Catalysts for the Simultaneous Production of Syngas and Carbon Nanofilaments Via Catalytic Decomposition of Biogas

The possibility of alleviation of methane and carbon dioxide levels in the atmosphere are of major global interest. One of the alternatives that attracts much scientific attention is their chemical utilization, especially because both of these gases are components of the biogas. Thus, the rapid and extensive shale gas development makes them abundant raw materials. The development of an effective catalytic process that could be scaled-up for industrial purposes remains a great challenge for catalysis. As well, understanding of the mechanisms of molecular activation and the reaction pathways over active centers on heterogeneous catalysts needs to be advanced. It has been shown that biogas is a very interesting source of renewable energy. Because of its elevated methane content, biogas has excellent potential, as reflected in its year-over-year rise in production. This is because its manufacturing promotes the use of organic waste, prevents uncontrolled dumping and minimizes atmospheric methane and carbon dioxide emissions. Moreover, its use as an energy source is in some cases an alternative to fossil fuels and can help to minimize energy dependence. Another aspect of interest is that it can be used in situ, allowing agro-livestock farms or small industrial plants to achieve energy self-sufficiency.

Oxygen overload

A structure that helps algae photosynthesize when carbon dioxide levels are low may also play a role during hyperoxia conditions.

Baseline hypocapnia is associated with intubation in COVID-19 diagnosed patients

ABSTRACT Introduction Hypocapnia may be one of the several factors predefining the need for intubation of patients needing hospitalization for COVID-19 pneumonia. Methods A retrospective evaluation of patient files hospitalized for COVID-19 pneumonia from October 2020 until January 2021. Univariate and multivariate regression was used, as well as a multinomial regression to account for multiple endpoints (discharge, intubation, death). Results Hypocapnia was strongly associated with intubation (OR: 0.86, 95% CI: 0.76, 0.97). Additionally, last pCO2 (OR: 1.08, 95% CI: 1.01, 1.16), baseline FiO2 (OR: 1.05, 95% CI: 1.03, 1.07) as well as last FiO2 (OR: 1.21, 95% CI: 1.11, 1.46), total severity score on admission (OR: 1.18, 95% CI: 1.03, 1.37) and last pO2 (OR: 0.89, 95% CI: 0.85, 0.92) were found to have a significant impact on intubation. Incorporation of deceased patients withheld the negative association with pCO2 levels (OR: 0.88, 95% CI: 0.78, 0.98). Conclusion The dissociation between respiratory failure and a clinically comfortable patient is partly due to decreased carbon dioxide levels and clinicians should bare it in mind when handling patients with COVID-19 pneumonia. Hypocapnia seems to be a determinant factor of intubation in patients with COVID-19 pneumonia in this study.

Investigating Increased CO2 concentration on the pH of various plant species

The concept of bioremediation is quickly becoming the norm in the resolution of environmental issues. The steady increase in carbon dioxide levels, as documented by NASA, inspired scientists to engineer plants to absorb excess carbon dioxide from the atmosphere. Here, we have explored the consequences of the uptake of excess carbon dioxide by select plants. Carbon dioxide dissolves in water to produce carbonic acid, which dissociates to yield H+ ions. We hypothesized that increased carbon dioxide absorption results in decrease in pH of plant sap. Three plants (Byophyllum pinnatum, Romaine Lettuce and Nevada Lettuce), exposed to increased carbon dioxide concentrations (15%), demonstrated a consistent increase in pH towards alkalinity compared to control plants. Based on the outcome being opposite of what we have hypothesized, our results suggest Byophyllum pinnatum, Romaine lettuce and Nevada lettuce, all have a unique homeostatic system to prevent over-absorption of carbon dioxide in a carbon dioxide-rich environment.

Indoor Air Quality in New Zealand Office Buildings: Studies of Airborne Bacteria and Fungi

<p>The aim of this thesis was to investigate the levels of indoor airborne bacteria and fungi in fully sealed mechanically ventilated offices in New Zealand. One of the main objectives was to examine the indoor airborne bacterial and fungal levels in Auckland and Wellington offices and to compare the quality of indoor air in offices in both cities. Examining the differences in indoor airborne bacterial and fungal levels between complaint and non-complaint offices as well as comparing those levels with those of similar indoor environments overseas was also one of the main objectives of this thesis. Indoor and outdoor air data used in this thesis were recorded during commercial investigation of 235 offices in Auckland and Wellington by the Institute of Environmental Science and Research (ESR) and Advanced Building Services (ABS). This data included measurements of indoor microclimatic parameters (temperature and relative humidity), indoor and outdoor airborne bacterial and fungal concentrations and indoor carbon dioxide levels. Statistical analyses showed the indoor bacterial levels in Auckland offices were significantly higher than those of Wellington offices. Indoor fungal levels in Auckland offices, on the other hand, were significantly below those of Wellington offices despite the fact that outdoor fungal levels in Auckland were at least three times higher than those of Wellington. No significant differences have been observed between airborne bacterial and fungal levels in complaint and non-complaint offices. Indoor airborne bacterial and fungal levels in New Zealand offices appeared also to be within the levels of those of overseas offices. However, as the bacterial and fungal sampling techniques used by ESR and ABS were different from those used in overseas studies and this can affect airborne bacterial and fungal absolute counts significantly, care is needed in making such comparisons. Finally, an evaluation tool has been developed to overcome the difficulties associated with comparison between indoor airborne fungal levels obtained using different measurements techniques. This tool can be used to establish whether elevated fungal problems exist in an office environment and the likely causes of these problems.</p>

Indoor Air Quality in New Zealand Office Buildings: Studies of Airborne Bacteria and Fungi

<p>The aim of this thesis was to investigate the levels of indoor airborne bacteria and fungi in fully sealed mechanically ventilated offices in New Zealand. One of the main objectives was to examine the indoor airborne bacterial and fungal levels in Auckland and Wellington offices and to compare the quality of indoor air in offices in both cities. Examining the differences in indoor airborne bacterial and fungal levels between complaint and non-complaint offices as well as comparing those levels with those of similar indoor environments overseas was also one of the main objectives of this thesis. Indoor and outdoor air data used in this thesis were recorded during commercial investigation of 235 offices in Auckland and Wellington by the Institute of Environmental Science and Research (ESR) and Advanced Building Services (ABS). This data included measurements of indoor microclimatic parameters (temperature and relative humidity), indoor and outdoor airborne bacterial and fungal concentrations and indoor carbon dioxide levels. Statistical analyses showed the indoor bacterial levels in Auckland offices were significantly higher than those of Wellington offices. Indoor fungal levels in Auckland offices, on the other hand, were significantly below those of Wellington offices despite the fact that outdoor fungal levels in Auckland were at least three times higher than those of Wellington. No significant differences have been observed between airborne bacterial and fungal levels in complaint and non-complaint offices. Indoor airborne bacterial and fungal levels in New Zealand offices appeared also to be within the levels of those of overseas offices. However, as the bacterial and fungal sampling techniques used by ESR and ABS were different from those used in overseas studies and this can affect airborne bacterial and fungal absolute counts significantly, care is needed in making such comparisons. Finally, an evaluation tool has been developed to overcome the difficulties associated with comparison between indoor airborne fungal levels obtained using different measurements techniques. This tool can be used to establish whether elevated fungal problems exist in an office environment and the likely causes of these problems.</p>

Carbon dioxide levels and ventilation in Acromyrmex nests: significance and evolution of architectural innovations in leaf-cutting ants

Leaf-cutting ant colonies largely differ in size, yet all consume O 2 and produce CO 2 in large amounts because of their underground fungus gardens. We have shown that in the Acromyrmex genus, three basic nest morphologies occur, and investigated the effects of architectural innovations on nest ventilation. We recognized (i) serial nests, similar to the ancestral type of the sister genus Trachymyrmex , with chambers excavated along a vertical tunnel connecting to the outside via a single opening, (ii) shallow nests, with one/few chambers extending shallowly with multiple connections to the outside, and (iii) thatched nests, with an above-ground fungus garden covered with plant material. Ventilation in shallow and thatched nests, but not in serial nests, occurred via wind-induced flows and thermal convection. CO 2 concentrations were below the values known to affect the respiration of the symbiotic fungus, indicating that shallow and thatched nests are not constrained by harmful CO 2 levels. Serial nests may be constrained depending on the soil CO 2 levels. We suggest that in Acromyrmex , selective pressures acting on temperature and humidity control led to nesting habits closer to or above the soil surface and to the evolution of architectural innovations that improved gas exchanges.

Climate change impacts on pest ecology and risks to pasture resilience

It is well understood that damage by insect pests can have serious consequences for pasture resilience. However, the impacts of climate change on pastoral systems, the responses of insect pests, and implications for pest impact mitigation are unclear. This paper reviews pest responses to climate change, including direct impacts such as temperature and carbon dioxide levels, geographic range expansion, sleeper pests, and outbreaks resulting from disturbance such as drought and farm system changes. The paper concludes with a plea for transdisciplinary research into pasture resilience under climate change that has insect pests as an integral component – not as an afterthought.

Carbon dioxide levels in initial nests of the leaf-cutting ant Atta sexdens (Hymenoptera: Formicidae)

Claustral foundation of nests by Atta sexdens Forel (Hymenoptera: Formicidae) involves great effort by its queens, solely responsible for the cultivation of the fungus and care for her offspring at this stage. The minimum workers, after 4 months, open access to the external environment to foraging plants to cultivate the symbiotic fungus, which decomposes the plant fragments and produces gongilidea nodules as food for the individuals in the colony. Colony gas exchange and decomposition of organic matter in underground ant nests generate carbon dioxide (CO2) emitted into the atmosphere. We described the carbon dioxide concentration in colonies in the field. The objective was to evaluate the carbon dioxide concentration in initial A. sexdens colonies, in the field, and their development. The CO2 level was also measured in 4-month-old colonies in the field, using an open respirometric system fitted with an atmospheric air inlet. The CO2 level of the respirometric container was read by introducing a tube into the nest inlet hole and the air sucked by a peristaltic pump into the CO2 meter box. The CO2 concentration in the initial colony was also measured after 4 months of age, when the offspring production (number of eggs, larvae, pupae and adult workers) stabilized. Ten perforations (15 cm deep) was carried out in the adjacent soil, without a nest of ants nearby, to determine the concentration of CO2. The composition of the nests in the field was evaluated after excavating them using a gardening shovel and they were stored in 250 ml pots with 1 cm of moistened plaster at the bottom. The CO2 concentration was higher in field nest than in adjacent soil. The concentration of carbon dioxide in A. sexdens nests in the field is higher than in those in the soil, due to the production of CO2 by the fungus garden and colony.