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561.
Yasin Şöhret Olcay Kıncay T. Hikmet Karakoç 《International Journal of Green Energy》2018,15(3):145-150
Emitted exhaust gases from aircraft are an issue of concern from an environmental perspective. Many research studies have been conducted aiming to reduce aircraft emissions in the hope of preventing any further increase in climate change and global warming. Within this scope, the present study intends to present a methodology for an optimum gas turbine engine selection with regard to emitted exhaust gases. The methodology focuses on five different turbofan engines which constitute the power unit of a commonly used passenger aircraft. At the end of the study, it is considered to be impossible to achieve a minimum exhaust emission for each gas. For this reason, it is considered to be better to optimize the engine with the aim of reducing nitrogen oxide emissions or other exhaust emissions. 相似文献
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Based on the physical and chemical properties as well as calorific values of pulp sludge and textile sludge, this study investigates the differences between manufacturability, relationship between extrusion pressure and formability, as well as stability and combustion behaviors of extruded sludge-derived fuel briquettes (ESBB) and cemented sludge-derived fuel blocks (CSBB). The optimum proportion and relevant usage ESBB policies are proposed as well. Experimental results indicate that a large amount of water can be saved during the ESBB manufacturing process. Additionally, energy consumption decreases during the drying process. ESBB also has a more compact structure than that of CSBB, and its mean penetration loading is approximately 18.7 times higher as well. Moreover, the flame temperature of ESBB (624–968 °C) is significantly higher than that of CSBB (393–517 °C). Also, the dry bulk density and moisture regain of ESBB is significantly related to the penetration loading. Furthermore, the optimum mix proportion of ESBB is co-determined by the formability of pulp sludge and the calorific values of textile sludge. While considering the specific conditions (including formability, stability and calorific values), the recommended mix proportion for ESBB is PS50TS50. 相似文献
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ABSTRACT: Bivariate and trivariate distributions have been derived from the logistic model for the multivariate extreme value distribution. Marginals in the models are extreme value type I distributions for two-component mixture variables (mixed Gumbel distribution). This paper is a continuation of the previous works on multivariate distribution in hydrology. Interest is focused on the analysis of floods which are generated by different types of storms. The construction of their corresponding probability distributions and density functions are described. In order to obtain the parameters of such a bivariate or trivariate distribution, a generalized maximum likelihood estimation procedure is proposed to allow for the cases of samples with different lengths of record. A region in Northern Mexico with 42 gauging stations, grouped into two homogeneous regions, has been selected to apply the models. Results produced by the multivariate distributions have been compared with those obtained by the Normal, log-Normal-2, log-Normal-3, Gamma-2, Gamma-3, log-Pearson-3, Gumbel, TCEV and General Extreme Value distributions. Goodness of fit is measured by the criterion of standard error of fit. Results suggest that the proposed models are a suitable option to be considered when performing flood frequency analysis. 相似文献
565.
M. Azizul Moqsud Kiyoshi Omine Noriyuki Yasufuku Masayuki Hyodo Yukio Nakata 《Waste management (New York, N.Y.)》2013,33(11):2465-2469
Microbial fuel cells (MFCs) have gained a lot of attention recently as a mode of converting organic matter into electricity. In this study, a compost-based microbial fuel cell that generates bioelectricity by biodegradation of organic matter is developed. Grass cuttings, along with leaf mold, rice bran, oil cake (from mustard plants) and chicken droppings (waste from chickens) were used as organic waste. The electric properties of the MFC under anaerobic fermentation condition were investigated along with the influence of different types of membranes, the mixing of fly ash, and different types of electrode materials. It is observed that the maximum voltage was increased by mixing fly ash. Cellophane showed the highest value of voltage (around 350 mV). Bamboo charcoal is good for anode material; however carbon fiber is better for the cathode material in terms of optimization of power generated. This developed MFC is a simple cell to generate electricity from organic waste. 相似文献
566.
Linking 3D spatial models of fuels and fire: Effects of spatial heterogeneity on fire behavior 总被引:1,自引:0,他引:1
Crown fire endangers fire fighters and can have severe ecological consequences. Prediction of fire behavior in tree crowns is essential to informed decisions in fire management. Current methods used in fire management do not address variability in crown fuels. New mechanistic physics-based fire models address convective heat transfer with computational fluid dynamics (CFD) and can be used to model fire in heterogeneous crown fuels. However, the potential impacts of variability in crown fuels on fire behavior have not yet been explored. In this study we describe a new model, FUEL3D, which incorporates the pipe model theory (PMT) and a simple 3D recursive branching approach to model the distribution of fuel within individual tree crowns. FUEL3D uses forest inventory data as inputs, and stochastically retains geometric variability observed in field data. We investigate the effects of crown fuel heterogeneity on fire behavior with a CFD fire model by simulating fire under a homogeneous tree crown and a heterogeneous tree crown modeled with FUEL3D, using two different levels of surface fire intensity. Model output is used to estimate the probability of tree mortality, linking fire behavior and fire effects at the scale of an individual tree. We discovered that variability within a tree crown altered the timing, magnitude and dynamics of how fire burned through the crown; effects varied with surface fire intensity. In the lower surface fire intensity case, the heterogeneous tree crown barely ignited and would likely survive, while the homogeneous tree had nearly 80% fuel consumption and an order of magnitude difference in total net radiative heat transfer. In the higher surface fire intensity case, both cases burned readily. Differences for the homogeneous tree between the two surface fire intensity cases were minimal but were dramatic for the heterogeneous tree. These results suggest that heterogeneity within the crown causes more conditional, threshold-like interactions with fire. We conclude with discussion of implications for fire behavior modeling and fire ecology. 相似文献
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