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121.
Andreas Züttel 《Mitigation and Adaptation Strategies for Global Change》2007,12(3):343-365
Hydrogen storage and transportation or distribution is closely linked together. Hydrogen can be distributed continuously in
pipelines or batch wise by ships, trucks, railway or airplanes. All batch transportation requires a storage system but also
pipelines can be used as pressure storage system. Hydrogen exhibits the highest heating value per weight of all chemical fuels.
Furthermore, hydrogen is regenerative and environment friendly. There are two reasons why hydrogen is not the major fuel of
toady’s energy consumption: First of all, hydrogen is just an energy carrier. And, although it is the most abundant element
in the universe, it has to be produced, since on earth it only occurs in the form of water. This implies that we have to pay
for this energy, which results in a difficult economic task, because since the industrialization we are used to consuming
energy for free. The second difficulty with hydrogen as an energy carrier is the low critical temperature of 33 K, i.e. hydrogen
is a gas at room temperature. For mobile and in many cases also for stationary applications the volumetric and gravimetric
density of hydrogen in a storage system is crucial. Hydrogen can be stored by six different methods and phenomena: high pressure
gas cylinders (up to 800 bar), liquid hydrogen in cryogenic tanks (at 21 K), adsorbed hydrogen on materials with a large specific
surface area (at T < 100 K), absorbed on interstitial sites in a host metal (at ambient pressure and temperature), chemically bond in covalent
and ionic compounds (at ambient pressure), oxidation of reactive metals e.g. Li, Na, Mg, Al, Zn with water. These metals easily
react with water to the corresponding hydroxide and liberate the hydrogen from the water. Finally, the metal hydroxides can
be thermally reduced to the metals in a solar furnace. 相似文献
122.
123.
An efficient, reproducible and rapid fused silica capillary column gas chromatographic method, in splitless mode, for analysing of the three chloroanthracene isomers is described. The method affords efficient separation and good linearity for each isomer in the range of 0.2 -200 μg/ml. The method can also be used in separation and determination of another thirty three aromatic and their halosubstituted compounds. This paper also presents the applications of the method in analysing of complex products mixture from reaction of the selected aromatic compounds with hydrogen chloride on fly ash surface from municipal incinerator. 相似文献
124.
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126.
CLIMATE CHANGE AND NATURAL HAZARDS IN NORTHERN CANADA: INTEGRATING INDIGENOUS PERSPECTIVES WITH GOVERNMENT POLICY 总被引:1,自引:0,他引:1
John?NewtonEmail author C.?D.?James?Paci Aynslie?Ogden 《Mitigation and Adaptation Strategies for Global Change》2005,10(3):541-571
A study of the relationship between natural hazards and climate change in the international context provides the background
for a discussion of the expected changes. In the context of this global discussion, this paper reviews the current perspectives
of those natural hazards that are likely to be influenced by climate change, using northern Canada as a regional case study.
The northern implications of the United Nations Framework Convention on Climate Change are examined, including the status
of climate change action by the northern territorial governments, the evolving role of indigenous people, and the responsibility
for climate change impacts. The difficulties surrounding natural hazards research in remote locations, and the approaches
of indigenous people to natural hazards are then presented. The paper concludes with a suggested policy approach for climate
change and natural hazards in northern Canada, underscoring the need for more comprehensive adaptive strategies to complement
the current tendency to focus on the mitigation of greenhouse gases produced in this region. 相似文献
127.
Model oligo esters of terephthalic acid with 1,2-ethanediol, 1,3-propanediol, and 1,4-butanediol have been investigated with regard to their biodegradability in different biological environments. Well-characterized oligomers with weight-average molar masses of from 600 to 2600 g/mol exhibit biodegradation in aqueous systems, soil, and compost at 60°C. SEC investigations showed a fast biological degradation of the oligomer fraction consisting of 1 or 2 repeating units, independent of the diol component used for polycondensation, while polyester oligomers with degrees of polymerization higher than 2 were stable against microbial attack at room temperature in a time frame of 2 months. At 60°C in a compost environment chemical hydrolysis also degrades chains longer than two repeating units, resulting in enhanced degradability of the oligomers. Metabolization of the monomers and the dimers as well by the microorganisms could be confirmed by comparing SEC measurements and carbon balances in a Sturm test experiment. Based on these results degradation characteristics of potential oligomer intermediates resulting from a primary chain scission from copolyesters consisting of aromatic and aliphatic dicarbonic acids can be predicted depending on their composition. These results will have an evident influence on the evaluation of the biodegradability of commercially interesting copolyesters and lead to new ways of tailor-made designing of new biodegradable materials as well. 相似文献
128.
The toxicity of ammonia to Hyalella azteca at constant pH in artificial media was controlled by sodium and potassium, and not by calcium, magnesium, or anions. Small increases in the LC50 for total ammonia (from 0.15 to 0.5 mM) occurred as sodium was increased from 0.1 to 1 mM and above, but major increases in the LC50 (to over 10 mM total ammonia) required the addition of potassium. Potassium was, however, more effective at reducing ammonia toxicity at high (1 mM) sodium than at low (0.1 mM) sodium. Ammonia toxicity was independent of pH at low sodium and potassium concentrations, when ammonia toxicity appeared to be associated primarily with aqueous ammonium ion concentrations. At high sodium and potassium concentrations, the toxicity of ammonia was reduced to the point where un-ionized ammonia concentrations also affected toxicity, and the LC50 became pH dependent. A mathematical model was produced for predicting ammonia toxicity from sodium and potassium concentrations and pH. 相似文献
129.
130.
Evacuation mapping: the utility of guidelines 总被引:2,自引:0,他引:2