Hypercapnia Research Articles

High velocity nasal insufflation vs non-invasive positive pressure ventilation in the management of acute hypercapnic respiratory failure

ABSTRACT Introduction High-velocity nasal insufflation (HVNI) is a type of high-flow nasal cannula that depends on the dead-space clearance. HVNI utilizes small-bore nasal cannulae resulting in high velocity flow greater than the flow of the wider bore cannulae that were previously in use. Aim Assess the efficacy of high-velocity nasal insufflation in managing acute hypercapnic respiratory failure and compare between high-velocity nasal insufflations and noninvasive positive pressure ventilation (NIPPV) regarding efficacy and outcome in managing acute hypercapnic respiratory failure. Patients and Methods Over 12 months 48 patients admitted with a diagnosis of acute hypercapnic respiratory failure were enrolled in the study. Twenty-four patients were managed with HVNI, and the other 24 patients were managed with non-invasive ventilation. Patients were closely monitored in the respiratory intensive care unit (RICU). Oxygen saturation, respiratory rate, and Arterial Blood Gases (ABG) were measured before the start of treatment, then 1 hour, 4 hours, 2 days, and 3 days after treatment. Patients were allowed to crossover to the other arm of treatment or endotracheal intubation according to the clinical situation. Results pH, P Co2 levels showed similar changes in the two studied groups and improved with time. Treatment failure and mortality rates were also comparable in the two groups. Failure of treatment occurred in 16% in the group managed with HIVNI and in 33% in the group managed with NIPPV. Intubation at the end of 72 hourswas 16.7% in the group managed with HVNI and 25% in the group managed with NIPPV. Conclusion High velocity nasal insufflation is effective in managing acute hypercapnic respiratory failure. HVNI offers an effective way alternative to NIPPV in managing acute hypercapnic respiratory failure.

Development and validation of hydrophobic molded pulp nursery pots made of hemp hurd

Biodegradable nursery pots (BNPs) composed of 50 % hemp hurd and 50 % recycled cardboard fibers (w/w dry basis) were produced using a custom-built handheld molded pulp device. Milling followed by sequential peracetic acid and sodium hydroxide delignification treatment reduced lignin content of hemp hurd from 23.76 % to 2.39 %, liberating cellulose and hemicellulose fibers for enabling the formation of interfiber interactions in molded pulp formulations. Beeswax and precipitated calcium carbonate based hydrophobic coating at ~10 μm thickness significantly enhanced hydrophobicity of the BNPs, as indicated by the surface contact and sliding angle of 116.25° and 34.82°, respectively. Anaerobic biodegradability of BNP was confirmed via carbon dioxide and methane gas accumulation measurements. Developed BNPs were successfully validated through an eleven week greenhouse planting trial. This study introduced a new biodegradable molded pulp formulation made from hemp hurd and validated its application as an alternative to single use plastic nursery pots for growing seedlings.

Rapamycin improves satellite cells autophagy and muscle regeneration during hypercapnia.

Both CO2 retention, or hypercapnia, and skeletal muscle dysfunction predict higher mortality in critically ill patients. Mechanistically, muscle injury and reduced myogenesis contribute to critical illness myopathy, and while hypercapnia causes muscle wasting, no research has been conducted on hypercapnia-driven dysfunctional myogenesis in vivo. Autophagy flux regulates myogenesis by supporting muscle stem cell -satellite cell- activation, and previous data suggests that hypercapnia inhibits autophagy. We tested whether hypercapnia worsens satellite cell autophagy flux and myogenic potential, and if autophagy induction reverses these deficits. Satellite cell transplantation and lineage tracing experiments showed that hypercapnia undermines satellite cells activation, replication, and myogenic capacity. Bulk and single cell sequencing analyses indicated that hypercapnia disrupts autophagy, senescence, and other satellite cells programs. Autophagy activation was reduced in hypercapnic cultured myoblasts, and autophagy genetic knockdown phenocopied these changes in vitro. Rapamycin stimulation led to AMPK activation and downregulation of the mTOR pathway, which are both associated with accelerated autophagy flux and cell replication. Moreover, hypercapnic mice receiving rapamycin showed improved satellite cells autophagy flux, activation, replication rate, and post transplantation myogenic capacity. In conclusion, we have shown that hypercapnia interferes with satellite cell activation, autophagy flux and myogenesis, and systemic rapamycin administration improved these outcomes.

Comparison of the Competitiveness for Danish, Dutch, and German Piglet Producers under Consideration of Country-Specific Methods of Piglet Castration with Anesthesia

Pig producers in Europe adopt different production methods for male pig fattening. More than half of the animals are surgically castrated. The different interpretations of animal welfare in different countries lead to market differentiation and economically different production conditions, which do not restrict trade, but economically lead to drastic competitive changes for local producers. While the Netherlands has already implemented surgical castration for the export market, using CO2 narcosis (NL), Denmark and Germany are each introducing their strategies with local anesthesia (DK) and isoflurane anesthesia (DE), respectively. Using typical pig farms from the agri benchmark Pig Network, the additional costs and economic impacts of animal welfare regulations are calculated. In Germany, isoflurane anesthesia increases costs by EUR 28.54 to EUR 49.86 per sow, or EUR 1.93 to EUR 3.81 per male piglet. This corresponds to a cost increase of around 5% per piglet. In Denmark, the costs of local anesthesia with procaine increase more moderately by EUR 3.55 to EUR 5.05 per sow, or around EUR 0.30 per male piglet. The cost increase here is less than 1% per piglet. The additional costs are leading to a loss of competitiveness for Denmark and Germany compared to the Netherlands. However, Germany is also losing profit significantly compared to Denmark. This study highlights that animal welfare regulations can negatively impact the competitiveness of the pig sector. It emphasizes the need for countries to implement such regulations carefully, ensuring that they do not lead to the loss of production or international competitiveness. A balanced approach that supports both animal welfare and economic sustainability is essential.

New algorithm of three-phase equilibrium calculations for CO2-hydrocarbon-water systems

In this century, global warming caused by the accumulation of atmospheric carbon dioxide has become an essential concern. The industry has two main decarbonization options: CO2 capture for permanent storage in geological formations and CO2 utilization for enhancing oil recovery (EOR). Both methods require accurate reservoir simulation to correctly describe the fluids flowing process and design an optimal injection plan. However, existing reservoir simulation practices often neglect the interaction and dissolution of CO2 and hydrocarbon components in water, leading to inaccurate predictions. Neglecting CO2 dissolution in water undermines storage estimation for capture and results in unreliable EOR descriptions. Therefore, to address this, our study focuses on developing a reliable and accurate phase equilibrium calculation package for hydrocarbon-CO2-water three-phase systems, which meets the demanding efficiency and robustness criteria of reservoir simulation. In this paper, we first introduce the methodology of the three-phase equilibrium calculation algorithm, then illustrate the numerical techniques employed to improve computational efficiency and finally demonstrate superior robustness of this algorithm through comprehensive case studies. Our research contributes three key improvements. First, we have increased the reliability of phase behavior descriptions by considering the dissolution of CO2 and hydrocarbon components in water. Second, we have enhanced the robustness of the three-phase equilibrium calculations algorithm, enabling accurate determination of three-phase statuses and fluid behaviors where standard commercial software may fail. Third, our algorithm exhibits notable efficiency improvements, ensuring its suitability for three-phase compositional simulations. The findings of this research provide valuable insights into the accurate modeling of hydrocarbon-CO2-water three-phase systems and offer practical solutions for designing effective CO2 reduction strategies.

A 4IR-Driven operational risk model for CO2 storage in deepwater abandoned hydrocarbon reservoirs

This study presents the development of an advanced operational risk model that leverages Fourth Industrial Revolution (4IR) technologies to optimize carbon dioxide (CO2) storage within deepwater abandoned hydrocarbon reservoirs. The model systematically combines Artificial Neural Networks (ANN) with the optimization capabilities of Genetic Algorithms (GA) and the probabilistic analysis strengths of a Bayesian Network (BN) to perform dynamic and comprehensive risk assessments. By applying the model to a dataset covering a 200-year timeframe, it effectively forecasts CO2 storage capacities while simultaneously evaluating associated risks across different operational scenarios. One of the key innovations of this model is the introduction of a novel loss function designed to precisely manage forecast deviations and enhance the efficiency of operational processes. This function is critical in ensuring that the model remains robust and accurate in real-time risk assessments, allowing for more reliable decision-making in CO2 storage operations. In addition, the study conducts an economic evaluation that underscores the crucial role of 45Q tax credits in bolstering the financial sustainability of carbon sequestration projects. The analysis highlights how these credits significantly reduce the economic barriers to adopting carbon utilization, storage, and sequestration (CUSS) technologies, making large-scale implementation more feasible. The model's performance is underscored by its ability to achieve a 49% CO2 retention rate over two centuries, with an impressively low average error margin of 0.249%. These results highlight the model's impressive efficiency and accuracy, while also demonstrating its capacity to markedly improve the predictability of CO2 storage outcomes. The findings suggest that this model could play a pivotal role in advancing global sustainability efforts by optimizing CO2 storage processes, thereby contributing to the reduction of atmospheric CO2 levels and supporting long-term climate goals.

High-Flow Nasal Oxygen in Patients with Acute Hypercapnic Respiratory Failure: A Narrative Review of the Physiological Rationale and Clinical Evidence.

Acute hypercapnic respiratory failure is a life-threatening condition caused by alveolar hypoventilation. It is mostly caused by an acute exacerbation of chronic obstructive pulmonary disease or conditions yielding muscle dysfunction. Noninvasive ventilation through a facemask is the cornerstone first-line strategy to support hypercapnic patients with acidemia, and current guidelines strongly recommend this intervention to improve survival and long-term clinical outcomes. Because of its benefits related to carbon dioxide washout from the upper airways and the enhanced comfort, high-flow nasal oxygen has been proposed as a respiratory support strategy in patients with hypercapnic respiratory failure, both as an alternative to and in combination with noninvasive ventilation. When compared to noninvasive ventilation as a first-line intervention, high-flow nasal oxygen shows a higher rate of failure. Hence, if not contraindicated, the use of noninvasive ventilation should be preferred. After the resolution of acidemia with noninvasive ventilation, high-flow nasal oxygen showed promising physiological effects compared to conventional oxygen. During weaning from mechanical ventilation in patients with or at risk of developing hypercapnia, high-flow nasal oxygen showed encouraging results, especially when applied alternating with sessions of noninvasive ventilation. Optimal settings of high-flow nasal oxygen in hypercapnic patients include the use of a smaller-size cannula, flows ranging between 30 and 40 L/min, and FiO2 adjusted to obtain SpO2 between 88% and 92%. Specific interfaces, such as asymmetric cannulas, may further enhance the benefits of a high flow in terms of carbon dioxide clearance. In this narrative review, we provide an updated overview of the physiological rationale and clinical evidence concerning the use of high-flow nasal oxygen in patients with acute hypercapnic respiratory failure.

Long-term mortality in patients with chronic obstructive pulmonary disease requiring acute non-invasive ventilation with and without obstructive sleep apnoea

IntroductionChronic obstructive pulmonary disease (COPD)/obstructive sleep apnoea (OSA) overlap syndrome (OVS) is associated with higher mortality compared with COPD alone in stable outpatients. However, the prognosis of patients hospitalised with...

Brewery CO2 conversion into acetic acid at an optimized set of microbial electrosynthesis process parameters

Direct utilization of unpurified industrial CO2 is desired to minimize feedstock transportation and purification costs and develop cost-efficient carbon utilization technologies. To this end, utilization of brewery CO2, which is a readily available yet underexplored carbon source, is feasible via microbial electrosynthesis (MES) technology, though the productivity indicators remain lower. This study provides insights into enhancing the MES productivity from unpurified brewery CO2 through optimization of feed rate and cathode potential (Ecathode), besides assessing the impact of catholyte recirculation on overall production parameters. At an Ecathode of –1 V, the Acetobacterium-dominated enriched mixed microbial culture produced up to 6.6 g/L acetic acid at 85 % coulombic efficiency and cell voltage (Ecell) of 2.98 V from brewery CO2 fed continuously at 0.7 L/d rate. Acetic acid production decreased at the lower or higher Ecathode and gas feed rate conditions, emphasizing the importance of maintaining an optimal balance between the gas flow rate and Ecathode to achieve efficient H2-mediated production. With the catholyte recirculation loop in reactors operated under the optimized Ecathode and feed rate conditions, acetate production enhanced further to 7.6 ± 0.65 g/L at 92 % coulombic efficiency and 2.9 V Ecell. The improved productivity can be attributed to better mixing and retention of CO2 and H2 in MES reactors, besides the enhanced growth and dominance of key CO2-fixing acetogens belonging to Acetobacterium and Eubacterium genera under the catholyte recirculation condition. The findings suggest that fine-tuning various process parameters is pivotal to achieving the desired MES productivity.

GEOCHEMISTRY OF GROUNDWATERS AND SURFACE WATERS, AND GROUND ICE OF THE OKA PLATEAU, EASTERN SAYAN (RUSSIA)

The study area is located in the Eastern Sayan hydrogeological folded area. The objects of the study were groundwaters, surface waters and ground ice in the Sentsa River basin on the Oka Plateau. Cold and thermal groundwaters are associated with Proterozoic and Paleozoic metamorphic and igneous rocks. Their discharge as springs occurs in the river valleys along fault zones. Ground ice was studied in mineral frost mounds (lithalsas) composed of clays, clayey silts and silts of lacustrine-alluvial and fluvioglacial genesis. It has been established that thermal and cold groundwaters have HCO3 Ca-Na compositions, river and lake waters, as a rule, have HCO3 Ca-Na compositions, and ground ice melts – HCO3, SO4-HCO3 and NH4-HCO3 Ca. Thermal waters are largely enriched in Li, Be, B, Si, Mn, Ga, Ge, Se, As, Br, Rb, Sr, Cs, Ba and all REE relative to river and rain waters, and have the highest values of trace elements enrichment factor (EFREE). The latter shows that atmospheric precipitation participates in the formation of the composition of groundwaters (cold and thermal) and surface waters. The specificity of the geochemistry of ground ice is determined by the composition of precipitation, the injection of ice-forming groundwater from taliks, the interaction in the water-rock system, and the presence of organic matter in unconsolidated sediments. The participation of river water and groundwater in the formation of the frost mound ice core is also evidenced by similar values of stable isotopes (δ18O, δD) in surface water, groundwater and ground ice. The 3He/4He ratio points to a possible influx of mantle helium into thermal waters, and δ13С points to the magmatic and thermometamorphic mechanisms of carbon dioxide accumulation in thermal waters. The 87Sr/86Sr ratio in travertines indicates a significant contribution of intrusive rocks to the formation of fluid composition.

Long-term reliable wireless H2 gas sensor via repeatable thermal refreshing of palladium nanowire

The increasing significance of hydrogen (H2) gas as a clean energy source has prompted the development of high-performance H2 gas sensors. Palladium (Pd)-based sensors, with their advantages of selectivity, scalability, and cost-effectiveness, have shown promise in this regard. However, the long-term stability and reliability of Pd-based sensors remain a challenge. This study not only identifies the exact cause for performance degradation in palladium (Pd) nanowire H2 sensors, but also implements and optimizes a cost-effective recovery method. The results from density functional theory (DFT) calculations and material analysis confirm the presence of C = O bonds, indicating performance degradation due to carbon dioxide (CO2) accumulation on the Pd surface. Based on the molecular behavior calculation in high temperatures, we optimized the thermal treatment method of 200 °C for 10 minutes to remove the C = O contaminants, resulting in nearly 100% recovery of the sensor’s initial performance even after 2 months of contamination.

7378 Glargine Induced Neuroglycopenia in Patients with End-Stage Renal Disease: Importance of Insulin Regimen Optimization in Haemodialysis Patients

Abstract Disclosure: M. Shrivastava: None. L. Kaur: None. B. Armendariz: None. R. Kaur: None. A. Shetty: None. In patients with end stage renal disease (ESRD), hypoglycemia accounts for up to 3.6% of all the admissions with mortality rates of up to 30%. A combination of impaired insulin clearance, changes in glucose metabolism and dialysis process makes the patients with end stage renal disease vulnerable to neuroglycopenia.Case description:53 year old female with past medical history of insulin dependent type 2 diabetes mellitus, ESRD secondary to diabetes, on hemodialysis(HD) thrice weekly since two years, presented to the emergency with altered mental status, respiratory distress, tachycardia. Lab work revealed blood glucose(BG) of 23 mg/dl, HbA1c of 8.4%, eGFR of 6, and arterial blood gas showed hypercapnic respiratory acidosis. Patient received dextrose, with no improvement of symptoms. Eventually she developed acute hypercapnic respiratory failure requiring endotracheal intubation with mechanical ventilation, and was transferred to the ICU. As per family, a night prior to presentation, last recorded BG after dinner was 253 mg/dl, she took her night time glargine, which was recently increased by her primary care for poorly controlled HbA1c levels. Brain MRI and long term EEG monitoring findings were consistent with underlying extensive brain injury secondary to prolonged hypoglycemia. Unfortunately, the patient's condition did not improve despite HD and BG correction, eventually she underwent compassionate extubation. Case Discussion:The insulin requirements in ESRD patients are reduced by approximately 50%, regardless of residual insulin secretion. Malnutrition and acidosis reduce hepatic glycogen stores and availability of gluconeogenic precursor, expected compensatory renal gluconeogenesis is compromised by decreased renal function causing hypoglycemia, which is further worsened by inappropriately high plasma insulin levels caused by reduced renal insulin breakdown. Diabetes mellitus patients with ESRD are frequently managed with basal-bolus insulin regimen, and HD up to thrice weekly, leaving them without HD for up to 3 days especially over the weekend. This can result in accumulation of insulin metabolites causing delayed insulin clearance as seen in our patient. In such cases even long acting insulin, such as glargine, can have compounding effects, which could possibly cause fatal complications such as neuroglycopenia. In such patients continuous glucose monitor use with tapering dose glargine regimen may help eliminate this compounding effect. Conclusion: Neuroglycopenia is a rare manifestation of diabetes mellitus with ESRD. Compromised renal gluconeogenesis and impaired insulin clearance can cause inappropriately high plasma levels of insulin. In such patients continuous glucose monitoring along with tapering dose of long acting insulin should be utilized for proper glycemic control to limit compounded effect of insulin metabolite accumulation. Presentation: 6/3/2024

Understanding and Managing Adenotonsillar Hypertrophy in Pediatric Otolaryngology

Adenotonsillar hypertrophy (ATH) is a common pediatric condition marked by the growth of lymphoid tissues within the Waldeyer’s ring, which includes adenoids, palatine tonsils, and lingual tonsils. These tissues surround the upper airway and food passage, and play an immunological role, enlarging until about age 12, before gradually reducing during adolescence and adulthood. Untreated or poorly managed ATH can severely impact multiple health aspects of children. It is the primary cause of upper airway obstruction and obstructive sleep apnea (OSA) syndrome in children, which disrupts sleep and can severely impair cognitive development, school performance and behaviour. Chronic mouth breathing from ATH can alter dental arches and facial growth, known as adenoid facies. More severe outcomes include increased pulmonary pressures and the potential development of pulmonary hypertension and cor pulmonale due to chronic hypoxia and CO2 retention. As a result, tonsillectomy, with or without adenoidectomy (T&A), has become one of the most frequently performed surgeries in North America, with over 530,000 operations performed annually on children under age 15. This paper discusses the significant impact of ATH on pediatric health and the frequent need for surgical intervention. It covers the immunophysiology, influence of atopy, community-based assessments prior to specialist referrals, and an overview of available medical and surgical treatment options. Additionally, it outlines general indications for referring patients to otolaryngology.

Study of Knowledge, Attitude, and Practices of Use of Masks among Health-care Workers at a Tertiary Care Center in Mumbai

ABSTRACT Introduction: Airborne transmission of infectious diseases poses a significant public health challenge. Nosocomial outbreaks of airborne infections such as influenza H1N1, H5N1, and drug-resistant tuberculosis (TB) variants have been documented, with substantial morbidity and mortality attributed to inadequate airborne infection control strategies. N-95 respirators and surgical masks (face masks) are the examples of personal protective equipment that are used to protect the wearer from airborne particles and liquid contamination of the face. Aim and Objectives: The aim of this study was to assess the knowledge, practices, and attitude of health-care workers (HCWs) regarding the use of mask, especially N-95 mask. Materials and Methods: A prospective, was conducted over a period of 6 months at a tertiary care hospital. This study was carried out in the department of microbiology of a tertiary care hospital over a period of 6 months. A total of 500 HCWs from various departments of the hospital were included in the study. HCWs were given a questionnaire based on N-95 respirator usage, and participation was voluntary. Results: The analysis of survey data provides insightful perspectives on respondents’ comprehension and attitudes toward airborne infection transmission and the usage of N-95 masks. 68.6% of respondents recognized that all listed diseases (measles, TB, and chickenpox) were spread by the airborne route. 55.6% of respondents correctly acknowledged that all masks, including surgical masks, N-95 masks, and cotton masks, do not offer airborne protection. 76.0% of respondents acknowledged that N-95 masks possess a high filtration efficiency against 0.3-micron particles, 58.3% correctly identified that “N” in N-95 stands for “not resistant to oil,” and 90.8% acknowledged that the N-95 respirator as the most common type of respirators. 41.7% correctly acknowledged that N-95 masks with an exhalation valve are not recommended for use. 22.2% of respondents incorrectly believe that wearing a face mask can lead to carbon dioxide poisoning, and 52.1% of respondents correctly identified that pulmonary TB patients need not be provided with N-95 masks in isolation rooms. 76.8% of respondents understood that fit testing is required every time one dons an N-95 mask. 95.5% of respondents recognized the necessity of hand hygiene before donning and after doffing N-95 masks. 82.7% of respondents agreed regarding the necessity for consultation before N-95 mask usage for chronic lung disease and asthma patients. 93.7% are aware that there is a protocol for donning and doffing N-95 masks. 71.3% of respondents understood that extended use involves wearing the same N-95 respirator for repeated close contact encounters without removing the mask between patient encounters, while 64.4% correctly define reuse as using the same N-95 respirator for multiple encounters but removing it after each encounter.

Fuzzy-Based Decision Support Model for Assessing Green Building Performance

Global warming is currently a major environmental issue that is capable of causing unpredictable climate changes. The phenomenon is due to the accumulation of gases and carbon dioxide in the earth’s atmosphere, partly attributed to building operation and construction. The Green Building Rating System (GBRS) is developed to assess and measure the level of green building practices to address this problem. The assessments have typically been conducted using conventional methods that require parameters to meet specific criteria. However, certain parameter values cannot be calculated using objective methods, such as bias, time series, and distance values. The existence of these challenges leads to the development and integration of the Decision Support Model (DSM) into the GBRS in the research. The DSM uses a mathematical model, Tsukamoto Fuzzy Inference System (FIS), and conventional methods to handle the parameter values. Moreover, data related to the parameters are collected and analyzed quantitatively. As a result, the DSM-GBRS model is successfully implemented with two findings. First, there are 83 parameters, related to policy, retrofit, construction, and utilization aspects based on Peraturan Menteri Pekerjaan Umum dan Perumahan Rakyat Nomor 21 Tahun 2021. Second, the model provides precise decision values by splitting the treatment into four types: conventional, Fuzzy logic, slope, and Euclidean distance to ensure a comprehensive assessment of green building performance.

Comparing the outcome of using high-flow nasal cannula oxygen therapy versus noninvasive ventilation for chronic obstructive pulmonary disease patients with acute hypercapnic respiratory failure

BackgroundNoninvasive ventilation (NIV) is frequently employed as a treatment option for acute hypercapnic respiratory failure (AHRF) resulting from chronic obstructive pulmonary disease (COPD). Limited research has substantiated the claims made in recent studies regarding the feasibility of employing high flow nasal cannula (HFNC).AimOur study assessed the outcome of using HFNC versus NIV for COPD patients with AHRF.Patients and methodsEighty COPD patients with AHRF were confined to the respiratory intensive care unit (RICU) at Ain-Shams University Hospitals from December 2021 to 2023 and subdivided into two groups (40/group), where the first group was placed on NIV while the second group was placed on HFNC. Data during their hospital stay as demographic data, vital data, arterial blood gases, device duration, treatment failure, and mortality were recorded.ResultsThe majority were males with mean age 63.75 ± 9.05 years along with treatment failure and complications 25%, 12.5.% in NIV versus 45%, and zero% in HFNC, respectively, with longer hospital stay in NIV 10–15 days to 7–10 days in HFNC, and with no difference in mortality rate in both groups.ConclusionBoth modalities NIV and HFNC were effective for treating COPD with AHRF. However, NIV group was significantly superior than HFNC along with apparently faster improvement in ventilatory and respiratory status especially in high CO2 level while less complications and duration of hospital stay in HFNC with no difference in mortality in both groups.

Research on Carbon Dioxide Computational Fluid Dynamics Simulation of Urban Green Spaces under Different Vegetation Spatial Layout Morphologies

Urban green spaces (UGSs) are considered an important natural approach for improving urban climatic conditions, promoting sustainable urban development, and advancing the global “Carbon Peak and Carbon Neutrality” targets. Previous studies have found that different vegetation spatial morphologies significantly impact the capacity to obstruct and absorb CO2, but it is not yet well understood which morphology can retain and absorb more CO2. This study takes Nantong Central Park as an example and conducts a CFD (Computational Fluid Dynamics) carbon flow simulation for CO2 under different vegetation spatial morphologies to identify their CO2 retention and absorption effects. First, the carbon sink benefits of elements such as “vegetation, soil, and wetlands” within the park were calculated, and the elements with the highest carbon sink benefits were identified. Then, the park was divided into carbon welcoming zones, carbon flow zones, and carbon shadow zones for carbon flow simulation with the highest carbon sink benefits. The results show that in the carbon welcome area, the one-block long fan-shaped plant community with a spatial density of 40 m thickness can best meet the requirements of absorption and induction of a small amount of carbon dioxide, with the smallest air vortex and uniform distribution of carbon dioxide in the surrounding area. In the carbon flow area, combined with the visual effect, the planting pattern of 6 m spacing herringbone combined with natural structure was adopted, which has a good carbon dioxide blocking and absorption capacity. In the carbon-shaded area, a herringbone planting pattern with a total width of 40 m and a base angle of 60° was chosen, which had the strongest hindrance and absorption capacity. Urban park environment optimization can use Fluent simulation to analyze the flow of carbon dioxide between different elements affected by wind dynamics at the same time. Based on the results, the form, layout, and spatial distance are adjusted and optimized. This study can better guide the spatial layout of vegetation and contribute to the realization of the goal of “carbon peak and carbon neutrality”.

CO2 retention in high-pressure/high-temperature reservoirs of the Yinggehai Basin, northwestern South China Sea

Global industry drillings targeted at deep-burial hydrocarbons have renewed the record of maximum sustainable overpressure in sedimentary basins. However, the influence of extremely high overpressure on natural fluid accumulation and artificial waste sequestration is not yet completely understood. To better understand the motion characteristics of the highly overpressured CO2-rich fluid, the CO2 retention capacity was quantified, and the CO2-rich fluid motion trails were evaluated in an ideal natural laboratory in the Yinggehai Basin. The hydraulic sealing capacity was higher than the capillary sealing capacity in the highly overpressured stratum. Relative to the situations of no breach or solely breached by capillary failure, the superposition of capillary and hydraulic failures resulted in the caprock integrity breakage by faults (or fractures), diapirs, and pipes. Meanwhile, the high expulsion flux of CO2-rich fluid caused the consumption of chlorite to generate illite in the caprock of dual-breached fields. The CO2-rich fluid flux of capillary invasion was limited by the inherently low permeability of caprock, which may be insufficient for a dramatic change of hydrogen ions or electron activities to induce remarkable chlorite dissolution in the caprock of the sole-breached field.

The ventilatory effect of High Velocity Nasal Insufflation versus Non-invasive Positive Pressure Ventilation in the treatment of acute hypercapnic respiratory failure in patients with AECOPD

The ventilatory effect of High Velocity Nasal Insufflation versus Non-invasive Positive Pressure Ventilation in the treatment of acute hypercapnic respiratory failure in patients with AECOPD

Engineering CALF-20/graphene oxide nanocomposites for enhancing CO2/N2 capture performance

Ever-increasing atmospheric CO2 concentrations has necessitated the development of novel and cost-effective nanostructured composites with favorable physicochemical properties. Recently, the potential of metal-organic framework (MOF)-based nanocomposites towards boosting CO2 capture capability has become apparent indicating the importance of the relationship between their structure and properties. Herein, a novel nanocomposite of zinc-based CALF-20 MOF hybridized with graphene oxide is successfully fabricated using the solvothermal method. The construction of the well-structured nanocomposite is confirmed by performing PXRD, BET, FTIR, FESEM/EDX, TEM, and TGA characterization analyses. CO2 and N2 adsorption capacities and CO2/N2 separation performance of these nanocomposites are evaluated by experiment and mathematical modeling for the first time. The CALF-20/GO interfacial interaction and CO2 adsorption mechanisms are also discussed. As the best-performing adsorbent, the CALF-20 containing 20 wt% GO indicates a 42.6 % increment in CO2 uptake at 1.6 bar and a 32.7 % enhancement in CO2/N2 selectivity at 1 bar and 298 K and 1.28 times more CO2 retention time in a fixed bed column compared to that of the pristine MOF. The results show that the MOF and GO form chemical bonds at the interface resulting in generating new pore structures and increasing the porosity which are mostly responsible for boosting CO2 capture capacity. Interestingly, no meaningful effect is observed by the variation of the zinc atomic concentration at the surface. The simple synthesis procedure and understanding the interfacial structure of the novel CALF-20/GO composite as a promising adsorbent for CO2 capture applications can provide new insights for future work.