Carbon Dioxide Research Articles

Engineering Insights into Tailored Metal-Organic Frameworks for CO2 Capture in Industrial Processes.

Despite the known impacts on climate change of carbon dioxide emissions, the continued use of fossil fuels for energy generation leading to the emission of carbon dioxide (CO2) into the atmosphere is evident. Therefore, innovation to address and reduce CO2 emissions from industrial operations remains an urgent and crucial priority. A viable strategy in the area is postcombustion capture mainly through absorption by aqueous alkanolamines, which focuses on the separation of CO2 from flue gas, despite its limitations. Within this context, porous materials, particularly metal-organic frameworks (MOFs), have arisen as favorable alternatives owing to their significant adsorption capacity, selectivity, and reduced regeneration energy demands. This research evaluates the engineering insights into tailored MOFs for enhanced CO2 capture, focusing on three series of MOFs (ZIF, UiO-66, and BTC) to investigate the effects of organic ligands, functional groups, and metal ions. The evaluation encompassed a range of aspects including adsorption isotherms of pure gases [CO2 and nitrogen (N2)] and mixed gas mixture (CO2 and N2 with 15:85% ratio), along with utilization of the ideal adsorbed solution theory (IAST) to simulate multicomponent gas adsorption isotherms. Moreover, the reliability of IAST for mixed gas adsorption prediction has been investigated in detail. The research offers valuable insights into the correlation between the characteristics of MOFs and their effectiveness in gas separation and how these characteristics contribute to the differences between IAST predictions and experimental results. The findings enhance the understanding of how to enhance MOF characteristics in order to reduce CO2 emissions and also highlight the need for advanced models that consider thermodynamic nonidealities to accurately predict the behavior of mixed gas adsorption in MOFs. As a result, the incorporation of MOFs with enhanced predictability and reliability into CO2 capture industrial processes is facilitated.

Photothermal Assisted Biomass Oxidation for Pairing Carbon Dioxide Electroreduction with Low Cell Potential.

Integrating anodic biomass valorization with carbon dioxide electroreduction (CO2RR) can produce value-added chemicals on both the cathode and anode; however, anodic oxidation still suffers from high overpotential. Herein, a photothermal-assisted method was developed to reduce the potential of 5-hydroxymethyl furfural (HMF) electrooxidation. Capitalizing on the copious oxygen vacancies, defective Co3O4 (D-Co3O4) exhibited a stronger photothermal effect, delivering a local temperature of 175.47 oC under near infrared light illumination. The photothermal assistance decreased the oxidation potential of HMF from 1.7 V over pristine Co3O4 to 1.37 V over D-Co3O4 to achieve a target current density of 30 mA cm-2, with 2,5-furandicarboxylic acid as the primary product. Mechanistic analysis disclosed that the photothermal effect did not change the HMF oxidation route but greatly enhanced the adsorption capacity of HMF. Meanwhile, faster electron transfer for direct HMF oxidation and the surface conversion to cobalt (oxy)hydroxide, which contributed to indirect HMF oxidation, was observed. Thus, rapid HMF conversion was realized, as evidenced by in situ surface-enhanced infrared spectroscopy. Upon coupling cathodic CO2RR with an atomically dispersed Ni-N/C catalyst, the Faradaic efficiencies of CO (cathode) and 2,5-furandicarboxylic acid (FDCA, anode) exceeded 90.0% under a low cell potential of 1.77 V.

Removable Photocatalysis Microneedle Reactor for Carbon Monoxide Delivery to Enhance Chemosensitization.

Carbon monoxide (CO) has emerged as a promising therapeutic agent, yet ensuring safe and precise CO delivery remains challenging. Here, we report a removable hydrogel-forming microneedle (MN) reactor for CO delivery via photocatalysis, with an emphasis on chemosensitization. Upon application, body fluids absorbed by the MNs dissolve the effervescent agents, leading to the generation of carbon dioxide (CO2) and triggering the release of the chemotherapeutics cisplatin. Meanwhile, the photocatalysts (PCs) trapped within MNs convert CO2 to CO under 660 nm light irradiation. These PCs can be removed by hydrogel-forming MNs, thereby mitigating potential biological risks associated with residual PCs. Both in vitro and in vivo experiments showed that MN-mediated CO delivery significantly improved tumor sensitivity to cisplatin by suppressing DNA repair, using an A375/CDDP melanoma model. This removable photocatalysis MN reactor offers safe and precise local delivery of CO, potentially creating new opportunities for CO or its combination therapies.

Insect tracheal systems as inspiration for carbon dioxide capture systems

Membrane technology advancements within the past twenty years have provided a new perspective on environmentalism as engineers design membranes to separate greenhouse gases from the environment. Several scientific journals have published articles of experimental evidence quantifying carbon dioxide (CO2), a common greenhouse gas, separation using membrane technology and ranking them against one another. On the other hand, natural systems such as the respiratory system of mammals also accomplish transmembrane transport of CO2. However, to our knowledge, a comparison of these natural organic systems with engineered membranes has not yet been accomplished. The tracheal respiratory systems of insects transport CO2at the highest rates in the animal kingdom. Therefore, this work compares engineered membranes to the tracheal systems of insects by quantitatively comparing greenhouse gas conductance rates. We demonstrate that on a per unit volume basis, locusts can transport CO2approximately ∼100 times more effectively than the best current engineered systems. Given the same temperature conditions, insect tracheal systems transport CO2three orders of magnitude faster on average. Miniaturization of CO2capture systems based on insect tracheal system design has great potential for reducing cost and improving the capacities of industrial CO2capture.

A novel nanoparticles spilled-over In2O3 microcubes-enabled sustainable chemiresistor for environmental carbon dioxide monitoring

Achieving sustainable future energy goals includes enhancing renewable energy production, optimizing daily energy consumption using feedback loops and minimizing/monitoring contributions to atmospheric carbon dioxide (CO2). Developing economic next-generation CO2 sensors enables local monitoring of industrial CO2 emissions, aiding energy management and climate monitoring. This study elucidates the efficacy of CO2 chemiresistor based on indium oxide (In2O3) micro cubes with spilled-over nanoparticles. The investigation primarily focuses on fabricating and optimising In2O3-based CO2 chemiresistors utilizing a hydrothermal technique, creating porous micro cubes essential for enhanced CO2 monitoring. As revealed by various characterization techniques, the minimum crystallite size was found to be 24.92 nm with optimum porosity and a high surface-to-volume ratio comprising spilled-over nanoparticle morphology. The fabricated chemiresistor demonstrated excellent CO2 sensing efficacy with a maximum response of around 4.1% at room temperature with selectivity, repeatability, and reversible sensing behavior. The sensing mechanism has been revealed, which is supported by theoretical density functional theory evaluations. Notably, the sensing results reveal the capability of In2O3-based sensors to detect CO2 at low concentrations as low as ⩽10 ppm, which enables the chemiresistor for practical implementation in diverse sectors to achieve sustainability.

Catalytic Approaches to Tackle Mixed Plastic Waste Challenges: A Review.

Plastics are widely used materials in our daily lives and various industries due to their affordability and versatility. The massive production of plastic waste, however, has recently emerged as a pressing environmental concern across all media. To address this, emerging technologies are being explored for the sustainable valorization of postconsumer plastic wastes including thermochemical, physical, and catalytic processes aimed at transforming them into higher value-added products. However, the chemical recycling of mixed plastic wastes poses a formidable challenge due to the diverse array of monomers and catalyst systems involved, each employing distinct mechanisms. Complicating matters further is that contaminants reduce catalytic efficacy, requiring rigorous and labor-intensive separation and purification processes to extract individual plastic streams from practical plastic waste mixtures. Consequently, the majority of such mixtures often end up in incineration and landfills, perpetuating environmental and societal challenges, such as leachate, carbon dioxide emissions, and other air pollutants. This review will introduce current technical developments available for recycling practical plastic waste mixtures through catalytic processes. The current challenges in process performance, low selectivity of the desired products, and catalyst deactivation from the catalysis of plastic waste mixtures are also discussed. Promising approaches to overcome the problems are suggested in future research directions.

The Respiratory Compensation Point: Mechanisms and Relation to the Maximal Metabolic Steady State.

At a point during the latter third of an incremental exercise protocol, ventilation begins to exceed the rate of clearance of carbon dioxide (CO2) at the lungs ( CO2). The onset of this hyperventilation, which is confirmed by a fall from a period of stability in end-tidal and arterial CO2 tensions (PCO2), is referred to as the respiratory compensation point (RCP). The mechanisms that contribute to the RCP remain debated as does its surrogacy for the maximal metabolic steady state of constant-power exercise (i.e., the highest work rate associated with maintenance of physiological steady state). The objective of this current opinion is to summarize the original research contributions that support and refute the hypotheses that: (i) the RCP represents a rapid, peripheral chemoreceptor-mediated reflex response engaged when the metabolic rate at which the buffering systems can no longer constrain the rise in hydrogen ions ([H+]) associated with rising lactate concentration and metabolic CO2 production is surpassed; and (ii) the metabolic rate at which this occurs is equivalent to the maximal metabolic steady state of constant power exercise. In doing so, we will shed light on potential mechanisms contributing to the RCP, attempt to reconcile disparate findings, make a case for its adoption for exercise intensity stratification and propose strategies for the use of RCP in aerobic exercise prescription.

Global value chains and carbon emission efficiency: evidence from 30 provinces in China

ABSTRACT The severity of global environmental change is a growing issue, primarily as an obvious result of carbon dioxide emissions. This article aims to recognize the causal relationship between Global Value Chains (GVCs) and Carbon Emission Efficiency (CEE) by using 30 provinces from 2000 to 2014 in China. This study calculates the GVCs level in the provincial level considering general trade, process trade, and intermediate trade agents; Besides, a model for the slacks-based measure of super-efficiency in data envelopment analysis (SBM-DEA) was used to measure the CEE. By applying fixed effect model techniques, our estimates reveal critical findings. First, we confirm the existence of the spatial-temporal evolution pattern of CEE in 30 provinces, showing an increased trend and noticeable east-west difference. Second, the econometric results suggest that the GVCs involvement is beneficiary for the CEE. Third, our results confirm that technological innovation and environmental regulation effects contribute to GVCs’ influence on CEE. These findings contribute to the formulation of appropriate carbon policies by the Chinese government, thereby advancing the objective of achieving carbon peaking by 2030 and carbon neutrality by 2050.

Near UV and Visible Light Photodegradation in Solid Formulations: Generation of Carbon Dioxide Radical Anions from Citrate Buffer and Fe(III).

Near UV and visible light photodegradation can target therapeutic proteins during manufacturing and storage. While the underlying photodegradation pathways are frequently not well-understood, one important aspect of consideration is the formulation, specifically the formulation buffer. Citrate is a common buffer for biopharmaceutical formulations, which can complex with transition metals, such as Fe(III). In an aqueous solution, the exposure of such complexes to light leads to the formation of the carbon dioxide radical anion (•CO2-), a powerful reductant. However, few studies have characterized such processes in solid formulations. Here, we show that solid citrate formulations containing Fe(III) lead to the photochemical formation of •CO2-, identified through DMPO spin trapping and HPLC-MS/MS analysis. Factors such as buffers, the availability of oxygen, excipients, and manufacturing processes of solid formulations were evaluated for their effect on the formation of •CO2- and other radicals such as •OH.

Assessment and analysis of polydimethylsiloxane-coated solar photovoltaic panels for cost-efficient solutions

Solar photovoltaic (PV) is a crucial renewable energy source in the fight against carbon dioxide emissions, aligning well with growing energy demands. However, solar PV efficiency naturally degrades over time, primarily due to uncontrollable outdoor factors such as irradiance, humidity, shading, soiling, aging, and temperature. These collectively lead to decreased efficiency in PV systems. Soiling on PV glass surfaces significantly impacts light penetration and subsequently reduces power generation. To combat this, a self-cleaning nano-calcium carbonate coating has been proposed. The effectiveness of this method is compared with a developed solar PV thermal (PV/T) system, evaluating both performance and cost-effectiveness. After six months of outdoor exposure, the coated glass solar PV achieved an efficiency of 7.6%, surpassing bare glass solar PV at 6.0%. Moreover, the coated glass solution boasts exceptional cost-effectiveness, incurring only an annual expense of 17.6 USD per panel compared to the PV/T system of 59.8 USD per panel. These findings highlight the potential of coatings to enhance solar PV performance and economics, particularly in addressing challenging uncontrollable factors like soiling.

A systematic review and meta-analysis compared the safety and effectiveness of the AirSeal system with traditional pneumoperitoneum systems in robot-assisted laparoscopic urologic surgery.

This study aimed to analyze perioperative results in robot-assisted laparoscopic urological surgeries, comparing the AirSeal system with traditional pneumoperitoneum systems. This study adhered to the PRISMA guidelines for conducting systematic reviews and meta-analyses. Extensive searches were conducted in PubMed, EMBASE, and Google Scholar, including randomized controlled trials (RCTs) and cohort studies up to June 15, 2024. A combined examination of the studies found that the AirSeal system had superior results in terms of surgery duration, end-tidal carbon dioxide levels, and tidal volume compared to the traditional pneumoperitoneum system. During robotic-assisted partial nephrectomy, the AirSeal team experienced a notable decrease in surgical time, ETCO2, and VT. In addition, the occurrence of SCE was lower in the AirSeal group. However, there were no significant differences observed between the groups regarding EBL, LOHS, overall complications, and major complications. Compared to conventional pneumoperitoneum systems, the AirSeal system offers several advantages in robot-assisted laparoscopic urological surgery: reduced operative time, lower end-tidal CO2 pressure, and decreased tidal volume. Furthermore, implementing the AirSeal system does not lead to higher rates of complications, estimated blood loss, or lengthier hospital stays.

Heat transfer characteristics of printed circuit heat exchangers under mechanical vibrations

Purpose The purpose of this paper is to investigate the impact of mechanical vibration on the heat transfer and pressure drop characteristics of semicircular channel printed circuit heat exchangers (PCHEs), while also establishing correlations between vibration parameters and thermal performance. Design/methodology/approach By combining experimental and numerical simulation methods, the heat transfer coefficient and pressure drop characteristics of supercritical carbon dioxide (S-CO2) in a semicircular channel with a diameter of 2 mm under vibration conditions were studied. Reinforce the research by conducting computational fluid dynamics studies using ANSYS Fluent 22.0, the experimental results were compared with the numerical simulation results to verify the accuracy of the numerical method. Findings The use of vibration has the potential to attenuate the degradation of wall heat transfer caused by buoyancy-induced PCHEs on the upward-facing surface. The heat transfer enhancement (HTE) was maximized by an increase of 18.2%, while the pressure drop enhancement (PDE) was elevated by over 25-fold. The capacity to enhance the heat exchange between S-CO2 and channel walls through increasing vibration intensity is limited, indicating maximum effectiveness in improving thermal performance. Originality/value Conducting heat transfer experiments on PCHEs with mechanical vibration enhancement and verifying the accuracy of the vibration numerical model. The relation based on the dimensionless factor is derived. To provide theoretical support for using vibration to enhance the heat transfer capability of PCHEs.

Renewable energy and institutional quality effect on carbon dioxide emissions empirical study: a multi-factor analysis

ABSTRACT With the development of society, the development of industry, the demand for fossil fuels and metal ores has also increased, leading to the uncontrolled exploitation of natural resources and their further reduction. Due to the widespread use of fossil fuels, carbon dioxide emissions are increasing every day. This is a common concern of many countries. In countries along the Belt and Road, carbon emissions have increased due to rising incomes, financial growth and urbanization. This paper investigates CO2 emissions in Belt and Road countries, using Stochastic Impacts by Regression on Population, Affluence, and Technology Framework and Driscoll-Kraay regression model were used for multi-factor analysis. Research shows that more renewable energy can help improve the energy system and reduce carbon dioxide emissions. In addition, research shows that the better the quality of the institution, the lower the carbon dioxide emissions. The government should also improve the system to reduce pollution from the second.

Advancing biohydrogen production through indirect photolysis: Insights from numerical simulation using the lattice boltzmann method

Hydrogen production through biochemical reactions is regarded as one of the most potential alternative technologies for producing hydrogen because of its efficacy, renewability, and environmental friendliness. Indirect biophotolysis is one of the most potential biohydrogen production technologies. In this study, a platform based on a coupled lattice Boltzmann method with cellular automata (LBM-CA) was developed to investigate the effects of different illumination intensities and carbon dioxide (CO2) concentrations on indirect photolysis in a bioreactor. The bioreactor was divided into two distinct parts. The first part as a photobioreactor had a transparent window at the top wall of the bioreactor that allowed solar illumination to enter the domain to generate glucose through the conversion of CO2 to carbohydrates (such as glucose) while the second was opaque where hydrogen was produced from carbohydrates by microorganisms. The results show that in the first part of the bioreactor, biofilm grew once CO2 was available. However, there is a lag in the biofilm growthand biohydrogen production between the first and the second part of the bioreactor because they depend on glucose production in the first part. The biofilm concentration increased as illumination increased, especially in the early stages, while the biofilm growth mainly occurred in the first part of the bioreactor. Increasing illumination could increase biofilm concentration by 92.4 % and reduce the lag time. It is also observed that increasing CO2 concentration changed the normalized biofilm concentration considerably, from − 40.9 % to 18.8 %. This can be attributed to increased nutrient availability for microorganism growth and glucose production in the first part of biophotolysis, resulting in greater concentrations of glucose as the main nutrient in the next part. Changing the inlet concentration leads to variations in the normalized hydrogen concentration in the range of − 72.9 % to 49.5 %.

Design of Cr-Based Molecular Electrocatalyst Systems for the CO2 Reduction Reaction.

ConspectusHuman influence on the climate system was recently summarized by the sixth Intergovernmental Panel on Climate Change (IPCC) Assessment Report, which noted that global surface temperatures have increased more rapidly in the last 50 years than in any other 50-year period in the last 2000 years. Elevated global surface temperatures have had detrimental impacts, including more frequent and intense extreme weather patterns like flooding, wildfires, and droughts. In order to limit greenhouse gas emissions, various climate change policies, like emissions trading schemes and carbon taxes, have been implemented in many countries. The most prevalent anthropogenic greenhouse gas emitted is carbon dioxide (CO2), which accounted for 80% of all U.S. greenhouse gas emissions in 2022. The reduction of CO2 through the use of homogeneous electrocatalysts generally follows a two-electron/two-proton pathway to produce either carbon monoxide (CO) with water (H2O) as a coproduct or formic acid (HCOOH). These reduced carbon species are relevant to industrial applications: the Fischer-Tropsch process uses CO and H2 to produce fuels and commodity chemicals, while HCOOH is an energy dense carrier for fuel cells and useful synthetic reagent. Electrochemically reducing CO2 to value-added products is a potential way to address its steadily increasing atmospheric concentrations while supplanting the use of nonrenewable petrochemical reserves through the generation of new carbon-based resources. The selective electrochemical reduction of CO2 (CO2RR) by homogeneous catalyst systems was initially achieved with late (and sometimes costly) transition metal active sites, leading the field to conclude that transition metal complexes based on metals earlier in the periodic table, like chromium (Cr), were nonprivileged for the CO2RR. However, metals early in the table have sufficient reducing power to mediate the CO2RR and therefore could be selective in the correct coordination environment. This Account describes our efforts to develop and optimize novel Cr-based CO2RR catalyst systems through redox-active ligand modification strategies and the use of redox mediators (RMs). RMs are redox-active molecules which can participate cocatalytically during an electrochemical reaction, transferring electrons─often accompanied by protons─to a catalytic active site. Through mechanistic and computational work, we have found that ligand-based redox activity is key to controlling the intrinsic selectivity of these Cr compounds for CO2 activation. Ligand-based redox activity is also essential for developing cocatalytic systems, since it enables through-space interactions with reduced RMs containing redox-active planar aromatic groups, allowing charge transfer to occur within the catalyst assembly. Following a summary of our work, we offer a perspective on the possibilities for future development of catalytic and cocatalytic systems with early transition metals for small molecule activation.

A Synopsis on CO2 Capture by Synthetic Hydrogen Bonding Receptors.

Carbon dioxide (CO2) is one of the most abundant greenhouse gases in Earth's atmosphere and responsible for global warming. Therefore, aerial CO2 capture and sequestration has become a major task for human community. Though several adsorbents for CO2 including activated carbon, zeolites, metal-organic frameworks (MOFs), and other surface-modified porous materials are well developed, the supramolecular approaches using synthetic hydrogen-bonding receptors are less explored. This review article highlights the synthetic development of various artificial receptors and their properties toward fixation of aerial CO2 as carbonate (CO32-), bicarbonate (HCO3-), or carbamate (-NHCOO-/>NCOO-) ions, induced by excess fluoride (F-) or hydroxide (OH-) ions as their tetrabutylammonium salts. The utilization of encapsulated carbonate/bicarbonate/carbamate complexes in anion exchange metathesis for separation of oxyanions from aqueous solutions are also discussed. In addition, the release of CO2 and regeneration of receptor molecules are described in a number of occasions. Most importantly, the formation of anion complexes as crystalline materials in solid-state is described in terms of supramolecular chemistry and correlated with their solution-state properties. Finally, the types of receptors containing various functional groups are scrutinized in CO2 uptake, storage, and release processes and hints of endeavours for future research are delineated.

Using eddy covariance observations to determine the carbon sequestration characteristics of subalpine forests in the Qinghai–Tibet Plateau

Abstract. Subalpine forests are a crucial component of the carbon cycling system in the Qinghai–Tibet Plateau (QTP). However, there are currently significant data gaps in the QTP, and it is essential to enhance continuous monitoring of forest carbon absorption processes in the future. This study investigates 2 years' carbon exchange dynamics of a subalpine forest on the QTP using an eddy covariance method. We first characterized the seasonal carbon dynamics of the subalpine forest, revealing the higher carbon dioxide (CO2) exchange rates in summer and autumn and lower rates in winter and spring, and found that autumn is the peak period for carbon sequestration in this subalpine forest, with the maximum measured value of CO2 absorption reaching 10.70 µmol m−2 s−1. Subsequently, we examined the environmental factors influencing the carbon sequestration function. Principal component analysis (PCA) shows that photosynthetically active radiation (PAR) was the major environmental factor driving the net ecosystem exchange (NEE) of CO2, significantly influencing forest carbon absorption, and the increase in relative humidity decreases the rate of carbon fixation. In addition, we explored NEE and its influencing factors at the regional scale and found that air temperature promotes carbon dioxide absorption (negative NEE values), while the average annual precipitation shows a minor effect on NEE. At the annual scale, the subalpine forest functions as a strong carbon sink, with an average NEE of −332 to −351 g C m−2 (from November 2020 to October 2022). Despite the challenges of climate change, forests remain robust carbon sinks with the highest carbon sequestration capacity in the QTP, with an average annual CO2 absorption rate of 368 g C m−2. This study provides valuable insights into the carbon cycling mechanism in subalpine ecosystems and the global carbon balance.

Ionic Liquids Functionalized Copper Catalytic Systems for Electrocatalytic Carbon Dioxide Reduction

The extensive combustion of fossil fuels results in excessive release of carbon dioxide (CO2), causing a global environmental crisis. It is imperative to develop sustainable methods for converting CO2 into renewable energy sources. Electrochemical reduction of CO2 (CO2RR) offers the potential to generate valuable chemicals, including C1 products (e.g., carbon monoxide, methane, etc.) and C2+ products (e.g., ethene, ethanol, acetic acid, propyl alcohol, etc.). Copper‐based (Cu‐based) catalysts show promise for producing value‐added C2+ products, but they face challenges like low selectivity and stability. The catalytic performances of Cu‐based catalysts can be promoted through electronic structure adjustment, selective crystal face exposure, as well as molecular additive approaches. Ionic liquids (ILs), known for their strong CO2 adsorption capacity, adjustable hydrophobicity, and wide chemical window, hold significant promise for addressing the current challenges associated with Cu‐based catalysts. This review provides a comprehensive overview of the structural characterization and catalytic mechanisms of ILs used in Cu‐based CO2RR catalytic systems. Additionally, it offers suggestions for future research avenues regarding IL‐functionalized Cu catalysts.

Determination of gas flux of growing steers under intensive grazing conditions

Abstract Ruminants produce one-third of the anthropogenic methane (CH4) emissions worldwide, and 47% of the CH4 emissions result from ruminants under grazing conditions. However, there is limited information regarding the appropriate number of visits to accurately determine enteric CH4 emissions using the automated head-chamber system (AHCS) from growing beef cattle under intensive grazing conditions. Data from one experiment was analyzed to determine the number of visits to assess gas flux (CH4, carbon dioxide (CO2), and oxygen (O2)) from Angus-crossbreed steers grazing in a pivot-irrigated improved pasture. A total of 110 steers (324 ± 37.3 kg initial body weight) were selected and divided into two blocks. Steers were under intensive grazing management for 84 days. Depending on forage availability, steers were rotated at 2 to 4 d intervals. Pastures were predominately composed of cool-season forages. Two different databases using the same animals (n=16) were defined to calculate the gas flux using the first 100 visits to an AHCS with 2 or more or 3 or more minutes of visitation length. The mean gas flux was estimated as the average for increasing (forward) or decreasing (reverse) the gas flux of 5-visit intervals starting with the first or the last 5 visits and increasing or decreasing until the full 100-visit dataset was utilized, respectively. Spearman and Pearson correlations were computed between the maximum visits and each shortened visit interval. Concurrently, the residual variance and the residual variance change were determined for each interval by fitting a mixed model. The minimum number of visits was defined when correlations with the total visits were greater than 0.95, and the residual variance was stabilized. The results indicated that the minimum number of visits needed to determine CH4 production varied between 45 and 70, while CO2 production and O2 consumption varied between 45 and 50 according to the visitation length. Additionally, steers that visited the AHCS for 2 or more minutes in visit duration required a greater number of visits than those that visited for 3 or more minutes. Thus, based on the average daily visitation in this experiment (1.4 visit/d), the assessment of CH4 emissions requires 32 days, while CO2 production and O2 consumption require between 32 and 36 days using 3 or more minutes of visit length from growing steers under intensive grazing conditions.

Economic growth of India: The role of production, trade, and CO2 emission based on the Granger causality

India’s economic growth is of significant interest due to its expanding Gross Domestic Product (GDP) and global market influence. This study investigates the interplay between production, trade, carbon dioxide (CO2) emissions, and economic growth in India using Granger causality analysis. Also, the data from 1994 to 2023 were analyzed to explore the relationships among these variables. The results reveal strong positive correlations among production, trade, CO2 emissions, and GDP, with production showing significant associations with export, import, and GDP. Co-integration tests confirm the presence of a long-term relationship among the variables, suggesting their interconnectedness in shaping India’s economic landscape. Regression analysis indicates that production, export, import, United States (US)-India trade, manufacturing cost of energy, and CO2 emissions significantly impact GDP. Moreover, the Vector Error Correction Model (VECM) estimation reveals both short-term and long-term dynamics, highlighting the importance of understanding equilibrium and deviations in economic variables. Overall, this study contributes to a better understanding of the complex interactions driving India’s economic growth and sustainability.