Stabilization of atmospheric carbon dioxide via zero emissions-An alternative way to a stable global environment. Part 1: Examination of the traditional stabilization concept

The concept of "stabilization" of atmospheric CO2 concentration is re-examined in connection with climate-change mitigation strategies. A new "zero-emissions stabilization (Z-stabilization)" is proposed, where CO2 emissions are reduced to zero at some time and thereafter the concentration is decreased by natural removal processes, eventually reaching an equilibrated stable state. Simplified climate experiments show that, under Z-stabilization, considerably larger emissions are permissible in the near future compared with traditional stabilization, with the same constraint on temperature rise. Over longer time scales, the concentration and temperature decrease close to their equilibrium values, much lower than those under traditional stabilization. The smaller temperature rise at final state is essential to avoid longer-term risk of sea level rise, a significant concern under traditional stabilization. Because of these advantages a Z-stabilization pathway can be a candidate of practical mitigation strategies as treated in Part 2.(Contributed by Taroh MATSUNO, M.J.A.).     

A constraint satisfaction method applied to the problem of controlling the CO2 emission in the Legal Brazilian Amazon

Socioeconomic-driven processes such as deforestation, forest degradation, forest fires, overgrazing, overharvesting of fuelwood and slash-and-burn practices constitute the primary sources of Greenhouse Gases (GHG) emissions in developing countries. Climate policies can induce the development of clean technology and offer incentives to accelerate reforestation. The Brazilian government has already acknowledged the urgency to invest in policies to reduce anthropogenic CO₂ emissions in the Legal Brazilian Amazon (BA). In this work, we propose a scheme to estimate the required investments in clean technology and reforestation to achieve a prescribed short term target value for the atmospheric CO₂ emission. Initially, a mathematical model is fitted to the available data to allow forecasting the values of the short term emissions of CO₂ under a combination of investments in clean technology and reforestation. The investments to reduce the emissions of CO₂ below a target value (400 million tons/year, starting at the initial value of 450) in 3 years’ time are proportional to the regional GDP. Using computer simulation it is possible to generate a range of possible investment values in clean technology and reforestation, so that the prescribed emission reduction is achieved without hindering economic growth. This strategy provides the necessary investment flexibility for the implementation of realistic climate policies.     

感应耦合非热等离子体催化转化二氧化碳

射频感应耦合等离子体能够在室温条件下选择活化并分解二氧化碳,本文通过调控等离子体放电条件(气体流量、放电频率等)获得了较高的一氧化碳产率. 研究发现网状金属催化剂在二氧化碳等离子体中能促进氧原子的复合反应,从而有效抑制其与目标产物一氧化碳的逆反应,提升反应整体效率. 本文为实时转化过剩的可再生电能(来自太阳能、风能、潮汐能等)为高附加值一氧化碳中的化学能提供了一个可行的方案.     

Effervescence in champagne and sparkling wines: From grape harvest to bubble rise

Bubbles in a glass of champagne may seem like the acme of frivolity to most of people, but in fact they may rather be considered as a fantastic playground for any fluid physicist. Under standard tasting conditions, about a million bubbles will nucleate and rise if you resist drinking from your flute. The so-called effervescence process, which enlivens champagne and sparkling wines tasting, is the result of the complex interplay between carbon dioxide (CO₂) dissolved in the liquid phase, tiny air pockets trapped within microscopic particles during the pouring process, and some both glass and liquid properties. In this tutorial review, the journey of yeast-fermented CO₂ is reviewed (from its progressive dissolution in the liquid phase during the fermentation process, to its progressive release in the headspace above glasses). The most recent advances about the physicochemical processes behind the nucleation, and rise of gaseous CO₂ bubbles, under standard tasting conditions, have been gathered hereafter. Let’s hope that your enjoyment of champagne will be enhanced after reading this tutorial review dedicated to the unsuspected physics hidden right under your nose each time you enjoy a glass of bubbly.     

A comparative study of FESEM and EDX analyses of Datong coal in N2 and CO2 environments

Field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy and Brunauer Emmett Teller surface area analyses of char produced in CO₂ and N₂ environments in a thermo-gravimetric analyzer, using thermo-plus II software, were investigated under different parametric conditions. These conditions include temperature, flow rate variations etc. for the implementation of oxy-fuel combustion technology. It was observed that, at high temperatures and low flow rates, the mass loss rate of coal in CO₂ was higher than in that of a N₂ environment. This may be due to one additional step of coal gasification i.e. char gasification by CO₂ at higher temperature. More importantly, during the reaction with CO₂ the formations of perfectly hexagonal nanorods at the particular temperature of 773 K were observed. However, the amount of these nanorods decreases and the dimensions i.e. size and shape change (smaller aspect ratio) with the increase of flow rate and temperature as well. The formation of these nanorods are attracted much because of their peculiar properties and potential applications in functional nano-devices and environmentally clean energy purposes i.e. CO₂ capturing.     

Studies of high-pressure n-butane oxidation with CO2 dilution up to 100 atm using a supercritical-pressure jet-stirred reactor

A novel supercritical-pressure jet stirred reactor (SP-JSR) is developed to operate up to 200 atm. The SP-JSR provides a unique platform to conduct kinetic studies at low and intermediate temperatures at extreme pressures under uniform temperature distribution and a short flow residence time. n-Butane oxidations with varying levels of CO₂ dilutions at pressures of 10 and 100 atm and over a temperature range of 500-900 K were conducted using the SP-JSR. The experiment showed that at 100 atm, a weak NTC behavior is observed and the intermediate temperature oxidation is shifted to lower temperatures. Furthermore, the results showed that CO₂ addition at supercritical conditions slows down the fuel oxidation at intermediate temperature while has little effect on the low temperature oxidation. The Healy model under-predicts the NTC behavior and shows little sensitivity of the effect of CO₂ addition on the n-butane oxidation. Reaction pathway and sensitivity analyses exhibit that both the low and intermediate temperature chemistries are controlled by RO₂ consumption pathways. In addition, the reactions of CH₃CO (+ M) and CH₃CO + O₂ become important at 100 atm. The results also revealed that fuel oxidation kinetics is insensitive to the third body effect of CO₂. The kinetic effect of supercritical CO₂ addition may come from the reactions involving H₂O₂, CO, CH₂O, and CH₃CHO, especially for the reactions of CO₂ + H and CO₂ + OH.     

Predictions of climate changes caused by man-made emissions of greenhouse gases: A critical assessment

Predictions of the most advanced computer models of the changes in the global climate that may result from man-made emissions of greenhouse gases are described and assessed in the light of the uncertainties in future emissions and atmospheric concentrations of these gases, and of the limitations of the models

Predictions of the globally averaged temperature rise, produced by the doubling of atmospheric carbon dioxide over 70 years, range from 1·3 to 2·6°C, on average about 0·3°C decade^?1. The scattering of solar radiation by atmospheric aerosols is calculated to reduce this global warming to about 1·0°C or 0·2°C decade^?1. Warming is predicted to occur everywhere but to be most marked in high latitudes of the Northern Hemisphere.

Globally averaged precipitation is predicted to rise by a few per cent but with large geographical variations and areas of both increase and decrease. The largest increases are expected to occur in intertropical convergence zone, and in middle and high latitudes, especially in winter. Decreases are predicted in the subtropics. The best current estimate of the rise in sea level resulting from an annual increase of 1% p.a. of carbon dioxide is 4 cm decade^?1.     

Comparison of chemical solvents for mitigating CO2 emissions from coal-fired power plants

There is a growing concern about the effect of greenhouse gases on global warming. Among the many greenhouse gases, CO₂ produced from burning fossil fuels is a major contributor due to the huge volumes emitted into the atmosphere. According to the estimates of the Intergovernmental Panel on Climate Change (IPCC), a worldwide reduction in the emission of greenhouse gases by more than 60% is necessary to avert significant global climate changes.This paper examines the key issues involved in greenhouse gas emissions from coal-fired power plants. At the present time, absorption by chemical solvents appears to be best option for the separation of CO₂ from low pressure flue gas streams. The costs of separation and disposal of CO₂ from existing coal fired, air blown boilers are estimated to increase the cost of electricity by about 75%. Therefore, there is a need to optimize the selection of processing solvents and operating parameters to minimize the cost of separation. Increasing the inlet flue gas pressure did not improve mass transfer rates sufficiently to compensate for the higher compression costs. The effects of other process variables were also examined.In this work, we have examined the cost effectiveness of six ethanolamine-based solvents. Overall, monoethanolamine (MEA) was found to be the best solvent.     

理论研究二氧化碳在有机吸收剂1，3-二苯胍中的氢键相互作用

如今碳捕获和储存技术已得到了迅速发展以减少对环境的二氧化碳排放. 研究发现胺基有机分子溶剂能有效地吸收二氧化碳,并通过氢键和二氧化碳形成的碳酸氢盐相互作用. 最近,实验报道了一种1,3-二苯基胍溶液,在室温条件下能捕获环境中的二氧化碳并将其转化为有价值的化学品. 然而,1,3-二苯基胍分子在溶液状态下如何与二氧化碳相互作用的机理仍不清楚. 在这项工作中,利用分子动力学方法模拟研究了溶液相中1,3-二苯基胍分子与二氧化碳的复杂作用细节. 模拟结果表明,质子化的1,3-二苯基胍分子和碳酸氢根离子倾向通过不同的双氢键模式作用形成稳定的复合物. 精确的密度泛函方法计算表明,这些双氢键复合物在热力学上相当稳定. 本研究有助于理解溶液相中1,3-二苯基胍分子中催化转化二氧化碳的机理.     

Baryon asymmetry in the inflationary universe

It is shown that the baryon asymmetry in the inflationary universe under certain constraints on the masses of superheavy bosons can be larger than that in the standard baryosynthesis scenario. An important property of the model considered is that the final baryon asymmetry does not depend on initial conditions in the early universe in contrast to what occurs in the standard scenario based on B?L conserving GUTs.     

Infrared and far-infrared laser emissions from a TE CO2 laser pumped NH3 gas

In this paper, infrared (IR) and far-infrared (FIR) laser emissions from a TE CO₂ laser pumped NH₃ gas are reported. 8 IR laser emissions near the wavelength of 12 μm were observed by using 4 different CO₂ laser lines for the pumping. 3 IR laser emissions in P-branch of vibrational-rotational band (ν₂ → G) oscillated simultaneously in two pumping cases, i.e. pumping with the R(30) or R(16) line of 9.4 μm band from the CO₂ laser. 26 FIR laser emissions (26.45 μm ～ 281.0 μm) were observed by using 12 different CO₂ laser lines, and the 10 FIR emissions of them may be new laser emissions as far as we know.     

Infrared multiphoton dissociation of vinyltrifluorosilane

Infrared multiphoton absorption and dissociation of vinyltrifluorosilane molecules under the action of pulsed TEA CO₂-laser were experimentally studied. The composition of the end dissociation products has been analyzed. Using quantum chemical calculations, we have identified the dissociation pathways that lead to the observed end products. Transition state geometries, enthalpies and activation energies for the dissociation pathways have been calculated. The dissociation channel ratio was determined under used experimental conditions. The silicon isotope selective infrared multiphoton dissociation has been performed at different wavelengths of the CO₂-laser radiation. PACS 82.50Bc; 82.30Lp; 31.15.Ew     

Nonlinear effects of the thermal stabilization theory of applied superconducting materials

The stability of dissipative states of a Bi₂Sr₂CaCu₂O₈ applied superconducting composite cooled by liquid helium or hydrogen with continuously increasing current-voltage characteristics described by a power equation has been studied. It has been shown that, under intensive cooling conditions, special conditions of thermal stabilization can exist for applied superconducting materials (technical superconductors) if the nonlinear temperature dependences of critical current density and specific resistance of the stabilizing matrix are taken into account. First, the minimum currents of existence and propagation of a normal zone can be absent. Second, the intensive cooling of a technical superconductor substantially increases the range of stable currents in the diapason of supercritical currents. Third, during the irreversible propagation of the thermal instability, the temperature of a technical superconductor can increase under conditions close to adiabatic, despite cooling by liquid coolant. These effects should be taken into account upon determining the conditions for overheating a technical superconductor. The numerical experiments have been compared with the results that follow from the thermal stabilization theory of combined superconductors, which assumes a linear temperature dependence of critical current density of a superconductor and a step-wise transition from the superconducting to normal state.     

UV-laser-light-controlled photoluminescence of metal oxide nanoparticles in different gas atmospheres: BaTiO3, SrTiO3 and HfO2

The photoluminescence (PL) enhancement has been studied at room temperature using various specimen atmospheres (O₂ gas, CO₂ gas, CO₂–H₂ mixture gas, Ar–H₂ mixture gas and vacuum) under 325 nm laser light irradiation on various metal oxides. Of them, the results obtained for BaTiO₃ nanocrystals, SrTiO₃ ones and HfO₂ powder crystal are given in the present paper. Their PL were considerably increased in intensity by irradiation of 325 nm laser light in CO₂ gas and CO₂–H₂ mixture gas. The cause of the PL intensity enhancements is discussed in the light of the exciton theory, the defect chemistry and the photocatalytic theory. The results may be applied for the utilization of greenhouse gas (CO₂) and the optical sensor for CO₂ gas.     

Effect of high CO2 concentration on char formation through mineral reaction during biomass pyrolysis

O₂/CO₂ combustion has attracted considerable attention as a promising technology for CO₂ capture. Using biomass for fuel is considered carbon neutral, and O₂/CO₂ biomass combustion can mitigate the deleterious environmental effect of greenhouse. In this study, the effect of CO₂, the main component gas in O₂/CO₂ combustion, on the pyrolysis characteristics of biomass is investigated. Cellulose, lignin, and metal-depleted lignin pyrolysis experiments were performed using a thermobalance. Information on the surface chemistry of the chars was obtained by Fourier transform infrared (FTIR) spectroscopy to investigate changes in the surface chemistry during pyrolysis under different surrounding gasses. When the temperature increased to 1073 K at heating rate of 1 K s^?1, the char yield of lignin in the presence of CO₂ increased by about 10% compared with that under Ar. However, for cellulose and metal-depleted lignin, no significant difference appeared between pyrolysis under CO₂ and that under Ar. FT-IR showed that a strong peak corresponding to carbonate ions appeared in the char derived from lignin under CO₂. Therefore, salts such as Na₂CO₃ or K₂CO₃ formed during the lignin pyrolysis under CO₂. At around 1650–1770 cm^?1, a significant difference appeared in the FTIR spectra of chars formed under CO₂ and those formed under Ar. C=O groups not associated with an aromatic ring were found only in chars formed under CO₂. It was suggested that these salts affected the char formation reaction, in that the char formed during lignin pyrolysis under CO₂ had unique chemical bands that did not appear in the lignin-derived char prepared under Ar.     

Pattern formation by local amplification and lateral inhibition: Examples from biology and geology

This article provides an overview of current and prospected climate changes, their causes and implied threats, and of a possible route to keep the changes within a tolerable level. The global mean temperature has up to 2005 risen by almost 0.8°C, and the change expected by 2100 is as large as glacial-interglacial changes in the past, which were commonly spread out over 10000 years. As is well known, the principle actor is man-made CO₂, which, together with other anthropogenic gases, enhances the atmosphere’s greenhouse effect. The only man-made cooling agent appears to be atmospheric aerosols. Atmospheric CO₂ has now reached levels unprecedented during the past several million years. Principal threats are a greatly reduced biodiversity (species extinction), changes in the atmospheric precipitation pattern, more frequent weather extremes, and not the least, sea level rise. The expected precipitation pattern will enhance water scarcity in and around regions that suffer from water shortage already, affecting many countries. Sea level rise will act on a longer time scale. It is expected to amount to more than 50 cm by 2100, and over the coming centuries the potential rise is of the order of 10 m. A global-mean temperature increase of 2°C is often quoted as a safe limit, beyond which irreversible effects must be expected. To achieve that limit, a major, rapid, and coordinated international effort will be needed. Up to the year 2050, the man-made CO₂ releases must be reduced by at least 50%. This must be accompanied by a complete overhaul of the global energy supply toward depending increasingly on the Sun’s supply of energy, both directly and in converted form, such as wind energy. Much of the information and insight available today has been generated by the Intergovernmental Panel on Climate Change (IPCC), in particular its Fourth Assessment Report of 2007, which greatly advanced both public attention and political action.     

Determination of aluminum-air burning velocities using PIV and Laser sheet tomography

In a context of growing concerns over climate change, aluminum has the potential to serve as a dense energy carrier in order to replace fossil fuels and reduce greenhouse gases emissions. Indeed, its combustion in air may provide carbon-free energy for applications in which a high-energy storage capacity is required. However, attempts of designing a metal-fueled combustor will conflict with a relatively large dispersion of the burning velocity values reported in the literature, even when similar powders are used. This uncertainty is partially due to the range of experimental conditions and techniques used on those previous studies. In the present work, an experimental Bunsen-type aluminum-air burner is introduced. It is shown that the setup is capable of generating stable dust suspensions under well-controlled conditions. The stabilized aluminum-air flames are studied using emission spectroscopy, Particle Image Velocimetry, laser sheet tomography, and direct visualization of the AlO(g) emissions. The measured burning velocities are then compared to previous results obtained for similar powders as a function of dust concentration. A reasonable agreement is obtained, and it is shown that metal flame tomography can yield a more precise indicator of the flame front position than AlO(g) emissions, helping to reduce the data scatter regarding dust-air burning velocities.     

Allowable overheat and limiting current in a superconducting composite with magnetic flux creep

Instability arising in a superconducting composite when the current is injected with an ultimately low rate is analyzed. Under these conditions, the nonuniformity of the temperature and electric field distributions over the composite cross section is negligibly small. Equations that allow one to estimate the effect of the magnetic flux creep on the maximum current and temperature of the superconductor before the onset of instability are derived. It is shown that the allowable overheat of the composite depends on conditions of its thermal stabilization especially near the steady-state stabilization range. It is noted that conditions for the existence of stable current states may differ when the magnetic flux creep is described by power and exponential I-V characteristics.     

13C Basal Abundance of Expired CO2 -Definition of Pre-Requisites for Kinetic Breath Tests

Abstract

A sufficiently stable rate of ¹³CO₂ exhalation is necessary when the diagnostic ¹³CO₂ breath tests are performed in healthy subjects and patients. The aim of the research was to define prerequisite conditions for kinetic breath tests in order to ensure a stable ¹³CO₂ background. A 3-part protocol was developed. Part I: a study of the one-day variation of ¹³CO₂ abundance in expired CO₂ confirmed that shifts of the basal ¹³C abundance in breath are inherent in nature. Part II: a study of the variations of ¹³C enrichment after the ingestion of different meals and beverages showed that ingestion of food items containing C₄ plant sugars, such as maize, induces a significant increase in isotopic abundance. Part III: a new test breakfast containing rice grain cereal, milk and orange juice was tested. This test meal induces no significant change on the basal ¹³CO₂ abundance in healthy subjects. This new finding allows to avoid the fasting period normally required prior to a breath test which is sometimes difficult for children and pregnant women.