Contribution of biodiversity to ecosystem functioning:a non-equilibrium thermodynamic perspective

Ecosystem stays far from thermodynamic equilibrium. Through the interactions among biotic and abiotic components, and encompassing physical environments, ecosystem forms a dissipative struc- ture that allows it to dissipate energy continuously and thereby remains functional over time. Biotic regulation of energy and material fluxes in and out of the ecosystem allows it to maintain a homeostatic state which corresponds to a self-organized state emerged in a non-equilibrium thermodynamic system. While the associated self-organizational processes approach to homeostatic state, entropy （a measure of irre- versibility） degrades and dissipation of energy increases. We propose here that at a homeostatic state of ecosystem, biodiversity which includes both phenotypic and functional diversity, attains optimal values. As long as biodiversity remains within its optimal range, the corresponding homeostatic state is maintained. However, while embedded environmental conditions fluctuate along the gradient of accelerating changes, phenotypic diversity and functional diversity contribute inversely to the associated self-organizing proc- esses. Furthermore, an increase or decrease in biodiversity outside of its optimal range makes the eco- system vulnerable to transition into a different state.

Thermodynamic Analysis on Interaction between Molten Ti Alloys and Oxide Molding Materials

A thermodynamic model has been built up for the interactions between molten Ti alloys and oxide molding materials in the way of decomposition and solution of molding materials, then the influences on the reaction free energy changes have been calculated and discussed.

Thermodynamic Stability of the Molding Materials for Casting Ti-6Al-4V Alloy

The interactions of Ti - 6Al - 4V alloy with wide potential applications in aeronautics and aerospace indus-tries with the molding materials have been analyed and calculated by a thermodynamic method. The molding materials involved in the calculation are special refractory of carbide, nitride and haride, such as ZrB2, TiB2, SiN4, AlN,TiN, ZrN, BN, SiC, TiC, ZrC and CaC2. Based on the Miedema model on heat formation of binary alloys, the changes of Gibbs free energy of the interactions of molten Ti - 6Al - 4V alloy and the above molding materials have been analyzed and calculated hy calculating the activities and activity coefficients of alloying elements in the Ti melt.The results show that the changes of Cibbe free energy of the interactions of the molding materials are all negative. It means that such reactions are spontaneous. But the free energy increases slightly as the content of alloying element in the Ti melt increases, where the effect of Al element is more notable than that of V. Meanwhile, the chemical activity of Ti meli decreases as the alloying elements are added.

Non-equilibrium thermodynamic analysis of coupled heat and moisture transfer across a membrane

Non-equilibrium thermodynamics theory is used to analyze the transmembrane heat and moisture transfer process,which can be observed in a membrane-type total heat exchanger(THX).A theoretical model is developed to simulate the coupled heat and mass transfer across a membrane,total coupling equations and the expressions for the four characteristic parameters including the heat transfer coefficient,molardriven heat transfer coefficient,thermal-driven mass transfer coefficient,and mass transfer coefficient are derived and provided,with the Onsager’s reciprocal relation being confirmed to verify the rationality of the model.Calculations are conducted to investigate the effects of the membrane property and air state on the coupling transport process.The results show that the four characteristic parameters directly affect the transmembrane heat and mass fluxes:the heat and mass transfer coefficients are both positive,meaning that the temperature difference has a positive contribution to the heat transfer and the humidity ratio difference has a positive contribution to the mass transfer.The molar-driven heat transfer and thermal-driven mass transfer coefficients are both negative,implying that the humidity ratio difference acts to reduce the heat transfer and the temperature difference works to diminish the mass transfer.The mass transfer affects the heat transfer by 1%–2%while the heat transfer influences the mass transfer by7%–14%.The entropy generation caused by the temperature difference-induced heat transfer is much larger than that by the humidity difference-induced mass transfer.

Non-equilibrium Thermodynamic Analysis of The Transport Properties of Formed-in-Place Zirconium (Ⅳ) Hydrous Oxide-Polyacylate Membranes in aqueous NaNO_3 solution

Nanofiltration of aqueous NaNO3 solution with a dynamically formed Zr(IV) hydrousoxide-PAA membrane is presented. The practical transpoft coefficients Lp, σ, ω were obtainedusing relationships of the non-equilibrium thermodynamics and were used to calculate thefrictional coefficients of a friction model.

Coherent Application of a Contact Structure to Formulate Classical Non-Equilibrium Thermodynamics

This contribution presents an outline of a new mathematical formulation for Classical Non-Equilibrium Thermodynamics (CNET) based on a contact structure in differential geometry. First a non-equilibrium state space is introduced as the third key element besides the first and second law of thermodynamics. This state space provides the mathematical structure to generalize the Gibbs fundamental relation to non-equilibrium thermodynamics. A unique formulation for the second law of thermodynamics is postulated and it showed how the complying concept for non-equilibrium entropy is retrieved. The foundation of this formulation is a physical quantity, which is in non-equilibrium thermodynamics nowhere equal to zero. This is another perspective compared to the inequality, which is used in most other formulations in the literature. Based on this mathematical framework, it is proven that the thermodynamic potential is defined by the Gibbs free energy. The set of conjugated coordinates in the mathematical structure for the Gibbs fundamental relation will be identified for single component, closed systems. Only in the final section of this contribution will the equilibrium constraint be introduced and applied to obtain some familiar formulations for classical (equilibrium) thermodynamics.

Predicting Ecosystem Response to Perturbation from Thermodynamic Criteria

The response of ecosystems to perturbations is considered from a thermodynamic perspective by acknowl-edging that, as for all macroscopic systems and processes, the dynamics and stability of ecosystems is sub-ject to definite thermodynamic law. For open ecosystems, exchanging energy, work, and mass with the en-vironment, the thermodynamic criteria come from non-equilibrium or irreversible thermodynamics. For ecosystems during periods in which the boundary conditions may be considered as being constant, it is shown that criteria from irreversible thermodynamic theory are sufficient to permit a quantitative prediction of ecosystem response to perturbation. This framework is shown to provide a new perspective on the popula-tion dynamics of real ecosystems.

Liquid vaporization under thermodynamic phase non-equilibrium condition at the gas-liquid interface

Liquid vaporization under thermodynamic phase non-equilibrium condition at the gas-liquid interface is investigated over a wide range of fluid state typical of many liquid-fueled energy conversion systems. The validity of the phase-equilibrium assumption commonly used in the existing study of liquid vaporization is examined using molecular dynamics theories. The interfacial mass flow rates on both sides of the liquid surface are compared to the net vaporization rate through an order-of-magnitude analysis.Results indicated that the phase-equilibrium assumption holds valid at relatively high pressures and low temperatures,and for droplets with relatively large initial diameters(for example,larger than 10 μm for vaporizing oxygen droplets in gaseous hydrogen in the pressure range from 10 atm to the oxygen critical state). Droplet vaporization under superheated conditions is also explored using classical binary homogeneous nucleation theory,in conjunction with a real-fluid equation of state. It is found that the bubble nucleation rate is very sensitive to changes in saturation ratio and pressure;it increases by several orders of magnitude when either the saturation ratio or the pressure is slightly increased. The kinetic limit of saturation ratio decreases with increasing pressure,leading to reduced difference between saturation and superheat conditions. As a result,the influence of nonequilibrium conditions on droplet vaporization is lower at a higher pressure.

粉末注射成形粘结剂组分相容性的热力学判据

对粉末注射成形粘结剂组分的热力学参数进行了计算 ,并通过实验观察得到了组分相容性的判据。分别以PVB ,EVA ,PMMA为高分子组分 ,讨论了它们与低分子量组分PEG的相容性 ,并通过混炼机混炼和偏光显微镜观察 ,得到了ΔG/T <1.5可工艺相容、ΔG/T >3.

菌体/粉煤灰复合吸附剂吸附酸性蓝

采用菌体/粉煤灰复合吸附剂吸附酸性蓝,通过单因素实验探究其吸附条件和吸附机理。结果表明:处理模拟酸性蓝废水最佳条件为:pH值6.6(自然),投加量3 g/L,搅拌时间25 min,静置时间1 h,此时去除率在85%以上。热力学和动力学的研究结果表明,Langmuir模型和Freundlich模型均可以用来描述吸附剂对酸性蓝的吸附,且吸附较好地符合Freundlich等温吸附模型;吸附剂对酸性蓝的吸附属于单分子层吸附,且其吸附过程容易进行,由Langmuir吸附计算得到吸附剂的最大吸附量为303.0303 mg/g。吸附剂对酸性蓝的吸附属于Lagergren准二级吸附动力学模型,菌体/粉煤灰对酸性蓝的吸附速率控制化学吸附过程,饱和吸附量为137.32 mg/g。

霉菌/膨润土复合吸附剂对Cr^(6+)的吸附研究

用霉菌/膨润土复合吸附剂吸附Cr6+,通过单因素试验探讨复合吸附剂对Cr6+的吸附条件,并对其吸附机理进行了研究。结果表明,在pH值为5、吸附剂投加量为0.9 g(即18 g/L)、搅拌时间为20min、静置时间为1 h的条件下,对Cr6+的去除率达93%以上。霉菌/膨润土复合吸附剂对Cr6+的吸附特性较好地符合Langmuir等温吸附模型,吸附剂对Cr6+的吸附过程容易进行,属于单分子层吸附,且吸附动力学数据符合准二级动力学模型。

Zr-Al-Ni-Cu块体非晶合金的制备及其耐蚀性能

块体非晶合金的耐蚀性能与合金元素本身的特性及合金成分密切相关。采用铜模吸铸法制备了Zr55Al10Ni5Cu30块体非晶合金,用X射线衍射(XRD)、差示扫描量热分析法(DSC)和差热分析法(DTA)考察了合金的非晶特性和热力学属性,通过电化学极化试验和盐雾腐蚀试验测试了合金的耐蚀性。结果表明,制备的Zr55Al10Ni5Cu30合金为完全的非晶相,且具有较大玻璃形成能力和热稳定性;腐蚀电流密度仅为12.6nA/cm2,经144h盐雾试验无质量变化,表明合金具有优异的耐腐蚀性能。

硅酸镁成型吸附剂的制备及其对亚甲基蓝的吸附研究

将硅酸镁颗粒与聚偏氟乙烯的N-N二甲基乙酰胺溶液充分混合后挤出成型,烘干得到硅酸镁成型吸附剂,并利用BET、SEM等方法分析表征样品。研究了它对亚甲基蓝(methylene blue,MB)的吸附性能。结果表明:硅酸镁成型吸附剂对MB的吸附过程符合二级吸附动力学模型,热力学研究表明对MB的吸附符合Freundlich吸附等温式。

香菇发酵料对菌丝及主要霉菌生活能力的影响

为了攻克污染率居高不下这一难题,摆脱了传统香菇栽培采取完全熟料,绝对无菌的培养模式,并结合发酵料栽培其它食用菌的原理,以香菇发酵料为基质,采用不同的热力处理方式,对香菇菌丝和两种主要霉菌进行接种培养,结果表明:香菇发酵料经100℃热力处理0.5至5小时,可有效抑制两种主要霉菌的生长,同时对香菇菌丝生长发育无明显不良影响。这一结论将会使香菇代用料袋栽建立一种新的模式,

菌体/粉煤灰复合吸附剂吸附阳离子黑的研究

用菌体/粉煤灰复合吸附剂吸附阳离子黑,通过单因素实验探究其吸附条件和吸附机理。结果表明,处理模拟阳离子黑染料废水最佳条件为:废水自然pH值6.1,吸附剂投加量2 g/L,搅拌时间5 min,静置时间1 h,此时废水脱色率均在90%以上。吸附剂对阳离子黑的吸附较好地符合Freundlich等温吸附模型,吸附属于单分子层吸附,且吸附过程容易进行。吸附剂对阳离子黑的吸附动力学过程属于Lagergren准二级吸附。

菌体/粉煤灰复合吸附剂对活性红的吸附研究

采用菌体/粉煤灰复合吸附剂吸附活性红,通过单因素实验探究其吸附条件和吸附机理.结果表明：处理模拟活性红最佳条件为：pH =4.0～ 10.0,吸附剂投加量3 g/h,搅拌时间15min,静置时间1h,此时脱色率均在89％以上.热力学的研究结果表明：Langmuir模型和Freundlich模型均不能用来描述吸附剂对活性红的吸附,吸附不属于单分子层吸附,吸附机理有待进一步研究.用颗粒内扩散方程、准二级吸附动力学方程和准一级吸附动力学方程对吸附进行分析,准二级吸附动力学方程能更好地描述活性红在复合吸附剂上的吸附,化学吸附过程由吸附剂对染料的吸附速率控制,饱和吸附量为49.15 mg/g.

超疏水表面微结构的设计及其注射成型

目的从超疏水表面的功能设计出发,主动设计三种深宽比的微结构阵列并洞察其在不同润湿接触状态下的疏水性能。方法首先,采用热力学分析方法,建立三种深宽比微结构的系统自由能与其接触角、结构几何参数之间的函数关系,探明自主设计微结构表面的润湿性能。继而,在热力学分析的基础上,采用紫外光刻、电铸和注射成型技术相结合的方法实现三种深宽比微结构聚丙烯(PP)超疏水表面的制备。最后,进一步测量与分析聚丙烯(PP)微结构表面的润湿性能。结果三种深宽比微结构表面的静态接触角测量值均大于150?,滚动角分别为12?、14?和15?,基本达到设计目标;同时,微结构表面的表观接触角测量值与理论计算值基本符合。表面的接触角滞后分别为15?、21?、22?,且接触角滞后随着深宽比的增加而变大,使液滴在PP表面的流动性也变差。结论在设计微结构超疏水表面的过程中,可以适当降低微结构的深宽比,以获取更好的超疏水特性。自主设计的微结构表面基本实现超疏水性,为高聚物超疏水表面的功能设计与高效制备提供了理论依据与技术支撑。

Recent progress in thermodynamics of radiation——exergy of radiation, effective temperature of photon and entropy constant of photon

The recent progress on thermodynamic properties of spectral radiant energy in the field of thermodynamics of radiation is reviewed. The effective temperature of photon Tλ representing the energy quality of photon is introduced. The relation between Tλ and the wavelength λ is given as λTλ =c3=5.33016×10?3 m·K. The en- tropy constant of photon is given as sλ=3.72680×10?23 J/K. The exergy, entropy and enthalpy of the spectral blackbody radiation, the equilibrium cavity radiation, the radiation flux in open system are discussed by using Tλ and sλ, as well as the en- tropy change in the process of the state transformation of photon gas. By analyzing the exergy of spectral radiation, the exergy efficiency of spectral radiant energy available for photosynthesis is proved to be higher than that of light energy. The method for the irreversible loss of exergy calculation in radiant energy converters is also discussed.

On the Liquid-Vapor Phase-Change Interface Conditions for Numerical Simulation of Violent Separated Flows

Numerous models have been proposed in the literature to include phase change into numerical simulations of two-phase flows.This review paper presents the modeling options that have been taken in order to obtain a model for violent separated flows with application to sloshing wave impacts.A relaxation model based on linear non-equilibrium thermodynamics has been chosen to compute the rate of phase change.The integration in the system of partial differential equations is done through a non-conservative advection term.For each of these modelling choices,some alternative models from the literature are presented and discussed.The theoretical framework for all phase change model(conservation equations and entropy growth)is also summarized.

Thermodynamic Analysis and Experimental Research of Water-Cooled Small Space Thermoelectric Air-Conditioner

This paper aims to find a more general analysis method for the refrigeration performance,and to design a high efficiency modular cooling structure of water-cooled plate.A new analysis method,namely current and refrigeration rate density analysis,is proposed.The general refrigeration performance calculation equations are obtained.A finite-time thermodynamic model of the thermoelectric device is established considering Thomson effect.The basic structure of water-cooled thermoelectric air-conditioner is designed and the specific calculation method is given.The influences of input current density,filling factor and heat transfer conditions on refrigeration performance of the thermoelectric air-conditioner are analyzed,which is compared with refrigeration performance of air-cooled thermoelectric air-conditioner.The results show that the maximum refrigeration rate density of the water-cooled thermoelectric air-conditioner is 8.65 k W/m^(2),and the maximum coefficient of performance(COP)is 2.27 in the case of the cooling temperature differenceΔT=5 K.Compared withΔT=5 K,the maximum refrigeration rate density and the maximum COP ofΔT=15 K decreases by 27.98%and 76.65%,respectively.At the filling factorθ=0.43,the refrigeration rate density and COP are 2.57 k W/m~2 and 1.24,respectively.The experimental device of thermoelectric air-conditioner is established to verify the model.The experimental results show that the maximum value of input current and COP is 4 A and 0.95 with the efficient water-cooling method,respectively.The experimental data coincides with the theoretical calculation,which shows the validity of the analysis method and cooling method.