18 resultados para energy environment
Resumo:
Processing networks are a variant of the standard linear programming network model which are especially useful for optimizing industrial energy/environment systems. Modelling advantages include an intuitive diagrammatic representation and the ability to incorporate all forms of energy and pollutants in a single integrated linear network model. Added advantages include increased speed of solution and algorithms supporting formulation. The paper explores their use in modelling the energy and pollution control systems in large industrial plants. The pollution control options in an ethylene production plant are analyzed as an example. PROFLOW, a computer tool for the formulation, analysis, and solution of processing network models, is introduced.
Resumo:
本文是首篇研究中国暖温带落叶阔叶混交林能量生态学的论文。在文中,笔者以详实的第一手资料从能量环境、能量流动、能量组合以及能量平衡几个方面,全面、系统地阐述、分析了辽东栎林——这一暖温带落叶阔叶混交林典型自然群落代表的能量生态学特征。 在能量环境一章中,笔者从能量流动,能量平衡的角度出发重点研究了辽东栎群落的辐射能量环境特征。笔者以1991-1993年的观测资料为基础,从乔木、灌木和草本三个层次分析了生长季总辐射、散射辐射、直射辐射、反射辐射、净辐射、先合有效辐射、透射辐射、吸收辐射以及乔木层和灌木层反射率的季节动态和日进程特征,并从天文因子、气象因子和群落自身发育特征几方面解释分析了辐射能量环境的这种时空动态特征,同时,分析了这种变化特征对群落能量流动、分配和平衡过程可能产生的影响。 另外,笔者也对群落湿度和风速环境的时空动态特征进行了分析。 在能量流动一章,笔者以1992-1993年的野外实验资料为依据,沿季节动态、月际变化和日进程的时间轴,从群落、乔木层、灌木层、草本层以及各乔、灌木种群的空间尺度详细分析、阐述了太阳辐射能在森林群落内的流动和转化特征,并从能量环境和群落发育的角度解释分析了能量在群落内的这种时空分布和转化特征。所讨论的能流对象包括群落、乔、灌、草各层及各乔、灌木种群的总能流固定量、叶片呼吸耗能量、剩余能流固定量以及沿枯枝落叶流出的能流量。 与分析能流过程同步,笔者从上述的时、空尺度分别以生长季内太阳总辐射和光合有效辐射为基础计算、分析了森林群落的光能转化率特征。 在这一章的最后,笔者概述性地介绍了辽东栎群落的能量平衡特征 在第四章,笔者从能值的角度出发,以能量密度为标准讨论了能量沿群落各层及各乔、灌木种群的积累、分配和组合特征,并讨论了能量流动和光能转化率与热值和能量密度的关系。 辽东栎群落能量生态学的研究不但为了解暖温带落叶阔叶林生态系统的结构和功能,为恢复和重建退化的森林生态系统提供了丰富详实的理论信息,而且,也为山区人工林优化模式的组建提供了理论依据和实践指南。
Resumo:
水文研究了北京东灵山地区落叶阔叶林和人工油松林的能量环境和能量固定,以及相关的生态学过程。重点研究了落叶阔叶林林冠表面、灌木层表面和草本层表面的总辐射、直射辐射、散射辐射、反射辐射、净辐射和长波将辐射、分光谱辐射,强调了自然条件下斜坡对上述辐射分量的影响。上述分量随森林内层次的下降而剧减,光谱组成也发生变化,长波辐射和短波红外辐射所受的影响较小。天气对辐射通量的日进程和月际变化都有重大影响。 落叶阔叶林主要树种叶片净光合速率在7月底8月初达到最大值,以辽东栎的最高,五角枫最低。除大叶白蜡外,正午或稍后有明显的午休现象。油松小技的光合速率上层)中层)下层,7月底和8月全月都是光合速率高峰期。白天净光合速率在中午没有明显的“午休”现象 自然环境下油松不同年龄的针叶的光合速率与光强度的关系近似于一种抛物线关系,而不是人工控制条件下测定所出现的双曲线关系。 主要落叶阔叶乔灌木和油松树干的呼吸速率7月份最高,10月最低,24小时连续测定结果表明,乔木树种树干呼吸在下午或傍晚达到最大值,是因为树干温度落后于空气温度的变化节奏造成的。 以油松为例,研究了树木侧枝长的年增长规律,发现侧枝年增长量随着年份发生有规律的变化,与气候因子的关联分析与回归分析表明,枝长的年增长量与空气温度、年降水量和年蒸发量关系最为密切。最后利用光合生产潜力逐步修正的途径和Lieth-Box途径,估算了被研究森林的潜在生产力,并分析了造成估计值偏高或偏低的原因。
Resumo:
Based on analyses of more than 600 surface sediment samples together with large amounts of previous sedimentologic and hydrologic data, the characteristics of modern sedimentary environments and dynamic depositional systems in the southern Yellow Sea (SYS) are expounded, and the controversial formation mechanism of muddy sediments is also discussed. The southern Yellow Sea shelf can be divided into low-energy sedimentary environment and high-energy sedimentary environment; the low-energy sedimentary environment can be further divided into cyclonic and anticyclonic ones, and the high-energy environment is subdivided into high-energy depositional and eroded environments. In the shelf low-energy environments, there developed muddy depositional system. In the central part of the southern Yellow Sea, there deposited the cold eddy sediments under the actions of a meso-scale cyclonic eddy (cold eddy), and in the southeast of the southern Yellow Sea, an anticyclonic eddy muddy depositional system (warm eddy sediment) was formed. These two types of sediments showed evident differences in grain size, sedimentation rate, sediment thickness and mineralogical characteristics. The high-energy environments were covered with sandy sediments on seabed; they appeared mainly in the west, south and northeast of the southern Yellow Sea. In the high-energy eroded environment, large amounts of sandstone gravels were distributed on seabed. In the high-energy depositional environment, the originally deposited fine materials (including clay and fine silt) were gradually re-suspended and then transported to a low-energy area to deposit again. In this paper, the sedimentation model of cyclonic and anticyclonic types of muddy sediments is established, and a systematic interpretation for the formation cause of muddy depositional systems in the southern Yellow Sea is given.
Resumo:
Shape Memory Alloy (SMA) can be easily deformed to a new shape by applying a small external load at low temperature, and then recovers its original configuration upon heating. This unique shape memory phenomenon has inspired many novel designs. SMA based heat engine is one among them. SMA heat engine is an environment-friendly alternative to extract mechanical energy from low-grade energies, for instance, warm wastewater, geothermal energy, solar thermal energy, etc. The aim of this paper is to present an applicable theoretical model for simulation of SMA-based heat engines. First, a micro-mechanical constitutive model is derived for SMAs. The volume fractions of austenite and martensite variants are chosen as internal variables to describe the evolution of microstructure in SMA upon phase transition. Subsequently, the energy equation is derived based on the first thermodynamic law and the previous SMA model. From Fourier’s law of heat conduction and Newton’s law of cooling, both differential and integral forms of energy conversion equation are obtained.
Resumo:
The variation of the energy interval between the intercombination line ( 1s2p(P-3(1))-> 1s(2)) and the resonance line ( 1s2p(P-1(1))-> 1s(2)) of He-like aluminium with plasma density and temperature is investigated. Since such energy interval is equivalent to the exchange energy of the state 1s2p(P-3(1)), we consider the dependence of this energy shift on the plasma environment. It was found that the shifts of exchange energy increase ( decrease) with the increase of electron density ( electron temperature), and the shifts of exchange energy become more sensitive to the electron density as the electron temperature decreases, i. e. in the strongly coupled plasma regime. An approximately linear relation is found between the shifts of exchange energy and the electron density. The results show that dense plasma effects are very important for the simulation of the spectral fine structure. The relative shifts between the intercombination ( 1s2p(P-3(1))-> 1s(2)) and the resonance line ( 1s2p(P-1(1))-> 1s(2)) are discussed for diagnostic applications.
Resumo:
We present the results of a study that uses theoretical and experimental methods to investigate the characteristics of the upconversion luminescence of Tm3+/Yb3+ codoped TeO2-BiCl3 glass system as a function of the BiCl3 fraction. These glasses are potentially important in the design of upconversion fiber lasers. Effect of local environment around Tm3+ on upconversion fluorescence intensity was analyzed by theoretical calculations. The structure and spectroscopic properties were investigated in the experiments by measuring the Raman spectra, IR transmission spectra, and absorption and fluorescence intensities at room temperature. The results indicate that blue luminescence quantum efficiency increases with increasing BiCl3 content from 10 to 60 mol%, which were interpreted by the increase of asymmetry of glass structure, decrease of phonon energy and removing of OH- groups. (c) 2005 Elsevier B.V. All rights reserved.
Resumo:
This paper analyzes the energy levels along the even-parity J=1 and 2 Rydberg series of Sn I by multichannel quantum defect theory. A good agreement between theoretical and experimental energy levels was achieved. Below 59198 cm~(-1), a total of 85 and 23 new energy levels, respectively, in the J=1 and J=2 series, which cannot be measured previously by experiments, are predicted in this work. Based on the calculated admixture coefficients of each channel, interchannel interactions were discussed in detail. The results are helpful to understand the characteristics of configuration interaction among even-parity levels in Sn I.