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31.
The reaction between hydrochloric acid and solid slaked lime was investigated by passing simulated flue gas through a fixed bed reactor. The influence of CO2 and H2O present in the flue gas was studied, as well as the influence of the reaction temperature in the range 423 to 673 K. The reaction was found to be of first order with respect to the two reactants. Expressions to account for the temperature and the CO2 and H2O concentrations were derived from the experimental data.  相似文献   
32.
This paper situates livelihood adaptations in two coastal villages within the broader context of Belize's colonial and post-colonial history and environmental processes of change. Through observations, qualitative interviews, and archival reviews, we explore the dynamics of livelihood change and analyse the diverse factors that have been influencing options and adaptation over time. The results reveal that both villages have undergone profound changes in livelihoods and productive activities on several occasions. While the villages' histories, geographies, and cultures are different, similarities in long-term trends include the transition from land-based to marine resources and the decline of small-scale agriculture. Our analysis illuminates the deep connections between local livelihoods and national as well as global political–economic processes, which favour extraction and export of natural resources throughout the period investigated, whereby resource access and market mechanisms create and constrict adaptation options for the villagers. Gradual environmental changes, such as erosion, and episodic events, such as hurricanes, have also influenced livelihood shifts and adaptations in combination with a wide range of political–economic factors. Despite the demonstrated importance of the influence of history and dimensions of political economy on contemporary adaptation options in the communities studied, the literature on climate change adaptation inadequately accounts for these factors. This paper adds new perspectives to current debates in climate change research by emphasising that longer temporal dimensions of livelihood change are important for understanding the current context for adaptation.  相似文献   
33.
Knowledge of how species interactions are influenced by climate warming is paramount to understand current biodiversity changes. We review phenological changes of Swedish butterflies during the latest decades and explore potential climate effects on butterfly–host plant interactions using the Orange tip butterfly Anthocharis cardamines and its host plants as a model system. This butterfly has advanced its appearance dates substantially, and its mean flight date shows a positive correlation with latitude. We show that there is a large latitudinal variation in host use and that butterfly populations select plant individuals based on their flowering phenology. We conclude that A. cardamines is a phenological specialist but a host species generalist. This implies that thermal plasticity for spring development influences host utilization of the butterfly through effects on the phenological matching with its host plants. However, the host utilization strategy of A. cardamines appears to render it resilient to relatively large variation in climate.  相似文献   
34.
The replacement of fossil fuels by biofuels could be an important means of reducing net carbon dioxide (CO2) emission. An estimation of the CO2 mitigation efficiency of biofuel systems depends on the method and assumptions used. Here, different parameters and methods are discussed for comparing fossil-fuel- and biofuel-based systems. Three parameters are suggested: the monetary cost, the primary energy cost and the biofuel cost of CO2 mitigation. They are defined as the difference in monetary expenditure, primary energy use and biofuel use between the compared systems, divided by the difference in net CO2 emission between the systems. Cogeneration and separate production of electricity and heat is then compared using these parameters and the methods of multi-functional products or subtraction. In both methods, either electricity or heat is regarded as the main product and the other is regarded as a by-product. The multi-functional method is preferable due to its transparency as both the main product and the by-product are part of the functional unit. Using heat as the main product illustrates the typical situation that the heat demand limits the use of cogeneration. When comparing systems the output from them should not differ. If the by-product is not fully, cogenerated part of the by-product has to be produced separately. A logical choice for producing this part of the by-product is to use a similar fuel and technology as used for cogeneration.  相似文献   
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36.
A method is presented for the determination of isocyanic acid (ICA), HNCO, in air samples as a di-n-butylamine (DBA) derivative. The method is based on sampling in midget impinger flasks containing 10 ml of 0.01 mol l-1 DBA in toluene. Quantification was made using liquid chromatography (LC) and electrospray mass spectrometry (MS) monitoring positive ions. The instrumental detection limit for the LC-MS was 10 fmol of ICA-DBA. ICA was generated by thermal decomposition of urea. A standard solution containing the DBA derivatives of ICA was prepared by collecting the emitted ICA in an impinger flask containing DBA. ICA in the reference solution was characterised by LC and time-of-flight (TOF) MS and quantified by LC chemiluminescent nitrogen detection (LC-CLND). The instrumental detection limit for the LC-CLND was 1 ng of nitrogen. ICA was emitted during thermal degradation of PFU resins and polyurethane (PUR) lacquers, from car metal sheets. ICA was the most dominant isocyanate and in PUR coating up to 8% of the total weight was emitted as ICA and for PFU resins up to 14% was emitted as ICA. When air samples were collected in an iron foundry during casting in sand moulds with furan resins, concentrations of ICA in the range 50-700 micrograms m-3 were found in the working atmosphere.  相似文献   
37.
During 24 h, water samples were taken for determination of a number of key parameters in a water system containing high concentrations of FeII at circumneutral pH. None of the major constituents (Ca, Mg, Na, K and sulfate) showed diurnal variations, while dissolved oxygen and pH increased during the night. This increase could entirely be explained by the decrease in water temperature. However, the concentration of FeII slightly increased at constant concentration of total Fe during the night, opposite to earlier observations in other systems where the presence of FeII was shown to be controlled by photoreduction. Nocturnal peaks of FeII have also been observed in other systems with high iron concentrations, however, at acidic pH, but without obvious explanation. The mechanisms for this process therefore need further investigation.  相似文献   
38.
Karlsson  Mikael  Gilek  Michael 《Ambio》2020,49(5):1067-1075
Ambio - Gaps between public policy goals and the state of the environment are often significant. However, while goal failures in environmental governance are studied in a number of disciplines, the...  相似文献   
39.
While much work has been invested in addressing the economic and technical basis of disaster preparedness, less effort has been directed towards understanding the cultural and social obstacles to and opportunities for disaster risk reduction. This paper presents local insights from five different national settings into the cultural and social contexts of disaster preparedness. In most cases, an early warning system was in place, but it failed to alert people to diverse environmental shocks. The research findings show that despite geographical and typological differences in these locations, the limitations of the systems were fairly similar. In Kenya, people received warnings, but from contradictory systems, whereas in the Philippines and on the island of Saipan, people did not understand the messages or take them seriously. In Bangladesh and Nepal, however, a deeper cultural and religious reasoning serves to explain disasters, and how to prevent them or find safety when they strike.  相似文献   
40.
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