Explosion characteristics of synthesised biogas at various temperatures

Water vapor and carbon dioxide species measurements in narrow channels

The world has focused on carbon mitigation as the only solution for climate change. This discussion paper considers how marine biodiversity regulates the climate, and the factors that control marine biodiversity. The main Greenhouse Gas (GHG) is water vapor, which accounts for 75% of all GHGs; the second most important is carbon dioxide, followed by methane and particulates such as black carbon (BC) soot. The concentration of water vapor in the atmosphere is regulated by air temperature; warmer conditions lead to higher evaporation, which in turn increases the concentration of water vapor, the Clausius-Clapeyron relation. This means that as the oceans and atmosphere warm, a self-reinforcing feedback loop accelerates the evaporation process to cause further warming. It is not considered possible to directly regulate atmospheric water vapor. This explains why climate change mitigation strategies have focussed primarily on reducing carbon dioxide emissions as the means to reduce water vapor. This report concludes that the current climate change mitigation strategy will not work on its own because it depends on decreasing the concentration of atmospheric carbon dioxide and on the assumption that water vapor is only regulated by temperature. 71% of planet Earth is covered by an ocean that has a surface microlayer (SML) between 1 µm and 1000µm deep, composed of lipids and surfactants produced by marine phytoplankton. This SML layer is known to promote the formation of aerosols and clouds; it also reduces the escape of water molecules and slows the transfer of thermal energy to the atmosphere. The concentration of water vapor is increasing in our atmosphere, and 100% of this increase is evaporation from the ocean surface; water vapour from land systems is decreasing. This means that the oceans are almost entirely responsible for climate change. The SML layer attracts toxic forever, lipophilic chemicals, microplastics and hydrophobic black carbon soot from the incomplete combustion of fossil fuels. Concentrations of toxic chemicals are 500 times higher in this SML layer than in the underlying water. Toxic forever chemicals combined with submicron and microplastic particles and black carbon particulates are known to be toxic to plankton. Marine primary productivity or phytoplankton photosynthesis may have declined by as much as 50% since the 1950s. Reduced phytoplankton plant growth equates to a degraded SML membrane, reduced carbon assimilation, and higher concentrations of dissolved carbon dioxide in ocean surface water, which accelerates the decline in ocean pH. The key phytoplankton species responsible for the production of the SML layer are the first to suffer from pH decline, a process called “ocean acidification”. Ocean acidification will lead to a regime shift away from the key carbonate-based species and diatoms below pH 7.95 which will be reached by 2045. The SML layer will decrease, allowing evaporation and atmospheric water vapor concentrations to increase. A reduced SML layer will lead to fewer aerosols, cloud formation and precipitation, as well as increased humidity and temperature. When clouds form under these conditions, the higher humidity will cause torrential downpours and flooding. The result could be catastrophic climate change, even if we achieve net zero by 2050. In parallel, ocean acidification and the collapse of the marine ecosystem could also lead to the loss of most seals, birds, whales, fish, and food supply for 3 billion people.

Comparative pyrolysis characteristics of representative commercial thermosetting plastic waste in inert and oxygenous atmosphere

When compared to the average annual global temperature record from 1880, no published climate model posited on the assumption that the increasing concentration of atmospheric carbon dioxide is the driver of climate change can accurately replicate the significant variability in the annual temperature record. Therefore, new principles of atmospheric physics are developed for determining changes in the average annual global temperature based on changes in the average atmospheric concentration of water vapor. These new principles prove that: 1) Changes in average global temperature are not driven by changes in the concentration of carbon dioxide; 2) Instead, autonomous changes in the concentration of water vapor, ΔTPW, drive changes in water vapor heating, thus, the average global temperature, ΔTAvg, in accordance with this principle, ΔTAvg=0.4ΔTPW the average accuracy of which is ±0.14%, when compared to the variable annual, 1880-2019, temperature record; 3) Changes in the concentration of water vapor and changes in water vapor heating are not a feedback response to changes in the concentration of CO2; 4) Rather, increases in water vapor heating and increases in the concentration of water vapor drive each other in an autonomous positive feedback loop; 5) This feedback loop can be brought to a halt if the average global rate of precipitation can be brought into balance with the average global rate of evaporation and maintained there; and, 6) The recent increases in average global temperature can be reversed, if average global precipitation can be increased sufficiently to slightly exceed the average rate of evaporation.

The proton and hole conductivities of BaZrO3-based perovskites depend on partial pressures of oxygen and water vapor. These conductivities affect the power generation characteristics of Proton Ceramic Fuel Cells (PCFCs) using the perovskite as an electrolyte. In this study, the effect of humidification conditions on the power generation characteristics of an anode-supported PCFCs was investigated.The configuration of the anode-supported PCFC was La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) cathode/BaZr0.8Yb0.2O3-δ(BZYb) electrolyte/Ni-BZYb anode. The diameter of the effective cathode area was approx. 10 mm. The cathode gas composition was fixed at 97% concentration of air and 3% concentration of water vapor. The concentration of water vapor in the anode gas was controlled to be 3-69%. The current density-voltage characteristics and AC impedance were measured by Bio-Logic SP-150.In all water vapor concentration conditions, the cell showed the highest OCV (approximately 1 V) at 3% concentration of water vapor. However, the maximum power density was highest at 30% concentration of water vapor (346 mW/cm2). The highest maximum power density at 30% concentration of water vapor can be explained by the following reason. The OCV values decrease with increasing the concentration of water vapor because of decreasing the concentration of hydrogen. On the other hand, from the results of impedance measurements, the ohmic resistance of the cell decrease with increasing the concentration of water vapor because of increase of proton conductivity of the cell. Thus, the increase of cell voltage by increase of proton conductivity should be higher than the decrease of OCV values.【Acknowledgements】This presentation is the result of the research and development of ultra-efficient proton-conducting ceramic fuel cell devices, JPNP20003, funded by the New Energy and Industrial Technology Development Organization (NEDO), Japan. We would like to express our gratitude to all parties involved.

A novel method has been implemented for measuring the concentration of various gas species (water vapor, carbon dioxide) within fuel cell gas channels and other minichannel applications in a non-invasive manner through the use of tunable diode laser absorption spectroscopy (TDLAS). An optically accessible test cell has been designed to allow for the passage of 1–0.5 millimeter diameter laser beams along 12 mm-12 cm long flow paths, while also allowing for visual observation of the channels in order to detect the formation of liquid water. Concentrations of water vapor and carbon dioxide have been measured in situ within the test cell with a temporal resolution of 0.5 secs and 2.5 secs respectively. The technique is portable to high aspect ratio channels yielding concentration measurements of species over 1 mm long passages with an experimental uncertainty of 5%.

The paper shows the results of measurements of wave number of electromagnetic wave, which supports burning of high-frequency torch discharge in the mixture of air with water vapor and carbon dioxide. The nonmonotonic dependence of attenuation factor of electromagnetic waves is set on a concentration of water vapor. It is shown that the attenuation degree of electromagnetic field in the plasma with water vapor significantly exceeds the attenuation degree of electromagnetic field in the plasma with carbon dioxide.

Detection of water vapour or carbon dioxide using a zirconia pump-gauge sensor

Oxidation of graphite by low concentrations of water vapor and carbon dioxide in helium

Temperature limitation by evaporation in hot climates and the greenhouse effects of water vapor and carbon dioxide

Synoptic-scale weather patterns affect local meteorological variables, such as vapor pressure deficit (VPD), temperature, and insolation, that are known to influence evapotranspiration (ET) and net CO2 flux (FC). However, little research exists that links synoptic-scale patterns to ET and FC. In this study, we seek to understand how synoptic-scale patterns influence ET and FC for the temperate mixed-hardwood forest at Hubbard Brook Experimental Forest (HBEF) in New Hampshire, United States. We use self-organizing maps to identify the most common synoptic pattern types impacting HBEF during the 2016–21 growing seasons and determine how ET and FC vary with these synoptic pattern types. Our analysis reveals that high ET and most negative FC days occur for the weather pattern phases starting after the departure of a low pressure system and through the approach of a high pressure system. ET and the magnitude of FC remain high if the latitude of the high is south of HBEF but moderate (especially for ET) if the high is to the north and causes east winds to advect a humid maritime air mass over the region. ET is lowest when HBEF is located between high pressure to the east and low pressure to the west, which causes humid southerly flow to decrease VPD and insolation. Meanwhile, FC magnitude may remain high when this pattern occurs in June–July when photosynthetic capacity is at its highest. Our results suggest that future changes in the frequency of passing low pressure systems and pathways of high pressure systems could impact the fluxes of water and CO2 from this forest. Significance Statement For decades, we have understood that local meteorological variables, such as insolation, temperature, and relative humidity, have a strong influence on a forest ecosystem’s use of water and carbon dioxide, two important greenhouse gases. We also understand that large-scale weather patterns and their interactions with forests shape these local meteorological conditions. This research advances knowledge of the relationship between various large-scale weather patterns and their impacts on forest’s use of water and carbon dioxide via local meteorological variables for a mixed-hardwood forest in the Northeastern United States. Connecting these results to the frequency of these various large-scale weather pattern types projected by global climate models will help us predict how forest ecosystems will influence water vapor and carbon dioxide concentrations and thus impact global climate.

photoacoustic spectroscopy for multi-gas sensing using near infrared lasers

ABSTRACTUse of vent-free gas heating appliances for supplemental heating in U.S. homes is increasing. However, there is currently a lack of information on the potential impact of these appliances on indoor air quality for homes constructed according to energy-efficient and green building standards. A probabilistic analysis was conducted to estimate the impact of vent-free gas heating appliances on indoor air concentrations of carbon monoxide (CO), nitrogen dioxide (NO2), carbon dioxide (CO2), water vapor, and oxygen in “tight” energy-efficient homes in the United States. A total of 20,000 simulations were conducted for each Department of Energy (DOE) heating region to capture a wide range of home sizes, appliance features, and conditions, by varying a number of parameters, e.g., room volume, house volume, outdoor humidity, air exchange rates, appliance input rates (Btu/hr), and house heat loss factors. Predicted airborne levels of CO were below the U.S. Environmental Protection Agency (EPA) standard of 9 ppm for all modeled cases. The airborne concentrations of NO2 were below the U.S. Consumer Product Safety Commission (CPSC) guideline of 0.3 ppm and the Health Canada benchmark of 0.25 ppm in all cases and were below the World Health Organization (WHO) standard of 0.11 ppm in 99–100% of all cases. Predicted levels of CO2 were below the Health Canada standard of 3500 ppm for all simulated cases. Oxygen levels in the room of vent-free heating appliance use were not significantly reduced. The great majority of cases in all DOE regions were associated with relative humidity (RH) levels from all indoor water vapor sources that were less than the EPA-recommended 70% RH maximum to avoid active mold and mildew growth. The conclusion of this investigation is that when installed in accordance with the manufacturer’s instructions, vent-free gas heating appliances maintain acceptable indoor air quality in tight energy-efficient homes, as defined by the standards referenced in this report.Implications: Probabilistic modeling of indoor air concentrations of carbon monoxide (CO), nitrogen dioxide (NO2), carbon dioxide (CO2), water vapor, and oxygen associated with use of vent-free gas heating appliances provides new data indicating that uses of these devices are consistent with acceptable indoor air quality in “tight” energy-efficient homes in the United States. This study will provide authoritative bodies such as the International Code Council with definitive information that will assist in the development of future versions of national building codes, and will provide evaluation of the performance of unvented gas heating products in energy conservation homes.

To investigate the effect of water vapor in the feed gas on the power generation characteristics of PCFCs, the water vapor concentration was changed to 3%, 15%, 30%, and 50%, while the hydrogen concentration in the gas fed to the anode was fixed at 50%. The impedance measurements showed that the ohmic resistance decreased with increasing water vapor concentration, which was attributed to the increase in the proton conductivity of the electrolyte. The measured current density-voltage characteristics showed that the power output increased with increasing water vapor concentration, which was attributed to the decrease in ohmic overvoltage caused by the increase in proton conductivity. In addition, as a more practical condition, the power generation characteristics were measured when the water vapor concentration was varied while the hydrogen concentration was varied in an anode gas consisting only of hydrogen and water vapor.

Stratospheric water vapor concentrations decreased by about 10% after the year 2000. Here we show that this acted to slow the rate of increase in global surface temperature over 2000-2009 by about 25% compared to that which would have occurred due only to carbon dioxide and other greenhouse gases. More limited data suggest that stratospheric water vapor probably increased between 1980 and 2000, which would have enhanced the decadal rate of surface warming during the 1990s by about 30% as compared to estimates neglecting this change. These findings show that stratospheric water vapor is an important driver of decadal global surface climate change.