抗地震结构的服役费用函数及其建立方法

讨论了服役工程结构的经济性问题 ,包括 :抗地震结构在服役过程中为完成预定功能所需要的经济花费、这些花费同结构抗震可靠度的函数关系以及它们的建立方法。形成的服役费用函数可以作为决策结构最佳抗震设防标准的依据。     

基于全寿命周期成本的压缩空气储能系统储气装置经济性分析

综合考虑压缩空气储能系统经济性对于储能系统的设计和大规模应用具有重要意义。本文基于全寿命周期成本模型分析的方法,建立了不同类型的储气装置成本模型。通过计算储气装置的理论金属消耗量、储气装置的数量,同时在考虑制造难易程度的基础上来确定不同类型储气装置的最佳参数。通过对不同类型的储气装置进行全寿命周期成本分析和比较,可作为设计压缩空气储能系统及其经济性分析的参考。储气装置的全寿命周期成本（LCC）包括早期和后期成本。早期成本主要由原材料和设备成本构成,后期成本主要是运行维护成本。根据分析结果,储气管道的投资成本最低,且没有压力限制。地面储气装置的设备成本一般在2USD/kW·h左右。在确保安全的前提下,降低地面储气装置的LCC有利于压缩空气储能系统的推广实施和工程应用,大规模、有效地提高可再生能源的利用率,降低可再生能源的间歇性对电网运行的影响。     

Sustainability-guided life-cycle design and assessment for bio-based composite foams: Integrate flame retardancy/lightweight in usage and energy utilization after service

Sustainable development strategy has aroused a great interest in biomass resources as alternative raw materials. A kind of biomass-derived poly(butylene succinate) (PBS), has been developed as porous foams to reduce resource exhaustion and meet lightweight demands. For fire-safety in-service, graphene oxide (GO) was functionalized by 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) to combine flame-retardant elements and heat-barrier function. Hence, a very low loading level of P-containing GO as only 5 wt% could reduce peak heat release rate (pHRR) and total heat release (THR) of PBS-based foams by 58.5% and 22.3%, respectively. Meanwhile, N-/P-doped mesoporous char with a specific surface area of 136 m²/g, which derived from combustion of flame-retardant foaming PBS, contributes to a potential of energy storage applications in the capacitor or the anode of Li-ion battery with long-term stability. Overall, the sustainability of bio-based polyester could integrate lightweight of foaming, and be extended to utilization after use via facile combustion inspired by flame-retardancy design.     

Semi-analytical solutions for a Gray-Scott reaction-diffusion cell with an applied electric field

An ionic version of the Gray-Scott chemical reaction scheme is considered in a reaction-diffusion cell, with an applied electric field, which causes migration of the reactant and autocatalyst in a preferred direction. The Galerkin method is used to reduce the governing partial differential equations to an approximate model consisting of ordinary differential equations. This is accomplished by approximating the spatial structure of the reactant and autocatalyst concentrations. Bifurcation analysis of the semi-analytical model is performed by using singularity theory to analyse the static multiplicity and a stability analysis to determine the dynamic multiplicity. The application of the electric field causes variation in the parameter regions, in which multiple steady-state and oscillatory solutions occur. Moreover, as the reactor is not symmetric, reversal of the direction of the electric field can cause bifurcation in the reactor between high and low conversion states. Comparisons with numerical solutions of governing partial differential equations confirms the accuracy and usefulness of the semi-analytical model.     

Implementation of an Indirect Control Structure for Composition in a Hybrid Distillation Column

In this paper a PID controller is proposed to ensure the fuel ethanol composition at desired value, above 92.5°INPM, at the same time as saving energy through the minimal use of reboiler power. Due to the fact that composition analyzers are expensive and have a high response time, an inference model was developed in which the product composition is inferred from the product temperature and thermodynamics equations, enabling the monitoring and the indirect control a posteriori of this variable. In addition, the inference of composition allows defining the reference value of the product temperature, which ensures the fuel ethanol production at the desired composition.     

Control of a Hybrid Energy Storage System for a Hybrid Compensation System

The combination of two or more different energy storage technologies in a hybrid energy storage system appears to be advantageous if the combination of technologies fulfils the storage purpose better than a single storage technology. Herein, requirements regarding the performance of the storage system are determined for a hybrid compensation system for provision of system services in medium‐voltage grids. In hybrid storage systems, a common control system ensures that the present storage technologies are utilized in such a way that total storage efficiency is highest and that usability of the application is maximized. The control system of a hybrid storage system consisting of a redox flow battery and high‐speed flywheel storage is introduced and evaluated.     

Transient convective mass transfer for a fluid sphere dissolution in an alternating electric field

In this study, we considered mass transfer in a binary system comprising a stationary fluid dielectric sphere embedded into an immiscible dielectric liquid under the influence of an alternating electric field. Fluid sphere is assumed to be solvent-saturated so that an internal resistance to mass transfer can be neglected. Mass flux is directed from a fluid sphere to a host medium, and the applied electric field causes a creeping flow around the sphere. Droplet deformation under the influence of the electric field is neglected. The problem is solved in the approximations of a thin concentration boundary layer and finite dilution of a solute in the solvent. The thermodynamic parameters of a system are assumed constant. The nonlinear partial parabolic differential equation of convective diffusion is solved by means of a generalized similarity transformation, and the solution is obtained in a closed analytical form for all frequencies of the applied electric field. The rates of mass transfer are calculated for both directions of fluid motion—from the poles to equator and from the equator to the poles. Numerical calculations show essential (by a factor of 2/3) enhancement of the rate of mass transfer in water droplet-benzonitrile and droplet of carbontetrachloride-glycerol systems under the influence of electric field for a stagnant droplet. The asymptotics of the obtained solutions are discussed.     

Air separation with cryogenic energy storage: Optimal scheduling considering electric energy and reserve markets

The concept of cryogenic energy storage (CES) is to store energy in the form of liquid gas and vaporize it when needed to drive a turbine. Although CES on an industrial scale is a relatively new approach, the technology is well known and essentially part of any air separation unit that utilizes cryogenic separation. In this work, the operational benefits of adding CES to an existing air separation plant are assessed. Three new potential opportunities are investigated: (1) increasing the plant's flexibility for load shifting, (2) storing purchased energy and selling it back to the market during higher‐price periods, and (3) creating additional revenue by providing operating reserve capacity. A mixed‐integer linear programming scheduling model is developed and a robust optimization approach is applied to model the uncertainty in reserve demand. The proposed model is applied to an industrial case study, which shows significant potential economic benefits. © 2015 American Institute of Chemical Engineers AIChE J, 61: 1547–1558, 2015     

An overall assessment of a new adhesive bonding process for composite materials,with regard to quality and cost

An assessment of innovative adhesive bonding process has been performed with regard to quality and cost. In this frame, the effect of two different atmospheric pressure plasma surface treatment conditions on the fracture toughness behaviour of adhesively bonded joints was experimentally investigated. Furthermore, the mechanical performance of a newly developed aerospace structural adhesive has been characterised experimentally in order to assess the quality of the bonded elements. To assess the feasibility of the new process, a complete cost-estimation analysis of the process has been carried out based on the activity-based costing modelling approach, thus serving to the estimation of the total cost/duration of the process. To this end, the newly developed process is assessed with regard to quality and cost. It could be shown that the new process offers tempting alternatives to the existing adhesive bonding and joining processes used in the aeronautic industry.     

Nanoclay dispersion in a miscible blend: an assessment through rheological analysis

In this study, miscible polymer blend nanocomposite of Poly(ethylene oxide)/Poly(methyl methacrylate), (PEO/PMMA), with sodium montmorillonite (Na⁺-MMT) clay were prepared at a constant concentration of nanoparticles via different solution intercalation methods. The resultant nanocomposites possess different structure and dispersion of Na⁺-MMT clays which are assessed through a combination of transmission electron microscopy (TEM) and X-ray diffraction (XRD). The rheology of the neat blend and two different layered silicate nanocomposites were investigated using linear viscoelastic measurements with a parallel plate rheometry at small strain amplitudes. It was found that regardless of the extent of dispersion, the storage and loss modulus increased by incorporating the nanoparticles into the matrix of PEO/PMMA. Moreover, at low frequencies the rheological response of the nanocomposite in which layered silicates benefit from a better dispersion becomes relatively invariant with frequency and represents a mediocre solid-like behavior in comparison to the nanocomposite in which the nanoparticles are intercalated or agglomerated.     

Droplet dynamic response in low-viscosity fluid subjected to a pulsed electric field and an alternating electric field

Droplet dynamic response in low-viscosity fluid under a pulsed direct-current (DC) electric field and a sinusoidal electric field is investigated by experiments and numerical simulations. The coupled level set and volume of fluid method is employed to capture moving interface and the numerical method is validated by experimental results. This article focuses on the effects of waveform, frequency and initial phase on the dynamic response. The deformation period is identical with the electric period for the pulsed DC electric field but the deformation period is half of the electric period for the sinusoidal electric field. As the frequency increases, the maximum deformation degree D_max first climbs steadily to a peak value, then decreases steeply and finally approaches an equilibrium value. The maximum D_max appears at f = 50 Hz for the pulsed DC electric field and appears at f = 100 Hz for the sinusoidal electric field according to numerical results. These results are helpful for the optimization of electro-coalescence.     

Initiation of combustion of a gas mixture by an electric explosion of an electrolyte

Initiation of combustion of a stoichiometric propane-oxygen mixture in a bubble located in an electrolyte near a dielectric or metallic wall is performed in experiments. It is demonstrated that combustion in the bubble is initiated by an electric explosion-breakdown of a thin electrolyte layer along the bubble boundary.     

电动汽车用La-Fe-B储氢合金的制备与电化学性能研究

研究了石墨烯含量对储氢合金物相组成和电化学性能的影响。结果表明,不同石墨烯含量储氢合金都主要由La₃Ni₁₃B₂、LaNi₅和（Fe,Ni）相组成,La₃Ni₁₃B₂和（Fe,Ni）相晶胞体积会随着石墨烯含量增加而增大,LaNi₅相晶胞体积会随着石墨烯含量增加而减小。当石墨烯质量分数从0%增加至6%时,储氢合金的最大放电容量先增加后减小,在石墨烯质量分数为4%时取得储氢合金放电容量最大值（288.5 mA·h/g）,且当循环周期为100次时,石墨烯质量分数为4%和6%的储氢合金的放电容量仍然高于未添加石墨烯的储氢合金。相同温度下,添加石墨烯的储氢合金的放电容量都高于未添加石墨烯的储氢合金,且石墨烯质量分数为4%的储氢合金具有最大放电容量。随着石墨烯质量分数从0%增加至6%,储氢合金的电荷转移电阻先减小后增大、电流密度和扩散系数先增大后减小,在石墨烯质量分数为4%时取得电荷转移电阻最小值、电流密度和扩散系数最大值,适宜的石墨烯添加量为4%。     

Chemical assessment of the electric arc furnace slag as construction material: Expansive compounds

To carry out a correct management of electric arc furnace slags (EAS) requires a detailed knowledge of their properties. From a chemical point of view, the EAS are surrounded by some chemical problems related to its volume instability when they are used as construction materials, due to the presence of potentially expansive compounds such as free lime and mainly free MgO. The current work focuses on the chemical assessment of the black slags coming from an electric arc furnace in order to know the possible chemical disadvantages as construction materials. A complete study of chemical and mineralogical compositions, pozzolanic activity and the quantification of main expansive compounds in EAS were realised. The results show that the nature of these slags has a very high crystallinity; total absence of pozzolanic activity and the presence of expansive compounds in slags (Cl⁻, SO₃, free CaO and free MgO) were very low, if not null concentrations.