It is widely recognized that global warming promotes soil organic carbon (SOC) decomposition, and soils thus emit more CO2 into the atmosphere because of the warming; however, the response of SOC decomposition to this warming in different soil textures is unclear. This lack of knowledge limits our projection of SOC turnover and CO2 emission from soils after future warming. To investigate the CO...

We propose a transparent climate debt index incorporating both methane (CH4) and carbon dioxide (CO2) emissions. We develop national historic emissions databases for both greenhouse gases to 2005, justifying 1950 as the starting point for global perspectives. We include CO2 emissions from fossil sources [CO2(f)], as well as, in a separate analysis, land use change and forestry. We calculate the...

BACKGROUND AND AIMS Woody plants can suffer from winter embolism as gas bubbles are formed in the water-conducting conduits when freezing occurs: gases are not soluble in ice, and the bubbles may expand and fill the conduits with air during thawing. A major assumption usually made in studies of winter embolism formation is that all of the gas dissolved in the xylem sap is trapped within the con...

Insects breathe through valved openings (spiracles) in their cuticle. Many insects open and close their spiracles in a cyclic pattern (discontinuous gas-exchange cycles, or DGC). These cycles were observed over half a century ago, their hypothesized function being to minimize loss of water from the tracheal system. However, numerous recent studies have found that respiration accounts for a smal...

Nine ecosystem process models were used to predict CO2 and water vapor exchanges by a 150-year-old black spruce forest in central Canada during 1994–1996 to evaluate and improve the models. Three models had hourly time steps, five had daily time steps, and one had monthly time steps. Model input included site ecosystem characteristics and meteorology. Model predictions were compared to eddy cov...

We evaluate how the heterogeneity of precursor may affect pyrolysis and CO2 gasification behavior aimed at activated carbon applications. Barley straw, ground classified into five size ranges, is characterized by non-isothermal thermogravimetry tests various heating rates. Fixed volatile matter contents decrease with particle size. Also, finest fraction enriched in minerals exogenous contaminat...

The feasibility of recycling carbon dioxide into concretes through their curing processes was investigated. The CO2 uptake capacities of four commonly used concrete building products: masonry block, paving stone, cement board and fiberboard, were evaluated. It was found that, based on the cement content used in the product, the uptake capacities of the four products ranged from 9.8% to 18.9% wh...

At room temperature, CO2 is transparent in the ultraviolet (UV) at wavelengths longer than 205 nm; however, at temperatures above 1000 K the CO2 absorption cross-section becomes significant in the region between 200 and 320 nm. Because CO2 is a major product of hydrocarbon combustion and because both the magnitude of the absorption cross-section and the shape of the UV absorption spectrum vary ...

Noninvasive ventilation with a plateau exhalation valve (PEV) is often used as an adjunct to exercise to achieve a physiologic training effect in severe chronic obstructive pulmonary disease (COPD) patients. However, during exercise, with the increase of exhalation flow and respiratory rate and limited capability of PEV to exhale gases out of the circuit, it is still unknown whether CO2 rebreat...

The influence of differing rates of increase of the atmospheric CO2 concentration on the climatic response is investigated using a coupled ocean–atmosphere model. Five transient integrations are performed each using a different constant exponential rate of CO2 increase ranging from 4% yr21 to 0.25% yr21. By the time of CO2 doubling, the surface air temperature response in all the transient inte...