy in order to restore the functions of the muscles and joints of the shoulder girdle; in case of respiratory regulation disorders — home ventilator systems; in case of persistent movement disorders after 1 month of age — transcutaneous electrical neurostimulation of the spinal cord. It is recommended to assess the size of the pregnant woman’s pelvis and the intrauterine presentation of the fetus in order to select the type of delivery to prevent birth spinal cord injury, rational drug therapy and anesthetic care for the pregnant woman in order to prevent dysfunctional labor.

Adaptive robust self‐scheduling for a wind‐based GenCo equipped with power‐to‐gas system and gas turbine to participate in electricity and natural gas markets

AbstractIntegrating renewable energy, particularly wind generation, into power systems brings significant uncertainty and intermittency, challenging generation companies (GenCos) to maintain economic operations. This paper proposes a strategy for a wind‐based GenCo equipped with a gas turbine and a power‐to‐gas (PtG) system to balance wind variability. The gas turbine offsets power shortfalls by consuming natural gas, while the PtG system absorbs excess wind energy, converting it to natural gas and injecting it into the natural gas network as a form of storage. The GenCo operates in day‐ahead electricity and natural gas markets and the real‐time electricity market, addressing uncertainties from wind output, energy prices, and natural gas access. A tri‐level adaptive robust optimization model is introduced for the GenCo’s short‐term operational scheduling. At the first level, decisions related to the GenCo's participation in the day‐ahead electricity and natural gas markets are made. The second level deals with determining the worst‐case realization of the uncertainties, constrained by the budget of uncertainty and the limited range of variations of uncertain variables. The third level sets the operational strategy on the actual day, considering power and gas balance, as well as constraints for the wind farm, gas turbine, and PtG unit. A column & constraint generation (C&CG) algorithm is used to solve the model. Numerical results demonstrate the model’s effectiveness in various case studies, showing that the GenCo can manage wind uncertainties, benefit from arbitrage opportunities in electricity and gas markets, and improve economic outcomes. This approach supports the broader integration of renewable energy into power systems.

Vulnerability of Arctic-Boreal methane emissions to climate change

The rapid warming of the Arctic-Boreal region has led to the concern that large amounts of methane may be released to the atmosphere from its carbon-rich soils, as well as subsea permafrost, amplifying climate change. In this review, we assess the various sources and sinks of methane from northern high latitudes, in particular those that may be enhanced by permafrost thaw. The largest terrestrial sources of the Arctic-Boreal region are its numerous wetlands, lakes, rivers and streams. However, fires, geological seeps and glacial margins can be locally strong emitters. In addition, dry upland soils are an important sink of atmospheric methane. We estimate that the net emission of all these landforms and point sources may be as much as 48.7 [13.3–86.9] Tg CH4 yr−1. The Arctic Ocean is also a net source of methane to the atmosphere, in particular its shallow shelves, but we assess that the marine environment emits a fraction of what is released from the terrestrial domain: 4.9 [0.4–19.4] Tg CH4 yr−1. While it appears unlikely that emissions from the ocean surface to the atmosphere are increasing, now or in the foreseeable future, evidence points towards a modest increase from terrestrial sources over the past decades, in particular wetlands and possibly lakes. The influence of permafrost thaw on future methane emissions may be strongest through associated changes in the hydrology of the landscape rather than the availability of previously frozen carbon. Although high latitude methane sources are not yet acting as a strong climate feedback, they might play an increasingly important role in the net greenhouse gas balance of the Arctic-Boreal region with continued climate change.