Wind turbines are a green energy source that Taiwan has been endeavouring to develop in the past five years. Excellent onshore wind farms have already been developed; however, offshore development is inevitable because of Taiwan's limited land area. With regard to energy sustainability, operation and trouble-free maintenance of wind farms are essential. If damage to fan components can be mostly prevented, the operating cost and maintenance time would be considerably decreased; thus, remarkable economic benefits could be achieved. An appropriate coating can help a structure resist the stress of the working environment and improve its durability, resulting in lower maintenance cost and less staff being required to perform on-site repairs. Diatomaceous earth (DE) has been widely used to produce composite porous materials. In this study, epoxy resin and titanium dioxide were mixed with DE to increase the hydrophobicity of the surface of coatings and provide them photocatalytic self-cleaning ability. The ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate was also added to the coatings to prevent the corrosion of coated metallic material. This study employed thermal analysis to investigate the thermal stability of the coatings and the corrosion resistance of coated iron blocks. Finally, a self-made quartz container was connected to a volatile organic compound detector, and sun exposure was simulated using ultraviolet light. The results confirmed that the modified coating retained its functionality under the harsh working environment and can be applied to the surfaces of large machinery used in offshore wind turbine towers. 相似文献
The influence of inlet parameters on the production and thermal risk of complex chemical systems can be cumbersome to evaluate. To determine the optimum safe operating conditions, one needs to solve complex differential equations derived from energy and material balances. This robust approach cannot be made on-site, and it is essential to propose simplest tools to evaluate rapidly the performance and safety of some operating conditions. This is the aim of this paper that establishes explicit relationships between the production and thermal risk parameters, and the inlet parameters. In addition, it also proposes a Pareto chart that can be used to make the tradeoff between safety and performance. Such relationships and chart were developed for the production of epoxidized cottonseed oil under isoperibolic and semi-batch mode. The kinetic model developed by Zheng et (Zheng et al., 2016). was used. First, a numerical approach, i.e., least square method, was used to find explicit relationships between thermal risk parameters, production parameters and six inlet parameters. The use of such an approach allows a better understanding of this process. Second, safety and performance indicators are proposed and discussed to evaluate the operating conditions thanks to a simple and intuitive schema. Besides, this approach can be used to find the optimum conditions more rapidly. 相似文献
Utility-scale lithium-ion energy storage batteries are being installed at an accelerating rate in many parts of the world. Some of these batteries have experienced troubling fires and explosions. There have been two types of explosions; flammable gas explosions due to gases generated in battery thermal runaways, and electrical arc explosions leading to structural failure of battery electrical enclosures. The thermal runaway gas explosion scenarios, which can be initiated by various electrical faults, can be either prompt ignitions soon after a large flammable gas mixture is formed, or delayed ignitions associated with late entry of air and/or loss of gaseous fire suppression agent. The electrical explosions have entailed inadequate electrical protection to prevent high energy arcs within electrical boxes vulnerable to arc induced high pressures and thermal loads. Estimates of both deflagration pressures and arc explosion pressures are described along with their incident implications. 相似文献
Many species are restricted to a marginal or suboptimal fraction of their historical range due to anthropogenic impacts, making it hard to interpret their ecological preferences from modern-day data alone. However, inferring past ecological states is limited by the availability of robust data and biases in historical archives, posing a challenge for policy makers . To highlight how historical records can be used to understand the ecological requirements of threatened species and inform conservation, we investigated sperm whale (Physeter macrocephalus) distribution in the Western Indian Ocean. We assessed differences in information content and habitat suitability predictions based on whale occurrence data from Yankee whaling logs (1792–1912) and from modern cetacean surveys (1995–2020). We built maximum entropy habitat suitability models containing static (bathymetry-derived) variables to compare models comprising historical-only and modern-only data. Using both historical and modern habitat suitability predictions we assessed marine protected area (MPA) placement by contrasting suitability in- and outside MPAs. The historical model predicted high habitat suitability in shelf and coastal regions near continents and islands, whereas the modern model predicted a less coastal distribution with high habitat suitability more restricted to areas of steep topography. The proportion of high habitat suitability inside versus outside MPAs was higher when applying the historical predictions than the modern predictions, suggesting that different marine spatial planning optimums can be reached from either data sources. Moreover, differences in relative habitat suitability predictions between eras were consistent with the historical depletion of sperm whales from coastal regions, which were easily accessed and targeted by whalers, resulting in a modern distribution limited more to steep continental margins and remote oceanic ridges. The use of historical data can provide important new insights and, through cautious interpretation, inform conservation planning and policy, for example, by identifying refugee species and regions of anticipated population recovery. 相似文献
The assessment of the consequences of high pressure releases of flammable gases is a fundamental requirement for the safe design and operation of industrial installations, plants and pipework. A scenario of interest concerns a high pressure jet-fire following the ignition of a gas jet release which results in a thermal loading to the surroundings and possibly leads to accident escalation.
In the present paper, a case study is presented: two parallel-laid natural gas pipelines have been considered, the accidental scenarios which may possibly occur as a consequence of a pipeline failure have been discussed and the thermal effects caused by the jet-fire developing from different rupture sizes have been assessed.
Three scenarios have been analyzed, considering the pipelines being within a highly congested area: (i) large failure and vertical jet with detached flame; (ii) small failure with jet fire directly impinging on the parallel pipeline; (iii) small failure with pipeline engulfed within fire.
Once the temperature gradient through the pipeline wall has been found, the stresses deriving from pressure load and steel differential expansion have been analytically calculated and compared with the yielding stresses at the temperature achieved by the pipeline wall.
In the first scenario the pipeline is able to resist without major problems; in the second case the pipeline rupture is likely to occur; in the third scenario the pipeline resists to the applied loads but with a low margin to yielding.
It is understood that the analysis results are very much dependent on the utilized hypotheses, therefore a sensitivity analysis was performed in order to assess the variation of the results as a function of the variation of problem data; this analysis identifies the large influence of the parameters on the final result. 相似文献
This study investigated the thermal degradation energy (activation energy, Ea) for nitrocellulose (NC) with low nitrogen content of 11.71 mass%, so-called NC3, by using two different kinds of thermal analysis instruments: thermogravimetric analyzer (TGA) and differential scanning calorimetry (DSC). A comparison of Ea for various nitrogen content NC samples at two scanning rates (5 and 10 °C min?1) tested by TGA and DSC is also discussed in this paper. Meanwhile, our aim was to analyze the anti-degradation of Ea for NC with high nitrogen content, as so-called NC1. Thermal stability for NC1 with diphenylamine (DPA) was tested via DSC with 10 DPA concentrations in weights of 0, 0.25, 0.50, 0.75, 1.0, 1.25, 1.50, 1.75, 2.0, and 3.0 mass%. Experimental results indicated that Ea of NC3s was 319.91 kJ mol?1. Moreover, that while dosing DPA into NC1 the best recipe could be employed to avoid any violent NC1 runaway and also can be used to distinguish the differences of thermal decomposition Ea between NC with different nitrogen contents. This study established a fast and efficient procedure for thermal decomposition properties of NC, and could be applied as an intrinsically safer design during relevant operations. 相似文献